Help - I need advice. I drove approximately 600 miles over the long weekend and noticed an occasional stumble in my '95 LT1. When I arrived at my destination I was showing my cousin the engine and started it up to describe an odd noise I could not identify. While we were listening and discussing, I noticed the rear passenger side plug bouncing around and concluded the plug was loose. We got the plug out and found it was fine except for exhaust gas deposits on the side of the insulator. Anyway, I tightened the plug and it seemed to help but didn't go away completely. Today I drove back home and the stumble seemed worse except when at highway speed where it was not noticeable. When I arrived home I poped the hood and found the same plug loose again. I also found the front drivers side plug was dancing around as well. I think what I have 2 plugs holes, one in either head, that are stripped. I've had the car a week so I don't have any history on whats been done and when. I've changed all the fluids and put on a new set of tires, but that's been about it.

The question is, what would you do if this was your car? Is Helicoil the answer of should I consider replacing the heads with some upgrades? Also, if I replace the heads, who is a good supplier in central North Carolina. I'm only an hour from Concord and the Charlotte area and there are PLENTY of engine builders in these parts.

 

If it were mine I would probley pull the head and plan to put helicoils in where needed.
Another option while you have them out get some head work done.
Or buy some remanufactured heads

used
http://cgi.ebay.com/ebaymotors/93-97...Q5fAccessories

new
http://cgi.ebay.com/ebaymotors/1994-...Q5fAccessories

reman
http://cgi.ebay.com/ebaymotors/CHEVY...Q5fAccessories

 

Did you try torquing the plugs to spec?

 

First check and make sure you have the right plugs in the engine. Then try to torque them to spec to see if there striped, if they are stripped they won't tighten up, they will spin..WW

 

pull those two plugs make sure they are the correct ones.maybe they put iron head plugs instead of aluminum head plugs. if they are correct get a thread chaser and run it through the threads if it tightens up while doing it stop and get a scope and look closely at the threads. usually if they are cross threaded it will close the up the electrode on the plug. if needed pull both heads and take them to Allison's machine shop there in Asheboro and they will repair the holes by welding them up and retreading them. that way you don't have to worry about pulling the coils out at your next plug change.

 

I did torque them down and they seemed to tighten up ok. I had not however checked to make sure they are the correct plug. That is the first item on my list for today.

Thanks for the help on this. I think what I'll do if they are stripped is pull the heads as Harsh20 suggests and get them welded.

 

Wow, 2 members from Asheboro!

 

I did torque them down and they seemed to tighten up ok. I had not however checked to make sure they are the correct plug. That is the first item on my list for today.

Get NGK TR-55 Double Platinum plugs and set gap to .035 I think you'll like them a lot better than the stock AC/Delcos.

 

there is one other option
get some good platinum plugs and some JB weld
put some JB weld on the plug around the head,let it dry and see if it works.
what do you have to loose, if it works you don't have to pull the heads.When its time for new plugs it will be probley be time for a rebuild,then you can deal with the head or buy new ones.

 

yeah and there are others in Greensboro and all around but I guess they have their cars running right or have sold out.
and they is another guy from Thomasville who has a ZR1 who needed head gaskets replaced.

 

We should plan a get together some time.

Last night when I posted this query I didn't know what I would drive to New Jersey today. I love to bring my Ultra up but I sometimes get stuck in bad traffic on I-95. If you've ever owned a Harley you know how much they LOVE to get in stop and go traffic.

Anyway, I decided I'd pull the plugs this morning to see if they were the proper ones (they were) and went to Advance Auto and bought a new set of NGK Iridiums. I then replaced the 2 that had been loose as well as another that I had pulled previously. Drove to NJ and checked when I got to the hotel. They were not moving with the engine idling so I think they will hold. Maybe I'll luck out and not have to pull the heads after all.

I still have the stumbling problem which I feel when the accelerator is at an 8th of travel or less. I can feel it most when in 2nd, 3rd or 4th with the accelerator pressed just enough to maintain a speed, say like 35 MPH. As soon as I give it some juice it smooths out and accelerates normally. I had a very simular problem years ago on an '84 Clutlass Supreme. I never had a check engine light or any code reported which is the same today. After many techs, the dealership and others, I finally ran into one that suggested pulling the vacumm line from the EGR and plugging it with a screw. Low and behold, problem solved. Since it occurs whether the engine is cold or not, I think I'll give that a try in the morning even though I only have a few miles to drive.

 

Are you serious?

 

Man, I hope not.....In that case why not just use red Thread Locker on the plug , I can guarantee it won't come out....Ever.....WW

 

In our maintenance dept we call it bubble gum, baling wire, and duct tape.
I feel if you can't do it right the first time, when are you going to find time to do it again?

 

I was wondering the same thing.

 

Since you have only had it a short time. You will need to do the visual inspection first. Inspect the MAF screen for debris. Inspect the butterflies for any loose or fluttering. clean the throttle body. replace the fuel filter. seafoam the next tank of fuel. look around the front and rear of the engine for leaks from the intake. (nothing should be wet or damp) then if it doesn't smooth out then hook up a fuel pressure gauge and drive around looking for any anything out of the ordinary.

 

Hey OP, what brand of old spark plugs were in there? Just curious.

 

 

I was thinking, why bother with JB Weld when you could tig the spark plugs in those heads. That'll keep them from backing out and seal combustion gasses in the chamber. Just chuck the heads when the plugs wear out.