Are theses heads really common for cracking? I haven't heard anything about it. Is it usually due to excessive heat?

 

ya they are prone to cracking. mine has some cracks, nothing major.

 

It's due to not enough metal between the injector bore and the valve seats. That's why they went to the 7 mm injectors.

 

so it may not be such a good idea to keep it?

 

Nope, better let it go like a hot potato--I'll give ya 50 bucks for it

Seriously, While the 9mm heads are more prone to cracking, that doesn't mean it's trash. There are just too many of these old trucks still rolling down the road with the original head and gasket for me to be too terribly concerned one way or the other. FWIW, Piers is having a sale on fully assembled heads for less than a grand, so there you go. We're all gonna get head work done eventually, don't 'cha know


edit:I can't find that Piers sale....maybe I was just wishing out loud

 

I like the fact that the injectors are 9mm. I personally think they have more potential. I'd hate to spend the money on getting it ported and polished if I cracked on me.

 

I likely won't have my head worked on when the time comes. Piers takes all the guesswork out for a fair price.

 

Don't forget the high dollar shipping to have that heavy head shipped all the way across the country. Piers is on the west coast. O-ringing ~$300, porting extra$$, head $495, doesn't say whether or not you have to ship your old head back to them. New valves, etc included? Doesn't say. Don't be afraid of your old head. Don't be afraid of a few cracks or let the machine shop tell you its too bad and that you need a new head. FWIW, I've heard the big time pullers machine their injector bores to 9mm so they can have a bigger/higher flowing EDM injector built. The old casting is not available anymore, gone with the dinosaurs, as with many of the old 1st gen stuff...

 

if the head gets some cracks can it be repaired in any way just to help keep the strength?

 

Cummins has what it refers to as 'acceptable' cracking. Past that point, a new head is in order. This is why it's best to have a machine shop familiar with diesel engines do any work you may need. Gasser shops see a crack and sometimes automatically think the casting is scrap.
greg

 

The heads at PDR are brand new heads....I don't THINK there is a need for cores.....just call and check...he'll give you a good deal.

pb....

 

I'm kinda running into a dilemma here too. I wont to get my head o-ringed and ported. Now i have both a IC head and a Non-IC head, but i don't know which one i should get done. What do all of you think. Shipping is not a problem as Piers is close to me. A 9mm EDM injector would produce some big power When i first got my non-ic truck i wished it would have been a IC truck, but now that i've added a IC/hybrid turbo and found out that the non-ic motors had some extra special features..... I love it

Jeff

 

Jeff if you have both heads already, by all means have the IC'd head ported and work done to it. More injector options for the IC'd head, you can vary the injector washer thickness with the IC'd head/7mm injectors. Non-IC'd head with 7mm injectors, all you get is a thick washer/adaptor. You can't play with washer thickness to vary the injector protrusion.

I also think I've read the newer heads flow more air. Don't quote me though.

 

Yes by all mean do your work to the 7mm head.
Cummins made a product improvement by changing from the 9mm to 7mm. Take advantage of that. They did it for a reason. To handle more heat.
Plus all of the performance injectors are 7 mm.....then you can take advantage of that plus have all the washer thickness options.
Jay

 

Can you use the 9mm injector adaptors with any injector for the 7mm head? Or is that just for POD's?