Tips and Troubleshooting

Locating Oil Screen Pick-Up

When installing an oil pan, make sure the oil screen pick-up is a minimum of 3/8" off the bottom of the pan, but no more than a 1/2".

Finding Elusive Vacuum Leaks

With the myriad of vacuum lines and hoses found on contemporary vehicles, it’s often difficult to locate pesky vacuum leaks. Also, after servicing or installing induction system parts {manifolds, carburetors, TBI or MPFT systems}, vacuum leaks can impair engine idle quality, throttle response and fuel economy. PMAG mechanics do the following: With the engine idling, squirt small amounts of “quick start” {ether} from an atomized can near any suspected leaks…or even areas where you suspect a leak might be. If the engine changes speed {typically an rpm increase}, you’ve found the leak. Take caution not to spray any of the “quick start” near the engine’s air inlet because any change from applications to this area are not leak-related, and will certainly increase rpm.

Diagnosing a Clogged or Partially Restricted Exhaust

This involves drilling a small hole {typically 1/8-inch o.d. maximum} in the exhaust pipe ahead of the suspected part {catalytic converter or muffler}. Insert a probe connected to a pressure gauge that can read positive pressure {a two-way vacuum gauge works well} into this hole. Bring engine rpm up to a cruise speed {2500-3000 rpm} and note the pressure indicated. Readings on the order of 5 inches are considered acceptable, but if they reach the range of 10-15 inches, chances are good an abnormal restriction exists. When the test is complete, a small pipe plug or self-tapping metal screw will plug the hole, especially when used in conjunction with some form of high temperature epoxy.

Identifying Restricted Radiator Cores

Bring the engine up to operating temperature. With the engine still running, slowly pass your hand around and in close proximity to the radiator core. Unless the surface is excessively hot, actually touching the surface is preferable. Temperature of this surface should be relatively uniform, over the entire radiator core. Any areas that appear noticeably cooler suggest regions where coolant is not circulating, thereby reducing radiator surface temperature. This condition often manifests itself as operating engine temperatures slightly higher, but not necessarily to excess, than normal radiator core temperature.

Diagnosing for Leaking Cylinder Head Gaskets

Aside from unusually high coolant temperature {this condition can be one of gradual increases over time}, bring the engine to operating temperature and check for bubbles in the coolant system…viewed through the open radiator fill neck. Short “blips” of the throttle should increase the intensity and size of any bubbles present. Another check involves running the engine, at operating temperature, for about two minutes at fast idle or cruise rpm. Allow the engine to cool and remove all spark plugs. Starter-crank the engine to observe any coolant displaced out the plug holes.

Tracing Air Flow Around Air Scoops or System Inlets

This check is usually applicable to racing or otherwise high demand driving conditions. Using regular-grade white grease, form small “tufts” of grease around the air entry. The shape of such “tufts” should resemble small Hershey candy “kisses.” Perform the type of driving for which the measurement is intended; e.g., a quarter-mile acceleration, etc. Examine the “tufts” to see how their shape has changed. For example, the grease will tend to relocate in the direction of airflow, while the extent of “smear” created relates to air flow velocity. This same test can also be used to determine the presence {or absence} of air around intended inlet points.

Diagnosing “Noisy” Serpentine Belts

Many times, these belts become embedded with dirt and other residue that finds its way into the grooves of these belts. And because serpentine belts are relatively expensive, the following method of service often works well. Simply remove the belt, reverse it, and scrub it {with a stiff bristle brush} in a solution of water and liquid dish soap. Allow the belt to dry before reinstallation.

Installation of Steel Bolts into Aluminum Parts
For any applications of steel bolts/studs into aluminum parts {cylinder heads, valve covers, etc.}, ALWAYS use some form of anti-seize compound on the threads. Further, it's best to use a bottom tap to "chase" the threads in aluminum parts and clean bolt threads before applying the compound. And if any factory-recommended torque settings are provided, adhere to them strictly. This may seem to be a suggestion of small importance, but only one experience installing Heli-coils in hard-to-reach places will underscore the benefits of anti-seize

Driveability Problems with ECM-equipped Cars
Especially with import vehicles, the electronic control module {on-board computer} is installed beneath the front seat. According to the PMAG, soft-drinks and coffee spilled on front seats finds its way into the ECM, resulting in sporadic {or permanent} driveability problems that are particularly difficult to diagnose…unless the spill is identified. Complete ECM replacement is considerably more expensive than the drink that may have caused the problem. Exercise caution because it’s not an infrequent problem.

