section 06 timing and ignition...

Tuning Your Engine – Section 6

- 107 -

Section 06 -

Timing and Ignition Systems

6.0 Timing Introduction

In this Section, we are concerned about tuning vehicles for both street and strip. Without modern knock sensors and sophisticated computer controls, one has to be more careful in the quest for power and drivability. In Sections 3 and 4 we stressed building an engine that can live with today's fuel. In this Section we will discuss how to ensure that you can maximize what you have built without destroying it.

Marking Your Harmonic Balancer

To set timing accurately above 4000 RPM, a new set of scribe marks will have to be added to the harmonic balancer, since the normal timing tab stops at 15° BTDC. These marks must be made on the balancer below the present mark (clockwise from the front of the car).

Timing can then be read using the 0° mark on the tab and the new marks on the balancer, while revving the engine to 4000 RPM momentarily.

Scribe the marks clockwise from the present mark on the harmonic balancer as shown in the drawing and per the chart below:

NOTE: the 330 engine will require a new 0 timing mark to be scribed on the balancer prior to these measurements. See the instructions in Section 3.9.

Balancers with Pre-set Timing Marks

You can purchase race-type balancers that have the timing marks scribed or etched into them. See Section 3.9; Installing a Harmonic Balancer, for suggestions.

Original Ignition Settings and Considerations

The following specifications in this section were recommended by Oldsmobile when these vehicles were manufactured. For all out competition, racing and aftermarket applications. Please refer to the specifications found later in this Section.

Stock distributors on each of the original high performance W-Machines had mechanical advance curves which paralleled best spark timing, given 100 Octane gasoline. The mechanical advance curves, vacuum advance curves and initial timing settings on all models were selected to give best performance – and included normal carbon build up and they assumed street equipment, not headers or modified carburetors. For off-road use, in a vehicle where the amount of idle and low speed operation can be held to a minimum, higher timing settings may be used.

The Factory recommended the following:

Run 103 or better racing gasoline (leaded or unleaded).

Disconnect vacuum advance hose at the distributor and plug the hose to avoid any vacuum leakage. Leave the distributor side of the vacuum connection open. This will preclude too much initial advance from the vacuum system, as well as load detonation, which must be avoided, especially with cast or silicon-based pistons.

Be conservative in initial timing. Increase timing in small steps, listening for any detonation or pre-ignition.

Diagram showing how to measure on the balancer for proper timing marks. Standard balancer shown.

OEM balancer (left) versus TCI calibrated balancer (right)


- 108 -

Check spark plugs after each setting and a short run under load (mild acceleration). If any signs of pre-ignition are present, reduce timing immediately.

The timing indicator tab on 1968 and newer cars is marked in 2° increments of: -4°, -2°, 0°, 2°, 4°, 6°, 8°, 10°, 12°. The top edge if the tab is: 14°-15° BTDC. Thus, you can only set up to 15° initial advance or see that much advance with a standard harmonic balancer. To see engine advance above 15, you must install an aftermarket unit as shown in Section 3.9 or mark the balancer as shown above.

The most important area to watch in changing timing is the advance above 4000 RPM (assuming the vacuum advance is disconnected). For off-road use, timing should be set to give no more than 35° advance BTDC above 4000 RPM.

Advance beyond 35° should be done in small steps and in conjunction with changes in carburetor jetting, slightly richening the system until ultimate power potential is realized.

The production curve method of setting the timing may be used if the mechanical advance curve is known (check the curve on a distributor machine). The following chart lists the original high performance production distributors with standard settings, as well as the Factory's suggested settings to achieve 35° BTDC above 4000 RPM. The Factory recommended dwell is 30° 2°. The Factory recommended spark plug gap for non-HEI is .032". For MSD and HEI ignition systems, the recommended spark plug gap is .045".

Practical Ignition Advance for Unleaded Street Gasoline

Nowadays it is not a good practice to use a distributor with a "quicker than stock" curve in it. This is because of or street octane and that it is difficult to set initial timing because it is likely that the counterweights in the mechanical advance mechanism are already moving due to lighter springs. We actually recommend a curve which is "all in at about 2800 rpm.

