Smoking dipstick, could it be bad rings?

callahanoffroad · Post by **callahanoffroad** » 15 Jul 2019, 17:46

Because I've put so much money into Herman over the last two months I felt like I should double check the compression numbers and make sure that Herman's engine was as healthy as all his other systems...

A quick refresher, Herman is a 1994/5 Volvo 850, non-turbo, with a manual transmission.

Pulled these compression numbers tonight with a hot engine:

Dry Run

Cylinder 1: 180 psi

Cylinder 2: 185 psi

Cylinder 3: 195 psi

Cylinder 4: 175 psi

Cylinder 5: 183 psi

After these numbers I did a wet compression test by adding about 1 tbsp engine oil into the spark plug tubes... PS Don't do that all at once... Just one at a time. It is quite messy.
I could only pull one number and that was Cylinder #1 which had a compression of 210 psi.

What what does the brain trust think? (That's you by the way.)

I'm thinking I need new rings, or a new to me low mileage engine.

I've been looking for new rings but I can't find them for the NA engine. Looks like they may not make them anymore?

This also explains the severely smoking dipstick and head.

Post by **ZionXIX** » 15 Jul 2019, 18:03

Those are excellent compression numbers. If you're worried about a smoking dipstick, I would look at the pcv again. Maybe drop the oil pan and do a thorough cleaning, inspection and replacement of any clogged parts. But that's just me, it's on my list anyway.

Post by **abscate** » 15 Jul 2019, 18:08

Im running very low compression measured in my T5 - I think under 150 psi

here, even worse than I remembered

Cold compression test was low to spec, but spec is warm

I showed 125-135 psi across all cylinders, spec is..

NOTE: Measure compression with the engine hot and at wide open throttle

Normal value B5234T and B5254T: 1.1-1.3 MPa (156-185 psi)
Maximum deviation between cylinders: 0.2 MPa (28.4 psi)
NOTE: This applies when the engine is warm and the throttle fully open and the engine being turned by the starter motor at 4.2-5.0 rps (250-300 rpm).

I use about 1 liter of oil per 2500 miles, and have good pep and fuel mileage.

Run it till the cows come home....

callahanoffroad · Post by **callahanoffroad** » 15 Jul 2019, 18:37

1993-1997 850 Non-Turbo: 185-213psi is spec according to FCP Euro's blog:

https://blog.fcpeuro.com/how-to-do-a-co ... nder-volvo

greg850r · Post by **greg850r** » 15 Jul 2019, 22:23

I have 160 or so in all mine and they run great and don't use oil. Your problem lies elsewhere.

Post by **erikv11** » 15 Jul 2019, 23:25

Those numbers look good for a 200k NA engine. Nice tight grouping too, healthy bottom end.

Post by **Clemens** » 16 Jul 2019, 01:22

As others said: Great numbers, very little difference, don´t worry!

callahanoffroad · Post by **callahanoffroad** » 16 Jul 2019, 05:49

Thanks for the input everyone.

Looks like I'm back to the pcv system... Again...

I really have half a mind to just replace all the tubing with pcv filters. Unfortunately it makes the car stink like you wouldn't believe.

Maybe I could rig a small air pump to suck the fumes out...

Post by **Clemens** » 16 Jul 2019, 07:06

Be sure to make the large diameter hose mod (you replace the palstic line with a regular oil proof rubber fuel line (I know rubber isn´t oil proof, but you get the idea) and run it to the ptc valve. After doing that, I finally got good vacuum. I´d go so far not even to touch anything else but replace just that hose if you had done the PCV recently.

(The theory is that with worn rings at 200.000 miles the blowby is too much to get sucked out of that plastic tube efficiently)

greg850r · Post by **greg850r** » 16 Jul 2019, 07:13

Did you clean out the passage in the bottom of the block when you had the PCV box off? They usually clog up inside the block where the bottom of the breather box mates to the front of the motor. I use copper A/C refrigerant line to replace the big hose. I just take the new elbows and the insulating cover off that hard plastic one they give you with the kit and throw it away.