3126 rebuild

[davekc]

Thought I would pass this along.
Ring Power Cat Dealer in Jacksonville Fl.
904-737-7730
Talked to Don Hutchison about rebuilding or replacing a cat3126
He states that per cat they no longer need to be replaced short of a cracked block.
Cat now has a sleeve installment that they use on a rebuild. They do have to machine the cylinder walls if they are pitted. Which he says is very rare. Most rebuilds are around $3,000 with warranty and $6,000 with a out of frame rebuild. Add some money if you replace turbo to have it covered under warranty as well. Most dealers tell you to replace engine in order to sell you a new one. He states that is not the case. He says only a few have ever come in that they couldn't rebuild. (because block was cracked).
I was always under the impression that they could not be rebuilt, or it was extremely expensive. He says that is a myth and is not true.
So if you need a rebuild ect., call the above.
Hopefully it helps someone out of a jam

 

[Weave]

That is good to know. Cummins has had a wet sleeve kit for the B5.9 for some time, but I never heard of one for the 3126 till now. To install sleeves on most parent bores, the engine will have to be removed from the frame to overbore the cylinders to insert the wet sleeves, unless the type CAT is using are made to fit into the original sized bores. In this case, a sleeved 3126 will lose some of its displacement with smaller bores. Subsequent rebuilds can then be done in-frame cheaply like the big engines. Kudos to CAT for coming up with something to save 3126 owners from having to buy new engines.
-Weave-

 

[davekc]

Yes, I thought the same thing but they say now that they rebuild it just like any other engine with these sleeve designs. The only exception was if the cylinders were bad and they had to re-machine them. That part would require them to pull the engine, remachine it, put the sleeves in and add a reman head.
I will keep everyone up to date as I am thinking of taking the 900,000 mile sled in for this rebuild. Rebuild and the new turbo for $5,000. Comes with cat warranty, either 100 0r 200,000. You can buy extended for 3 to 500,000, but not sure on that price.
The only thing to watch is, once it is rebuilt with sleeve design, coolant performance needs to be watched more carefully. If you don't change it for long periods, could eventually damage the sleeves like any other big truck. Original engine is not as effected as there are no sleeves.

 

[MattMO]

Great information and thanks for posting it !

 

[Weave]

Now we just have to pray that the block will take to having the sleeves in it without any cooling troubles.
-Weave-

 

[Larry]

You stated that "most rebuilds are around $3,000 with warranty and $6,000 with a out of frame rebuild." I am confussed on this. Could you be a bit more specific?

Thanks.

 

[davekc]

The difference is on a $3,000 rebuild, it includes sleeves and a remanufactured head. At $6,000, the engine must be removed because the cylinder walls must be machined. They could be pitted ect. That price would still include a reman head. Adding a turbo to get it covered under warranty would be in addition to this. If it is a out of frame rebuild, allow two weeks from start to finish. No longer than a week on a in frame.
This should give you some idea based on what they told me.

 

[Weave]

I am a little confused how they are going to put sleeves into the original bores without switching to undersized pistons? The procedure to use the same sized pistons involves removing and overboring the block to fit the sleeves. Somehow the thickness of the sleeves has to be accounted for. If they are in-frame installing this sleeve kit, it has to include smaller diameter pistons than the originals- most cylinder sleeves I am familiar with are relatively thick. Also wondering about the head. Sleeves have a little lip on them that goes over the cylinder deck, and the head pushes on this to keep the sleeve from moving in the bore with the motion of the piston. I can't see that the stock 3126 head could work with a sleeve design, this is something that has to be accounted for in design of the head and head gasket. The retrofit must use its own special replacement head. Is my thinking here right or screwy?
-Weave-

 

[Larry]

Thanks Weave. I kept reading this and became more confussed about how they could do this for $3000. It just seems like there is some information missing!!

 

[davekc]

Not exactly sure how they compensate for the difference in dispacement as you would think there would be some difference. I will have to check on that. He did say that they put a remanufactured head on it that I quess is just for this rebuild. I should have him address all the technical questions on here. I will ask him and see what he says.