If your distributor is curved as suggested and you have an adjustable vacuum advance unit, you should start with a low initial setting of 4-6°BTDC and then go up or down from there. If you are running no vacuum advance, you can usually start with a setting of about 8-10. What you are looking for is between 35-35 at about 3200.

Thus, if you are running vacuum advance it is important to know what the total vacuum advance is. For example, let's say that your total curve is in by 2800 rpm and you have 28° of mechanical advance and 8° of vacuum advance. What you would do is rev your engine, with the vacuum advance disconnected, to 3000-3200 rpm and set your timing at 28°.

Then tighten down the distributor. Hook up the vacuum advance and you will now have 36° total timing, including the vacuum advance. This is a good safe starting point. You can now advance or retard from that point for best results.

With unleaded fuel, 20°-22° of mechanical advance, plus 6°-10° of initial advance and little or no vacuum advance is a good starting point. You want to stay under 37.


- 109 -

6.1 Ignition System Upgrades Modifying Your Distributor

Check for Wear. Older distributors are a mechanical piece, just like the rest of your engine, and are subject to wear and even damage from misuse. It is highly recommended that for vehicles with more than 25 thousand miles, you replace your distributor with a reconditioned unit, at the least, or best, rebuild it with new bushings and a hardened shaft with a new cam gear (bronze), or replace it with a billet unit.

If you can wiggle the shaft up and down appreciably or back and forth in the housing, it needs replacement because that play will make your engine timing erratic.

Upgrading Parts – Standard Distributor. Both Accel and Mallory sell high performance points and condensers for the standard GM-era distributors. To insure against point bounce with high RPM usage, double springing of the production point springs may be done. The best method is to use Accel No. 110129 points or Mallory No. 102X Series Heavy Duty points. These points are good to 7000+ rpm without floating.

A heavy duty cap and rotor are easy upgrades, and one would be surprised by the amount of horsepower that can be gained with this change. Caps, rotors, points and condensers wear out rather quickly, especially where higher cylinder pressures and increased engine load are present, as in a modified or performance engine. If you are using a standard GM distributor and want great performance, you will find that changing these components at every other oil change is a good idea.

Going Electronic. Mallory and Accel sell conversion kits to make the system breakerless. This will ensure constant signal and no timing inaccuracies, as well as allow much higher voltage. To the plugs. Mallory's E-Spark Conversion Kit will convert their own point-type systems, and they have

a Unilite conversion for GM distributors. Accel sells both dual point and electronic conversion kits for conventional GM distributors plus replacement ultra-high quality replacement units.

HEI Upgrades. HEI units can be easily upgraded to give excellent performance, assuming the distributor itself is not worn out, with sloppy play in it. Mallory and Accel sell conversion kits and upgrade parts for these distributors.

Upgrading Your Ignition System with New Equipment

If possible, you should upgrade your ignition system to either a breakerless system or a "billet" distributor which are made with much closer tolerances that will keep timing more accurate. We recommend either Accel or Mallory Units.

Mallory offers complete setups for both street and track. The Mallory Unilite breakerless systems, Magnetic Breakerless Systems, Dual Point distributors, and HEI Billet Distributors; many of which are 50-state legal. They offer conversion kits and replacement parts as well. Please see the chart that follows and contact Mallory at www.malloryracing.com or call 216-688-8300.

Accel also offers performance replacement distributors for both standard and HEI systems that are 50-state legal. They also sell billet replacement electronic breakerless systems and high performance electronic breakerless distributors. Please see the chart that follows and contact Accel at www.accel–ignition.com or call 216-69-88-8300.

MSD ignition systems offer a host of ignition boosting systems, including high performance coils. Many of these components will work with either brand of distributor.