Identifying Cylinder Mis-fire on Racing Engines
Especially on engines equipped with headers, a couple of methods are handy to remember. With the engine idling, “dab” the headers with a wet rag, just beyond the header flange. If the moisture doesn’t disappear immediately, the mis-fire is found. Also, small holes {about 1/8-inch o.d.} drilled near the header flange allows you to see combustion flame, through the hole, if the cylinder is properly firing….ala Smokey Yunick of days gone by. You can also hook a timing light to each individual plug wire {one at a time} to see if firing voltage is present. Or, you could do all three!

Camshaft Break-in
The importance of this cannot be over-emphasized! Before starting a freshly-cammed engine, make certain initial ignition spark timing is correct by whatever method you wish. One such approach is to “starter-bump” the engine until crank damper timing marks align to the initial timing setting desired {a few degrees BTDC}. Position the distributor housing to align the rotor tip with the #1 spark plug wire terminal. Fill the cooling system. Make sure the induction system {carburetor, TBI, fuel pressure, etc.} is set for starting the engine. Once the engine fires, quickly adjust engine speed to about 2000 rpm {or whatever is recommended by the cam manufacturer} and continue running the engine for a minimum of 15 minutes. During this time, don’t allow the engine to idle. This procedure is recommended for any type valve lifter or camshaft location.

Plug Wires
Don't bundle spark plug wires together with tie straps. This can cause misfire because of leaking voltage between wires. On Chevy V-8 engines, when #5 fires , leaking voltage can cause #7 to fire 90 degrees too early resulting in damaged parts.

Warm Up Engine
Always warm up engine before racing to a miniumum of 160 degrees oil temp. Cool oil will show high pressure but won't be flowing through bearings. Results are damaged bearings and valve springs.

Jetting Alcohol Engines
When jetting alcohol engines, start with what you know is rich. You'll hear a miss or misfire in upper RPM range, or you'll feel engine leveling off. At this point, reduce jetting by trial and error until motor is crisp. Jetting by engine temp alone is very dangerous because if you have efficient cooling system, you can burn motor or send it into detonation while water temp shows cold.

Adjustable Timing Lights
When setting timing with adjustable timing lights, be sure if you're setting at 34 degrees on the back of the timing light that you are using TDC on the damper. We've had customers that have used 34 degrees on timing light and damper--results are burnt pistons and/or blown up motors. Always check timing after a motor is warm at the highest RPM your motor will see.

Adjusting Valves with Perma-Locks
When adjusting valves with perma-lock adjusters, after reaching desired valve lash, loosen adjuster 1/4 turn, tighten allen set screw, force lock adjuster tight (within reason) to desired lash. This will prevent lash adjuster from coming loose.

Valves with Stud Girdles
When adjusting valves with stud girdles, after tightening stud girdles you must recheck valve lash.

Mechanical Roller Lifters
When installing mechanical roller lifters, soak them in oil for 30 minutes prior to installation. This will prevent dry start-up and excessive wear on needle bearings. At the Well's Racing shop, we use no oil restrictors on Chevy engines with mechanical roller lifters. We want full oil pressure to needle bearings in roller lifters.

Disassembling an Engine
When disassembling an engine, be sure all rods and main caps are numbered before removing.

More on Disassembly
Use some type of protection such as a piece of rubber fuel line hose on rod bolts to prevent scarring journals when disassembling a motor.

Numbering Lifters
When disassembling an engine, especially on flat-tappet camshafts, make sure each lifter is numbered to go back on the same lobe of the camshaft.

Installing a Roller-Timing Chain Set
When installing a roller-timing chain set, bolt the cam gear to the camshaft and install the cam in the block with the chain on the gear. Press the cam gear towards the rear of the block, and check for a minimum of .050 clearance between the chain and the block. Most small-block Chevys require grinding to achieve proper clearance.

When Changing Cam Degree
When changing cam degree, you must recheck valve clearance. Each degree of change effects valve clearance approximately .010. Example: If you advance the camshaft .040, you will lose .040 intake valve clearance and gain .040 on the exhaust clearance. It will be the opposite if you retard the camshaft.

Main and Rod Caps
Don't mix up main or rod caps. When disassembling an engine, make sure all rods and main caps are numbered before removing.

Aftermarket Rods
When using after-market rods or a longer stroke crankshaft, check block and cam for a minimum of .060 rotating clearance.

Install Crank and Cam with Gear in the Block
Install crankshaft with gear in block. Install cam with gear in block. Hold a straight edge across both gears to check for alignment. Machining or shimming may be required.

Oil Pan Clearance
When installing an oil pan, you need to make sure the rods and crankshaft clear the pan. To check for clearance lay one hand on the pan and turn the motor over several times with the other. If you've got a clearance problem you'll hear noises and/or feel vibration.

Valve Replacement
When replacing valves, make sure they don't protrude higher in the chamber than your old valve. If they do, you'll have to recheck valve clearance. This might cause a gain in compression ratio.