Hey guys,

I have an 86 IROC TPI and I believe the dist gear is worn out. Need to replace. Composite is the best but most expensive. The cam is a bigger than stock cam, but I don't know which one it is (previous owner rebuilt the engine). Is it safe to say this composite one will work?

http://www.jegs.com/i/COMP-Cams/249/...791+4294829509

Thanks!

 

No need for anything crazy. 86 isn't even a roller cam. Rock Auto Delco replacement should be dirt cheap. Good enough for OE...

 

The cam was changed when the motor was rebuilt.. So I don't know what type of cam it is (material, roller, flat tappet, etc.) .. Isn't it a safer bet to get a composite one? Or is that unnecessary? I don't want to get one that is too hard and then have it eat the cam gear :/

 

Pull a valvecover and look down in the head to see what cam you have.

 

Hard to imagine anyone doing a pricey retro roller on a mild street build. Composite gear is only for billet roller cam without iron gear, pretty much solid roller race only stuff. Most hyd rollers, including the factory GM, have an iron dist/oil pump drive gear pressed onto the billet cam core for street use. Stock steel dist gear is what you want.

Why do you think your dist gear is worn? Pull the cap and see if you can rock the shaft back and forth. Maybe the timing chain is slack. Put a breaker handle on the crank bolt, with plugs out, and rock the crank back and forth. Look for more than about 5 degrees before the dist rotor starts to move either direction.

 

Isn't it easier to pull the distributor and check the gear? I have to change cap and rotor anyway.

 

Before you pull the dist, just check for lash. No centrifugal advance, there should be very little freeplay in the shaft. I suppose it is easier to pull the dist in a TPI than to pull the plugs. I'm just offering that advice in case it isn't the dist gear. BTW, if you do replace the gear, be aware that the teeth and the pin hole are not concentric to each other. It's possible to install the gear a half tooth off if you let the shaft rotate during the install. This can drive you nuts after you take the time to mark the dist and rotor for reference and they won't line up on install.

 

Pull valve cover and one push rod. Short roller cam, long flat tappet cam. Checking timing with light for steady reading. Put balancer on 0* and with dist. cap off rotate backwards slowly until rotor moves, read scale for how may degrees out the timing chain is.
Joe