Tim Pringle
10-15-2006, 19:26
Hi all! In reading the post about a boneyard engine v.s. a goodwrench engine, I can sure put in a couple of cents worth myself, as I am also seeking some rebuild advice.
I had been torn between using the 6.2 & finding a 6.5 for my BIG project. Well, saddly, my motorhome is still "motorless", and I mean that. Well, aside from my generator, that is. See my post on a "Really big swap" in the 6.2 section. It may end up that way anyhow.
Ok, I got offered a good running 6.5 from a trusted friend at a salvage yard. I am pretty sure it did run ok. The price was right, the mileage wasnt too bad, and it was complete, ready to pick up. I bit. I thought "this is great". Notice my choice of words "I thought"...
In needing to pull the heads to install it as a shortblock, I was pretty happy to see virtually no cylinder wear & only the start of one hairline crack between the valves. Even the guides were fine! I only had the valves ground to clean them from slight wear. But, my happiness turned sour when I found piston damage on 7 out of 8 pistons! Huh.... figures. So much for 'slapping the heads back on with a stud kit' & heading on down the road. Looks like it is gonna be a rebuild. Just what I DIDNT want to have to do!
I think the injectors were leaking through & damaged the lower bottom part of the pistons (or could be heat damage???). Anyway - I am looking for some advice from experiance about these pistons. I fear if I shut my eyes & run em, they will disintegrate somewhere between here & central Mexico at the worst time. So... here we go. With my wallet pretty well drained - pistons!
THE QUESTIONS:
Do you know if the pistons in the 93 6.5 (I belive it is the 599 block) are all the same, or is each piston unique to it's respective cylinder? In other words, can I swap pistons around to get a good set?
Is there anything I should know about knurling these pistons? I usually do so when I build a gasser if I re-use the old pistons. It seems to run in my mind that the pistons on a 6.2 are cylinder matched & cannot be swapped, or is limited, but the last 6.2 I built was in 98, and I have slept since then.
Is the compression ratio different between a n/a 6.2 & a TD 6.5?
If I can swing new pistons (outch), would the .010 less on the top option reduce the compression to a safer level, or make little to no difference? What about in combo with a .010 thicker gasket? I know there has been talk about lowering the compression of the 6.5 TD, but at $1000 for the special pistons, I guess I will work with what I have available.
I took quite a hit on this 6.5 salvage yard engine. I am hoping they (the yard) will help out, maybe with some new pistons, but I may be stuck. I may end up going back to building the 6.2 with the 6.5 top end. Keep this in mind when purchasing a boneyard engine - it may run ok, but is it really ok???
One last question, does the timing gear set keep the cranks from breaking or is it mainly to help keep things in time long term?
I am blessed in the fact that I am able to rebuild my own engines, it will hurt, but not like somone who would have to pay to have it done - I think about anything from a boneyard should be purchased as "rebuildable", unless proven good.
Thank you all & I look forward to hearing from you!
Tim
I had been torn between using the 6.2 & finding a 6.5 for my BIG project. Well, saddly, my motorhome is still "motorless", and I mean that. Well, aside from my generator, that is. See my post on a "Really big swap" in the 6.2 section. It may end up that way anyhow.
Ok, I got offered a good running 6.5 from a trusted friend at a salvage yard. I am pretty sure it did run ok. The price was right, the mileage wasnt too bad, and it was complete, ready to pick up. I bit. I thought "this is great". Notice my choice of words "I thought"...
In needing to pull the heads to install it as a shortblock, I was pretty happy to see virtually no cylinder wear & only the start of one hairline crack between the valves. Even the guides were fine! I only had the valves ground to clean them from slight wear. But, my happiness turned sour when I found piston damage on 7 out of 8 pistons! Huh.... figures. So much for 'slapping the heads back on with a stud kit' & heading on down the road. Looks like it is gonna be a rebuild. Just what I DIDNT want to have to do!
I think the injectors were leaking through & damaged the lower bottom part of the pistons (or could be heat damage???). Anyway - I am looking for some advice from experiance about these pistons. I fear if I shut my eyes & run em, they will disintegrate somewhere between here & central Mexico at the worst time. So... here we go. With my wallet pretty well drained - pistons!
THE QUESTIONS:
Do you know if the pistons in the 93 6.5 (I belive it is the 599 block) are all the same, or is each piston unique to it's respective cylinder? In other words, can I swap pistons around to get a good set?
Is there anything I should know about knurling these pistons? I usually do so when I build a gasser if I re-use the old pistons. It seems to run in my mind that the pistons on a 6.2 are cylinder matched & cannot be swapped, or is limited, but the last 6.2 I built was in 98, and I have slept since then.
Is the compression ratio different between a n/a 6.2 & a TD 6.5?
If I can swing new pistons (outch), would the .010 less on the top option reduce the compression to a safer level, or make little to no difference? What about in combo with a .010 thicker gasket? I know there has been talk about lowering the compression of the 6.5 TD, but at $1000 for the special pistons, I guess I will work with what I have available.
I took quite a hit on this 6.5 salvage yard engine. I am hoping they (the yard) will help out, maybe with some new pistons, but I may be stuck. I may end up going back to building the 6.2 with the 6.5 top end. Keep this in mind when purchasing a boneyard engine - it may run ok, but is it really ok???
One last question, does the timing gear set keep the cranks from breaking or is it mainly to help keep things in time long term?
I am blessed in the fact that I am able to rebuild my own engines, it will hurt, but not like somone who would have to pay to have it done - I think about anything from a boneyard should be purchased as "rebuildable", unless proven good.
Thank you all & I look forward to hearing from you!
Tim