Compression Test Results

[zolorin]

So I finally got a bit fed up with the smoking start on my diesel pickup and finally decided to do a compression test

So here is what I have found once I pulled the injectors

#3 injector had a black body and did not have a ring that is indicative of it being properly seated against the steel insert.  I could not find the steel insert what so ever -- hmmm I guess this was first reason to be worry about a low compression worries.

I then tested all of the pistons with the diesel compression tool

1. 220 (retested at 210, same way that I did all 4 other, about 10 rotations)
2. 300
3. 290 (did not tested without the insert)
4. 310

I did the test cold (how much does doing it hot increases by? 40 psi, 50psi?)

So from what I am reading I am below the wear limit by a lot and number 1 is below the delta limit of 71 psi

So what else would you guys recommend to test before plunging into an engine rebuild?

[libbydiesel]

The compression reading isn't from a certain number of revolutions, but rather the reading when the needle stops moving up regardless of the number of revolutions. 

[zolorin]

Agreed, I just did not have a helper who can tell me when the needle stop going up.  So I did one cylinder for trial to see how many revs did it stop rising and then added couple more.

The question is is the HG blown?
and should I be thinking of replacing pistons and rings??

[ORCoaster]

Question on procedure.  Did you do it by pulling the injector and replacing it with the test tool?  I think that is what you did.  Correct if I am wrong.

Once you have these readings you could squirt about a tablespoon of oil in the top then place the adapter in the injector hole and try again.  If rings are the issue you normally will see an increase in pressure.  Try it and see what you get.  I have one cylinder that is bad and oil gives me 80-100 lbs more on a stone cold engine.

Isn't the normal 480 lbs per cylinder?  And wear limit some where about your best cylinder?  Bentley check.  Wow your hosed!!!

Bentley says this for my 81 1.6 NA:  Normal compression pressure is 398 to 483 psi.  If pressure for any cylinder is below the 398 psi limit or pressure is 71 psi different between any two cylinders the valves, rings, or cylinders may need replaced or bored out.

Time for a teardown and measurements to be taken I'd say. 

[RabbitJockey]

could be a blown headgasket causing #1 to be so low.  But the other 3 are really close together so you're going to need rings at a minimum, you'll have to check if the bores are within their wear limit and also if there is too much ovaling.  and you'll have to inspect the head while its off.  if you're lucky you can get away with just a hone, new rings, headgasket, headbolts rod bolts, and rod bearings.  but you'd have to be really lucky haha.

[ORCoaster]

Sounded like this thing still runs just smokes on start up.  Wait till he rebuilds it and he will have a thread that his starter won't turn it over anymore.  Or the battery is weak.  Buhaawwwaaa

[zolorin]

"starter will not turn" -- that is funny.

But yes it does/did run but smokes and has a low power (max speed is about 65 to 70 on a straightaway).

Yep pulled the injectors (all 4 of them), installed the tool/converter

So ya, I am hosed -- way low.
BTW who do you suggest for parts (and please don't say prothe)

[libbydiesel]

Did you do the test with the engine at normal operating temp?  Does it have solid lifters? 

[TylerDurden]

Be careful with that "wet test"... these engines run on oil.

As Andrew alludes, valves are not yet ruled out.

>270psi in each could still be a reasonable runner, if the engine starts and the blowby is managed to avoid runaway.

[theman53]

If it isn't running away and you are just mildly upset about the smoke you could run it until you have a real problem. If it starts and runs it could keep going like this for anothe 100,000 miles. I would take the shot and find another block to rebuild in the meantime. That is me though. I just know the more you dig on these engines the more needs replaced and sometimes you could have done without it, sometimes not.

[ORCoaster]

I can't suggest many places for all your parts.  And if the valves are the problem you may not need many just some cleaning and polish about the inside.  I just picked up a set of Gotez (sp) rings for 80 off of Ebay.  Still haven't had time to get them in.  Like you I am smoking out the neighborhood instead of tearing it apart.  Oh, and checking the oil all the time.   

[tyb525]

Have you checked your timing? I had mine a little too retarded when I first timed it and it smoked really bad when cold, but once warmed up it didn't smoke at all and ran fine.

[ORCoaster]

Normally smoke on start up can indicate poor timing, but with the numbers he has, he is in need of more than a few degrees of advancement. 

[nwcali6]

Before settling in on the idea of a total rebuild rule out the head/valves.  Pulling the head will tell you a lot about the wear though.  Personally if I have to go with new rings, I'll change the pistons, and the mains.

  How many miles on the engine?  How tight is money? 

[libbydiesel]

Before even considering pulling the head, make sure the valves are opening far enough.  Compression check should be done with the engine up to temp.