- 110 -

6.2 Spark Plug Science and Spark Plug Wires Spark Plugs and Plug Heat Range

A hot plug has a slow rate of heat transfer; therefore it runs hotter and prevents fouling. A cooler plug has a much quicker rate of heat transfer to the cylinder head, due to the electrode length and thermal insulation. If temperatures in the combustion chamber exceed 1750° F, pre-ignition usually occurs. If the spark plug electrode temperature drops below approximately 600° F, then fouling becomes a problem. The deeper the ceramic insulator around the electrode, the longer the heat transfer path.

While most brands make good spark plugs, AC has the most heat ranges for GM vehicles. In resistor plugs (radio noise suppression), AC R43-S to R45-S are good choices, with

the R43 best for 10.0:1 and higher CR and the 44 for anything in the 9 range and the R45 for 8 range compression ratios. The same heat range theory can be applied to 73 to 75 Autolite plugs. Champion has only two heat ranges, J-12 or J-13-Y, with the 12 series for 10.0 and better and the 13 for lesser ratios.

Non-extended tip racing plugs for those with no piston to spark plug clearance. NKG plugs are available in three different heat ranges for this application, B-6-S, B-7-S and B-8-S. NKG and Mondello suggest that street/strip cars use an R-5670-6 "V" groove, and an R-5670-7 for bracket racing.

Vendor and Other Listings

- 111 -

Section 07 -


7.0 Listing Central

About These Listings

Wild About Cars, LLC lists these vendors for the reader's reference only. This in no way is an endorsement, guarantee or warrantee for or of the product, only the manufacturer can provide such. We can only say that we have used the products in previous project cars and they performed as advertised.

Further, any pictures in this document either supplied or used with permission do not endorse, guarantee or warrantee the product, process, or procedure depicted. The pictures are used to explain or demonstrate such product, process or procedure only.

7.1 Vendor Listings Vendor Name Specialties Web Address

Accel & Mallory Ignition Ignition systems and components www.malloryracing.com Mr. Gasket Company 10601 Memphis Ave. #12 Cleveland, OH 44144 (216) 688-8300 Air Inlet Systems OAI systems, scoops etc. www.ramairbox.com 177 Grace Ave. custom and pre-made Hamilton, Ontario Canada L8H-3X1 (905) 549-6135 – Fax (905) 549-9869

Arias Pistons Custom forged pistons for Olds www.ariaspistons.com 13420 South Normandie Ave Gardena, CA 90249 (310) 532–9737 - Fax (310) 516-8203

ATI Performance Products Performance auto transmissions www.atiperformanceproducts.com 6747 Whitestone Road flexplates, etc. Baltimore, MD 21207 (800) 284-3433 – Fax (410) 298-3579

AUTOMOTION Rochester Carb Service Remanufactured and blueprinted www.hotrodcarbs.com 837 – 36th Ave. N.E. Rochester carbs and parts Great Falls, MT 59404 (406) 453-5395

BFIC Fuel Systems (Carbs Only.com) Remanufactured and blueprinted www.carbsonly.com 1617 W. Magnolia Holley, Carter and Rochester carbs Burbank, CA 91506 (877) 333-3130 – Fax (818) 841-7887

Carrillo Industries, Inc. Forged connecting rods www.carrilloind.com 990 Calle Amanecer San Clemente, CA 92673 (949) 498-1800 – Fax (949) 498-2355

Mark Cornea Reproductions Decals and specialty parts www.drdecal.com P.O. Box 531445 Livonia, MI 48153-1445 E-Mail: [email protected]

Crower Cams & Equipment Co. Cams and connecting rods www.crower.com 6180 Business Center Court San Diego, CA 92154-5604 (619) 661-6477 - Fax (619) 661-6466


- 112 -

Dick Miller Racing Engine and chassis components www.dickmillerracing.com 5930 Hwy 305 South Engine building. Performance parts Hernando MS 38632 (662) 233-2301 - Fax (662) 233-2381

Edelbrock Heads, intake manifolds, carburetors, www.edelbrock.com 2700 California Street and fuel injection systems Torrance, CA 90503 (310) 781-2222 – Fax (310) 320-1187

