Compression test questions - Competition Diesel.Com

Carlosl151 · 01-18-2021, 08:10 PM

Hey guys, I have a 92 12v cummins. I just did a compression test and the results were this in each cylinder
1- 350 psi
2- 350 psi
3- 320 psi
4- 350 psi
5- 350 psi
6- 330 psi

Are these numbers healthy or am I on my way to a rebuild? Thanks

jasonc · 01-19-2021, 03:57 PM

Does the engine have any blow by when cold, and after it's at operating temp?

*Snedge* · 01-19-2021, 04:01 PM

Why did you do the compression test? Is it using oil or something ?

Carlosl151 · 01-19-2021, 07:09 PM

Quote:

Originally Posted by jasonc

Does the engine have any blow by when cold, and after it's at operating temp?

It has minimal when warm. Very slight haze but not enough to concern me

Carlosl151 · 01-19-2021, 07:11 PM

Quote:

Originally Posted by Snedge

Why did you do the compression test? Is it using oil or something ?

I bought this first gen cummins in Vegas and drove it home to Missouri. It’s going off to paint soon and wanted to check if It was on its way out so I can rebuild before paint so I’m not having to deal with pulling fresh painted body parts to pull an engine. I’m pulling head to do some conical valve springs, too hat valve seals, and hd push rods so I will check cylinder walls when the head is off

01-18-2021, 08:10 PM	#1
Carlosl151 Name: Carlosl151 Title: Rookie Status: Not Here Join Date: Feb 2020 Member`s Gallery Posts: 7	Compression test questions Hey guys, I have a 92 12v cummins. I just did a compression test and the results were this in each cylinder 1- 350 psi 2- 350 psi 3- 320 psi 4- 350 psi 5- 350 psi 6- 330 psi Are these numbers healthy or am I on my way to a rebuild? Thanks

01-19-2021, 03:57 PM	#2
jasonc Name: jasonc Title: Too Much Time Status: Not Here Join Date: Nov 2009 Member`s Gallery Posts: 4,412	Does the engine have any blow by when cold, and after it's at operating temp?

01-19-2021, 04:01 PM	#3
Snedge Name: Snedge Title: Comp Diesel Sponsor Status: Not Here Join Date: Sep 2006 Location: Western Pa. Member`s Gallery Posts: 18,859	Why did you do the compression test? Is it using oil or something ?