Diesel Place banner
21 - 40 of 50 Posts

·
Super Moderator Eco-Logistical
Joined
·
4,313 Posts
Of course… if you had the intake open during the swap… something could have fallen into the ports and be sitting on a piston.
 

·
Registered
Joined
·
17 Posts
Will the torque converter spin freely on its own? Any chance it's binding in some way with the flex plate ?

Edit- I read the thread again, I see the TC was pushed back. The flex plate is correct size compared to the old one?
 

·
Registered
95 K2500 Suburban, 6.5L
Joined
·
9 Posts
At nearly 400,000 miles, is it possible that a 6.5 could reuse the original pistons and only hone the cylinder walls before Installing new rings? 400k is nothing for a heavy duty diesel like in a semi truck, and they can usually be overhauled "in frame" without being bored out and having to have oversized pistons and rings - but would o be lucky enough to get away with that on a 6.5? Id like to put in new rings, gaskets, bearings, oil pump, etc... But without the expense and time associated with new pistons and having the cylinders bored out. Something is up with my 6.5 and it won't make a full revolution anymore even with the glow plugs out and the torque converter unbolted - if you spin it all the way around either direction, it stops in the same spot every time. This is while turning the engine over with a 24" breaker bar using the crank pulley bolt. It has 3 or 4 tight spots on the way around, but this one spot it just won't rotate through - ive pushed and pulled so hard that I though I was going to snap the breaker bar or the enormous crank pulley bolt. Anyway, its probably going to have to be taken apart but I sure don't want, nor do i have, thousands of dollars to spend completely rebuilding this thing. I love the truck and I've had it for about 15 years now so I really hate to get rid of it. But, its got a decent amount of blow-by now and since it's going to need work internally now, now is gonna be the best time to do an overhaul if i can in fact get away with that. If not, I may have to get something else unfortunately. Anytime the word "diesel" is involved, even if it isnt an especially popular like the 6.5, the price of a replacement engine goes up. A lot. Looks like about $4,000 USD for a reman 6.5 and that's just ridiculous.

Anyway sorry for the rant - but what do you all think about a re-ring "overhaul" of a high mileage 6.5. Is it possible that it would work and be worth the cost and effort?

Sent from my Pixel 2 using Tapatalk
At 440,000 mine finally blew a head gasket. We tore it down to the short block, still in the truck, and simply replaced everything from the heads up (except the injection pump), including the turbo, timing change, damper, rocker arms, etc. I also replaced every rubber hose under the hood I could find, being careful to use the correct hoses for things like the turbo oil return. It runs great, no issues at all. Once thing I didn't do that I wish I had, when the heads are off, replace the lifters. Removing the heads in the only way to get them out so take advantage of that. I didn't know that until after the heads were back on.
 

·
Registered
Joined
·
783 Posts
At 440,000 mine finally blew a head gasket. We tore it down to the short block, still in the truck, and simply replaced everything from the heads up (except the injection pump), including the turbo, timing change, damper, rocker arms, etc. I also replaced every rubber hose under the hood I could find, being careful to use the correct hoses for things like the turbo oil return. It runs great, no issues at all. Once thing I didn't do that I wish I had, when the heads are off, replace the lifters. Removing the heads in the only way to get them out so take advantage of that. I didn't know that until after the heads were back on.
"At 440,000 mine finally blew a head gasket." Only 440,000 miles and the piece of crap blew a head gasket? GM junk.
 

·
Premium Member
1995 Chevrolet Silverado Z71 6.5 TD
Joined
·
517 Posts
Already have the glow plugs out. Still have the same issue. I had wondered about that myself

Sent from my Pixel 2 using Tapatalk
Pull the heads and that will tell you if you have rust, hydro lok, cracked pistons.
 

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #27 ·
Ok here's an update. I finally got a chance to pull the heads off. Without the heads on, the crank and cam both make full 360 degree revolutions without an problems. There was antifreeze in the passengers rear cylinder, but I believe that it came from the head as I removed it. It tipped backwards as it pulled upwards on the front to loosen it up after removing the bolts.

Therefore I believe that there must be a stuck valve in one of the heads, i cant think of any other explanation. There's no way it could've been hydrolocked even if the antifreeze i saw in the cylinder was already there (i assure you that it wasn't, tho) since the glow plugs were out of it.