Fusick Automotive Olds restoration and specialty parts www.fusick.com 22 Thompson Road P.O. Box 655 East Windsor, CT 06088 (860) 623-1583 – Fax (860)623-3118

Gear Head Café GM service manuals www.gearheadcafe.com 2214 Estates Drive Nampa, ID 83686 (208) 860-4694

GM Parts Direct Factory replacement parts www.gmpartsdirect.com Flow Chevrolet, LLC 1400 South Stratford Road Winston-Salem, NC 27103 (336) 760-7000

Holley Corporation Fuel systems, carburetors, etc. www.holley.com 1801 Russellville Road Bowling Green, KY 42101 (270) 781-9741 – Fax (270) 781-9940

Kanter Auto Products Engine rebuilding kits for Olds www.kanter.com 76 Monroe Street 1930-1990 Boonton, NJ 07005 (800) 526-1096 – Fax (973) 334-5423

K-B Pistons Forged and Silvolite pistons www.kb-silvolite.com United Engine and Machine Company 4909 Goni Road Carson City, NV 89706 (800) 648-7970 – Fax (775) 882-7773

Mahle – Clevite Olds and others replacement engine www.clevite.com MAHLE Clevite, Inc. and other vehicle parts 1959 and Olive Branch newer MS, 38654 (800) 637-7654

MagnaFlow Performance Exhaust Exhaust and catalytic converter www.magnaflow.com 22961 Arroyo Vista systems Rancho Santa Margarita, CA 92688 (800) 824-8664 - Fax (949) 858-3600

Mondello Performance Products Engine building, Olds specialty parts www.mondellotwister.com 1103 Paso Robles Street Paso Robles, California 93446 NOTE: Complaints have been received from numerous customers (805) 237-8808 - Fax (805) 237-8814 on certain parts. Cams, valve assemblies, and rocker arms seem OK.

Olds Performance Products Oldsmobile performance parts www.oldsperformanceproducts.com Andrew Miller and services, performance short (845) 369-9602 – Tech and long blocks (800) 382-1320 - Orders


- 113 -

Sealed Power – Rock Auto Olds and others replacement engine www.rockauto.com Rock Auto, LLC and other vehicle parts 1953 and 6680 Odana Road newer Madison, WI 53719 (608) 661-1376 - Fax: (608) 836-5694

Standard Crankshaft Company Remanufactured crankshafts www.standardcrankshaft.com 724 Montana Drive – Suite A and connecting rods Charlotte, NC 28216 (704) 392-4371

Supercars Unlimited Oldsmobile performance parts www.supercarsunlimited.com 13980 SW T.V. Highway, Suite 5 Beaverton, Oregon 97005 (888) 653-7442 – Fax (888) 653-8050

The Carb Doctor Remanufactured and blueprinted www.carburetor.ca Box 2752 Holley, Carter and Rochester carbs Stony Plain Alberta T7Z 1Y3 Canada (780) 968-6622

The Carburetor Refactory Carburetor rebuilding kits www.carbkits.com 815 Harbour Way South, #5 Richmond, CA 94804 (510) 237-1277

The Carb Shop Remanufactured and blueprinted www.thecarbshop.com 2945 Randolph Avenue Holley and Rochester carbs Costa Mesa, CA 92626 (714) 556-2181

TOMCO Incorporated Carburetor repair kits www.tomco-inc.com 6241 Lemay Ferry Road St. Louis, MO 63129

Venolia Piston Forged pistons for Olds www.venolia.com 2160 Cherry Industrial Circle Long Beach, CA 90805 (323) 636-9329 – Fax (562) 633-9439

Year One Restoration and specialty parts www.yearone.com P. O. Box 521 primarily Chrysler, GM and Ford Braselton, GA 30517 (800) 932-7663 – (800) 680-6806


- 114 -

7.2 Photo Credits Page Credit Notes

Cover: Oldsmobile Public Relations circa 1969 Cro-Sal Aluminum 455 block. Few are known to exist

