Morning Guys,

I need some opinions on the damage in these pics. The pistons are 3 of the 4 on the passenger's side. It looks like something broke off, possibly a glow plug tip and beat the tops up pretty good. My mechanic tells me the pistons need to be replaced because of the damage close to the edge. He said it will likely pinch the top ring and prevent if from sealing properly.

The head has a gouge out of it right beside the water port. Mechanic says it's from previous head gasket failure and will not seal properly unless machined.

Please let me know what you guys think. This is the used block and one of the heads from the used engine that I bought that I was going to put in my truck.

It's hard to tell the depth of the marks in the pics but they are quite deep. Also see if you detect any cracking between or around the valves in the head pic. We thought we found a crack but it's hard to see anything in the pic.

Thanks,

Dave

Here are a few more pics of the pistons.

Dave

The pistons don't look good, i'd think about replacing them and maybe building one of the 18:1 engines. :D That head area is pocketed with corrosion and will need to be machined or i'd bet on a water leak. Machine both the same amount and you'll have a better setup.
Don

Pistons and head look rough - do you still have your 506 engine?

My 506 is still in the truck and running...for now anyway.

Dave

If I were you, I would use the pistons out of your 506 and have your 506 heads magnafluxed.

Between the two engines you should have plenty of useable parts. Listen to your mechanic, he sounds like he knows what he is talking about.

New/used block would have to be bored out. It's a 660 casting with 6.2 cylinder bore diameter. Would be getting into big bucks for something that I thought I was basically going to be able to swap parts from one to the other.

Dave

Resurfacing the heads should be a relatively inexpensive venture. They should only cost about $40 per head to get the sealing surface reground. Make sure the machine shop you are using machines the heads with a surface grinder and not a resurfacer with a carbide cutter/cutters. The pre-cups will likely suffer chipping or worse damage with a cutter.

The 6.5 pistons have a hard steel or cast iron insert that holds the upper "keystone" compression ring in place. Your mechanic is correct about pinching the upper ring in gasoline applications but most diesel engines use a keystone ring in the upper groove. It is unlikely that the piston ring is siezed up in your engine. Does that mean that you should be using the pistons with damage over? I would not. Damage on the crown means damage on the hard anodized surface. Dips and peaks on the surface will create hotspots, marks through the anodizing can eventually develop into cracks. GM started anodizing pistons on the 6.5 in late 1993 to prevent heat damage, take a look at all the cracked pistons in the 6.5 I just tore apart. It was a 1993 with no anodizing on the pistons.

If the block that you intend on using has its bores in good shape and you need to save a buck find some used pistons, get your block cylinders de-glazed and put a new set of rings in it.

I maybe missed it somewhere but I am unsure of what your intentions are for the engine and what sort of money you were or were not trying to spend on it.

If I were you, I would use the pistons out of your 506 and have your 506 heads magnafluxed.

Between the two engines you should have plenty of useable parts. Listen to your mechanic, he sounds like he knows what he is talking about.

X2

Resurfacing the heads should be a relatively inexpensive venture. They should only cost about $40 per head to get the sealing surface reground. Make sure the machine shop you are using machines the heads with a surface grinder and not a resurfacer with a carbide cutter/cutters. The pre-cups will likely suffer chipping or worse damage with a cutter.

The 6.5 pistons have a hard steel or cast iron insert that holds the upper "keystone" compression ring in place. Your mechanic is correct about pinching the upper ring in gasoline applications but most diesel engines use a keystone ring in the upper groove. It is unlikely that the piston ring is siezed up in your engine. Does that mean that you should be using the pistons with damage over? I would not. Damage on the crown means damage on the hard anodized surface. Dips and peaks on the surface will create hotspots, marks through the anodizing can eventually develop into cracks. GM started anodizing pistons on the 6.5 in late 1993 to prevent heat damage, take a look at all the cracked pistons in the 6.5 I just tore apart. It was a 1993 with no anodizing on the pistons.

If the block that you intend on using has its bores in good shape and you need to save a buck find some used pistons, get your block cylinders de-glazed and put a new set of rings in it.

I maybe missed it somewhere but I am unsure of what your intentions are for the engine and what sort of money you were or were not trying to spend on it.

and X2

Jason,

Thanks for the info. Here a bit more of the story.

