Hi! I have a 1990 TGP with only 76k that was, at one time, my daily driver. It started with a random stalling problem that turned into a non-starting problem that no one seemed to be able to cure so I took it off the road for awhile until I had the budget to fix it right. Well, awhile turned into almost 2 years and now the compression is very low. My mechanic replaced the timing chain as it had some slack in it but we still have very low compression. Any suggestions as to what to look at next?
do you have numbers for the compression levels per cylinder? Did you change the oil before initial start up after the 2 yr hiatus? Try adding a solution called Rislone in place of 1 qt of oil on the next change, it's good for cleaning buildup on rings and lifters.
The front 3 cylinders were at 50. The back 3 were not checked. An oil change was done as well as new plugs and wires.
Something is not jiving. Rockers all nice and tight?
yeah thats probably something Rislone won't fix. If the fronts are that low there is obviously something going on. Did it overheat ever? Burn oil?
Rebuild? Could be anything, but for all 3 to be that low. Warped head/bad headgasket?
The car never overheated, nor did it burn oil. The car ran quite nicely until it started with the random intermittent stalling. Certainly no signs of head damage. I love the car but I'm not sure I want to sink a ton of money into a rebuild.
Coolant in the oil? Oil in the coolant?
The oil was clean when we changed it last week. I'll ask the mechanic about the coolant in the morning but I would think he would have noticed that.
I would verify the compression with another gauge besides the one you used already. ;)
Quote from: mfewtrail on November 11, 2008, 10:19:23 PM
I would verify the compression with another gauge besides the one you used already. ;)
x2, good idea
Compression has been verified at 50 on the front 3 cylinders, 100 on the back 3. In response to an earlier post, no oil in the coolant.
Can the motor be replaced with a standard 3.1 and just transfer the turbo-specific parts, or are there internal differences?
realistically it can be done but there are several major and probably dozens of minor details to deal with. The oil pan would need to be swapped, the oil pump upgraded, intake and exhaust manifolds changed, I'm not 100% on the heads, mainly top end stuff. It's not a direct drop in, but it can be done.
1990 NA 3.1s have different heads, the 91-93 comes with the same head as the TGP.
Quote from: killinprixs on November 12, 2008, 03:22:48 PM
1990 NA 3.1s have different heads, the 91-93 comes with the same head as the TGP.
Just very curious as to I never had the chance to really compare that... How do you know? There's a few things I'm curious about with these engines and the n/a version... I know the cr's are the same. I have a book for a 1990 cavalier and beretta and they both say 8.8:1... which iirc is the same for the tgp, correct?
Quote from: R Dubya on November 12, 2008, 02:44:09 PM
realistically it can be done but there are several major and probably dozens of minor details to deal with. The oil pan would need to be swapped, the oil pump upgraded, intake and exhaust manifolds changed, I'm not 100% on the heads, mainly top end stuff. It's not a direct drop in, but it can be done.
After relaying this info to my mechanic he has decided to pull the heads and see what is going on. Hey, "In for a penny, in for a pound!" I always say! Hmmm..... That may explain why I'm broke! LOL! I'll keep everyone posted on it's progress.
the 511 casting heads were first introduced on the 89-90 turbo 3.1, they are better flowing heads compared to what the aluminum 2.8s and 1990 3.1 NA were using. This cylinder head became standard for the 3.1s after 1990. The combustion chambers were leveled out a little instead of the ridget heart shape found on 88-90 NA heads. Not sure about the compression ratio, i always thought NA was 8.9:0.
The GM shop manual states 8.8:1.
(http://i37.tinypic.com/zjywpz.jpg)
looks like the 2.8s say 8.9:1 and 3.1s say 8.8;1 even tho they had the same 2.8 heads on the first 3.1s?? Must be in the pistons.
Eh who cares about the 2.8... lol.
yea i dont give a crap im pretty sure my 3400 car is 9.5:1.
The compression difference IS in the heads. It's been discussed before. As far as listed #'s, they vary from source to source.
Quote from: killinprixs on November 13, 2008, 08:37:31 AM
looks like the 2.8s say 8.9:1 and 3.1s say 8.8;1 even tho they had the same 2.8 heads on the first 3.1s?? Must be in the pistons.
I thought it was in the stroke
Anyone have a spare engine they want to sell? :icon_cry:
Where are you located? There are several engines floating around for sale.
Just re-ring it, clean up the bores, check tolerances and install some new bearings. Probably cost the same a buying that nasty looking "TGP" engine off ebay.
or go to the local pick a part and get a low mileage 3.1 out of a 93 w body or better yet a 3400 ;)
Or is it using antifreeze? to have all 3 that consistently bad makes me think you might have a bad headgasket? Are you getting bubbles in the overflow tank when the car is running? Someone correct me if I am wrong on this one..........
From my very recent blown head gasket encounter, if you have your radiator cap off and try to start the car anti freeze will shoot out of the radiator. And yes there wil be bubbling in the overflow bottle and consistent air in the system. And mine was a small head gasket blow. LOL
Quote from: cobracmdr on November 20, 2008, 05:34:37 AM
or go to the local pick a part and get a low mileage 3.1 out of a 93 w body or better yet a 3400 ;)
Is the 93 motor a drop-in replacement? Is the 3400? If not, what is involved with either? Thanks!
It doesn't have to be a 93. Any 3.1 from 1989-1993 will work fine. It should drop right in, just swap over your turbo specific parts.
Quote from: TGed on November 20, 2008, 03:32:25 AM
Just re-ring it, clean up the bores, check tolerances and install some new bearings.
Very good idea.
Quote from: cobracmdr on November 20, 2008, 05:34:37 AM
to have all 3 that consistently bad makes me think you might have a bad headgasket?
Exactly what I was thinking. I thought I posted that earlier, but I guess my post didn't go through when I hit submit. Every now and then I get errors on the board when submitting new posts...
Quote from: TGP Nick on November 20, 2008, 06:31:57 PM
It doesn't have to be a 93. Any 3.1 from 1989-1993 will work fine. It should drop right in, just swap over your turbo specific parts.
Very good idea.
Yes nick but a 93 block has stronger cross webbing I think and better head design. If he was to go that route but I'm pushing for a head gasket to be honest. It is a cheep repair if you do it yourself and you don't have to pull the motor, hell you can just replace the front head gasket and see where that takes you, that should be easy.
Ken
I agree the head gaskets are not that hard to do. In my opionon you might as well do both of them if you go that route. And get new head bolts they are cheap and give you a peace of mind.
the better flowing heads on the TGP were specific to turbo 3.1s in 89-90... you find them on 91 --> NA 3.1s. But i agree its probably the head gasket... the car is 18 years old and those gaskets deteriorate, if it hasnt been done before its probably a good idea.
Something I wish I had done was 4.3 vortec v6 swap......I opted for the 3400 because I knew how to do it and it was already setup for front drive. 4.3 I think you just have to redrill the starter holes in the block on the other side. Hmmmmm no more projects Ken!
4.3's sounds like butt, just like a L67. The 660's have a good tune when properly exhausted.