HELP Compression Test Results BAD

[boosted954g63]

Well my car was overheating really bad so i did a compression test and the results were bad. 1st Cyl-80 2nd, 3rd and 4th were all in the 130's. so i put a cap full of oil in it and it went up like 5. So what should i do? Is it time for a new head or rebuild the whole engine? Thanks Nick

 

[rowlex]

I have no direct experience with this but I do read A LOT. From what I understand, running a compression test +oil is suppose to seal the ring gap if you have worn rings -- if your compression only rose 5PSI, you either have no rings left at all, or their is a different problem (IE: burnt valves? bent valves? blown headgasket?)

If you want to find out exactly what it is your next test is called a leak down test. DO a search for it, I know the directions on how to do it are on vfaq. (basically you fill the cylinders with compressed air and find out where it is leaking from).

 

[oldman]

http://www.dsmloggers.com/products.html

 

[boosted954g63]

Well i took off the head and the head gasket was not broken.
thanks nick

 

[oldman]

Well i took off the head and the head gasket was not broken.
thanks nick

Nick, you should have done a leakdown to pin point the problem before you took the head off, now you can only guess.

 

[boosted954g63]

Well i did not know about that or i would have waited. It was my day off so i just went ahead and did it. So i am stuck now on what to do, and all i can do is just guess? are there any other ways to tell? Thanks nick

 

[oldman]

1. Was the car smoking besides overheating?

2. Was the compression done with engine fully warmed up?

3. Have you tried all other over heating remedies besides the HG?

4. Do you smell gas in oil?

5. Inspect the top of the piston edges, especially the one registering 80psi, for signs of inconsistent carbon build up as well as scratch marks. Also check the cylinder walls for signs of damage.

6. Flip the head and check for burnt/bent valves, make sure they're all seated properly. Again, pay special attention to the suspected cylinder.

 

[boosted954g63]

the car always had a white tint to it, yes the engine was warmed up, i tried all of the usual over heating things that i know of like flush the radiator, the correct coolent levels, thermostat, a link some where in the coolent line, the coolent cap i have not smelled the oil i will do that when i get home and i will inspect the head and the pistons when i get home
Thanks for all the help
Nick

 

[rowlex]

if you had no blue smoke I would guess your rings are probably OK. at 80psi you would definently have seen some blue smoke out the back if it were your rings. How do the plugs look?? Gummy with oil?

This may help check your head: on each cylinder make sure the valves are fully closed, turn the head over so the valves are facing up and pour rubbing alcohol or water onto the valve "cup" (leave the spark plugs in and tight), if the water/alcohol disappears -- drains out any of the valves you will probably need a basic head rebuild.

 

[boosted954g63]

Ya there was only white smoke, i have never see blue smoke come out of my car. not sure on the spark plugs right now ill check them when i get home. I will also try that test too when i have time.
Thanks for the help
Nick

 

[rowlex]

good luck

 

[oldman]

Also, considering the car has been over heating, use a straight edge and make sure both the block and head are leveled, I'm thinking possibly a warped head.

 

[boosted954g63]

Thanks i need it. I will also do that too with the ruler.
Thank you so much
Nick

 

[ddavisaf]

coolent is spelled coolant

So were you losing coolant, or oil?

Overheating remedies include.......
1) Replace Rad. Cap
2) Replace T-stat
3) Make sure the hoses are not leaking
4) Radiator flush
5) Make sure your fans are operating properly, or if aftermarket fans, set on push/pull accordingly
6) Compression Test
7) Leak down test
Not necessarily in that order.

If you're unsure of anything, take a picture and post it up on here. We can help you identify anything you're not positive about.

 

[boosted954g63]

The plugs have normal build up on them it is not bad, the head and the block is strait. when i did the test on the head with water, all of them linked bad, but the one that i was getting a low compression was only linking a little bit. the rest of them would not hold any water and just empty it. so is it my head? Also i just smelled the oil and it smelled like fuel.
Thanks nick

 

[rowlex]

did you make sure the cams were not holding the valves open?? You can take them out to be absolutely sure. But if they were fully closed then yes you need to rebuild the head, so you will have to pull the cams out anyway.

 

[boosted954g63]

All the valves looks to be closed i will try to get a pic up here and show you guys.
Thanks nick

 

[rowlex]

it would probably be impossible for us to tell if they are closed or not with a picture. Do you still have the cam gears on? If so what position were they in when u did the test? IIRC You could probably line the cams up to TDC (cam marks facing eachother and dowel pins up) to close all the valves (someone please confirm this!)


BUT if your sure they are closed pull the cams out and try it again (you will have to dissaseble it anyway)

 

[boosted954g63]

If i just pull out the cams would that make all the valves close? If so i will do that. I have not taken off the cam gears also.
Thanks alot
Nick

 

[sYnOnYx]

if its white smoke, im thinking valve seals, or something else in your head.....

 

[boosted954g63]

Ya i hope it is the head, because it would be a lot easier to replace than the piston rings.
Thanks
Nick

 

[huafist]

Just do the test as rowlex suggested, and take the cams out of the head before you do it. The cams are what cause the valves to open, so with them out all valves will be shut.

Also, I'd take the head to a machine shop and have it checked for straightness there. Just because you put a regular ruler on it doesn't mean it's not warped.

 

[rowlex]

Just do the test as rowlex suggested, and take the cams out of the head before you do it. The cams are what cause the valves to open, so with them out all valves will be shut.

Also, I'd take the head to a machine shop and have it checked for straightness there. Just because you put a regular ruler on it doesn't mean it's not warped.

Yes the springs pull the valves closed. I believe your suppose to use a straight edge not just your normal crap ruler.

 

[boosted954g63]

Well i used a Long thick metal ruler, but if you think i need to get it checked out at a machine shop i will try.
Thanks Alot,
Nick

 

[boosted954g63]

OK sorry for taking so long to get backwith you guys, but i took out the cams and did the water test and 3 valves on the exhaust side were linking out water and 1 on the intake side. So does that mean i need to get my head rebuilt, because the valve seals are linking?
Thanks Nick