A Tale of two engines

**Heart of Dixie** · 12-12-2005, 10:49 AM

I am looking at two used trucks. Both trucks are D units with about 300 k miles on them. One unit has a Cat 3126 and the other a Cummins ISC. Both are set up for about 300 hp. Both units have had regular maintenance, complete with records, and have had no major problems. My question is: Based on your knowledge of these two engines, which would you prefer and why?

I do not mean to open a can of worms, just trying to do some due diligence.

Thanks

**RichM** · 12-12-2005, 10:49 AM

Based on what has been posted on EO over the last few years I would stay away from the Cat and go with the Cummins.The Cummins is what is called a "wet sleeve engine" so it can be rebuilt without removing the engine from the chassis whereas the Cat would need to be pulled out,maybe rebored etc. Look into the archives in this forum,lots of engine info here.
I might add that DaveKC has had good results with his Cat engine.

**davekc** · 12-12-2005, 12:31 PM

I am with Rich on this one. If running it a year or so, the Cat would be pretty reliable. My opinion would shift to a Cummins if you are going to run it for a extended period of time.
Ease of rebuild and cost would be the major factors.
Resale at say 400,000 will be simular so no real advantage there.

Davekc

**Heart of Dixie** · 12-12-2005, 02:03 PM

Thank you Rich and Dave for the input, it has been a great help.

**LDB** · 12-12-2005, 04:34 PM

I'm going with the experts. I'd also choose the Cummins if everything else is equal.

Leo Bricker
OOIDA 677319
truck 3034
73's K5LDB
Support the entire Constitution, not just the parts you like.

**mhoy40** · 12-17-2005, 05:36 PM

did alot of research on both of these type engines when i bought my truck looked at two trucks basically the same both fl-80 both 2000 one 112 sleeper and no gen and a 3126 cat engine withh 450000 miles the other the same truck but a 84 inch sleep. and a gen but had the 300 isc cummins with 517000 miles on it after talking to several mechanics that work on deisels that wre not affilated to freightliner cummins or cat went with isc cummins for several factors the biggest being the cost to rebuild the cat engine is basically what they called a throw away engine when it goes its gone u probably have to do complete replace quotes for that were between 7000 and 10'000 dollars the isc cummins as alreadey staded is a wet sleeve wich means it dont even have to be removed from the frame to rebuild it. if u r mechaniclly inclined and can rebuild it yourself u can get away with about 2500.00. 5500 to have it done. i have driven both of these engines in the last year and preffer the cummins over the cat anyday.just check it out really good before gettig them parts are expensive fuel line to no 5 injector 95.00 #5 injector itself about 500.00 parts and labor. high pressure fuel pump 2600 plus labor air compressor 1216 dollars and change.but the truck now has 623720 and runs like a champ. just my opinion her. know matter which way u go do your homework thouroly.

**FlameMerc** · 12-18-2005, 12:05 PM

I have the Cummins 8.3 315hp in a KW T-300 24' box. Can haul 13k with very little effort. A few months ago, I was at a Shipper with another driver from a differant carrier,and we both were there to take a load to the same place.
So we decided to travel together. He had a FL70 with a Cat. When we got into the mountains of PA,and he would slow down to about 35 MPH. I was able to maintain 55-60 with no problem. Bigger is Better when it come to HP, not to mention the rebuild factor. Good Luck and Happy Holidays to you and yours...Butch :D :D :D

**davekc** · 12-18-2005, 07:41 PM

At that speed the Cat was likely only a 250. The larger 300 plus Cats will climb much better than that.

Davekc
owner
21 years
PantherII

**raceman** · 12-26-2005, 02:20 PM

> I have had two CAT 3126 engines and currently drive one every day. I have had mixed feelings over the last two years with these. One day I say they are crap and the next I love them. However I will always say Merc is right about them going up hill. Slow. Even this is different though. When I am loaded 5000 lbs or better as long as I keep the RPMs up this baby will go right on up anything. If a four wheeler makes me slow no matter how long, bingo I am crawling up the hill.

I just had to put injector sleeves in mine but other than that this has been a good engine for the 300000 of its 500000 miles. I have had front cover gasket go and a few other things but I will say it has done well for me. The other is still going as well and I think it is at about 400000.

Everybody has a favorite get what seems right to you. Used is used something is gonna creep up on you no matter what. They are both good companies and good products. Be sure you check everything you can and rebuild bothers you, others are right. get the Cummins.
>At that speed the Cat was likely only a 250. The larger 300
>plus Cats will climb much better than that.
>
>
>
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>Davekc
>owner
>21 years
>PantherII

Raceman
OTR O/O