Complete teardown and rebuild... what are your suggestions?

[BeastV6]

Ok.. looks like we've decided to go ahead and pull the motor and tear it down completely and rebuild it. What are any suggestions for this?? With your replies keep in mind that I got the car just a few days ago and this is all pretty much a learning experience for me. I don't know much about the performance options for these cars, except what I've read in the Poston parts catalog that the seller gave me. I'm thinking I'll start with a rebuild kit from that catalog. Here's a rundown of the parts that come with it (straight out of the catalog):
High performance forged pistons, street/strip moly rings, GN 110T cam, high-rev lifters, high perf valve springs, high perf cam buttong with spring, high perf cam bearings, full gasket set, rod bearings, main bearings, brass freeze plug set, and high perf double roller timing chain set.

Now I know what about half of that is ... It seems to be a decent set. Anyone have experience with the GN 110T cam?

What other things should I look into while the engine is out and apart for this rebuild? How much should I bore the engine over? Any and all suggestions/advice please. Thanks.

 

[cool 84]

Bore it over as little as possible. It looks like a good start. What are the specs on that cam? For a stock to fairly modded motor, something from a 200-200 to a 210-205 are good. Stock crank, rods, and block are good to the 10s. The forged pistons are good insurance. Run stock steel shim headgaskets with ARP bolts. Beadblasting the oil pump gears is cheap and it will boost pressure a little. Try and get the oil pump gear to bottom cover clearance to ~.001. This will make a big difference in oil pressure. Make sure main and rod clearances are tight and within stock spec. Don't build it loose like a Chevy or you will have a motor that will wear out in 10,000 miles. Unfortunately that's how 99% of the machine shops will build the motor without your input. I've had some flat out refuse to build it that way. 90-no more than 100lb valve springs work good. If you have the money, while the heads are off, at least do a little bowl work and port matching. The intake is easy to do yourself and is a big restriction. Porting the runners makes a big difference. I polished the beams on the rods myself and got rid of all the casting marks on the crank. I'm sure there's a lot I'm forgetting but that should help a little.

 

[BeastV6]

Originally posted by cool 84
What are the specs on that cam? For a stock to fairly modded motor, something from a 200-200 to a 210-205 are good.

The GN 110T is a 212-206. I wanted something even a little more agressive than that. Here's the thing with this car... I'm splitting this project 50/50 with my dad. He wants a show car, and I want a race car. We're going to have to make some very interresting compromises, but I think it's gonna be a sweet car when it all comes together. As far as internals go, my dad doesn't care, as long as it's streetable.

Don't build it loose like a Chevy or you will have a motor that will wear out in 10,000 miles. Unfortunately that's how 99% of the machine shops will build the motor without your input.

I've read this (the last few GMHTP's have been really helpful). I think I'm actually going to end up sending my block and heads to Jack Merkel (the guy that got the 3 part feature in GMHTP: May, July, Sept 2002) to bore the block, then port and o-ring the heads.

If you have the money, while the heads are off, at least do a little bowl work and port matching.

As I said above, the heads will be ported and o-ringed. I'm taking my time (and money) with this build. If I'm lucky it'll be running by the end of the year. Before the engine goes back in it will be fully balanced and blueprinted as well. Anything else you always wanted to do but never wanted the hassle of pulling the engine for???

Thanks for the reply, cool 84.

 

[FJM568]

Since no one has asked yet, I will...

Is there any reason why you want to rebuild the motor??? ie, does it not run right now??? rod knocking, lifters ticking, major mechanical problems???

The reason I bring this up, if the motor is mechanically sound and the cam is still good, leave it alone...That cam is the same cam that can take the 86/7 GN/TRs deep into the 11s...And GM did some kind of voodoo magic on these motors when they built them to have them stay together under a lot of abuse that after a rebuild never seem to want to stay together...

If everything is still okay, just replace the timing chain with a stock replacement from Autozone, O'Reilly's, etc., change the valvesprings to either CC979 with the stock cup or CC980 without the stock cup, do the 87 ecm upgrade, put some 009's or 50# injs on, bolt on a TA33 turbo, tune it in with a scantool of your choice, crank up the boost and kick some butt...

These cars don't need a lot of internal work to get them to run decent times...Buick actually did some things right(except the intake design on the hotairs, but that's another thread )...This ain't no CHEVY!!!

Then when it blows up at some point down the road, then do a rebuild...

Just my .02

 

[BeastV6]

Originally posted by FJM568
Since no one has asked yet, I will...

Is there any reason why you want to rebuild the motor??? ie, does it not run right now??? rod knocking, lifters ticking, major mechanical problems???

Actually no, the engine is not running right now. I bought it partially disassembled. The previous owner had blown both head gaskets the day he got the car. He replaced them, but didn't finish the job and never put it all back together. Currently the heads aren't bolted down tight (though they are held loosely by some ARP bolts), the headers are unbolted, all the vacuum lines are cut or disconnected. The turbo is just kinda resting there, the radiator hoses are removed, and all the accessories (a/c, power steering pump, etc) are sitting in the trunk. I had planned on putting it back together then seeing how it ran, and rebuilding later down the road if it was necessary. However, after the car sat in my garage for a day and a half, I pushed it out today to clean all the dirt off of it, and I found two medium sized puddles. One was oil, the other was transmission fluid. This didn't look too good. Furthermore, this is a project car for me, and if I'm gonna do it I want it done all the way. Should be alot of fun too.

 

[cool 84]

A 212-206 will make enough power to scare you. The stock cam has gone into the 10s. I definately wouldn't go any bigger. I had a 206-206 in the old motor and it would rev to 5,500 and never lost a street race. Anything over 5,500rpm is asking for trouble.