Forward: Oldsmobile Public Relations circa 1970 Rallye 350 intro PR photo

7-1: Motor Trend - 1964

7-2: Oldsmobile in Action – 1985 Bob Gerometta co-authored this book

8-1: Oldsmobile in Action – 1985

8-2: Oldsmobile Public Relations circa 1965


13-1: Oldsmobile Public Relations circa 1969 Engine is not running – they spun the fan by hand

15-1: Oldsmobile in Action – 1985

15-2: Mondello Olds Performance

16-1 Edelbrock Performance Products

17-1: Oldsmobile Public Relations circa 1971 Olds W-43. Some say the engine ran in a mystery 1971 W-30 that prowled Woodward Avenue looking for LS6s and Hemis back in the day.

17-2: Oldsmobile Chassis Manual – 1965


20-1: Offenhauser Corporation

20-2: Oldsmobile Chassis Manual - 1968







43-1: Unknown, from the archives of Bob Gerometta

44-1 Oldsmobile in Action – 1985


45-1: Dick Miller Racing





47-2: Edelbrock Performance Products



51-1: Oldsmobile Division, General Motors Corporation











62-1 Mondello Olds Performance

64-1 Mondello Olds Performance

67-1: Mondello Olds Performance 67-2: Mondello Olds Performance





- 115 -




72-1: Rocket Racing




75-1: Supercars Unlimited

75-2: TCI Incorporated












93-1: Rocket Racing






97-3: Eckler's Camaro

97-4: Ram Air Systems

98-1: Ram Air Systems

98-2: Holley Corporation




102-1: Rochester Products Corporation, General Motors Corporation


102-3: Doug Roe

104-1: Doug Roe

105-1: Rochester Products Corporation, General Motors Corporation

105-2: Doug Roe

105-3: Doug Roe

105-4: Doug Roe

105-5: Doug Roe

106-1: Doug Roe

107-1: Doug Roe

107-2: Doug Roe

108-1: Doug Roe

108-2: Doug Roe

109-1: Doug Roe

109-2: Doug Roe

110-1: Doug Roe

111-1: Doug Roe

111-2: Doug Roe


Assembly Worksheets and Other

- 116 -

Section 08 -

Assembly Worksheets & Other Key Specifications

8.0 Torque Specifications The following torque specifications generally apply. Please refer to the Chassis Service Manual specific to your year engine and type if uncertain.

