WeaselWerks
11-13-2006, 23:37
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.
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.