6.5 GEP turbo pre combustion cups

[Godspeed131]

Hey all I got the 6.5 pulled out from my 1152 sitting on a stand in the garage and just had a question on the pre cups. I know cracking is a common issue, and all 8 are cracked. I’m on the path to pull the heads and change them. I mean the engine is out, sitting in the garage so why wouldn’t I change them right? I’ve just not dealt with cups on idi engines before so I’m not sure how bad that cracking is and didn’t want to replace them if that’s what they are going to look like 10k miles later. I just wanted, more or less, from people way more experienced than I to either agree or disagree in replacing them. Here’s two snap shots from the borescope before I pull the heads.

 

[87cr250r]

In the right pic the pre cup is starting to lose material. That's bad. Do replace that one. In the left pic, that cracking is normal. In turbo machinery we call that stress relief cracking.

The general rule is that you don't want the cracks to extend across the head gasket fire ring. I think 8mm is the maximum crack length allowed in the manual.

 

[MarkM]

It is normal but honestly if I had the heads off I would take them down to a machine shop and have them check the heads out. Much easier then putting her back together and running into an issue. I believe the "Diamond" stamped pre-cups are supposed to be the better ones. Keep us updated.

Mark

 

[Retiredwarhorses]

Send the heads out or buy new NOS heads….I think I have one new turbo head in stock

 

[Godspeed131]

Got the heads off today. The intakes were “super sealed” lol with two intake gaskets each with red rtv in between. more is better I guess was their motto. The cup’s definitely need replaced most are all cracked and some are near, if not in the fire ring. Other than that nothing jumps out. Neither had any cracks between valves and the cylinders look good here’s a few pictures. Next step is run them down to the machine shop by work. Also dropped off the injection pump and injectors off at the shop today to have them checked out. If I get time tomorrow I’m going to drop the oil pan and check the rest, but we’ll see. Gotta try and spread the gold plated pellets of fertilizer on the hay fields if weather cooperates.

 

[87cr250r]

That engine looks fresh. I'm surprised you have no head cracks and the pre-cups are so bad. Is your pump turned up or something? Does this thing run petal to the metal all of the time?

I've moved on from head cracks. I'm convinced the head is relieved between the valves to cause it to crack there. The only real question now is whether to let them be or pin them. In either case I wouldn't junk heads over cracks.

 

[Godspeed131]

It is a non runner from Yermo, so who knows really. take it for what it is but the odometer was 2,093 miles and tach says 1402hrs. Wether that’s correct or not who knows, but that’s a lot of idle or high idle time if it by chance was correct.

 

[M1165A1]

It is a non runner from Yermo, so who knows really. take it for what it is but the odometer was 2,093 miles and tach says 1402hrs. Wether that’s correct or not who knows, but that’s a lot of idle or high idle time if it by chance was correct.

That miles/hours discrepancy wouldn't be unusual if the truck had been equipped with a shelter and the engine was kept running for power.

 

[Godspeed131]

That’s what my thoughts were, if it is correct. It did have the 200 amp umbilical going behind the passenger.