Item Torque to

Air cleaner to Carburetor Stud ............................................................................................. 5 foot lbs. Carburetor to Intake Manifold............................................................................................... 15 foot lbs. Choke Tube and Plate to Intake Manifold ............................................................................ 15 foot lbs. Connecting Rod Nuts (Stock Nut & Bold Arrangement)34 .................................................... 42 foot lbs. 400-455 Crankshaft Bearing Cap Bolts ............................................................................... 120 foot lbs. 260-403 Crankshaft Bearing Cap Bolts #1-4 ....................................................................... 80 foot lbs. 260-403 Crankshaft Bearing Cap Bolts #5 .......................................................................... 120 foot lbs. 7/16" Cylinder Head Bolts ..................................................................................................... 85 foot lbs. ½" Cylinder Head Bolts ....................................................................................................... 130 foot lbs. Distributor Clamp to Cylinder Block ..................................................................................... 17 foot lbs. EGR Valve to Intake Manifold .............................................................................................. 25 foot lbs. Engine Mount to Cylinder Block ........................................................................................... 75 foot lbs. Engine Mount to Frame ....................................................................................................... 50 foot lbs. Exhaust Manifold/Header to Cylinder Head ........................................................................ 35 foot lbs. Exhaust System (pipe bolts) ............................................................................................... 20 foot lbs. Fan Drive Pulley to Fan Hub ................................................................................................ 20 foot lbs. Fan Drive Pulley to Balancer ............................................................................................... 20 foot lbs. Flex Plate (AMT) to Crankshaft (use Loctite) ...................................................................... 60 foot lbs. Flywheel (SMT) to Crankshaft (use Loctite) ........................................................................ 90 foot lbs. Front Cover to Cylinder Block – 3/8" bolts .............................................................................. 35 foot lbs. Fuel Pump Eccentric to Camshaft ....................................................................................... 65 foot lbs. Fuel Pump to Engine Block (nut on bolt) ............................................................................. 25 foot lbs. Harmonic Balancer to Crankshaft (use Loctite) ................................................................... 180 foot lbs. Intake Manifold (cast iron) to Cylinder Head ....................................................................... 40 foot lbs. Intake Manifold (aluminum) to Cylinder Head ..................................................................... 35 foot lbs. Oil Deflector to Bearing Cap ............................................................................................... 35 foot lbs. Oil Filter Assembly to Cylinder Block .................................................................................. 35 foot lbs. Oil Pan Bolts ....................................................................................................................... 10 foot lbs. Oil Drain Plug ...................................................................................................................... 30 foot lbs. Oil Pump Cover to Pump .................................................................................................... 8 foot lbs. Oil Pump to Bearing Cap .................................................................................................... 35 foot lbs. Rocker Arm Pivot to Head ................................................................................................... 25 foot lbs. Spark Plug to Cylinder Head ............................................................................................... 35 foot lbs. Starter Motor to Cylinder Block ........................................................................................... 35 foot lbs. Timing Gear to Camshaft (use Loctite) ............................................................................... 65 foot lbs. Valve Cover to Cylinder Head ............................................................................................. 7 foot lbs. Water Outlet (Thermostat Housing) to Intake Manifold ........................................................ 20 foot lbs. Water Pump to Front Cover ................................................................................................ 13 foot lbs.

Special Fasteners: Rocker Arm Studs (7/16" – bottom thread/use Loctite) .......................................................... 50 foot lbs. Rocker Arm Studs (5/16" – bottom thread/use Loctite) .......................................................... 30 foot lbs. All 7/16" Studs (Heads & Mains)35 ....................................................................................... 92 foot lbs. All ½ " Studs (Heads & Mains) .......................................................................................... 110 foot lbs. All Chrome Moly #8740 3/8" Rod Bolts ................................................................................ 50 foot lbs. ARP 7/16" Flywheel & Flexplate Bolts (use Loctite) .............................................................. 85 foot lbs. ARP 7/16" Head Bolts ........................................................................................................... 90 foot lbs. ARP ½" Head Bolts ............................................................................................................. 130 foot lbs.

34 Clean under the head of the bolt and the threads. Coat the threads with clean new engine oil prior to tightening to obtain the correct value. If

using ARP Molly Assembly Lube, the torque values will be less. ARP supplies specifications to assist you in making this determination. 35 Studs should be hand tightened into cylinder block.


- 117 -

8.1 Assembly Worksheet – All Blocks How to Use These Sheets

The sheets are designed a s a guide – a checklist. Nothing will replace the Oldsmobile Chassis Service Manual for your year vehicle as the definitive handbook for any engine build or any other repair of your car. The Manuals are available from places like Amazon, but we prefer the CD which is available for the years 1901-1981 from Gear Head Café www.gearheadcafe.com. Gear Head Café has the later years of Chilton's Manual available on CD. The specifications listed here are based upon our best information and practice both from experience and professional engine builders' practice. Additionally, for any specifications not found, please refer to the Oldsmobile Chassis Service Manual for the year of your vehicle or the year and engine type which you are installing.

You can give these sheets to your engine builder and they can use them as a documentary of the build, if they do not have a similar check list of their own. You can also use these sheets as a discussion document when working with the builder to get an estimate of the work. By checking off what you want, you can outline your project for them.

As you complete a rebuilding or repair function, mark any significant measurement or specification and check the box next to the item completed. If an item does not pass inspection, mark as such and acquire a replacement.


