Suggestions:

Check the water pump pulley bolts & the balancer pulley bolts + the balancer to crank bolt.

Auto trans? Check for a crack in the flexplate. They normally crack near the crank hub, you should see a line of rust @ the crack.

The loose pulley(s) & cracked flexplate will cause a knocking noise.

If the above checks ok: Engine @ idle pull one plug wire at a time from the distributer. You may be able to isolate the noise to a particular cylinder.

EDIT: Just reread your first post, the heads were "freshened"? Was this done on the car? You may have a worn valve guide which will also cause a ticking noise.


Luck with your search.

Nice find Steve40th.

I recall someone mentioning that the pad may not be seated properly in the caliper :~)

After machining a kazillion rotors I can tell you that it is impossible to machine a rotor on a rotor lathe so that the brake surface is at an angle to the hub surface. If the rotor was mounted improperly on the rotor lathe the rotor will wobble (laymans defination of run out) when installed on the hub. The result is a pulsating brake pedal. If you have access to a dial indicator use it to determine if the rotor is running true.

IMHO the caliper is/has spread or the pads are not seated/installed properly in the caliper housing or the caliper is not installed properly on the upright. Perhaps some trash/junk between the caliper & upright

Probably not needed for AX.

Sustained 3000 + rpm will heat the oil.

If its a driver & track car you will want the thermostat sandwich adaptor.

I never know exactly what the engine temp is on my 90 as the factory gauge only has a sweep bar. If you have an aftermarket gauge suggest letting the car idle with the ac off until the primary fan turns on. IIRC it should come on at 228* then compare that temp to your gauge reading. You may have a low reading gauge.

Regardless of cold ambient temps the engine should run at the stat temperature & maintain it. Hot weather operation is a different story with C4's.

If possible post some pix of the head damage & the top of the piston.

SWAG: Water in the cylinder created steam during ignition. The ensuing shock wave from the steam expansion damaged the spark plug.

Nice mod!! Please post in progress pix. Installation in a separate hood is a good idea or a winter time project on an original hood.

As far as hood vents & water, there is an aftermarket
f-glass co that makes hood vents & under hood diverters to eliminate water intrusion to vital areas. I cannot recall the company name (CRS).

Found it.

http://www.greenwoodcorvettes.net/gc4/louvers.htm

Does anyone know what rocker panels are on the car in the top photo or who makes them? I would be interested in a rocker box change without adding pieces to the doors etc.

Have a low mileage t56 for sale.

IMHO: The 115V wire feeds are so-so. I used a Lincoln 115V that was ok but only good for sheet metal & exhaust. The duty cycle gets shorter as the amps are increased. If you decide on the 115V welder suggest installing a dedicated electrical circuit using 10ga wire & a 30 amp circuit breaker. You can use CO2 as the inert gas.

For SS & aluminum you will need a TIG welder. I have a Lincoln square wave TIG that will also run stick. They are a bit pricey for a home shop, you may want to farm out the SS & aluminum work. You will need argon gas with a TIG.

The mig I have is a 200 amp HTP America. The higher amperage rating = better control & weld quality @ lower amperage settings. This machine will weld razor blades up to 1/2" plate.

Good used welding equipment is always in demand, I have been able to sell my used equipment for 70% of the new cost each time I upgraded.

Suggest an entry level 220/230V wire feed (MIG), they are much better than the 115V models.

"If I get the pressure tester, what is that going to tell me about why I'm breaking springs? "

Nothing.

The feeler gauge will work, I used that method at the track a few times.

Just a reminder, check the underside of the rockers to insure that they are not contacting the retainers.

Found some info on your cam

.560" lift intake/exhaust with 1.6 rr's.

If memory serves 113 heads will only allow about .540 lift however I think the area of interference is the guide to retainer.

You need to know the total valve lift with the 1.6 rockers.

You need to know the distance between the spring seat cup & the spring retainer. Check it with this tool:
http://www.summitracing.com/parts/SUM-900032/

You need to know the spring height when coil bind occurs.

If you have coil bind:

You may be able to purchase spring seat cups that are thinner, get retainers that position the spring higher on the valve, get springs with a smaller wire diameter, remove the heads & have the spring seats machined or install 1.5 rockers.

Also check the under side of the rockers for an interference wear mark. Some rockers will contact the retainer & the spring will bind on one side causing failure.

You can clearance the rockers with a die grinder.

IMHO you problem is the difference in rubber compound between the old & new tires & possibly a difference in footprint size.

Suggest comparing compounds with a durometer.

255 50 16 = 799 revolutions per mile

275 35 18 = 811 revolutions per mile.

Good find Leatherman.

Suggest working with or changing the accelerator pump cam to dial out the off idle stumble. If memory serves, there's an assortment of 5 cams in a Holly track pack.

Finicky carbs may require a squiter nozzle change & or a larger volume accelerator pump to get past the off idle flat spot.

A few suggestions.

Replace the power valve. If the engine has ever backfired through the carb the power valve is probably toast. This a common Holley problem.

Check/set the float levels.

With as much cam as you have you may have the the base idle screw adjusted down/in to far which will cause the carb primary to engage the main metering system at or just above idle. The trick with cammed engines is to adjust the stop screw for the secondary butterflys so the throttle plates for the secondaries are cracked open a bit allowing more air into the engine at idle. This will allow you to back off the throttle stop screw & get the carb back on the primary idle circuit. Reset the idle/air adjustments.

Manifold vacuum to the distributor vacuum advance is a bad thing. Reason: As soon as you apply throttle the engine vacuum drops causing a drop in timing which aggravates an off idle stalling condition. Attach the vacuum advance to a ported vacuum source.

Use a center punch to dimple the bore that the ujoint cap lives in. This will raise the metal around the punch mark. Put a half dozen dimples evenly spaced around the ID near the bottom (the area closest to the ujoint cross) & top of the bore for a total of 12 dimples.

After installing the ujoint cross, caps & lock rings use the rounded end of a ballpeen hammer to relieve the stress on the shaft ujoint yoke caused by hammering or pressing the caps in. New joints will always be tight & need to rotate freely.

The technique: Hold the shaft up off the work bench & give the yoke several hard raps on the yoke finger centered between where the yoke is welded to the shaft & the ujoint cap bore. Rotate the shaft 180 degrees & repeat the process on the other finger. The ujoint should now rotate freely. If the joint is still tight repeat the above with a bigger hammer. I use a 1# ballpeen.

Depends on piston to wall clearance. .004 or more clearance & you can hear the pistons slap on cold start up. If this is the case its a good idea to let the engine run a bit to get some heat in the pistons before driving.

Had a similar problem on a 89 vert. Miss at cruise, full power at WOT. Had one injector that would not seat properly. Two cans of NAPA injection cleaner through the fuel rails solved the problem. This procedure requires specialized equipment.

Suggest reading the plugs when you remove them, if one or more show signs of running rich you may have a similar problem.