I'm dealing with a suspected cracked block on my truck. No way of knowing for sure until it's torn apart. I'm assuming worse case scenario so I went in search of a used long block that would be useable without and sort of rebuilding. I found this "complete but disassembled" 6.5 out of a 95 3/4 ton. The seller stated that it was pulled because of a cracked head which was professionally repaired (water passage sleeve under the crack between the valves). The other head (the one in the pics) was magnafluxed and showed now cracks but no mention of needing to be resurfaced. I asked some questions about casting numbers. It turns out that it's a 660 casting that has not been bored out, so it's a 6.2. I did a little more research and found that it would work in my application, not idea, but it would work. I don't have endless amounts of money to spend on this and my intention was not to buy something to rebuild. The seller told me that there was some light surface rust in the cylinders from anti-freeze that was not properly cleaned out and that the cylinders would have to be honed. I did not have a problem with that but I was not aware that the pistons would have to be removed for it to be honed. That's my fault, not the sellers. I bought this used engine with the intention of using the long block and to sell off the extra parts to help cover my expenses. I've managed to sell off most of the parts but now it's looking like I won't be able to use the block as I had intended.

So after inspection we find the damage to the head which the seller says is not an issue and the damage to the pistons which the seller also says is not an issue. My mechanic says different, the seller questions my mechanics knowledge.

My intention was not to buy a rebuild project but it's looking like that is what I'm dealing with. I don't have the skills, tools, time or facility to do this myself and I don't have the money to spend on extra parts and labour to have it rebuilt or have internal parts (pistons etc) swapped from one to the other.

There you have it. I'm not looking for sympathy. I'm just letting you guys know what I'm dealing with.

Ultimately I'm looking for opinions on whether it came be used in the condition that it is in or if pistons have to be replaced and heads have to be machined.

Thanks,

Dave

I would not use it as is, i think it would leak water within a few months and the pistons would crack. I've been building engines since the mid 70's and had 1 failure in 22 rebuilds. I over-revved that one, so that's my fault. Maybe grab used pistons on flea-bay, some rings and surface the heads at the minimum If the rods/mains passed the quick/dirty plastic-gauge test. the way it sounds, your mechanic wants to stand behind what he does, so he does not want to install "marginal' equipment and i can't blame im for that.
Don

X2 on what daustin said. You need new (to the engine) pistons and at least get the heads checked out. I don't think the seller knows much about engine machining, that won't fly (Ok maybe it will.... fly apart that is)

I can give you a number of a guy that might have some 6.2 pistons. His shop is out in Bowmanville though.
He's a good guy and has a ton of gently used 6.5/6.2 parts.

The crank, rods and pistons in mine are "used" and "new" to the engine.

Could be the camera angle, but I don't see any oem hone marks in the cyls, which could mean repeated bouts with overheating - the deck and head surfaces appear to reinforce that - broken glow plug in the cylinders and water account for the piston damage - not useable, as is - not useable with new rings, even with no cylinder ridges
- would never use a sleeve-repaired head, as that further restricts coolant-flow thru the valves\precup area - only one repair would mean that cyl would always run hotter than the rest - one head with 4 repairs would mean that bank would always run hotter than the other bank
- block needs to be decked, heads need surfacing: requires much thicker head gaskets to maintain same intake manifold placement
- can't have 6.2 pistons flycut, re-anodized for 18:1, because 6.5TD piston crowns are ~0.060" thicker than 6.2 crowns for turbo use, also losing those steel stiffener reinforcements in the process (makes 6.5 pistons same weight as 6.2 pistons, requiring no rebalancing of rotating assy - can use same crank\rods for either engine with no rework)

This is all moot, unless you've had the pan off and verified the mains-webbing
- the 599 block is cast for dual bore, 6.2 or 6.5, so the 6.2 version is way stronger
- any 6.2 block is stronger than any 6.5 block because of the smaller bores, less mains-web undercutting
- the cracks generally start between the outer main-cap bolts and the pan-rail, so check there

Agreed, not useable as is, impo - Peninsular carried 6.2L 18:1 pistons at one time, would be my rec, if the block magnafluxes out sound and the deck can be minimally resurfaced - any head resurfacing will compound the intake manifold problem, requiring re-cutting the intake flanges - don't want to run 0.100" thicker head gaskets to make up for reduced head-to-crank dimension, in an 18:1 Diesel street motor

I am pretty much that same opinion as the other guys. Mechanics have to cover their azz. Even though you and your mechanic might have a good relation I promise that he could tell you a couple of costly horror stories. They usually go something like this: Mechanic diagnoses problem, customer convinces mechanic to go cheap on the repairs, vehicle comes back in worse shape than before and mechanic has to eat the bill. I am not pointing fingers at all but simply stating the mechanics point of view. Add that to his correct diagnosis of your engine needs and there is no question.