- 118 -


- 119 -


- 120 -


- 121 -


- 122 -


- 123 -

Appendix

- 124 -

Section 09 -

Appendix

9.0 Standard Piston Information The following is a listing of the pistons offered in the Oldsmobile engines covered in this manual. Factory part numbers are the standard size piston part number – though Olds fitted the piston in "A" – through "D" sizes to allow for 0.005" bore size adjustment. In most cases the part number shown is for the "C" or "D" size.

9.1 Engine Bore and Stroke Compression Changes The following chart shows how bore and stroke changes affect the compression ratio and what changes may need to be made.

Appendix

- 125 -

9.2 Degreeing Your Camshaft Degreeing Procedures

Before you start, be sure that you have access to a set of offset cam bushings, one solid (mechanical) lifter or a checking lifter bar, and a cam degreeing kit (degree wheel and dial indicator).

1. Turn the engine to Top Dead Center (TDC). The # 1 cylinder should be at the top dead center of its compression stroke. (Always rotate the engine clockwise, never CCW).

2. Install the camshaft and timing chain set. Align the “0” marks on the timing gears as closely as possible.

3. Bolt the degree wheel to the front of the crankshaft. Attach a pointer to point to TDC (0) mark on the degree wheel. If the wheel did not come with a pointer, one can be made from welding rod, or a coat hanger, or even some aluminum sheet that you cut to come to a point.

4. For an accurate TDC use one of the two following methods:

Without Heads Installed (Preferred). Attach a dial indicator on the deck surface over # 1 cylinder and turn the engine clockwise until # 1 piston begins coming up on the compression stroke. Be sure the piston is as centered in the cylinder bore as possible. When the piston is at its highest point and the dial indicator briefly stops moving, that is TDC. Align the TDC mark on the degree wheel with the pointer.

With Heads Installed. If the heads are installed, use the “piston stop” method. Before attaching the timing chain, screw a mechanical piston stop into the spark plug hole and then rotate the engine clockwise until it stops. Mark the balancer or degree wheel. Then rotate the engine counter-clockwise until it stops and place another mark on the balancer or degree wheel. The true point of TDC is the distance halfway between the two marks on the balancer or degree wheel. After finding TDC, you may remove the mechanical piston stop.

5. At TDC on the compression stroke (both valves closed and the lifters on the “heel” or back side of the camshaft lobe), insert the solid or mechanical lifter or a checking lifter bar on the #1 intake lobe. Then, install and zero the dial indicator on the lifter or lifter bar so that it will measure the lifter’s rise.

6. Rotate the engine until the lifter begins to rise. Continue rotating the engine clockwise until the dial indicator shows the lifter is at the lift specified that the camshaft is to be checked. This is usually 0.050”and will be stated on your camshaft’s specification sheet. Record that position of the degree wheel as this number is the intake opening event.

7. Continue rotating the engine and record the position at the dial indicator’s maximum lift. This is the intake lobe lift of the camshaft.

8. Continue rotating the engine until the dial indicator shows the lifter dropping down to the cam check height (0.050”) and again record the position of the degree wheel. This number is the intake closing event.

9. Return the engine to TDC and re-check your TDC mark.

10. Relocate the solid lifter or lifter bar to the exhaust lobe, rotate the engine to TDC again and reset the dial indicator at zero. Check repeat the rotation using the same method as on the intake, recording the opening, closing events and the maximum lobe lift.

You may check as many lobes as you like. You should at least check number 8 cylinder to verify the accuracy of the camshaft.

Calculating Actual Valve Lift

To calculate the actual valve lift, multiply the recorded lobe lift by rocker arm ratio. Olds rockers are 1.6:1, so if the lobe lift was 0.300” then the valve lift would be 0.480” per the following equation: 0.300” (lobe lift) x 1.6 (rocker ratio) = 0.480” (valve lift).

