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Is This Engine Still Good? (Compression Numbers)

 
Old 02-05-2019, 06:13 PM
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89’Vette
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Default Is This Engine Still Good? (Compression Numbers)

1-135 (141 Wet). 2-135

3-134 (140 wet). 4-131

5-130 (130 wet). 6-126

7-145 (147 wet). 8-150


Sorry, I didn’t get the wet PSI for the other side. It was enough of a pain in the *** getting the hose in, and out the first time.
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Old 02-05-2019, 06:55 PM
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number 6 is a little low but not enough to really worry much about if its just a cruiser type car, its within the 20% range, if you are capable of doing you're own valve job on a bench. maybe that would be all it needs to bring those numbers closer together again and by doing you own i mean just hand lapping them with some compound and cleaning the valve seats up, its not that hard really i use a power drill and some 1/4 inch id fuel line on a 5/16 drill bit with hose clamps tightened up good,then put the other end on the valve stem, run it one direction then backwards several times util you hear it start to sound nice n smooth it works great and saves a lot of time. i love doing budget stuff like that it saves money for better things
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Old 02-05-2019, 09:57 PM
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https://youtu.be/0cK8tt6FdCs

this is how i "ground" my valve seats. it worked awesome.

forgive my narrative, it was my very first engine and im sure there are things i said that are not true. but i can verify this works well. if done right.
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Old 02-05-2019, 10:23 PM
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yeah, thats it... just don't yoink it hahaha good video though man
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Old 02-05-2019, 10:27 PM
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Originally Posted by bud40oz View Post
number 6 is a little low but not enough to really worry much about if its just a cruiser type car, its within the 20% range, if you are capable of doing you're own valve job on a bench. maybe that would be all it needs to bring those numbers closer together again and by doing you own i mean just hand lapping them with some compound and cleaning the valve seats up, its not that hard really i use a power drill and some 1/4 inch id fuel line on a 5/16 drill bit with hose clamps tightened up good,then put the other end on the valve stem, run it one direction then backwards several times util you hear it start to sound nice n smooth it works great and saves a lot of time. i love doing budget stuff like that it saves money for better things
So you think it’s just the valve seats, and not the pistons rings?
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Old 02-05-2019, 10:39 PM
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is it smoking or anything? running poorly? to be honest in my opinion, no its not much to worry about usually when you have a cracked ring you have around 50 psi or so. if you look at the video link viking posted there he shows the little carbon deposit in his valve seats, even that little bit will cause some minor compression loss. you might even get away with some .. cant think of the name right now.. but its the cure all for engines haha.. man its on the tip on my tongue but follow the directions and it says how to use it for cleaning valve train. its not lucas but that other stuff.... ooo sea foam, maybe try some sea foam and see what it does, ya never know for 8 bucks a can its worth a shot before you tear it apart. i would fill the tank up pour a can of sea foam in the tank and then buy another can and use it to pour into the intake as per instruction on cleaning valves.then in a month or so after the tank of gas is used, try another compression test and see if it helped at all

Last edited by bud40oz; 02-05-2019 at 10:49 PM.
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Old 02-05-2019, 10:49 PM
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why did u do the comp test? having issues?
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Old 02-05-2019, 11:31 PM
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Now do a leak down test. It will tell you if there are ring or valve seal issues.
H
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Old 02-06-2019, 08:59 AM
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Originally Posted by VikingTrad3r View Post
why did u do the comp test? having issues?
Whenever I drive about an hour on the freeway then exit, and hit my first stop light it stalls out, then when I turn the key it starts right back up. I think it may be the EGR valve staying open. Idle is a bit rough too. Swapped out the air filter, fuel pump, fuel filter, spark plugs, spark plug wires, ignition coil, cap, rotor, TPS, IAC, O2 Sensor, cleaned out throttle body and it’s still rough. I did a Fuel Pressure Test at start up, and under load conditions up to 70 mph. The fuel Pressure was perfect. It does have crappy acceleration when I try to accelerate gradually, but if I go full throttle it hauls ***.

Last edited by 89’Vette; 02-06-2019 at 11:09 AM.
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Old 02-06-2019, 09:01 AM
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Originally Posted by bud40oz View Post
is it smoking or anything? running poorly? to be honest in my opinion, no its not much to worry about usually when you have a cracked ring you have around 50 psi or so. if you look at the video link viking posted there he shows the little carbon deposit in his valve seats, even that little bit will cause some minor compression loss. you might even get away with some .. cant think of the name right now.. but its the cure all for engines haha.. man its on the tip on my tongue but follow the directions and it says how to use it for cleaning valve train. its not lucas but that other stuff.... ooo sea foam, maybe try some sea foam and see what it does, ya never know for 8 bucks a can its worth a shot before you tear it apart. i would fill the tank up pour a can of sea foam in the tank and then buy another can and use it to pour into the intake as per instruction on cleaning valves.then in a month or so after the tank of gas is used, try another compression test and see if it helped at all
There is a small ring of oil above the threads on my #6 spark plug though. No it doesn’t smoke at all. I will be sure to give that a try!

Last edited by 89’Vette; 02-06-2019 at 11:11 AM.
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Old 02-06-2019, 01:52 PM
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Your stalling problem is not your compression. I think if you change your injectors [FIC] your idle will be good and in the process of inj. change you can inspect/clean your egr valve. Good luck!
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Old 02-06-2019, 01:57 PM
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x2 egr valve & associated pieces if not working right can cause goofy symptoms. Do you have a vacuum pump?(there are cheap handheld units out there)
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Old 02-06-2019, 05:35 PM
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Originally Posted by cuisinartvette View Post
x2 egr valve & associated pieces if not working right can cause goofy symptoms. Do you have a vacuum pump?(there are cheap handheld units out there)
I can rent one from autozone. What do you have in mind?
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Old 02-06-2019, 05:42 PM
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slip the vacuum pump over the nipple on the egr valve. pull a vac and see if it holds.
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Old 02-06-2019, 10:20 PM
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So I put the Sea Foam into the Intake. It didn’t smoke too much, but a decent burst came out. Still going to swap out the EGR Valve, EGR Solenoid, and Fuel Injectors.

Last edited by 89’Vette; 02-07-2019 at 11:45 AM.
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Old 02-07-2019, 12:12 PM
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Originally Posted by 89’Vette View Post
So I put the Sea Foam into the Intake. It didn’t smoke too much, but a decent burst came out. Still going to swap out the EGR Valve, EGR Solenoid, and Fuel Injectors.
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