I am amazed that even after 385,000 miles, you can still see the crosshatch marks in the cylinder walls. I've been inside many gasoline engines with far less miles than this on it that had far more wear in the cylinders. They've always had a ridge at the top that you could feel with your fingers and never any visible crosshatch.

With this said, I think that I could hone the cylinders and install new rings on the existing pistons without any problems.

The cylinder heads however i am not sure about. There appears to possibly be cracks in between the intake and exhaust valve for 3 or 4 different cylinders. The cracks don't appear to stop at the valve seat, and not into the valve seat nor any further up than that. The valves and seats all look pretty good to me, but there is/was some really really tough carbon or something built up on a few of the intake valves. I scraped and wire brushed them while trying not to gouge or score them up any. The intake ports were oily and the intake valve seals (o-rings) were brittle and fell apart on the few valves that I have removed so far. See the attached pictures and tell me what you all think about them. I talked to to the machine shop today and they said they would clean/check and do a valve job if necessary for $315 (plus parts) for the pair which sounds pretty good to me. The only thing I am concerned about is those cracks between the valves.


Sent from my Pixel 2 using Tapatalk
 
  • Like
Reactions: 56pan

·
Administrator
Joined
·
20,216 Posts
At a minimum have those heads checked and tested.
 
  • Like
Reactions: Dadddyoh

·
Premium Member
1995 Chevrolet Silverado Z71 6.5 TD
Joined
·
517 Posts
Looks like one side is running better than the other with one head valve surface being black from I would assume diesel sludge.
 

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #30 ·
Looks like one side is running better than the other with one head valve surface being black from I would assume diesel sludge.
I must've cleaned that one up some before I took the picture there's no gasket crud in the water jackets or anything like that in that picture like there is on the other head...

Sent from my Pixel 2 using Tapatalk
 

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #31 ·
Looks like one side is running better than the other with one head valve surface being black from I would assume diesel sludge.
Upon looking at the pictures again, picture 4 is the passengers side head and picture 9 is the drivers side head, before any cleaning was done. I remember because the first head i pulled was the passenger side one and i stood it up on its end in front of the truck on a piece of tar paper that was laying there for some unknown reason. The drivers side head I laid down on it's side on a red block. The other pics of the heads are after i cleaned the bottom side so I could see things better.

Sent from my Pixel 2 using Tapatalk
 

·
Registered
Joined
·
1,108 Posts

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #33 ·
Is that piston melted or is it just me?
Ill look at it closer but I don't think so, it has a lot of carbon built up on it tho

Sent from my Pixel 2 using Tapatalk
 
  • Like
Reactions: Dadddyoh

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #35 ·
That motor is past wore out, just because you can see what looks like cross hatch, doesn't mean there is anything there for the rings to seat to...
I think the rings are worn out, but I think the cylinder walls are OK. It had blowby, so something is certainly worn out. I think im going to hone the cylinders and put in new rings when it gets put back together tho. The cylinders look great to me.

Sent from my Pixel 2 using Tapatalk
 

·
Premium Member
1995 Chevrolet Silverado Z71 6.5 TD
Joined
·
517 Posts
I think the rings are worn out, but I think the cylinder walls are OK. It had blowby, so something is certainly worn out. I think im going to hone the cylinders and put in new rings when it gets put back together tho. The cylinders look great to me.

Sent from my Pixel 2 using Tapatalk
Are you going to send the heads in to have them checked and at least surfaced.
 

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #38 ·
Are you going to send the heads in to have them checked and at least surfaced.
Yes. The machine shop I use is running a month behind on work right now though. I'm going to look and see if I can find another one that can get to it quicker because I really want this truck back asap.

Sent from my Pixel 2 using Tapatalk
 

·
Registered
Joined
·
2,734 Posts
Discussion Starter · #39 ·
My eyes aren't good enough to gauge taper and roundness.
No, but not having any ridges or scratches in the cylinder walls is certainly a good thing. Its better than any gasoline engine that ive ever had apart.

Sent from my Pixel 2 using Tapatalk
 

·
Ronald Reagan fan
Joined
·
4,680 Posts
No, but not having any ridges or scratches in the cylinder walls is certainly a good thing. Its better than any gasoline engine that ive ever had apart.

Sent from my Pixel 2 using Tapatalk
Try using a ball/flex hone to do the honing pattern.Some guys use the three legged hone which is okay too.The ball hone does a pretty good job overall.I bought a couple different grits from eBay.
 
21 - 40 of 50 Posts
Top