Calculating Cam Duration

To calculate the duration, add the opening event to the closing event plus 180°. As an example; a camshaft checked at 0.050” lift might be:

Measured Intake Opening 22° BTDC; and Measured Intake Closing 50° ABDC The duration would be: 22° + 50° + 180° = 252° @ 0.050”. In another example:

Measured Exhaust Opening 65° BBDC; and Measured Exhaust Closing 15° ATDC The duration would be: 65° + 15° + 180° = 260° @ 0.050”

Check these figures against the provided “cam card” to check the accuracy of the camshaft. You may also do this to get specifications for a camshaft that you bought used or don’t have timing specifications for. You may now wish to advance your camshaft timing, depending on your application. Advancing your camshaft 1° - 2° is preferable even for stock applications, as it will help compensate for chain stretch.

Appendix

- 126 -

9.3 Outside Air Induction Scoop Fitment Introduction

Oldsmobile experimented with OAI to a greater degree than did other members of the GM family, with in bumper scoops, under bumpers scoops and scoops on the hood.

1966 OAI Scoop Fitment

The following is a copy of the factory Olds Product Information Manual, 1966. The fitment requires that a rectangular hole be cut in the fender filler plate. A complete set of a reproduction of the change sheets (1-6), including fitment of the trunk mounted battery system can be purchased from Wild About Cars for $5.00 including shipping. For more information or to purchase this document, contact [email protected].

These diagrams show how to measure and install the OAI scoops inside the bumper and through the filler

plate into engine compartment.

This is where the opening needs to be cut and the size of the opening.

This picture shows how the inside of the scoop bolts up to the opening

This shroud bolted to the Tri-Carbs and forced fresh air from the ducts/scoops via hoses to the carbs.

It was supposedly worth 35-50 HP.

Keeping hot engine air out of the carb is valuable.

Appendix

- 127 -

1967 OAI Scoop Fitment

The following is a copy of the factory Olds Product Information Manual, February 1968. The fitment requires that a 4.00" diameter circular hole be cut in the fender filler plate. A complete set of a reproduction of the change sheets (1-6), including fitment of the trunk mounted battery system can be purchased from Wild About Cars for $5.00 including shipping. For more information or to purchase this document, contact [email protected].

This is the 1967 shroud bolted to the Special Quadrajet carb and forced fresh air from the ducts/scoops via hoses to the QJ It was supposedly worth 35-50 HP.

Keeping hot engine air out of the carb is valuable.

These diagrams show how to install the OAI ducts/scoops in the grille and through the filler plate

into engine compartment.

The '67 duct/scoop area appeared less than the '66 and later '68-'69 units, but it not seem to affect

performance in a negative fashion, likely because the inlet location was in the best possible

air flow region.

Appendix

- 128 -

1968-1969 OAI Scoop Fitments

The following is a copy of the factory Olds Product Information Manual, February 1968. The fitment requires that a 4.00" diameter circular hole be cut in the fender filler plate.

The 4.0" diameter hole needs to be cut on both sides where the ducts penetrate into the

engine compartment

These diagrams show how to install the OAI scoops under the bumper and through the filler plate into

engine compartment.

The '68-'69 units, (1968 shown at left) were quite efficient, but they really only came into their own over 50 MPH.

They also collect road junk so it is advisable to clean out the air cleaner once a week and never

run the unit without an air cleaner element, except at the drags.

This 1968 system has been sanitized for the photo session. The brackets that held the scoops to the

bumper/filler area have been removed. Looks impressive, though.

Appendix

- 129 -

1970-1972 OAI Hood/Air Cleaner Fitment

The following is a copy of the factory Illustration for the Parts Manual, May 1971. The most difficult item to find are the "clip" (item 19) that hold the springs (item 2 & 9) which held the adapter to the air cleaner assembly. These may be sourced from Fusick Automotive www.fusick.com (catalog, page 33), along with an entire NROS Adapter and seal, etc. including the hood.

Appendix

- 130 -

9.4 Carburetor Part Numbers The complete listing of carburetor part numbers would require a book unto itself as the factory had a habit of making running changes when the unit was modified to deal with a problem that may have surfaced. The following listing includes the commonly accepted numbers.

Appendix

- 131 -

section 06 timing and ignition...

Documents