[outofrshell]

I just rebuilt a 2.6 for the Trooper and had it bored .020 over with new pistons and rings. I used an AMC head that was redone in August (not sure what year of application it was on the Trooper when I got it). I have about 500 miles on the new engine and wanted a base figure for the compression before we left for Moab. Just wondering what is normal for this engine? I had 120 on #1,2 & 4 and 105 on #3. Seems a little low to me, #3 was lower on the old engine also and that may be a valve but the other ones ( old engine) were in the 120 range. Hoping it gets better with some miles and doesn't use too much oil. That was the big issue with the old engine, 1quart per 100-200 miles. Thanks DAVE

 

[psguardian]

Is that 'dry' or 'wet' compression? Another member just did a head job & got (with wet comp check) 175ish on 2 cyls & 140ish on other two cyls.

~psguardian

 

[outofrshell]

That is dry, I did #3 wet and it came up to 118. This is on a 1988 block and the head was on my 1991 when I got the truck. The head was surfaced in August but the block was not when it was bored. I was expecting the the numbers to be around 140 so I am a little concerned that the rings didn't seat. I am also getting a little blue smoke when I first start it after it sits for awhile. DAVE

 

[fibersport]

Were the valve guides replaced on the head? I had a Firebird that would puff blue smoke in the morning too, it was because of worn valve guides.

 

[squatch]

Your numbers are low. Isuzu says to rebuild when they get down to around 115-120. A 2.6 in good shape should have numbers up around 150-160+. I just posted my numbers and an old reference in my Red Beans thread. The second one in my sig. If the rings are in good shape there should be little difference between wet and dry. If wet raises them up much rings and cylinder are worn.

 

[outofrshell]

Guides were replaced on exhaust valves. I am not sure on the intake my memory just didn't retain it. I was running a Delta cam and it had worn the guides visibly egg shaped so I'm going to say I most likely changed all the guides. I can only hope that more miles will help but my experience has been that if the rings don't seat in the first miles they never will. DAVE

 

[squatch]

If you are using a synth oil run dino instaead for a while. It will help with ring seating I'm told. Did you position the ring gaps to Isuzu specs? Isuzu is pretty specific where they want the gaps placed. It's not just 120 degrees apart.

 

[outofrshell]

I hate to admit it but no I couldn't find the info when I was putting the pistons in and got impatient and just used my normal offset. Then later I seen on the Planet where it was pretty specific as to how you space the rings. Usually the kits I get have that info in the ring box but this one didn't so I have never had this problem with other rebuilds on 2.6s. DAVE

 

[fibersport]

Another thought, what type of rings are they? Cast iron ones will seat in no time, chrome-moly will take more miles since they are so hard.

 

[outofrshell]

This may sound dumb but I'm not sure ( do you remember me saying pay attention to details) I order the kit from RPM Machine in Utah and it does not specify what the rings were. Just guessing by what they looked liked I would say they were moly which if they are they may never seat I have never had good luck with moly rings. I did find the ring spacing (in the manual- Engine Rebuild section 3 under rings DAH!!!! I think I'm slipping)The good thing is that the spacing is close to what I used. I will watch the oil closely on this trip and hope that it is not excessive. It is not that expensive to rering it's just a lot work for nothing.Good thing is every thing is nice and clean and I know every bolt by first name. BTW I use reg. 10-30 oil. DAVE

 

[squatch]

May take a while. I've been told by a couple of machinists that the 2.6 block casting is pretty hard stuff. 2 hard metals together will take longer for sure. When I bought my 1st trooper new I had about 15-16,000 miles on it before the engine loosened up and started giving better fuel mileage and performance.

 

[future RS]

10w 30 should be ok.

on most performance and non performance applications its recommended to run a standard dyno oil such as straight 30 for the first couple hundred to 1k miles then switch to the oil you will be using from there on out.

good luck!

 

[outofrshell]

Then there is hope! THANKS DAVE

 

[psguardian]

If its Moley rings you've got then there is still time to do THIS BREAK IN METHOD. Thinking of it mechanically it makes PERFECT sense, give it a read.

~psguardian

 

[BroncoDave2163]

The thing I find interesting about that MOTOMAN BREAK-IN METHOD is that I have been breaking-in motors that same way for 35 years and have never had a problem. Almost got into more than a hundred fist fights with customers when they hear how I drove the piss out of the new engine they just paid me a small fortune to build and install in their "BABY". They go away in a huff when I give them a full money back guarantee, but they always came back and thanked me for breaking-in their motors. Never had to give anybodys money back.

 

[outofrshell]

This is an up date on this thread.We took the Trooper to Moab by the way of Durango Co. Close to a 1,000 and didn't use any oil and was running great (20+ MPG) so I guess the rings finally seated. We did 3 trails in Moab with no problem then on the 4th and final day 2 ex. seats came loose in the head #3&4 Didn't hurt the engine but ruined the head this explains the low compression on #3 not sure what to think of #4. Bought a used head in Vernal, Utah and put it on in the motel parking lot but it had issues also so we ended up trailering the Trooper home.Engine shop is rebuilding a head this week it will be interesting to see the comp. #s when this is all done. Later DAVE

 

[squatch]

Ouch, sorry to hear about the head issues. Hopefully this will soon be all behind you.

 

[outofrshell]

Actually it's more over my HEAD than behind me. I am going to leave head work like that up to the experts from now on I can build lower ends but I am just not set up to do head work except the very basics. When I get the head back from the shop and get the truck running again it is suppose to be sold and I am going to start a build on a 1989 V6. DAVE