Cylinder Wall Question - Head Gasket Replacement (1 Viewer)

[btslaser]

First post... I've been reading MUD for sometime and it's simply incredible how much great information there is on this site. Thank you all. It's one of the reasons I started looking at cruisers.

I recently purchased a 1995 FJZ80 with a known head gasket issue. Overall, the truck is in great shape, has lockers, and I got it for a good price. It started and ran fine, would idle at the proper temperature all day, but when pushed it would start to overheat. I did a cylinder pressure leak test and cylinders 3 and 4 had air coming into the radiator. So the plan was to remove/rebuild the head and do the normal PM when in there. The head removal process went fine and it's now at the machine shop getting rebuilt.

My question is that I have some marks on the walls of cylinders 3 and 4 (see picture attached). You can barely feel anything with your finger nail, it's almost like buffed shiny in these places. Is this a major problem? What can cause this? Anything I should do?

 

[sbman]

Without removing the piston, hard to tell what caused it, but it is certainly an area of concern. The only solution, unfortunately is to remove the block and do the bottom end. If you can feel it with your fingernail, I would say you aren't going to be happy for too long before it has to be dealt with. Other than that, you can put it back together and hope for the best. Thats some heavy rust in the cooling passage, seems like the engine may not be cooling properly partly due to poor heat transfer through all that internal rust.

You might want to just find a used short block in good condition to bolt your newly rebuilt head onto and then swap it in.

 

[Whileemptyheadsdream]

Possible cracked ring. Obviously you have a heat Issue, that engine needs to be hot tanked. All cooling and oil passages need to be clear. Decked and Inspected by a professional shop. If you just replace the head Gasket you can with reasonable certianty expect to blow It again. Water pump, radiator all hoses and rear heater hard lines, or do run around all connected cooling Items. There Is more but a good shop will know what to do...Good Luck..!

 

[elhombre]

What I don't see is a bunch of carbon built up on the top of the piston or where the "fire ring" should be. How carboned up were the other cylinders? I think it has be run for a while with the blown HG. Antifreeze gets into the oil and eats up the bearing surfaces. How did the oil look? Was it milky white? I too believe you are going to have to drop the pans and dig in further if you want to use the Cruiser for more than a hunting rig.

Used engine may be your best bet.

 

[Pin_Head]

It is no bueno.
It is caused by metal or some other piece of hard stuff that is stuck in the piston at the top ring.
The options are to rebore and replace the pistons and rings or button it up and run it or flip it. It is probably going to burn oil. If it was me, I would just button it up. I would not bother rebuilding the head.

 

[half k cruiser]

1. the only thing you should be able to feel with a fingernail is the ridge at the top of the cylinder. This can be taken out with a ridge reamer.
2. there is no carbon on those two because of the leak, it steams out the cylinder, not really a big deal as long as moisture doesn't sit in the cylinder and cause pitting.
3. Your best bet is to take it to the machine shop and have them take a look. It may be that you can just get a set of NPR rings and have them step hone the block for you.
4. Worst case you may have to bore the bottom end and throw in the next size up pistons.

 

[btslaser]

What I don't see is a bunch of carbon built up on the top of the piston or where the "fire ring" should be. How carboned up were the other cylinders? I think it has be run for a while with the blown HG. Antifreeze gets into the oil and eats up the bearing surfaces. How did the oil look? Was it milky white? I too believe you are going to have to drop the pans and dig in further if you want to use the Cruiser for more than a hunting rig.

Used engine may be your best bet.

All the cylinders have quite a bit of carbon on them, they all looked pretty similar, #6 was a little different. The coolant definitely had some oil in it, but the oil looked ok from the dipstick. I might drain the oil this weekend to see for sure.

 

[sbman]

Used short block is the cheapest, easiest fix. Rebuild with bore is a lot of dollars and time. A good scrap yard will let you inspect the bores and bearings. Find one with no scratches and bolt your head on it, swap it out. Job done.

 

[btslaser]

Used short block is the cheapest, easiest fix. Rebuild with bore is a lot of dollars and time. A good scrap yard will let you inspect the bores and bearings. Find one with no scratches and bolt your head on it, swap it out. Job done.

Thinking this might be the best thing to do if I can find a short block. If the cylinders were in good shape I'm tempted to replace the rings and button it up if everything checked out like this build:

While at it with engine rebuild question

Any short blocks available in DFW...