Any reliable corvette shops in the CA bay area?

[AyeRon]

Hi, everyone.

Im new to the group, and as the title suggest, I'm looking for any recommendations on mechanics/shops in the bay area that specialize on the LT5 engine.

A little backstory: I picked up a 1990 ZR1 that ran great to my knowledge, until I got back to the house and noticed that the secondary vacuum pump was continuously turning on and off. I took it to my mechanic and sure enough they found a leak. They used a smoke machine and traced is back to the Secondary Port Throttle shaft seal. Unfortunately, the seal is behind the bearing, which they do not know how to remove and they've chosen not to proceed. They'll be putting everything back together for me to pickup.

This leaves me with a few options:
- I find another mechanic that specializes in the LT5's uniqueness.
- I tackle the job myself and risk turning my running car into a parts car
- Decide to drive her at half power FOREVER (not happening)

Any advice is welcome and greatly appreciated. Thanks!

[-=Jeff=-]

I would suggest reaching out to Marc Haibeck. It might be in your best interest to ship the car to IL to his shop. I think the place you took it to does not seem to know these cars..

mhaibeckz@gmail.com

http://www.zr1specialist.com/

[WARP TEN]

I would suggest reaching out to Marc Haibeck. It might be in your best interest to ship the car to IL to his shop. I think the place you took it to does not seem to know these cars..

mhaibeckz@gmail.com

http://www.zr1specialist.com/

I second Jeff's suggestion if you can. Vacuum leaks are quite common, often under the plenum, and that is a fix that is certainly possible for you to tackle yourself if you're handy, as many have. Marc has a very good video on how to remove your plenum and there is lots written here about fixing vacuum leaks. This forum is a huge resource for C4 ZR-1s, with lots of experienced members willing to help.

However, as Jeff says, if you have just bought the car the very best thing you could do for it is to ship it to Marc for a thorough going over. Your ZR-1 is, after all, more than 30 years old. I understand of course that may not be in your budget, but if you plan to keep the car a good while and if you can do it financially, I would strongly urge you to do so. I did that when I bought my 19,000 mile '95 in 2012 and it was the best (very reasonably priced) money I could have spent (although I admittedly live fairly close to his shop, so no big shipping charge to deal with). He changed all the fluids, changed the serp belt (hanging on by a couple threads), checked everything and made sure it was running right. He found issues that I would never have even thought to ask about, and even found a hidden car alarm installed, which I had him remove. When I got the car back it was running perfectly and continued to do so for many years. Until of course I sent it back to him for his 510 HP package and then it ran even better! Good luck with your new ZR-1!--Bob

[grahambehan]

I cannot answer your question re corvette shops in the bay area. But although the port throtte shaft seal leakage is not good, it has nothing to do with the on/off cycle time of the vacuum pump. So you still have a leak in the port throttle vacuum system to resolve.
Graham

[tccrab]

Can't agree with the previous posts more, a trip to Marc Haibec's is in your very best interest.
Not cheap or quick, but it is your very BEST option.

As far as I know, there are NO shops in the SF Bay area that have even seen a LT5 much less worked on one.

That being said, if you're handy, have reasonable mechanical skills, tools and somewhere to work your car, here's all you will need to narrow down what you need to fix and give you a thorough understanding of how/what/where the secondary vacuum system does and how it does it.
https://www.corvetteactioncenter.com/tech/knowledgebase/article/1990-1995-corvette-zr-1-technical-article-lt5-secondary-port-operation-vacuum-diagnosis-482.html

A plenum pull is a rite of passage for many (if not all) a ZR1 owner.

Do not, and I repeat loudly, DO NOT drop your ZR1 off at the local Chevy shop and expect them to know anything about your car.
They will not.
It's almost a guarantee that they will make whatever problem you're having 10x worse.
Only Chevy master techs were allowed to work on the LT5 when new, and even then the policy was to diagnose whatever the issue was, yank the engine and replace it with a new engine.
No mechanic in any Chevy shop was ever trained to address anything deeper than regular tune up items.
30 years later, anyone that was allowed to work on a LT5 is now long retired.

I'll throw this out there, I'm not all that far away (Folsom, CA) and I could make room in my garage for your car for a few weeks.
I'd be willing to take her in for a little while and see if I can perform some magic for you.
Trouble is, I don't have a ton of spare time (am still working full time, *this close* to retirement but not there yet) and it might take a little while to diagnose and then acquire the necessary parts to effect the repair.
Nothing would happen overnight, expect the entire process to eat up a lot of Spring and maybe into the Summer.

