Mismatched 6.2 Precups

[WeaselWerks]

Hello! I've been a member of TDP since April of this year, and I've gotta say for someone who's just learning diesel-craft, TDP, its tech manuals and articles have been invaluable thus far.

I'm in the process of rebuilding a 1991 6.2L diesel for an economy conversion project. The engine is a J code with a military block casting. The heads that came with the engine have the 3-dot (A) precups, but the heads are scrap due to cracks around the valve seats. A local machine shop had a set of 6.2 heads that were rebuilt but never picked up, so they were able to make me a very very good deal. They are different from the ones that came with the engine in that they are a different casting #, have a 45-degree injector style, and have larger valves, but have no cracks whatsoever, even in between the valves.

Now here is the big question:

One head has three 2-dot precups, and one 1-dot precup. Is this an acceptable configuration, or should all the precups match? The second head may have been reworked, as such, the precups have no dots on them. Would a difference between heads cause any major problems during operation? The old set of 3-dot (A) cups are cracked, but not past where the cylinder bore ends. I am trying to build an economical engine, so as per the 6.5 precup article, the 3-dot (A) cups don't seem to be the logical choice, but in this case at least i would know the entire set of precups is matched.

Any advice?

Thanks.

[dieseldummy]

You'll want 8 matching precups. If you're going for economy snag a set of "c" cups. (Ideally you'd want "d", oh wait that's the wrong topic... ) The Diesel depot in Georgia could probably set you up or Penninsular could too. Contact info for both can be found in the vendor list here.

[Robyn]

Angled injectors are probably from a van application.
Check out Clear water cylinder head in FL
I used a set of their NEW ones on my 95 and they seem to be great. 10,000 on them now and not a hitch. Cost was great and they pay to ship back your pld heads.
These are NEW castings not rebuilt

[WeaselWerks]

Thanks dieseldummy, I'll be sure to try those places for a set of "c cups".

Robyn, as for the heads the local shop offered me, they were completely overhauled and offered up to me for $253 each with no core charge. Does the injector angle make a difference in terms of fuel economy or overall power? Do you have a ballpark price for those heads? Most of the places I've seen them are asking about $420 a piece, is this reasonable?

Thanks guys for all the advice.

[dieseldummy]

John8662 here has some opinions on how the different injector angles affect an engine maybe he will chime in with his thoughts. I'd take the deal your machine shop has. Good crack free OEM heads are a rarity, I'd rather use them than the china castings.

[WeaselWerks]

I placed an order today for the (C) cups from The Diesel Depot, as well as picking up some other parts I've been after for a while. One curiosity though, I was quoted $80 for a set of used precups, and $85 for a single new cup. Does that sound right?