Its been a long while since I posted in these forums, and I long while since I raced the little LT1.

My buddy just bought an LT1 T/A and ran a 13.7 at the track, well we raced and I barely beat him. My car ran a best of 12.9 LONG ago.

I need opinions here, my car now has 90k miles with stock tranny. Ive beat it to hell from 30k to 70k and it seems like its been slowly going down hill since then. Is it time for a motor rebuild?

It blows alot of black smoke if I dont "open it up" every now and then. I want to get my car back to its prime.... if possible.

As for maintaince, oil changes are regular. And know matter if I change it at 5000 or 3000 the oil is always pitch black (mobil 1). Ive done the opti twice, once about 10k ago (or less than that). Plugs were some expensive delco plugs about 20k ago. Wires were down about 40k ago. PCV is something I need to check.

Also, I have pacesetter LTs. I removed the AIR but I still have the EGR on the intake, I never blocked it off, is this affecting anything?

Sorry I'm a bit rusty as its been a very long time since Ive worked on my car.

Basically I need opinions on what else do I need to do or test to make sure my LT1 does or doesnt need a rebuild. Is 90k normal for a rebuild? Im surprised my tranny has lasted this long and still shifts hard like it does. I appreciated anyone who takes the time to read this and teach an old dog new tricks.

Thanks,
Robert

 

If theres no blowby, I'd just keep driving it. 90k isn't bad for an LT1 and if you're worried you can always do a compression/leakdown test.

 

I plan on doing a leakdown test. And I wont want to just drive it, I want to consider heads/cam and If I possibly need a rebuild. 355 with forged pistons/rods

Really just look at a mild street/strip setup. something for mid to low 12s

 

90K isn't necessarily time for a rebuild. If you are blowing out black smoke, I would suspect you are running rich and that could account for the lack of power. I would also check the car over for exhaust leaks, check the plugs again, and it may be time for some 02 sensors.

 

Well I dont really dont open her up on the street. I talking i didnt go WOT for like 8k miles and the first couple of times I finally cracked her open it was pouring black smoke. Now it doesnt do it so much, but does every now and then.

Ive changed my 02s twice since 28k. First was with bosch and they went out very quickly. Then i put some high quality delcos in it, im sure they're good.

I should probably do a seafoam on it?

Is replacing the valve train smart? Worn on springs? seals? Maybe even throw some RR's while im at it

Also I really need to clean my engine bay. Is it possible to cover up the opti and carefully was everything?

 

im sure its not your motor, mine has 145k on it and still fine with compression and such
do you have any way of scanning for codes?
you c ould have an 02 sensor out, or maybe your cat went out throwing stuff off, its hard to say without scanning it

 

A topend refresh would probably be a good idea with that mileage. My car is in need of one at this point with 95K. I'm gonna do everything though, LE2heads/cam, lifters, rockers, pushrods, ect.

 

Nice exactly what I have in mind.

Only thing ive been worrying about is, somehow the car got slower over time. Ive had 3.73 gears in it since i dunno 50k miles maybe. So for the past 40k miles its been cruising at really high RPMs on the highway, thus in my mind wearing out the motor much faster.

I think my 02s are fine, the gas mileage went down a little bit, but not horribly. No check engine lights have been on.

 

ttt

 

Hi guys,
this is my first post ever (somewhat unrelated buy w/e ). anyways, as for the 3.73 gears and revving higher on the highway, that wouldn't contribute to motor wear because it's actually easier on the motor to have the lower gear ratio. the "load" or "resistance" (i.e. the car's weight) is easier to move at a higher rev (exactly why we downshift if someone is in the way and you want to pass on the right ). OK, in conclusion, the increased rev's wouldn't wear the motor out faster, ESPECIALLY @ 90 000miles.

 

Interesting, any material on paper about that subject?

 

check your valve springs
at 20k I had 35lb. of seat pressure

 

There is a very good possibility that the valve guides are worn, and you are burning oil. That should be blueish smoke, but you need to have some one else drive your car in front of you during the day and have them go WOT a couple of times. The valve guides wear out on these cars in no time, as little as 20K. The valves are not going to wear out and drop in the engine or anything, it's just that they wear in a good amount of clearance, and after the seal wears out oil starts to drip into the cumbustion chamber. That's why, one of the features of, a premium clyinder head uses bronze liners, instead of the factory just leaving them aluminum. Even if you pull the springs off and just change the seals the problem will come back after a few thouand miles. There is also a very good possibility that there is nothing wrong with your short block. Do a compression test, and leak down test if you have the time or means, before you take it appart and document your results. If it ain't broke don't fix it, but there is nothing wrong with taking it appart, cleaning it, and reassebleing it (meaning gaskets only). Most people can't help them selves and start finding excuses to buy more stuff. Sounds cool but it starts cutting into your cam and head budget fast. Before you know it that couple of hundred anxious dollars could of been Ti retainers, or a timing chain set, or any number of things you would like to do or have.
It mainly depends on what you want the car to do. I did a budget 355, I think the short block came in at arround $2,500 machined & out the door. There are way to cut corners even on this price, I just don't see how people can use that eagle stuff .
Good luck with the project. If you need help, we'll be here