Before you do anything else or stress about the engine any more pull the pan off and take a peek. You can remove the center three main caps quite easily and inspect the blocks for the cracks that are mentioned above. Do not bother to do anything else until you do that. The oil pan only uses silicone for sealing, so you will not be out a gasket for that when you take a look inside. If all is ok with the bearings they can go right back into the engine as well.

If the block is cracked you should be looking for at least a partial compensation from the guy that sold you the engine. If that is the fact you are better off moving on to another engine.

Take the pan off and if you need a hand with some coaching through the proccess and inspection myself and the others are surely willing to help.

Thanks for the input everyone. The seller has made good on my request for compensation. As to whether I end up using the block remains to be seen. If anyone is interested in a project for cheap let me know. :D

Dave

Hey, I might have missed it somewhere but you still don't know for sure your block is cracked right ? Maybe you'll get lucky. That really sucks that the guy missrepresented the motor like that. I could never in good conscience sell someone a junk motor. Maybe the 6.5 Mafia needs to pay the guy a visit.....:D Also Just I thougt and I may be way off but IF your motor is in good shape would it pay to just buy a block and a freshen up kit ? Just trying to throw out some ideas.

Thanks for the input everyone. The seller has made good on my request for compensation. As to whether I end up using the block remains to be seen. If anyone is interested in a project for cheap let me know. :D

Dave

He gave you your money back and let you keep the parts???

He gave you your money back and let you keep the parts???

Some of it. Enough to make both of us happy.

Kenny,

He did not misrepresent it intentionally.

The issue has not been that the block is possibly cracked. It's the one head and the pistons. It's been worked out and I doubt I'm going to end up using the block. It is probably still very usable, it just needs a litte rebuilding than I wasn't counting on. I'm going to have to re-explore my options.

Any issues with the seller have been resolved so there is no need to assemble the mafia. :D

Dave

OK. Just hate to see someone get ripped but sounds like he did the right thing. Probably just as well. Don';t know if we coulda go there with all the domestic plane problems...:D

dave how did you arrive at the dianosis that your block is cracked?
(in your truck)
nick

Nick,

That is a good question. Low coolant. Excessive glycol in oil. Pressure testing the system. To be honest I really don't know that it's cracked for sure and wouldn't know until it was torn apart. I, and the mechanic, are assuming worst case scenario and going based on that.

Dave

Nick,

That is a good question. Low coolant. Excessive glycol in oil. Pressure testing the system. To be honest I really don't know that it's cracked for sure and wouldn't know until it was torn apart. I, and the mechanic, are assuming worst case scenario and going based on that.

Dave

i,d tear into it first before i assumed anything,. you know the old saying about AssUming,.I,m pretty sure you could rip the heads off yourself,.
you got an oil cooler in the rad? oil in the coolant?
Now that it's mild out,. drain the glycol out and replace it with straight water,. thats not so hard on all the bearings,.if you're driving it,. you can change the oil once a week till you can get to it,.glycol murders babbitt,.
Nick

Nick,

I don't have the time of the facility to start tearing an engine apart, not sure if I have the skills either. :D

I hate to make the assumption that it's a cracked block but I also hate to pay a mechanic to change the gaskets/heads only to find out it's the block.

No time to think about is right now. I've got one foot out the door on a trip to Maryland for the weekend to run 2 of my dogs in a hunt test, no I'm not taking my truck, I'll get to figuring my situation out when I get back.

Dave

Nick,


I hate to make the assumption that it's a cracked block but I also hate to pay a mechanic to change the gaskets/heads only to find out it's the block.
Dave
i understand,. but paying for a look see might still be cheaper than the route you're going,. a decent mechanic will find the problem with the heads off,. if the heads and gaskets are fine,. then you,ve a set of heads to use,. you need a short block,. or a block you can put your reciprocating assembly into,. you were already going that route with an unknown quantity,. why not do it with yours,.
best of luck with the truck,. and the dawgs,..
Nick