So why do I have no compression in #5 cylinder? pics with head off
06-19-2006, 11:43 PM
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So why do I have no compression in #5 cylinder? pics with head off **EDIT**2nd page last post, found a 1" chunk of the ring missing in #5
Okay, I give up, see my previous post here:
https://ls1tech.com/forums/generation-iii-internal-engine/527503-help-compression-leakdown-results-possible-blown-headgasket.html
The car started idling bad, had pressure at the oil cap.
Was smoking constantly white/blue smoke very heavy.
I pulled the plugs and #5 is wet and covered in oil.
Compression test - 5 cylinder was about 30-45 psi, #7 was at 90psi all others were at 160psi (cold)
Leakdown - I'm getting 100% leak on #5 / 80% leak on #7
Coolant in Rad seems to be low, car was never overheated. So I pulled the head off and can't see any glaring reason as to compression, unless the head itself is screwed up. Doesn't look like any holes in the head gasket, and I don't see anything wrong with the rings or walls. Sorry for the big pics... Engine was rebuilt 3000 miles ago.
**removed pictures since you couldn't see the piece of the ring missing anyways**
Any ideas?
Okay, I give up, see my previous post here:
https://ls1tech.com/forums/generation-iii-internal-engine/527503-help-compression-leakdown-results-possible-blown-headgasket.html
Originally Posted by nytoy
The car started idling bad, had pressure at the oil cap.
Was smoking constantly white/blue smoke very heavy.
I pulled the plugs and #5 is wet and covered in oil.
Compression test - 5 cylinder was about 30-45 psi, #7 was at 90psi all others were at 160psi (cold)
Leakdown - I'm getting 100% leak on #5 / 80% leak on #7
Coolant in Rad seems to be low, car was never overheated.
**removed pictures since you couldn't see the piece of the ring missing anyways**
Any ideas?
Last edited by nytoy; 06-21-2006 at 03:12 PM.
06-20-2006, 02:35 AM
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if like the ring theory, and if thats the case i would think you would be burning alot of oil through the exhaust. is that the case?
if the car is on the bottle you could of put a crack in the cylinder wall that may out of sight. i did that along with alot of other **** when my motor detenated on the gas.
if the car is on the bottle you could of put a crack in the cylinder wall that may out of sight. i did that along with alot of other **** when my motor detenated on the gas.
06-20-2006, 06:21 AM
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i think the ring land theory sounds pretty good from looking at that plug pic he posted. looks like it has been burning lots of oil. if it would have been a problem with the head (blown gasket or bent valve) i doubt the plug would look like that.
pull the piston and see what you got...
pull the piston and see what you got...
06-20-2006, 07:24 AM
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Looks like some detonation on top of the piston...and the piston is pretty oily. If it was a cracked ring land, it would also smoke. Something is causing that cylinder not to fire as well...Mostlikely the dead plug but Id pull the piston for sure...Show us pics of the head.
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06-20-2006, 07:38 AM
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Originally Posted by dirty2kTA
if like the ring theory, and if thats the case i would think you would be burning alot of oil through the exhaust. is that the case?
if the car is on the bottle you could of put a crack in the cylinder wall that may out of sight. i did that along with alot of other **** when my motor detenated on the gas.
if the car is on the bottle you could of put a crack in the cylinder wall that may out of sight. i did that along with alot of other **** when my motor detenated on the gas.
The car was burning a shitload of oil, at idle, at high rpms.
I'll post pics of the head shortly. Is it possible that it is cracked and should I have it pressure tested?
I'd REALLY rather not pull the engine out...any other way to trouble shoot it? Could I slap another head gasket on there and bolt down the head and do some compression checks?
06-20-2006, 08:58 AM
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Head pics.
**EDIT** removed pics since they didn't show anything anyways, see 2nd page about chunk of ring missing from #5.
**EDIT** removed pics since they didn't show anything anyways, see 2nd page about chunk of ring missing from #5.
Last edited by nytoy; 06-21-2006 at 03:13 PM.
06-20-2006, 09:11 AM
#12
Looks like #5 has seen a lot of oil, from the looks of it. I'd agree w/ the ring land or damaged piston comments. Looks like the block needs to come out. Call around for some guestimates to repair. I'd have the heads cleaned, decked & tested while you're @ it.
06-20-2006, 10:01 AM
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The engine was rebuilt 3000 miles ago by a local builder that was recommended to me. The heads were also totally redone at that time. I'm going to try pouring gas down the intake and exhaust runners to see if it was a valve sticking open. If it's not, then it either is the headgasket or rings at that point I assume.
06-20-2006, 10:21 AM
#14
What was done as part of the re-build? By the looks of piston #3, your coolant level was probably low. Were the piston rings or pistons replaced during the engine rebuild?
Any warantee on the work? If the heads were done, they're probably ok (& no sticky valve). If it were a head gasket problem, there would be coolant in the oil (milky) & likely white smoke & times.
Any warantee on the work? If the heads were done, they're probably ok (& no sticky valve). If it were a head gasket problem, there would be coolant in the oil (milky) & likely white smoke & times.
06-20-2006, 10:50 AM
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Originally Posted by LS1-450
What was done as part of the re-build? By the looks of piston #3, your coolant level was probably low. Were the piston rings or pistons replaced during the engine rebuild?
