1995 z28 convertible no special mods just a K&N CAI 160k on the body, 100k on the motor (so I'm told)


Well I just traded my truck for this car from a buddy who took it to a mechanic that we both know very well. the original problem was that he could smell oil burning and it would be about a half quart low between oil changes. sounded like a simple intake gasket leak to me, pretty common right? then comes the fun part.

I go up to the shop and they were putting back as I got there in my Z and I asked "wtf is wrong?" (ran fine going up there) they said "Idk I think the head gasket is leaking now, I just went and pressure washed the motor to try and find the oil leak" im thinking WOW, MORONS. so now it will idle sometimes other times its pretty rough, it has like NO ***** compared to what it did before. it still gets up and goes but won't throw you back in the seat anymore. does anybody have any suggestions as to what you might think could be wrong? it sat for 2 weeks and tried it again and shes still runnin kinda rough. also sounds like timing is off hear kind of a knock in the exhaust.

sorry for my run-on's I hope most of you can decipher my chicken scratch and help me out here. thanks in advance.

 

Pressure washing the engine could be the source of the issue. Try soaking the spark plug wires and opti cap with wd-40 to see if it runs better. Just spray it on and let it soak in a while then start it up. If it runs better them replace the wires and opti cap.

Another place to look is the short harness going to the opti found along side the intake manifold. He probably had it off to fix the leak. Check the connector for corrosion or bent pins and seat it fully....

Good Luck!

 

You could have water intrusion in nearly any connector. Injector clips don't like water in them. Certainly the distributor doesn't like water in it. If it did get in the distributor, you may never get it out. A carefully positioned blow dryer might help there.

 

the irony of it all was that they didn't even fix the car, just said that it needed a head gasket, intake gasket, and a bunch of other crap and wanted to charge over 900 dollars for parts and labor after they messed it all up. just took it to my friends dad. He does a lot of lt1's and hes reasonably priced.

 

Sounds like they soaked the Opti... those and water do NOT get along.

The Oil leak is most likely the back of the intake manifold to the block or a valvecover gasket. Also check the oil pressure sending unit behind the intake as mine cracked as was leaking there.

The stumble/running issue is most likely going to require a new Opti-spark. I suggest a GM/Delphi factory unit; and while you're at it do the plugs and wires.

 

Thanks I appreciate the quick replies. any suggestions on plugs and wires to run? I'm new to the lt1 world and have no idea what runs best with these motors. I see some run NGK's and I had a shop tell me if you run anything but Delco's it will foul the plugs.

 

I ran NGKs and AC Delco's for a while; both ran fine.

My personal preference is AutoLite's though. I just used the regular Copper Ones; and swapped them out once a year.

Wires, I'm not sure who makes a good set now; I'd say you're going to have to do a search on here. (My car has been in pieces for a few years; life got in the way of my car hobby for a little while).

 

You said they wanted to charge $900 for parts and labor. Did you pay anything? I would never let anyone like that touch the car again! I always ask a few specific LT1 questions and if they have no clue, then on to the next guy.

 

No they didn't get a dime. I told the owner to f*** off and he better hope that they didn't ruin the motor otherwise they will be paying for a new one. I didn't originally take it to the shop to begin with. however the place its at now I know its in good hands. my friends dad has been an ASE mechanic for over 30 years and has worked at many chevy dealerships and he immediately told me they probably ruined the optispark, he said that we might be able to just replace cap and rotor but IDK seems like it would almost be better to just do the whole thing while in there ya know?

Anyways car is at his home garage and I gotta take him the gaskets so he can do the intake and ill have to wait for next check for all the ignition crap. lot of money for those damn optisparks.

One last question for you guys since im gonna be having that done, assuming it runs good after. would it be wise to think about putting headers on it? I mean the car does have a lot of miles and I just got it, but I think its something I'm going to keep around for awhile. and I've thought about some performance mods like headers, cam maybe. throw in a slightly larger stall converter.