Pulled Heads...thoughts on my cylinders?

[troy_caleb]

The number 8 cylinder was knocking intermittently and and I had oil in the coolant and coolant getting into the cc gasses somehow and was noticeable when I pulled the air filter off...there was some milky coolant tasting substance in the turbo inlet....none in the oil though . Engine had a lot of blow-by... enough so it didn't even disappear at 2000 rpm's... Decided to pull the heads...the cylinders are more polished and less carboned up towards the rear of the motor...the junk in the cylinders is head gasket debris...I wish I would've taken the hood off...or had a friend...or rigged up some handles...
My machine shop guru says that quite a few valves and valve guides were shot...he attributes some or a lot of the blow-by to that? Just wondering if I should re-ring...or re-piston the engine....sleeving or boring and sleeving is not an option...the closest full service machine shop is an 18 hour ferry ride away...my heads are at the closest place to do valve work which is a three hour ferry ride and is plenty far...
If it come to anything like needing sleeved I'm going to get a re-manned engine. I don't have a micrometer but could probably track one down when I get back home on monday...basically my question is...does this type of wear look normal for an engine with 110,000 miles....that sat for five years? Also...no scoring of the cylinderwalls...the edges of the pistons looked a little worn

 

[Diesel JD]

Troy I can't see enough detail on those bores to give you my opinion which probably isn't what you wanted anyway since I have only seen mine with the heads off. On mine, I still saw factory crosshatching in the bores, the bores were plenty worn at the top especially where there was a bit of a ridge to the point that the pistons would have had to be removed from the bottom or a ridge reamer used to clean out the bores to remove them from up top. The valve issues probably account for the knocking noise and are a common weak point on 7.3s. It's the coolant issue that has me worried to advise you to spend any money on this engine. I'd be worried about the cylinder liners being pitted from cavitation. I remember there are ways to pressurize a block and see if there are cavitation pinholes in the bore. It could only be either that or a cracked block, a cracked head or a blown headgasket, and generally with the 7.3s it is cavitation unless it was an overheated engine or a turbo engine that was overboosted. I would want to rule out cavitation if it were mine before I spent money on it, I say this because it sounds like where you live you probably need this truck to be reliable and can't afford to screw around with it for the next couple of months. If I were in your shoes I'd probably buy a shortblock reman, and have your machinist make those heads as close to perfect as he can and then bolt it all together. If I had it here, I'd pressurize the block and check it for cavitation, and if it was cavitated I'd sleeve the bad holes and the other "high risk" holes and call it good, but you said extensive block machine work is not an option and I don't know off the top of my head what it takes to pressurize the block and test it off the top of my head.

 

[troy_caleb]

Thanks for the response! I'm pretty sure it was the head gasket on the drivers side, cylinder 6. I don't think that there's anyone around here that can pressurize the block for me...I know cavitation is a major problem for these engines...I'm just hoping it hasn't happened...and 109,000 miles is pretty low...but you never know. I've driven it 10,000 miles in the last year and 1,000 of those miles were in a 20 hour time period and no over heating...granted it was -10 out...
Tried pressurizing the cylinders with a compressor but the valves were leaky even with the rockers loosened...the cylinders looked really good...except a little more polished than I would like, no scoring or ridges at the top...so I don't think they are worn...although I will check with a micrometer...I'm thinking I should do the rings at the least...I don't suspect anything is wrong with the lower end...I hope...especially not cavitation

 

[hesutton]

If the valves where that loose, it's a good thing you are getting the heads rebuilt. One of them was going to drop and kill the engine. That certainly could explain the oil loss and blow by. If the head gasket did fail, that could be why there was water/oil contam. It stinks you have such limited access to machinists there. But, it's a small island in Alaska.......What can ya do?

What I can see doesn't look terrible, but like JD, I can't see much detail. I'd put each piston at the bottom of the stroke and look at each cylinder very, very closely to see if there is any sign of cavitation. Can your head guy pressure test and magnaflux the heads?

I'd be hard to do a compression test with leaking valves, but doing it after the heads are rebuilt and back on would be less than ideal as any problems found there would require pulling the heads yet again, wasting new headgaskets and a valley pan.

Tough situation for sure. Let us know what you head guy says/does and whatever else you find.

