Compression test

[870josh]

I bought this 92 talon with a blown head gasket due to what the guy claimed to be a boost spike. So I replaced the head gasket and there was still smoke coming from the valve cover breather and dipstick

I did a compression test and got 135-145 for pistons 4 - 2 and 1 had a compression of 90, so I put some oil into the cylinder and it tested 90 again. I walked away and pondered a while, then came back and tried it again except this time I cranked it a few times after putting the oil in the cylinder hoping some would splash onto the walls and slide down etc, yet it read 90 psi still.

Is it possible that the valves leak? would that cause compression to be lost into the oil "system"?

I'm pretty sure my dad may have incorrectly torqued the head down, might it be that it needs to be retorqued?

I don't have the tools to re-torque or do a leakdown test at the moment, so I'm just asking to make sure you agree so I don't waste 50 dollars on either tool

The guy I bought it from claimed the car had some head work done and the engine was rebuilt 5k miles ago, then again he also said all that it needed was a head gasket and it'd run fine so I'm not giving him much credibility.

 

[JFatch1890]

the 135 in the two cylinders is below the service limits (per the haynes manual) and 90 in the other two would most def. be rings. highly doubt a rebuild was within the last 5k

I bought this 92 talon with a blown head gasket due to what the guy claimed to be a boost spike. So I replaced the head gasket and there was still smoke coming from the valve cover breather and dipstick

I did a compression test and got 135-145 for pistons 4 - 2 and 1 had a compression of 90, so I put some oil into the cylinder and it tested 90 again. I walked away and pondered a while, then came back and tried it again except this time I cranked it a few times after putting the oil in the cylinder hoping some would splash onto the walls and slide down etc, yet it read 90 psi still.

Is it possible that the valves leak? would that cause compression to be lost into the oil "system"?

I'm pretty sure my dad may have incorrectly torqued the head down, might it be that it needs to be retorqued?

I don't have the tools to re-torque or do a leakdown test at the moment, so I'm just asking to make sure you agree so I don't waste 50 dollars on either tool

The guy I bought it from claimed the car had some head work done and the engine was rebuilt 5k miles ago, then again he also said all that it needed was a head gasket and it'd run fine so I'm not giving him much credibility.

If pressure stays low after trying the oil, a valve may be sticking or seating improperly.
If compression in any two adjacent cylinders is low and if oil does not help compression, there might be a leak past the gasket surface.Might have to replace the cylinder head gasket.

 

[870josh]

by 4-2 i meant 4 through 2, and 135 isn't below the service point as per http://www.geocities.com/dsmgrrrl/FAQs/compression.htm for a 90-94 talon I'll have to find my haynes or whatever to double check that

and basically my whole post is just to ask if leaking valves could, some way or another, cause the car to smoke out of the valve cover breather and dipstick

PCV valve is working correctly and the smoke isn't coolant, smells like it MIGHT be burning oil, not 100% though don't quote me on that

 

[->PrOjEcTGS<-]

The service limit on a 1g is 120psi and below. I would perform a leak down test to find out where the leak is coming from that way you can diagnose it to further know what the problem is.

A wet test does not always work well on our cars due to the dished low compression piston. It ends up just pooling in the dish and not really sealing the rings.

 

[JFatch1890]

yes, i just double checked... i read for a non-turbo...........service limit is 121 psi

 

[870josh]

i'd say the smoke coming from the valve cover breather and the dipstick points towards rings, i'm asking if it could be the valves in any way since 2 wet tests pointed towards no (i realize the piston is dished but like i said i'm just asking)

 

[jrohner]

Time for a valve job.

 

[870josh]

So, in other words, what you were trying to say, is "Yes it IS possible!" right?