 

[davekc]

I wondered about this as well, and he is saying that they have quite a few of them out there now and haven't had any problems that would make it stand out to any other rebuilt motor of a different size.
Keep in mind that I am far from the expert here, and am passing the information as I get it.

 

[Larry]

Another question about this. If they do this by going to a smaller piston, that means less displacement, which would mean less horsepower in an already undersized engine. Right?

 

[Weave]

The thickness of the sleeve walls X2 will have to come off of the piston diameter, thus decreasing displacement and some power if the original sized bores are sleeved.
-Weave-

 

[davekc]

That would be my thoughts. If they are machined, maybe they make them larger to compensate. That would require engine removal. If not, it seems like you would be giving up some power somewhere. The only other thought would be if they turn it up. Harder on the engine but cheaper than a new one. We have ours turned up and so far it does fine. Dealer turned it up with there computer. I think you sacrifice fuel economy, but at least you get some pulling power and a reasonable top end. Truck new topped out at 75, and now it is close to 90. Without a doubt this is on flat ground, no hills, no wind, and no load.

 

[Weave]

I just thought of another thing you might want to discuss with the shop. With sleeves in the original bores, the pistons are going to be
that additional thickness of the sleeve width away from the water jackets in the block, thus decreasing heat transfer to the cooling system.
With a conventional bore-out sleeve job, the distance remains the same, as the thickness of the sleeve is removed from the bore so the sleeve fits close to the water jacket. This is how they have been doing it on the little Cummins 5.9-ISB's. You bite the bullet the first time around, but subsequent rebuilds can be done in frame, and the engine loses no displacement or power.
-Weave-

 

[davekc]

it makes sense with what you are saying. I would rather pay the extra $3,000 up front to get that accomplished. Especially if you are going to keep the truck awhile. Probably not recommended on our old log truck as it is getting up there and is a old fl70. But I like that idea on our kw. I would like to get some more technical info from this guy so I can pass it along. Or anyone can call him as I listed his number earlier.

 

[D Green]

Don't know if Cat has figured this out, but many years ago, I ran drilling machines that had the old 3208 V8 Cats in them. A local machinist had a way to attach a boring machine to the top of the block, bore & install sleeves without engine removal. It was somewhat cheaper & a heck of a lot faster than engine removal.

 

[Weave]

Not to sound cynical, but that would scare me. Three reasons why- 1: Metal flash removal. Blocks that are bored should be flushed clean.
2: Decking. A block that is bored and sleeved should have its deck resurfaced to be sure it is perfectly flat. This will also be an issue with this in-frame sleeve kit. If not flat, usually a lot of head gasket failures, which are a major pain. 3: Re-boring for sleeves must be done absolutely perfectly. If things are off even the tiniest of a fraction, the engine will chew up its crankpin bearings quickly.
Sleeving an engine not designed for sleeves can in cases cause more problems than they solve. It is not a real simple thing, so it is a good idea to get all the facts about it before committing to it.
-Weave-

 

[Jimmy]

Right-ON Mr Green!!!
Same as I have watched countless times on Cummins & & Mack engines.
Put boring bar on engine deck bore hole.060-083 counterbore deck & drop in new sleeve. that way you don't loose any bore size & could possibly over-size by .020-.040& increase displacement. just hope some Jack-leg does't want to use silver paint to gain an advantage like they used to on the old 71 series liners!!!LOL!!!
Jimmy

 

[Weave]

You seem to know what you are talking about Jimmy, so help me out. What we are dealing with here is fitting sleeves into a CAT 3126, which is a parent bore engine. This is not cleanup reboring for replacement sleeves, it is fitting sleeves into a parent bore for the first time. I don't think this should be attempted in-frame for this engine, and the small trucks these engines are in probably won't allow it. Am I right or wrong? Oh, you gotta tell me what the silver paint thing was about- am familiar with the old 2 stroke Detroits, but what was the deal with the silver paint?
-Weave-