Heath

 

[typ4]

That looks like normal ALaska lots of idling wear to me, thats what takes out the guides
block looks fine.

 

[troy_caleb]

So I have a new few pump...if I turn the crank will I have a problem getting the pump timed enough to run decent...I think one of the shops on the island would have a timing meter...although none have a pop tester...slackers. I'm in anchorage until monday night so I won't know more unfortunately. I don't think my valve guy can do pressure testing or magnafluxing...makes me miss living in juneau...almost...that and skiing. Pretty sure I had some leaky injectors...and plenty of air intrusion on the return side which wasn't helping things. Right now...I'm thinking at least re-ringing the pistions, headstuds, IP, injectors(matched that is), oil cooler rings, return lines, gp's, gp controller-wasn't working right and broke pulling it out, and gaskets...oh...and the rebuilt heads of course

 

[hesutton]

If you're going to put new rings on, go ahead and get a hone and hone the cylinders while you've got the pistons out. If you've got the front cover off of the engine, it will be really easy to get the gear timing back to where it needs to be. If not, there are some tricks to help get the IP gear in time with the cam gear, but not as easily as it would be with the naked gear set infront of you eyes.

If you haven't taken the IP gear housing off and you aren't planning on removing the front cover, just leave the IP gear cover on. The gear won't jump time with the cover on and you can rotate the engine all you need to.

Heath

 

[whenry912]

Looks a lot like mine when I pulled the heads to do the gaskets...

 

[troy_caleb]

The head guy has almost finished with my heads. He reground all the valve seats, replaced all the guides, and decked the heads...i'm anticipating a large bill...
I couldn't find an inside micrometer anywhere but i cleaned the carbon rings out of the tops of the cylinders and the is a lip there from cylinder wear like a .004 worth of wear meaning .008 to .01 wear on the bore...there isn't a machine shop that feasible to get the engine too is there any point in re ringing the pistons or should i just look for another block?

 

[troy_caleb]

And they guy said that the heads looked as if they had 300,000 miles worth of wear, not the 109,000 that's reading on the odometer

 

[troy_caleb]

Just to update anyone who is following this at all: My heads are done 551.24 total to rebuild the heads and deck them...the cylinders are too worn to put the heads back on so I will be pulling the engine, stripping it down, and shipping it over to get bored 20 thousands over...if everything looks good, the machinist quoted 300 for boring and another 700 for the rebuild kit or something...sounds good?
On a brighter side not i got a doner truck today for free! The engine has high miles 234,000 but low blow by when warmed up and great oil pressure and preforms well...the tranny over-heated and puked out most the at. The owner had gotten a new truck and was only using the idi for firewood so he didn't feel like fixing it...put ten quarts of at in and drove it 30 miles to home and over a few passes...tranny definitly is fubarred but it's got a good engine for my truck, pretty new batteries, and pretty new snow tires...like 80 percent tread or better. And alot of spare parts for my dads 91. Will be swapping the engines out shortly and rebuilding my current one at my leisure!

 

[OLDBULL8]

If the crosshatch is worn away in your old engine it more than likely has 300K + on it. I don't think I'd bore it 20 over. Cavitation usually starts at 150K if the SCA's have not been kept up. Inspect those bores real close. My 90 had cavitation in #6 bore when I bought the truck, 6 and 8 being next to each other and fireing 6 then 8, they are the ones most prone to cavitation. The only solution would be to sleeve all the bores. Good luck with the doner engine.

 

[troy_caleb]

If I'm keeping my current transmission should i just leave it in while i pull the old block out and put the doner engine in? And I will definitely go over the block well, might even look for one with less wear to rebuild...important thing is that I have a running engine in my truck at the moment.

 

[gunz]

I dont see any reason to pull the trans. leave it in place.

 

[hesutton]

Troy, I'm glad you've got a runner to use while you rebuild the othere IDI. I bored my 7.3 20 over, but, that was before I knew about the cavitation worries. I've keep the coolant treated with DCA-4 and have not had problems, but it still worries me. Keep those newly rebuilt heads dry as possible while waiting to go on the rebuild. And, I'd coat them with some rust preventative (whatever you've got handy) just to be sure.

Yup, keeping the trans in there is no big deal.

Heath