njansenv
njansenv Reader
2/9/10 11:15 a.m.

Greetings all. I bid farewell to my M3 sedan a few weeks ago in a (failed) attempt to reduce my car content. It turned out that the new owner (a member here, and a pleasure to deal with!) of the M3 had a LT1 6-speed C4 available for a very reasonable price but which needed engine work done....

I can't help myself.

A few emails later, and it looks like my father and I have decided to purchase the car together as something of a project/auto-xer, and I was wondering if you could point me in a reasonable direction to learn more about the car, and specifically about the engine.

IF it turns out I have to get into the motor to fix it, I'd love some pointers as to some budget friendly "while your in there" tips. No need (or desire) to get crazy just yet. ;)

The motor has been replaced in the recent past (and may in fact be under warrantee: need to investigate further), so I don't know for certain if it is a 4 bolt mains or not. Opti has been upgraded, FWIW.

Thanks! Nathan

neon4891
neon4891 SuperDork
2/9/10 11:23 a.m.

Hope the warrantee is still good, OR, LSx

njansenv
njansenv Reader
2/9/10 11:49 a.m.

I'm told the LSx swap isn't in fact as trivial as it sounds. The car does have a good ZF "black tag" trans, and I'd like to keep that. (I believe I'd need to locate a T56 to put the LS1 in)

It seems the LT1 is a very good motor in it's own right, but overshadowed by Ellis Juan...

Strike_Zero
Strike_Zero Reader
2/9/10 11:57 a.m.

Optispark replacement??

I've only seen this on the LT1 forums. There are some guys that run this without neery a complaint. . .

Install Information

Hope this helps. . .

Soma007
Soma007 New Reader
2/9/10 11:59 a.m.

What year? What's wrong with it? How was the opti upgraded? When I sold mine in '06 there were not aftermarket opti's available but I hear that's changed now.

When I had my LT1 Trans Am I posted at camaroz28.com a lot. No idea what its like these days but I don't imagine the signal to noise ratio has gotten any better. frrax.com was pretty good too.

All Corvette LT1's came with 4 bolt mains. No telling if the replacement motor did without dropping the oil pan.

The LT1 is a pretty decent motor. Think of it as a fuel injected SBC with a funny distributor.

Bobzilla
Bobzilla Dork
2/9/10 12:00 p.m.

LT4 intake, HOT Cam and rockers.

njansenv
njansenv Reader
2/9/10 12:16 p.m.

I believe it's an OEM Opti, but the later "vented" style. I've heard good things about the HOT cam: good tip. I'm ok with Dodge turbo 4 bangers and some BMW 6's...but the SBC is completely new to me.

I've never even looked at (non C5) Corvettes before this one came along... Nathan

itsarebuild
itsarebuild GRM+ Memberand New Reader
2/9/10 12:22 p.m.

a good cam swap will help. so will headers if it doesnt already have them

even if it isn't a 4 bolt main you don't need to worry about it unless you really try to change the RPM limit. 5 to 6 K is about max for the heads to flow anyway so there really isn't much of a purpose for that in an autocross car.

congratulation on finding a family project. SBC's are pretty hassle free so you should get a lot of time to play with other things!

Gearheadotaku
Gearheadotaku GRM+ Memberand HalfDork
2/9/10 12:29 p.m.

Check out Corvette guru.(was c4guru) Was started by C4 guys with a grassroots way of thinking.

mw
mw Reader
2/9/10 12:49 p.m.

Paint it a different colour! Assuming it's Rob's car you bought.

njansenv
njansenv Reader
2/9/10 1:04 p.m.

:) It was....and I like that it's not a "Red Corvette". (I'm not ready to buy a Corvette twill jacket just yet.)

Good tips here: I've just checked out C4guru...and it looks like a great source. GRM thinking is key! Thanks all, Nathan

mw
mw Reader
2/9/10 1:10 p.m.

You need the jacket! That's step one. Step two is the hat and step 3 is the hawaiin shirt with corvettes on it.

ZOO
ZOO GRM+ Memberand Dork
2/9/10 1:25 p.m.

Nothing wrong with this colour:

Gearheadotaku
Gearheadotaku GRM+ Memberand HalfDork
2/9/10 1:37 p.m.

if you are going for a brake upgrade, do the C5, not the J55. Ask me how I know....

ZOO
ZOO GRM+ Memberand Dork
2/9/10 1:59 p.m.
Gearheadotaku wrote: if you are going for a brake upgrade, do the C5, not the J55. Ask me how I know....

