Motor rebuild tips

[Holdenbr]

So my turbo mechanic went to put my GN on the dyno after changing out fuel system and found valve sticking so he recommends a motor rebuild since we will have the heads off anyway.
I need tips on what to go back with.
This will be for the street with an occasional run down the strip so I want what I can get out of it but still be able to just cruise around.

 

[Phoneguy]

Without knowing any further details of the existing build, I am going to say this is completely ridiculous....
There is a BIG difference in cost to you !!! A sticking valve now requires a rebuild?

Post your location as it is not in your profile.

Bryan

 

[achalmersman]

Yea that's nuts. Plenty of problems have been caused "fixing" problems that didn't exist.

And what is a sticking valve? Is it floating valves? Leaking compression?

Sent from my VS990 using Tapatalk

 

[Turbo Tinkertoy]

You need to ask the turbo mechanic to explain how a valve is sticking after he did a fuel system repair. Why did he do a fuel system repair? I would be suspicious that some dirt got past the filter and is restricting a fuel injector or causing it to leak and run a cyl too rich. You need diagnostic data. compression test, dry and wet (eng must be at operating temp) cyl contribution test, which cyl is weak, fuel or spark or comp, what is plug gap, plug wire ohms, spark plug brand and number, are there exh leaks ie; cracked man flange leaks turbo gskt) egr working, cat plugged, o2 sensor efficiency, maf....clean it, check breather tube for cracks in hose connections, vac hoses leaking, pcv, scan comp for codes, fuel psi, when was your last oil change and which oil did you use. All these things must be verified before you condemn the eng and tear it down. Good luck on your car

 

[Pronto]

Is it sticking because it's bent? If it kissed the piston there could be other issues that would make rebuilding needed. You need to be more specific with your goals for the car. I would say go roller with the cam if it's not already. Ported irons are always good to have.

 

[Holdenbr]

I am in the Tulsa, Ok area. The fuel system replacement consisted of higher psi injectors and fuel pump because since it has 60mm Garrett turbo it was running very lean on the dyno. This has been an "issue" car since I bought it. Previous owners have done numerous "work arounds" instead of proper repairs as well as making modifications on a tight budget that have been failing. I have been working to get this back to reliable for a couple of years now. He told me he could just replace the valves but since the heads will be off we might as well do a warrantied rebuild. I would like to be able to drive this car without having a tow truck on speed dial which has been the case since I have owned it. It has more miles vertically then horizontally. I love this car and want to feel confident I will make it to my destination when I get behind the wheel. This car has had a "tick" since I owned it and just assumed it was the exhaust manifold leak since it would pretty much go away after it warms up. Now that the exhaust leak is gone since gaskets are finally on the exhaust manifold instead of high temp silicone, which apparently what was there before, the tick is more prominent and will not go away after it is warmed up. The engine has 106,000 miles on it since I found out the claim of a rebuilt motor was a lie by previous owner. As I have state in previous posts I do not have much mechanical acumen so I have to rely on others to tell me what this car needs. The mechanic has a shop full of turbo cars, albeit the are Japanese and he seems to know what he is talking about and I trust him. I'm OK with the money part but need help on what I should ask him to upgrade while he is in there.

 

[~JM~]

I think you need a second opinion.

 

[Pronto]

I would seek out an experienced TB mechanic in your area.

 

[Boost231]

Can you tell me more about these "high pressure injectors" who's chip? How much fuel pressure? What regulator?

 

[Holdenbr]

After reading your replies I am thinking it would be prudent to pick up the car and do some more research before opting for a rebuild.
I believe a second opinion is a good idea.
I have a line on a TB mechanic who also owns an 87 GN in the area. I believe that will be my next course of action.

 

[Pronto]

Start a new thread with all the mods you have and all the symptoms you have had since owning it. It will be easier for guidance.

 

[dynoman]

You should have come on here asking questions a couple years ago , it would probably be running great by now ! This board will be your best source of Turbo Buick knowledge period !
With that said , do as Boost231 & Pronto said but when you list mods be specific , as in 255lph fuel pump instead of just "fuel pump" or 40 lb injectors instead of "high pressure injectors" . I'm sure you get my point , this will help us with your problems and get you pointed in the right direction . Good luck , Sam