Cab Off Compression Testing

[Keith Browning]

This is the engine with the broken rocker and cracked y-pipes. Since the relative compression test was so bad and I knew the cab was destined to come off for one reason or another I decided to wait until the cab was off to perform the manual compression test. It worked out well and I was able to test cylinder #7 which I have never been able to do with the cab on and the heater box in the way.

 

[joshbuys]

I do the battery the same way for a compression test with the cab off. I've compression tested #7 with the cab on, if you pull the wheel well you can go behind the lower part of the heater box for relatively easy access, and using the glowplug lineup tool makes it real easy to do. But it's certainly easier with the cab in the air!

[mchan68]

It's funny how deceiving the relative compression is on 6.4Ls isn't it? I've been able to run a manual compression test on cylinder #7 using the same method as Joshua's. My shop foreskin fabricated a cart with two BXT-65-850s connected in parallel with heavy duty booster cables for me boost up dead diesels in the parking lot. I also connect it in a similar method to the way you've illustrated it in the photo above. I'll even go step further and manage to start the engine with the cab up in the air for a few seconds with Brake Parts Cleaner.

[Bruce Amacker]

There's no compression test adapter in the 6.4 tool kit. You're using the 6.0 adapter, right?

 

[joshbuys]

That's correct Bruce, it's the same adapter as the 6.0

[Keith Browning]

Yes Mr. Amacker. Yes indeed!

 

The adapter #303-757 was released in the tool kit for the 6.0L #TKIT-2003N-F. It is for use with the 4.5L, 6.0L and the 6.4L PSD engines.