PSI for a healthy LT1
#11
RE: PSI for a healthy LT1
Well, it's a good thing it wasn't up to 115, or you'd really be screwed.
With those numbers, and the way she runs,that engine was broke in very well.
Sure, you have some leakage, but you have balance between cyl. I collapsed the rings in the ol' 350 and she smoked like heck, but she still ran very strong. I didn'tdo a comp check 'cause I already knew that it was time for a rebuild.[&o]( ....that's when the 454 was dropped in the hole....)
With those numbers, and the way she runs,that engine was broke in very well.
Sure, you have some leakage, but you have balance between cyl. I collapsed the rings in the ol' 350 and she smoked like heck, but she still ran very strong. I didn'tdo a comp check 'cause I already knew that it was time for a rebuild.[&o]( ....that's when the 454 was dropped in the hole....)
#12
RE: PSI for a healthy LT1
ORIGINAL: C3 Starship
Oh ya,.... if you're goin' to do a comp test, you're wastin' your time if ya don't do bothdry and wet. I don't care what your initial readings are, get the whole story. ( especially if your lookin' to buy )
Oh ya,.... if you're goin' to do a comp test, you're wastin' your time if ya don't do bothdry and wet. I don't care what your initial readings are, get the whole story. ( especially if your lookin' to buy )
ORIGINAL: C3 Starship
It is just possible that your 160 reading is due to oil in the cyl., helpin' out some worn rings. Ya think? Hmmmm,.....could be........
It is just possible that your 160 reading is due to oil in the cyl., helpin' out some worn rings. Ya think? Hmmmm,.....could be........
RACE ON!!!
#13
RE: PSI for a healthy LT1
ORIGINAL: 78buckshot
A compression test at cranking speed can be misleading, if the cam has allot of overlap which would normally be considered a high horsepower cam then it will show lower than normal compression.
A compression test at cranking speed can be misleading, if the cam has allot of overlap which would normally be considered a high horsepower cam then it will show lower than normal compression.
RACE ON!!!
#14
RE: PSI for a healthy LT1
[blockquote]quote:
ORIGINAL: C3 Starship
Oh ya,.... if you're goin' to do a comp test, you're wastin' your time if ya don't do bothdry and wet. I don't care what your initial readings are, get the whole story. ( especially if your lookin' to buy )
[/blockquote]
"( especially if your lookin' to buy )" and you don't want to purchase a project, why would you perform the wet test if the dry rest shows a problem?
[blockquote]quote:
ORIGINAL: C3 Starship
It is just possible that your 160 reading is due to oil in the cyl., helpin' out some worn rings. Ya think? Hmmmm,.....could be........ [/blockquote]
Let me see if I understand what you are saying. On one hand you say, "you're wastin' your time if ya don't do bothdry and wet" Then you suggest that a dry test on a worn engine is really a wet test. If that is what you are saying, how do I do the wet test that I would be "wastin' your time if ya don't do bothdry and wet"? And what would it rell me?
Why test your's at all?, it's already obviously shot. [sm=icon_rofl.gif]
Any and all info is a help. What if you are lookin' to buy a project?
Does it need a head job, or a complete overhaul? Warped valve, weak springs,or busted rings? All knowledge is important to me.
Sounds like you have a real prob with doin' a "wet" test. It's real easy, since you already have the plugs out anyway, just squirt a little oil in the hole, and test again. Unless it's just too much bother.
Is this a test? I'm just makin' a reccomendation as to get full info.
You don't wanna do a wet test? I don't care, but I always do a "dry" and "wet" test. The amount of oil you're burnin', don't bother with any tests at all, just junk the engine and start over. (or don't, it's up to you )
I won't argue about it, 'cause I really don't care if you want to "wet" test or not. Others may learn from what they may find.
I know that I do.
ORIGINAL: C3 Starship
Oh ya,.... if you're goin' to do a comp test, you're wastin' your time if ya don't do bothdry and wet. I don't care what your initial readings are, get the whole story. ( especially if your lookin' to buy )
[/blockquote]
"( especially if your lookin' to buy )" and you don't want to purchase a project, why would you perform the wet test if the dry rest shows a problem?
