New to me 86 GN

[Turbo Zach]

It may have a weak cylinder. So move on to the next thing to check with that in mind. Don't worry about rebuilding the turbo until you are sure the engine is up to snuff. If the turbo is shot for some reason? Stock turbos come up for sale often cheep. Go through the spring cleaning guidelines. No sense in spending a bunch of money until you know what you got.

 

[kornball426]

It may have a weak cylinder. So move on to the next thing to check with that in mind. Don't worry about rebuilding the turbo until you are sure the engine is up to snuff. If the turbo is shot for some reason? Stock turbos come up for sale often cheep. Go through the spring cleaning guidelines. No sense in spending a bunch of money until you know what you got.

I'm wondering, assuming it is a problem with that cylinder, if the engine can just be honed and install fresh rings. Of course there's no way to really know that without taking it apart to see how the cylinders look. Think I'll try to borrow a bore scope, or buy a cheap one, and have a look in that cylinder see if there is any visible signs of abnormal scoring/scratches, or wear on the bore. I'm trying to be optimistic right now and hope that the compression will come up on that cylinder with some miles on the engine to "blow the cob webs out" as they say.
I think the engine was rebuilt at some point, I'd be pretty stoked if I find out it's got billet main caps lol.

If the weather wasn't so gross today I'd go out and hook up the scanmaster and start going through the different functions and adjust the sensors, but I really don't feel like it, it's cold and damp.

I did install the power logger on the ECU and put it back in the car, and fired it up just for a minute. Runs terrible, will idle but doesn't want to rev whatsoever, some smoke out the exhaust (which I suspect is from the turbo). However it does start right up immediately which is encouraging lol.

 

[Turbo Zach]

What is the oil and fuel pressure reading? If you think the turbo is bad? Take the intake tube off and inspect impeller. Feel how much up and down play and in and out play. If you think it is pumping oil into the intake? Take the up pipe loose and look for oil in the pipe. Don't worry about fixing things until you know what you got and were you stand. If you start fixing it before you assessment you might end up with a bunch of money in a pyle of sh*t!

 

[kornball426]

What is the oil and fuel pressure reading? If you think the turbo is bad? Take the intake tube off and inspect impeller. Feel how much up and down play and in and out play. If you think it is pumping oil into the intake? Take the up pipe loose and look for oil in the pipe. Don't worry about fixing things until you know what you got and were you stand. If you start fixing it before you assessment you might end up with a bunch of money in a pyle of sh*t!

I literally only ran it for like a minute just sitting idling, oil pressure was good, I don't know why it seemed low to me before because it was sitting at about 25 psi at idle cold, the little bit I could rev it up (just a hair off idle) it climbed to like 40 psi. I'll have to get around to hooking up the scanmaster or getting new fuel pressure gauge to tell you what the fuel pressure is, as the hood mounted fuel pressure gauge that's on there doesn't work at all, just sits at zero which is obviously wrong or it wouldn't run at all.

And yeah I should pull the intake tube off the turbo and see if the impeller is really wobbly. I'm getting very little done at a time on this thing, just an hour or two at a time, once or twice a week.

 

[Turbo Zach]

Is the car at your home? If not that would make a big difference. I have young kids and I am a Heavy Equipment Field Mechanic, so I know all about not having the time or want to work on the old car. I set small goals and try to do a little each day until the project is done.

 

[kornball426]

Is the car at your home? If not that would make a big difference. I have young kids and I am a Heavy Equipment Field Mechanic, so I know all about not having the time or want to work on the old car. I set small goals and try to do a little each day until the project is done.

I work nights, so my days I'm usually asleep till it's time to get ready for work, then when I get home it's dark (need to move the car inside so I can work on it at night).

Another issue is I work in a restaurant so I have to be careful not to go in with dirt under my nails or anything like that lol. So basically I get a bit of work in on it on Tuesdays and Saturdays if it's not raining or freezing (again, need to move the car inside, but I have like 7 project motorcycles in there at the moment).

 

[kornball426]

So, as I already kinda knew without confirming... The turbo on the car is wasted. Has like 2 mm of up down, side to side play in the compressor wheel. now the question is, what the hell is this turbo?

I posted pics of it before but will again if need be. It doesn't have a bolt on neck/Venturi going into the compressor. I haven't taken it off and measured the compressor wheel diameter but it's clearly bigger than stock. I think 60 or 62 millimeter just by looking at it. Only identifying markings I can see on it are "Precision" cast into the turbine (hot side) housing, and A/R .70 cast into the compressor housing. No ID tag or model number.

My brother is trying to tell me precision is junk... I don't really respect his opinion because he's an idiot, but is he right? He's trying to get me to buy a 62mm turbonetics. I personally just want to rebuild this turbo and run it if the parts are available... Assuming I can figure out what the hell it actually is.

 

[fleming442]

Maybe you could just call their tech line and ask? 🤔
https://www.precisionturbo.net/contact/

 

[fastNYsix]

There will be a small amount of up and down play with a journal bearing turbo. There should be no in and out play. They are not hard to rebuild. As long as the compressor wheel and turbine wheel are not damaged, and didn't rub on the housing. Does it spin freely by hand? If there's no signs of damage, I would rebuild, save some money to spend elsewhere.

 

[kornball426]

There will be a small amount of up and down play with a journal bearing turbo. There should be no in and out play. They are not hard to rebuild. As long as the compressor wheel and turbine wheel are not damaged, and didn't rub on the housing. Does it spin freely by hand? If there's no signs of damage, I would rebuild, save some money to spend elsewhere.

Yeah it spins freely give it a little flick and it'll go around once or twice. I'm no expert but it seems pretty sloppy, not just a little bit of play, but a lot.