a few '93 Z28 questions (including LT4)

[wako29]

okay, I bought a '93 Z28, wrecked, and am planning on putting the drivetrain in my hot rod ('36 Chevy Master). So, naturally, I have a few questions:

What is a good rebuild kit? This motor has like 120k, and we just would like to rebuild the thing before we put it in the '36. Anyone have any suggestions?

What about a cam? We have considered the LT4 hot cam kit (as well as the head package, but we dunno if we want to spend that much money and open a whole can of worms by doing that), but we want overall driveability over balls-out performance. Would a good Comp work better?

What about headers? Any good universal fits worth a look? Does any 'ol SBC headers work?

Is there any way to stop the water pump problem (as well as the coil?)? I have heard that this is a problem.



Any other questions or suggestions would definetly be appreciated

[wako29]

nobody

[tabahr]

as part of your rebuild, put on a new water pump. The water pumps on these last a long time because there is no belt on it puting lateral tension on the bearing. The coil should be fine assuming it ran well in the wrecked car. I've had 3 lt-1 cars and never had a coil problem, or water pump problem.

The opti-spark unit behind the water pump on the 93 is the non vented version and prone to forming condensation and croaking.
You may want to convert to the 95 and newer vented opti as part of your rebuild. The conversion will require a new opti, new timing cover and other parts. If it works, and price is a consideration, I would recommend keeping the 93 opti with a new water pump (so it doesnt leak on the opti)

As far as hopping it up... I'd have the stock heads and intake ported, then install the LT4 hot cam. And... I'd get a stroker kit to push it to 383 ci. that with a good exhaust/headers and you will have (just a guess) 375 - 400 horsepower.

The exhaust ports are "D-ports" and I'm not sure if that would be a consideration purchasing headers. I do know, that the bolt pattern is standard small block. I'm guessing that any small block header would fit.

Hope this helps a bit

[wako29]

Originally posted by tabahr
as part of your rebuild, put on a new water pump. The water pumps on these last a long time because there is no belt on it puting lateral tension on the bearing. The coil should be fine assuming it ran well in the wrecked car. I've had 3 lt-1 cars and never had a coil problem, or water pump problem.

The opti-spark unit behind the water pump on the 93 is the non vented version and prone to forming condensation and croaking.
You may want to convert to the 95 and newer vented opti as part of your rebuild. The conversion will require a new opti, new timing cover and other parts. If it works, and price is a consideration, I would recommend keeping the 93 opti with a new water pump (so it doesnt leak on the opti)

As far as hopping it up... I'd have the stock heads and intake ported, then install the LT4 hot cam. And... I'd get a stroker kit to push it to 383 ci. that with a good exhaust/headers and you will have (just a guess) 375 - 400 horsepower.

The exhaust ports are "D-ports" and I'm not sure if that would be a consideration purchasing headers. I do know, that the bolt pattern is standard small block. I'm guessing that any small block header would fit.

Hope this helps a bit

yea, that helps a lot, thanks


but how "hot" is the LT4 cam? Does it still idle okay? We really want overall driveability to be the biggest concern. Would a Comp work better for that situation?

also, what is the best brand for the stroker kit? Will any 'ol SBC stroker kit work?

[Brandon94za4]

I had the hot cam in 94z and it was very streetable, it is a good mild cam. It sounds good too!! I wouldn't go any smaller than a hot cam. If it were me I would just do a 355 rebuild, I wouldn't mess with stroking it because you said you werent too worried about it being balls out fast. You will def want to run a comp.
Brandon

[bn_bullet]

Another consideration to get rid of the Optispark is to convert to a carburetor instead of the fuel injection. Typically, in a late model car I would prefer to stay fuel injected but GM Performance Parts does make an intake (p/n 24502592) that accepts a standard 4-bbl carburetor (Holley, Edelbrock, Quadrajet, etc...) and an HEI distributor. They also make one (p/n 24502574) that will work with the LT-4 heads if you so desire. Using one of these manifolds would do away with the Optispark but would require you to convert the engine to a carburetor and standard SBC distributor arrangement. For a streetrod such as yours, I would stick with the LT-1 heads, use the LT-4 Hotcam or possibly a Comp Cams 218/224 Extreme Energy cam, and the GM Performance Parts 4-bbl intake. For headers, you will need some that work with the SBC D-port heads and angled spark plugs. As long as they meet these criteria and fit in your car, any SBC header will work fine.

Just my 2 cents...

Brian

[wako29]

Originally posted by Brandon94za4
I had the hot cam in 94z and it was very streetable, it is a good mild cam. It sounds good too!! I wouldn't go any smaller than a hot cam. If it were me I would just do a 355 rebuild, I wouldn't mess with stroking it because you said you werent too worried about it being balls out fast. You will def want to run a comp.
Brandon

wait. Did you run the LT4 Hot Cam, or the Comp one? I am guessing the comp one by the last sentence. Which one did you use (specifically)? I have the newest Summit in front of me, and it shows specific LT1 cams, but just gives specs.