Fortunately for Nathan the brakes have already been upgraded to C5 calipers and rotors. I'd concur with the post, though -- the C5 upgrade is infinitely superior to the J55 upgrade, both in terms of stopping power and cost of pads, rotors, and even calipers.

Stainless brake lines, and a master cylinder bias spring from Doug Rippie also made a huge difference, especially on the track.

patgizz
patgizz GRM+ Memberand SuperDork
2/9/10 2:45 p.m.

definitely hang around corvette-guru.com and not CF.

as soon as i get my tuning right in the spring i'm doing a c6 z51 front brake swap on my 91. think they are something stupid like 13.4" rotors. have everything on the shelf, but my original brakes are still in good shape so i'm hoping to wear out the pads more first.

ClemSparks
ClemSparks SuperDork
2/9/10 2:50 p.m.

I asked for some LT1 discussion a while back and got some good information in this thread FWIW: http://grassrootsmotorsports.com/forum/grm/the-chevrolet-lt1-thread/12156/page1/

I'll be interested in hearing how your project goes!

Clem

vwcorvette
vwcorvette GRM+ Memberand New Reader
2/9/10 3:31 p.m.

I have an LT1 from a Caprice trooper car. 2 bolt main. It's apart now in the garage awaiting a rebuild. Never heard of corvette guru but gonna check it out. HP books makes a good rebuild book for the LT1/4 motors. Good luck finding a kit without pistons however. Seems like most include pistons. Which my motor doesn't need. The originals are fine. Will be putting it into my C3 eventually with the 4l60e. Hoping to get the TCI paddles shift set-up on it someday. Keep us up to date on the motor rebuild. I'm interested in what you end up doing, parts, gaskets used, etc.

Hot cam, intake and rockers for sure.

George

njansenv
njansenv Reader
2/9/10 3:54 p.m.
ZOO wrote: Fortunately for Nathan the brakes have already been upgraded to C5 calipers and rotors. I'd concur with the post, though -- the C5 upgrade is infinitely superior to the J55 upgrade, both in terms of stopping power and cost of pads, rotors, and even calipers. Stainless brake lines, and a master cylinder bias spring from Doug Rippie also made a huge difference, especially on the track.

:) ^ Owner of said vehicle, and a pleasure to work with! We're pretty excited, and will keep you posted. I'm glad to have found a better source than CF forums.

I just about spit my coffee out at the "hat and t-shirt" comment. Gold. :)

Nathan

Apexcarver
Apexcarver SuperDork
2/9/10 6:35 p.m.
njansenv wrote: I just about spit my coffee out at the "hat and t-shirt" comment. Gold. :) Nathan

You mean GOLD CHAIN!

pres589
pres589 Reader
2/9/10 7:28 p.m.

MSD has the Opti-Spark system covered, I think they have everything you need to completely rebuild and improve on the stock ignition. I don't think it's cheap but they seem to be the only ballgame in town, from what I've read in other mags even GM themselves aren't really that great at supporting these things anymore.

Sounds like there are some good support sites out there to steer you in the right direction.

orphancars
orphancars New Reader
2/9/10 10:16 p.m.
vwcorvette wrote: Hot cam, intake and rockers for sure.

If by Intake you mean the LT4 intake....................can't just add that to the LT1 motor -- you need to add the LT4 heads as well -- otherwise the intake ports won't exactly line up.

As an alternative......go here/talk to this guy:

elliots port works

He knows his stuff. It will be easier/cheaper in the long run to have the heads ported and still use the LT1 intake instead of looking for an original GM LT4 intake ($$$$$) or getting the Edelbrock LT4 intake ($$$).

GM HOT cam is still the thing to have, although there are other similar grinds out there.....

Gearheadotaku
Gearheadotaku GRM+ Memberand HalfDork
2/10/10 9:14 a.m.

Yeah, CF turned into a lot of waxers and whiners, not racers and wrenchers. The good guys defected and stared the guru site. It was just C4's at first, but has expanded. Haven't hung out there in a while, hope it's still good.

BoxheadTim
BoxheadTim GRM+ Memberand HalfDork
2/10/10 9:31 a.m.

CG seems to be chock-full of info, something I'm missing on CF. The other forum that seems to have a better signal/noise ration than CF is digital corvettes but I'm keeping an eye on CG with the occasional peek over to DC (I'm trying to learn about, well, C4s mostly as I'm planning buy one if the insurance plays ball).

CLNSC3
CLNSC3 Reader
2/10/10 9:53 p.m.

There should be some good info on ls1tech.com!

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