Any warantee on the work? If the heads were done, they're probably ok (& no sticky valve). If it were a head gasket problem, there would be coolant in the oil (milky) & likely white smoke & times.
Any warantee on the work? If the heads were done, they're probably ok (& no sticky valve). If it were a head gasket problem, there would be coolant in the oil (milky) & likely white smoke & times.
Didn't have the usual oil milkshake by looking at the dipstick, I'll drain the pan, but I'm sure there is coolant in the oil now, since I removed the head and coolant went everywhere down the cylinders.
The rebuilder was saying it's possible for the headgasket to leak "under" the gasket, so the gasket itself doesn't look like it's torn. So I guess I'll remove the gasket and see if there are any marks showing a sign or trail of coolant going under the gasket. I hope to god he is going to warrenty it, but I doubt it, I'm wondering if he put the rings in wrong and that had something to do with all this.
Thanks for the help.
06-20-2006, 11:14 AM
#16
Originally Posted by nytoy
Just a basic rebuild, light hone on the cylinders, new rings, bearings, same stock pistons. The rad was a little low on coolant, but it never overheated.
Didn't have the usual oil milkshake by looking at the dipstick, I'll drain the pan, but I'm sure there is coolant in the oil now, since I removed the head and coolant went everywhere down the cylinders.
The rebuilder was saying it's possible for the headgasket to leak "under" the gasket, so the gasket itself doesn't look like it's torn. So I guess I'll remove the gasket and see if there are any marks showing a sign or trail of coolant going under the gasket. I hope to god he is going to warrenty it, but I doubt it, I'm wondering if he put the rings in wrong and that had something to do with all this.
Thanks for the help.
Didn't have the usual oil milkshake by looking at the dipstick, I'll drain the pan, but I'm sure there is coolant in the oil now, since I removed the head and coolant went everywhere down the cylinders.
The rebuilder was saying it's possible for the headgasket to leak "under" the gasket, so the gasket itself doesn't look like it's torn. So I guess I'll remove the gasket and see if there are any marks showing a sign or trail of coolant going under the gasket. I hope to god he is going to warrenty it, but I doubt it, I'm wondering if he put the rings in wrong and that had something to do with all this.
Thanks for the help.
My meaning about #3 wasn't that the engine overheated. The burnish mark on the top of the cylinder usually happens because of low coolant. The air pocket created by the low coolant condition starts @ the water pump end of the engine because that is the high point (engine is tilted ). Wouldn't surprise me to see the same mark on #1. Really not a big deal yet, but, an example of why keeping coolant levels topped off is important. Eventually, that hot spot could lead to piston or ring failure.
Under the gasket thing may be posiible, but, doubtfull & you would have seen white smoke & milky oil. Leaking coolant isn't the cause of the #5 problem. It's most likely a ring or piston. Also, look into your exhaust header @ the number 5 port. Is the carbon deposit oily? If he won't warantee the fix, it may be less expensive to buy an assembled block. May want to look into it.
06-20-2006, 12:26 PM
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Originally Posted by nytoy
Just a basic rebuild, light hone on the cylinders, new rings, bearings, same stock pistons. The rad was a little low on coolant, but it never overheated.
Didn't have the usual oil milkshake by looking at the dipstick, I'll drain the pan, but I'm sure there is coolant in the oil now, since I removed the head and coolant went everywhere down the cylinders.
The rebuilder was saying it's possible for the headgasket to leak "under" the gasket, so the gasket itself doesn't look like it's torn. So I guess I'll remove the gasket and see if there are any marks showing a sign or trail of coolant going under the gasket. I hope to god he is going to warrenty it, but I doubt it, I'm wondering if he put the rings in wrong and that had something to do with all this.
Thanks for the help.
Didn't have the usual oil milkshake by looking at the dipstick, I'll drain the pan, but I'm sure there is coolant in the oil now, since I removed the head and coolant went everywhere down the cylinders.
The rebuilder was saying it's possible for the headgasket to leak "under" the gasket, so the gasket itself doesn't look like it's torn. So I guess I'll remove the gasket and see if there are any marks showing a sign or trail of coolant going under the gasket. I hope to god he is going to warrenty it, but I doubt it, I'm wondering if he put the rings in wrong and that had something to do with all this.
Thanks for the help.
06-20-2006, 01:14 PM
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Originally Posted by rocketman442
Def looks like ring or piston failure, would have been nice to do a leakdown test before you tore it down.
80% loss in #7
I pulled the head gasket off and it looks fine, no tears anywhere, no coolant trails on the block or head, so I am doubting that the coolant went under or over the gasket.
I poured some gas in the exhaust and intake ports on the head and it's tight as a drum.
I'm still shocked it could be a ring issue but leave no marks or traces on the cylinder wall.
My rebuilder is coming over tomorrow afternoon to look at it, should I start getting on his case about assembling it wrong or not untill I pull the engine and pistons out and figure out what happened?
06-20-2006, 01:38 PM
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Originally Posted by LS1-450
Leaking coolant isn't the cause of the #5 problem. It's most likely a ring or piston. Also, look into your exhaust header @ the number 5 port. Is the carbon deposit oily? If he won't warantee the fix, it may be less expensive to buy an assembled block. May want to look into it.
Like the ringland could be cracked or something like that?