Also, the only rebuild kit that they sell for the 355 is for pre-'86 motors. Should I be using another source other than Summit? What brand is the best? etc, etc, etc.

Sorry for being such a pain, guys

[wako29]

Originally posted by bn_bullet
Another consideration to get rid of the Optispark is to convert to a carburetor instead of the fuel injection. Typically, in a late model car I would prefer to stay fuel injected but GM Performance Parts does make an intake (p/n 24502592) that accepts a standard 4-bbl carburetor (Holley, Edelbrock, Quadrajet, etc...) and an HEI distributor. They also make one (p/n 24502574) that will work with the LT-4 heads if you so desire. Using one of these manifolds would do away with the Optispark but would require you to convert the engine to a carburetor and standard SBC distributor arrangement. For a streetrod such as yours, I would stick with the LT-1 heads, use the LT-4 Hotcam or possibly a Comp Cams 218/224 Extreme Energy cam, and the GM Performance Parts 4-bbl intake. For headers, you will need some that work with the SBC D-port heads and angled spark plugs. As long as they meet these criteria and fit in your car, any SBC header will work fine.

Just my 2 cents...

Brian

good advice, but there is no way we are going to a carb setup. EFI is the whole reason we bought a LT1 . All the other stuff is good, though.

BTW, for the LT4 Hot Cam, it has the option of coming with a kit that has new 1.6 ratio roller rockers, valve springs, valve caps, valve keys, and valve spring shims (no lifters) for $510 versus the $205-240 for just the cam. Is the whole kit worth it, or should I just get the cam?

[bn_bullet]

Also, I think I would stick with just rebuilding it to a 355. This way, you can use the stock crank and possibly rods. If you really want to swap the stock crank out, you could look at a Scat 9000 series crank. You need one that will work with the one piece rear main seal. But, if it were me in your situation, I don't think I would mess with that. I would most likely use the stock crank, SRP pistons, maybe Manley Sportsman series 5.7" rods and call it a day. These are good pieces for the relatively low cost and should be more than strong enough for the hp levels you are looking at.

Again, just my 2 cents.

Brian

[bn_bullet]

The LT-4 Hotcam kit is a good buy. It ensures you are getting the right parts and is a bit cheaper than purchasing new parts seperately. Unless you want more horsepower than the Hotcam can offer or really want to go to non-self aligning rocker arms, then the kit is the way to go.

BTW, good choice on staying FI but it unfortunately means you don't have alot of option in the distributor department other than the Optispark. You could look at the LTCC or Dyna-spark for a slight improvement but I think the cost of those items prohibits most people from using them. Personally, I have not had a lot of trouble from the Optispark on my car but everyone's experience with it seems to vary.

Brian

[wako29]

Originally posted by bn_bullet
Also, I think I would stick with just rebuilding it to a 355. This way, you can use the stock crank and possibly rods. If you really want to swap the stock crank out, you could look at a Scat 9000 series crank. You need one that will work with the one piece rear main seal. But, if it were me in your situation, I don't think I would mess with that. I would most likely use the stock crank, SRP pistons, maybe Manley Sportsman series 5.7" rods and call it a day. These are good pieces for the relatively low cost and should be more than strong enough for the hp levels you are looking at.

Again, just my 2 cents.

Brian

hm, good advice.
However, I like to get those kits because they include all the misc. little stuff (i.e. bearings, gaskets, rings, etc.). I take it that no one has any experience rebuilding a LT1?

[bn_bullet]

wako29,

Check this link out:

http://www.cmotorsports.com/93-97-fb...ml#engine-kits

They have LT-1 engine rebuild kits with everything that you need. I have never ordered from them but several people another message board I visit have had very good luck with them. They have packages from the budget rebuild to the all out race motors. Maybe this is what your looking for? I have rebuilt my LT-1 but I chose to build mine with the pieces that I wanted and did not use a rebuild kit. I really couldn't find one that had everything that I wanted in one kit without throwing half of the kit away. But your situation may be different.

Brian

[wako29]

anyone else have anything to add?

[pete]

I went with the L-4 Hot cam kit set up, and so far am very satisfied, since my car is a daily driver.

Coolant leak on the opti-spark can be held off by adding a hose to the weep hole of the water pump and routing it to a safe location.... simple easy to do, drill a 3/16" hole in the existing weep hole of the pump, push in a 90 deg. 3/16' elbow, and a couple of feet of 3/16" hose, cable tie the hose away from the belt and to the frame or other spot where you could see coolant comming from.

[wako29]

Originally posted by pete
I went with the L-4 Hot cam kit set up, and so far am very satisfied, since my car is a daily driver.

Coolant leak on the opti-spark can be held off by adding a hose to the weep hole of the water pump and routing it to a safe location.... simple easy to do, drill a 3/16" hole in the existing weep hole of the pump, push in a 90 deg. 3/16' elbow, and a couple of feet of 3/16" hose, cable tie the hose away from the belt and to the frame or other spot where you could see coolant comming from.

wow, never heard of that solution for the opti-spark. You wouldn't happen to have any pics laying around, would you? j/w. Also, thanks for the affirmitive on the cam