Hi all. I just became the lucky owner of an 86 roadster. I bought it knowing that there had been an overheating problem and coolant in the oil. My fears were confirmed today when the guy at the machine shop called to let me know that BOTH of my aluminum heads are cracked at the center bolt, and warped at least .025". My thoughts are: Replace heads and hope the bottom end is ok(102k), swap in an LT1 complete from a donor car, buy a replacement motor at the local auto store and swap on the TPI stuff, or ?. I am looking for advice and/or suggestions. I would like to keep the project cost below $2000, and not too keen on rebuilding my current bottom end. TIA

Ron

 

Buy a set of aftermarket heads and bolt em on.

 

Would it be safe to assume the bottom end is okay? The machine shop guy was concerned that the rings might be seized on the pistons due to the probable excessive overheating. The piston tops are clean, and the bores look good with no "lip" wear. I just don't want to buy new heads, install them, and then still have to pull the block. But if the consensus is the bottom end is probably good, I'll be more than happy to not have to pull the entire motor. If this is the route I take, are there any suggestions on heads, and would a cam replacement be worth the $100-$200? Cam suggestions?

Ron

 

Since it had coolant in the oil and the pan will have to be dropped, have the mechanic pull a main bearing cap and look at the bearings, and pull a rod/piston assembly and check the bearings and the rings. While it's in this state, it would be pretty easy to replace all the bearings. Could even do a little ridge reaming and file-fit new rings. If you don't want to go through all that, just slap some heads on it and hope for the best.

 

With the state of the heads and the fact that there was coolant in the oil and 102,000 miles on the stock engine I would be worried about the condition of the rest of the motor.
If you wanted to try just replacing the heads you could watch the parts for sale section and watch e-bay for a set of factory aluminum heads.
You can find the 88 and newer aluminum heads with the inproved D-port exhaust now and then at good buys.
As far as a cam change goes if you are changing the cam yourself it is a good project that I enjoyed but it is pretty involved and you will more than likely pay a shop dearly for this work.
Good luck and welcome to Corvettes.

 

Yes, buy a set of AFR 180s (about $1200 new). If your shortblock is damaged, rebuild it or just replace the rings, bearings, and oil pump ($200 to $500 in parts). An LT1 swap will quickly get out of hand, in terms of time and money. And you don't want a 185hp parts store replacement engine with 8.5 to 1 compression.

 

Why not consider doing the whole motor??? The L98 is a solid and strong mill. Bogus just did a complete rebuild for $2000 so he can lend a hand in the info dept. My take is why do the top end now only to have to tackle the bottom end in due time? If you can get it done in one project, it makes more sense to me.

 

Many thanks for the quick replies!! It really seems like a very strong corvette family here.

OK, based on the some the replies, how does this sound.

Pull motor, replace main bearings, rod bearings, new rings, new oil pump, new/good heads, go ahead and do new lifters, push rods, possible cam. What are my chance of not needing machine work on the block? Anything I'm missing? With this work, i guess the motor should be good to go for another 100k. I don't really want a "race car" but something very streetable and low maint.


I'm trying to put together several possible solutions, obviously some at different budget levels, plus I am kinda excited to get the car on the street

 

One more question. What is the benefit to deleting the EGR system, and what all is involved in it. It seems that if it is not a problem, it would simplify the re-install of the top end. I will be removig the AIR pump, and cats too.

Ron

 

in consideration of the problem:
crack heads
coolant to oil
age of 100k

i would have to agree to have the entire engine rebuilt..it would cost a little more now. consider new edelbrock performer heads..(afr are have production problem and are hard to get). the crank may need polishing, new bearing throughtout. timing chain and gears, have new cam installed (a mild performer) new lifters, push rods, roller rockers, oil pump,have rods sized and checked. with 100 k it will need over sized piston, use 345NCP piston hyper's..flat top telfon coat on skirts, .020" OS , good set of chrome moly rings, may have to deck block depending on surface condition.gasket set ..in light of cost, probably abit bit more than bogus becuz you need new heads..

there is another way...cheaper if you perfer..chey bowtie drop in .. about 1500- bolt the intake tpi in basically your done. you may want to check crate motors as well..

emissions, egr, cats can be totally removed. this was successfully done on both of my rags. improved fuel mileage, and power. considerably. air pumps eliminators clean up engine compartant and have been stated as a few hp gains.. there are some in the for sale section. i hope this helps

 

Something to consider... pick up any mass published car magazine and find an advertisement for PAW. Last I looked, they have a full rebuild kit that replaces the crank, cam, pistons, rings, rods, bearings, and everything else involved for $800-1000. If you do the work yourself you cna save big

I will also add that if the engine overheats, you will need to bore, mill, and deck the block to ensure it is true. PM Bogus and ask him for his advice. There were several members here that helped him with his project so there are a few of them that know what you are up against.

We are a pretty close knit group. We all share as much info as possible... and some of us like me are smart a$$es too.
Welcome to the addiction and good luck

 

Well, after some thought and some much appreciated advice, I have decided to find a decent set of used L98 heads and throw them on. Hopefully the bottom end will make it thru the season, and I will pull and do a full rebuild this winter. The wife is kind of pressuring to get the thing running for the spring/summer season. Many thanks to all who helped, and I will be posting again soon.

Ron

 

Most of the costs will be labour, that's expensive! So the difference in price I would go for new heads, it might save you more than one might think.

 

I will be doing all of the labor myself(except machining), so labor is not too much of a concern. If I go with new heads, what do I need to look at? I have been away from building american cars for >10 years so my memory is quite foggy on what I need to consider. I am assuming I need to stay around a 58cc chamber, and 1.90/1.50 valves, what else needs to be taken into consideration for a mild street car running the factory TPI? Is there a decent aluminum head out there for $800-$1000 that is complete, if so, point me in the right direction!

Thanks!!

Ron

 

Well everyone is great that I can say, Have recieved more help on this car site than any other, But the L98 is a SBC, I have had coolant in the Bottom of a SBC with 120,000 miles on it. Pulled the heads had them resurfaced. Put them back on drained the oil filled and went another 130,000 miles. A SBC is a SBC just because it is in a vette doesn't mean you have to be a car Hypocondriac...

 

Ron, where are you in KY?

 

Hi, gang!

Blown L98s is my new speciality!

First off, sorry to hear the heads are crap... but, if the heads are THAT far gone, and there is coolant in the oil, the rotating mass is junk.

Once coolant mixes, especially for any period of time (long enough for the heads to warp that much!) the bearings and crank have been eaten. Too late. Done. Finished.

As for options:

Rebuild the L98 yourself. I did. It's fun and easy. The hard part is getting the motor in and out. A suggestion, remove the hood, then take the engine and tranny out as one.

I did a 87 L98 for just about $2000.00, so yes, it can be done. Just find the right machine shop.

I will promise you that the block will need to be bored, and decked. If the heads warped, the block can't be very pretty.

I actually like the LT1 swap. If you have the engine, harness and ECM, why not? Some of the electronics might be tricky, but it can be done.

 

So how is this done? I know someone who is ready to do a L98 rebuild...

 

Yea... right out the front.

It's how I will do it when I do my LT1. It's a bitch to realign the transmission and such inside the car.

 

Bogus, do you have to have the car on a lift? or did you use an engine hoist and pull both up at the same time?

Thanks...