View Full Version : boring over

12-11-2002, 06:07 PM
can you bore over a cummins? if so where can i get the parts?<br>lunchbox

12-12-2002, 06:01 PM
Yes, you can bore over a 5.9. Since the B series is not sleeved. You will have to go to a bigger size sleeve or pistons. But, my question is why? Are you rebuilding it? If not, you can achieve all the hp you need by bolting on aftermarket parts and still staying within the limits of your engine. If you decide to do this. Get ALL of your engine parts from Cummins.

Rammin On
12-12-2002, 06:09 PM
You can go to .090 ... and then sleeve the bores .. or just sleeve them ... if you are there .. how many miles? or tell us what failure you had

12-13-2002, 10:57 PM
no failure just wondering, it would allow more hp like in gas engines wouldn't it? you know larger bore = more room for air and fuel.<br>lunchbox

12-14-2002, 11:54 AM
Diesel angines are not like gasser's to get power from these engines requires, timing, fuel and air. In other words the more you can stuff in the cyclinders and burn the more horsepower you make. :o

12-14-2002, 03:22 PM
Jrr-do you really beleive what you just wrote above??

12-14-2002, 08:19 PM
There are so many ways to get horsepower that are far, far cheaper than increasing displacement.<br><br>Fuel plates (or fueling boxes for 24v), GSK's, twin turbos, bigger injectors, cams, blah, blah, blah...<br><br>I have an estimated (no dyno run) 375 at the wheels and I never took the head off. Just a fuel plate, injectors, GSK, AFC springs, timing and a larger housing on my turbo. It may or may not be 375, but it hauls a$$ and only cost less than $2,000 (plus trans work).<br><br>Tackett

12-14-2002, 08:39 PM
Maybe what I should have said is the approach to turning our diesel truck engines up is not like a gasser. For one strokers, pop up pistons different manufacturers of heads with different combustions chamber designs are not an option in these trucks. We do have a few manufacturers of Cams now, and alot of people doing pumps, injectors and turbos. Until 2 weeks ago I had an experimental turbo and injectors so alot of shops are joining the free for all. As for overboring and sleeving one of these motors you are talking big bucks and custom parts. As stated above there is alot of horsepower available without expensive machining and custom parts. There are guys I know over 600rwhp and some at over 800 rwhp that i have not seen and with the stock Bore and stroke.

12-14-2002, 09:49 PM
That sounds a little better. No need expensive custom parts....you just have to be creative. Mill and lathe are very helpful. Lots of people do cams, there's only a few advertisers on these boards that sell them. And you would be surprised how cheap they are if you go straight through a cam-maker. Pumps,chargers,injectors,etc. is not new technology. Some people on these boards like to make you believe it, though.$$$$$$!!! But you are right....it's not practical for most people.

12-15-2002, 03:19 PM
how much hp/ torque can you gain from a cam change and how much difference will the cam make after you start piling on the mods?<br>lunchbox

12-16-2002, 09:45 AM
Not sure about the cams. How much power do you want? -Anthony

12-16-2002, 03:11 PM
enough power to light up 38's or 40's at will.<br>lunchbox

nascar mark
12-16-2002, 08:35 PM
The cams for sale don't really gain you any hp or torque. They are built for faster spool up, lower egt's and flatter, longer hp/ftlb curves. You can expect about 2/10th's faster in 1/4 mile due to faster spool up as power comes on sooner.