[blockquote]quote:
ORIGINAL: C3 Starship
It is just possible that your 160 reading is due to oil in the cyl., helpin' out some worn rings. Ya think? Hmmmm,.....could be........ [/blockquote]
Let me see if I understand what you are saying. On one hand you say, "you're wastin' your time if ya don't do bothdry and wet" Then you suggest that a dry test on a worn engine is really a wet test. If that is what you are saying, how do I do the wet test that I would be "wastin' your time if ya don't do bothdry and wet"? And what would it rell me?
Why test your's at all?, it's already obviously shot. [sm=icon_rofl.gif]
Any and all info is a help. What if you are lookin' to buy a project?
Does it need a head job, or a complete overhaul? Warped valve, weak springs,or busted rings? All knowledge is important to me.
Sounds like you have a real prob with doin' a "wet" test. It's real easy, since you already have the plugs out anyway, just squirt a little oil in the hole, and test again. Unless it's just too much bother.
Is this a test? I'm just makin' a reccomendation as to get full info.
You don't wanna do a wet test? I don't care, but I always do a "dry" and "wet" test. The amount of oil you're burnin', don't bother with any tests at all, just junk the engine and start over. (or don't, it's up to you )
I won't argue about it, 'cause I really don't care if you want to "wet" test or not. Others may learn from what they may find.
I know that I do.
#15
RE: PSI for a healthy LT1
ORIGINAL: C3 Starship
Any and all info is a help. What if you are lookin' to buy a project?
Does it need a head job, or a complete overhaul? Warped valve, weak springs,or busted rings? All knowledge is important to me.
Any and all info is a help. What if you are lookin' to buy a project?
Does it need a head job, or a complete overhaul? Warped valve, weak springs,or busted rings? All knowledge is important to me.
The purpose of a compression test is to get an idea of the overall condition of the engine. If all the readings are reasonably high and more importantly, fairly close (at least within 10%) of one another, the engine passes the test. There is nothing more to be learned from the compression gauge. If the results of the compression test show problems, and ifyou only want a car with a healthy engine, once again, you are done. If the car is no longer in consideration, why go to the effort of diagnosing a car you won't buy? On the other hand, of you are willing to buy a project, then a wet test will help you decipher to what degree the valves, and to what degree the rings, contribute to the problems.
ORIGINAL: C3 Starship
Sounds like you have a real prob with doin' a "wet" test. It's real easy, since you already have the plugs out anyway, just squirt a little oil in the hole, and test again. Unless it's just too much bother.
Sounds like you have a real prob with doin' a "wet" test. It's real easy, since you already have the plugs out anyway, just squirt a little oil in the hole, and test again. Unless it's just too much bother.
RACE ON!!!
#16
RE: PSI for a healthy LT1
Well then, for the sole purpose of continuing the argument with CFI/EFI, since it appears as that is your focus here, what part of the cam grind is going to influence the pressure if it ain't the overlap? Lift at cranking speed?, duration at cranking speed? If the cam has aggressive overlap, the the compression stroke is going to "scavenge" a good deal of the cylinder volume before the exhaust valve closes, effectively lowering the compression pressure at low RPM.
#18
RE: PSI for a healthy LT1
O.K., CFI/EFI, a comp test will not show weak or broken springs, it won't show a warped valve, it won't show broken rings. all it will show is comp loss, O.K.? BUT, these are some things that could possibly be wrong.
You go ahead and do thiings your way and I'll do them mine. I really don't give a squat. I'm a curious little bugger and want to see what's up with an initial test, whether I'm buyin' or not.
You are just so much smarter than I. [&o]Maybe,...some day,......I'll get it right.
So,.....race on...
CStewTamu, I too, apologise for the rant. This is not common practice here. ( and it stops right now )
You go ahead and do thiings your way and I'll do them mine. I really don't give a squat. I'm a curious little bugger and want to see what's up with an initial test, whether I'm buyin' or not.
You are just so much smarter than I. [&o]Maybe,...some day,......I'll get it right.
So,.....race on...
CStewTamu, I too, apologise for the rant. This is not common practice here. ( and it stops right now )
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Texas Jim
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02-15-2008 09:35 AM