Diesel compression check?

[sreigle]

In a recent discussion someone told me they had checked compression on their gas engine. I remember doing that years ago. Now I wonder how one would do a compression check on a diesel engine since there are no sparkplug holes? Anyone know? Curious minds...

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'03 3295RK
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[Wrenchtraveller]

Compression test
To perform a compression test on this engine, you need to have a diesel compression gauge and a glow plug adapter. Remove all the glow plugs to check any cylinder. Crank the engine at least five revolutions and the same number of revolutions for each cylinder. It would probably be a good idea to have a battery charger hooked up during the test. Ford lists no compression specs for these engine, only stating the lowest cylinder should be no more than 25% lower than the highest cylinder, with a low to high comparison chart showing a range of 195 to 440 PSI. In reality the compression should be at least 350 psi.

Timing these engines depends on what equipment you have. Luminosity probe timing gauges depend on fuel cetane level, engine and ambient temperature and can read as much as 10 degrees retarded from the actual injection time.

Cylinder missfire

Don & Donna
Vancouver Island
2005 Ford F350 V10 Lariat CC 4x4 LB SRW 11200 GVWR
2006 Montana 2955RL
click on the little pic to see a big pic

[Wrenchtraveller]

Steve, I copied this from an article I found. He is talking about an older IDI Ford diesel
so this procedure might be different for a PSD. Don.

Don & Donna
Vancouver Island
2005 Ford F350 V10 Lariat CC 4x4 LB SRW 11200 GVWR
2006 Montana 2955RL
click on the little pic to see a big pic

[skypilot]

And for those of us who don't have 'glow plugs?' Cummins has a heater grid; I'd guess (and this is only a guess) that a mechanic would have to remove the injectors on such models to do the same. Interesting question though, especially if you've had an injector go bad and have had raw diesel diluting the lubricating oil for any amount of time.

Ceara and Mia Osa

06 Dodge 3500, 06 Cedar Creek

[sreigle]

Thanks. So it's similar to a gas engine except through the glow plugs. I don't need to do a compression check, I was just wondering. Thanks for the info. I'm curious how to do the check on the Cummins, too, as Skypilot asks.

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'03 3295RK
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[jerryb]

Steve, I belive you have a heat sensor gun, just aim it at each cylinder on the exhaust manifold.

[sreigle]

Hmmm, interesting idea. I never thought of that. I'll have to see if I can even see the block enough to do that. Thanks.

See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'03 3295RK
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4

Our RV Travels (now Firefox-compatible)

[trukdoc]

Diesel diagnosis is more on intepreting smoke, color, how much smoke what does it smell like, and blow by. A good ear can detect compression unbalance while cranking.
This is used more than compression tests. I have the guages but seldom use them.
The temp gun is useful for narrowing down which cylinder.

Rick & Wanda R.
2005 F250SD Lariat 4DR.
6.0 Powerstroke
2005 Mountaineer 328RLS
Sulphur Springs, Texas
Kids: Lexus and Sunshine