Engine/Transmission (1998.5 - 2002) Boring One Cylinder Only

[Partyat33]

Engine seems to have injected some metal into #6. I know the manual is clear you can bore on cylinder or any combination. I also know every engine builder I can find says that is a bad idea. At ~200 per piston kit, I would surely like to replace one only and go with new rings on the other five.



So, if you have ever done this or know somebody who has, please post some information on how it worked out.



Thanks



Dennis

 

[Mhannink]

i ahve heard that you can get oversized pistons that are the same weight as original, this is the main concern with boring only one cylinder, however and probably why engine builders suggest against it, is the larger bore although only slightly bigger tends to create more power then the other 5, its a bit unbalanced and could potentially cause problems. my suggestion would be to bore it out and press in a sleeve, that brings it back to exactly the same size as the rest, this would eliminate vitually any concerns with longevity. if you do this however make sure the machine shop leaves a lip at the bottom to set the sleeve on, otherwise it could get sucked into the crankcase and really cause problems, i have seen it happen.



also you might look into aftermarket pistons, pure diesel power offers what appear to be some pretty good ones at a lot less than $200. might make over boring all 6 and installing good pistons a more palletable idea.



Stock Replacement & Upgraded Parts for the 2nd Generation Dodge 24 Valve Cummins

 

[chipster]

Engine seems to have injected some metal into #6. I know the manual is clear you can bore on cylinder or any combination. I also know every engine builder I can find says that is a bad idea. At ~200 per piston kit, I would surely like to replace one only and go with new rings on the other five.



So, if you have ever done this or know somebody who has, please post some information on how it worked out.



Thanks



Dennis

I have built a couple dozen different chevy small and big block engines with only one or two cyls . 030 over and the rest std. all went into work trucks or motor homes. most pulled heavy trailers and had NO problems. most went over 100,000 miles before they were sold or traded. in my over 50 years of engine building, I`ve seen more than 20 chevy truck engines with only one or two cyls . 030 or . 020 over from the factory. most were in heavy duty one ton or larger trucks. If cummins says it`s okay to mix oversize pistons in the same engine, I believe`em. all oversize pistons I`ve ever seen, weigh the same as a std piston, within a gram or two. the power difference between cylinders is immeasureable. if you want to run only one oversize , do it you`ll never be able to feel the difference. the reason I built `em with only one or two oversize pistons was there was rust, or scores, in those cyls, and the customer coulden`t afford a whole set of pistons. in a lot of them we used good . 030 over used pistons, no problem.

 

[Bob4x4]

Cummins will do one cylinder only,and they

Are a very conservative group.....

Do it and don't look back

 

[HBarlow]

That's good information provided by chipster and Bob. Answers which I did not know.

 

[dresslered]

I've heard of this and am not onboard myself. However, if Cummins says so, I guess it is alright--however, they did let their mighty-6 go into a Chrysler.

 

[Joseph Donnelly]

For me, the decision would depend on how the engine had been used, and the mileage. Ring grooves in the pistons can wear also, so new rings might not be enough (with honing to seat them, of course). Mahle makes sets of pistons that are high quality and reasonably priced.

 

[Partyat33]

For what its worth I did all 6. Got a good deal on some aftermarket Mahle pistons. We will see how it goes from here. Having some ring fitting issues. Put up a separate thread.

Thanks

Dennis

 

[BIGNASTY]

Question If you bore the cylinders and put sleeves in what hold's them in place? On the big cummins motors BIG Cam 2 Im familiar with the sleeves sat in counter bores in the block and the counter bores had to be machined or shimmed to all be the same. And then 1 of the 3 heads held the sleeve in place If you sleeve our cummins motors what holds them in place just a pressure fit? Ive never been in one of our motors just a curiosity thing thanks for the info. BIG

 

[BIGNASTY]

I really need to read the post's all the way thru if I had done so Mhannink gave me what I was looking for. A counter bore in reverse and the head on top. LIVE AND LEARN. How well does that work ? If it were me I would bore all if it can be done with enough cylinder thickness left. And go oversized pistons. I understand the piston weight could be matched but the cylinder pressuere would have to be different if just 1 or 2 were done. I have seen guys rebuild cummins motors that way. If you add 1 new hole do 2 holes as long as they were under the same head.

 

[jughead]

my buddy will bore one put sleeve in it bore back to std seen him do it several times on s b chevy should work on cummins????