Just so you know, the "BrotherHood of the Beast" is alive and well.

'Crabs

[AyeRon]

Thank you everyone for the quick feedback!

I was hoping there may have been something locally, but I think you all may have pursuaded me to give Marc a call tomorrow.

After going through what I went through, I would rather have someone who understands the ins and outs of the car taking a look. I also seen that he has quite the catalog of services outside of engine work, so this may be the best route.

While on the subject of shops, does anyone recommend any body shops that can repair a urethane bumper? Upon receipt of my car, one of their employees also ran into a lift which cracked the bumper under the turn signal... They're taking care of the expenses to fix, but I would rather stay away from an aftermarket fiberlass bumper to keep it as original as possible.

- Aaron

[Z51JEFF]

I'm in Fremont,what part of the Bay Area are you in?

[Z51JEFF]

As far as I know, there are NO shops in the SF Bay area that have even seen a LT5 much less worked on one.Crabs

Precision Motive in Hayward has worked on ZR-1s in the last. They put the auto trans in the Steel Blue Shinoda body car.

[AyeRon]

Hi Jeff,

Im actually in Fremont too. I gave Marc a call quickly after these messages and have been put on his waiting list. After speaking to him, I realized that it wouldnt be a bad idea to have him sort out a few other items while its in his possession. I do appreciate the recommendation, and I will definitely keep them in mind as a secondary option.

-Aaron

[Z51JEFF]

Hi Jeff,

I?m actually in Fremont too. I actually gave Marc a call quickly after these messages and have been put on his waiting list. After speaking to him, I realized that it would?t be a bad idea to have him sort out a few other items while it?s in his possession. I do appreciate the recommendation, and I will definitely keep them in mind as a secondary option.

-Aaron

What year,color is the car?

[Z51JEFF]

There is absolutely no reason the send that can halfway across the Country to have some minor issues takin care of. First off,find out what the issue is and address it it,a vacuum leak at the linkage shaft,if I read that correctly? How did the mechanic come to that conclusion,the car couldn't have been running,did this mechanic know how to activate the secondary system with the plenum off? I'll bitch and moan everytime I've got to work on one of my cars but in reality I'm fortunate that I can do my own work. When the injectors died having someone work on the car was never an option,did the job myself. 20457

20458

[AyeRon]

Hi, Jeff.

1990 Polo Green/Saddle

A vaccum smoke test was done to trace exactly where the leak was coming from.

I appreciate the your thoughts and I do agree, its not totally necessary. I just figured that having someone who works on these cars regularly could also sort out a few other items specific to these c4s seeing as they are a specialist. The Engine, FX3, and Bose system for starters. Im no stranger to getting my hands dirty, but between work/school/life, I do not have the time (or space) to take on another major project myself.

As far as sending it across country. Its really no biggie... I figured the wife and I could fly out to pick it up and enjoy a road trip back home once its gone through.

(BTW, That engine of yours looks great. It is outrageously clean compared to mine haha)

[Z51JEFF]

Hi, Jeff.

1990 Polo Green/Saddle

A vaccum smoke test was done to trace exactly where the leak was coming from.

I appreciate the your thoughts and I do agree, its not totally necessary. I just figured that having someone who works on these cars regularly could also sort out a few other items specific to these c4s seeing as they are a specialist. The Engine, FX3, and Bose system for starters. Im no stranger to getting my hands dirty, but between work/school/life, I do not have the time (or space) to take on another major project myself.

As far as sending it across country. Its really no biggie... I figured the wife and I could fly out to pick it up and enjoy a road trip back home once its gone through.

(BTW, That engine of yours looks great. It is outrageously clean compared to mine haha)

Can't go wrong with Marc H looking at the car. But this smoke test means absolutely nothing when it comes to these cars as far as what your mechanic has described. What exactly is the car doing,vacuum pump constantly cycling? If that's the case it could be a loose,worn rubber fitting at the vacuum pump,cracked line going to the check valve,vacuum tank. There's a few things that would cause the pump to cycle constantly but a leak at the secondary cross shaft doesn't make sense. The amps and or the CDM controller need to come out of the car and rebuilt. The FX3 could be a bad actuator at one of the shocks or a broken gear on the shock. Have the injectors been replaced in the car?