C27 overhaul

[absoluteyukon]

Hey all, currently have a C27 on the table of healing, figured I'd post some pictures of the job as it progresses for anyone who might be interested. Some background on the job; engine is out of a Cat MD6250 mobile drill, around 10k hours total runtime. Came in locked up solid. Cut filters, dropped the pan, complete carnage. #1 and 2 main bearings welded to the crank, #'s: 1, 2, 11 and 12 connecting rods welded as well. #7 main wasn't far behind. Crankshaft was toast and the customer was SOL on a core for a reman option (if it was even available, which it wasn't) so they elected to have it overhauled by us. Got some new caps, our machine shop line bored the main bores .025" over, put in a few new lower liner bores, stainless steel inserted 8 water ports and milled the decks down .005" to clean em up. I prepped up the block and gave it a fresh coat of paint and started assembling it yesterday when the parts arrived. I've still got the old crank on the shop floor, I'll take some photos tomorrow and post em up. Lemme know what ya think, cheers!

 

[mg2361]

Nice work absolute!

I know what picture Vetech is going to home in on!

 

[Nige]

I assume you have access to SIS. I suggest that you make sure to do all the latest updates on the fuel lines around the top of the block/cylinder head area when you rebuild it. There have been multiple ones for all C27 engines over the years, I guess it all depends what vintage the engine is. Also you need to be anal in getting all the right clamps in the right place with the right hardware and making sure nothing rubs on anything. One I recall was that a fuel line could rub on the main alternator cable - not good. Any hose that springs a leak blows high-pressure fuel right on the turbos. Make sure your fire suppression system is up to snuff.

In fact when it comes to the latest and greatest regarding fuel lines the D10T C27 installation is usually at the head of the line as regards improvements. As well as your engine S/N prefix I suggest that you check out whatever is listed under RJG (D10T) or RAB (D10T Series II) S/N prefixes

Don't ask me how I know all this ...........

 

[Nige]

This is what I'm talking about.........
The red is just one of the many locations where electrical wiring can rub on fuel lines.
The blue is where the later engines were improved to eliminate kinks like this in flexible hoses. The new hoses are part steel line with a flexible hose on the end of it instead of the 100% flexible hose in the photo. See below.

 

[Nige]

As an anecdote I even hd to pull up our dealer (at the time) when they were rebuilding a (very) early D10T engine for us. They simply replaced the fuel lines with what was listed for the engine Serial Number instead of carrying out the updates. Red faces everywhere because the fuel line updates had been the subject of more than one Red Top over the years. Resulting from, I suspect, multiple dozers burning to the ground ........

 

[absoluteyukon]

Yup, I definitely have access to SIS. Still getting used to 2.0 so I tend to grab the old field laptop first out of familiarity. Thanks for the advice on the fuel lines, Nige. We stock Greenline (Pulsar) products and press hydraulic hoses in-house. I like to make my fuel lines out of this: (https://www.pulsarhydraulics.com/buy/product/151h-06/2698?ID=/Hose/Truck-Hydraulic-Hose/dept-1AST), definitely going to make sure everything is nice and secured with no interference. Engine SN: TWM5493. Time to go to work!

 

[Nige]

I'm still getting up to speed with SIS2.0 as well. Certain things I could do with "legacy SIS" I still can't do with 2.0 but it seems that 2.0 changes almost daily to include more & more of the functions of the old system. The one thing I DO like is that the back arrow on the browser now works 100% of the time instead of as & when it felt like it on the old system.

Our drill engines were TWM-prefix (C27 Industrial) as well, but in Atlas Copco machines. In fact IIRC we had some engines round about your Serial Number.

Honestly if it was me I would use genuine Cat hoses for the fuel system if for no other reason than knowing the back story regarding fuel hoses leaking/failing and engines catching fire. Also there is a lot of pulsing & cavitation going on inside those HP fuel hoses. At least if you use OEM hoses then provided they are correctly installed (clamped correctly using correct hardware & not rubbing in other words) then if anything goes wrong it's on Cat, not the engine rebuilder.

My 2c. - *other opinions may be available.

 

[kenworth]

Very nice shop that you have, super clean and organized.
Please keep the pictures and information coming about this project.

 

[absoluteyukon]

Hey all, thanks for the interest in the project! Heres where things are at now; crank, pistons, cooling jets, partial front gear train and front housing are installed. Totally neglected to take some photos of the crank install, but everything worked out great. Our machinist nailed the alignbore, mains and connecting rod journals all have around .003", which is a little on the tight side, but still within spec and 0.013" end float on the crank which is fine by me. I platiguage every journal to verify my mic'd measurements and for peace of mind. I also completely disassemble the pistons and connecting rods to measure and verify all clearances and ring orientation. Of note 8 of the 12 pistons had wrist pin bores that were between .0007 and .0013 out of spec on the large side which I was definitely not pleased with considering all parts are directly sourced from Cat. The liner packs are remanufactured but I would have expected things to be a little tighter than that. The end gap orientation was also unacceptable. I am aware that Cat will not warranty parts on liner packs that were disassembled before installation but I believe that if one takes the time to measure and verify everything before it is installed you will not need parts warranty. We also consulted SIMSi to see if there has been reports of piston failure with these reman liner packs and nothing really came up worldwide, that, in addition to the lead time on new liner packs and I'm forced to go with what I've got. It is what it is I guess. Anyhow, heres a few progress photos, enjoy!

 

[absoluteyukon]

Here are a few photos of the failed rotating assembly. I had to cut one of the connecting rods out of the block with the cutting torch due to it being welded to the crank and the cap bolts being inaccessible. Right up on the wall of shame she goes.

 

[JPV]

Any idea what caused the failure?

 

[absoluteyukon]

I've been pondering that myself JPV. The machine itself is still at site, but is scheduled to come down for a major overhaul once I have the engine completed. Definite lack of maintenance, and judging from the condition of the valve seats and liner walls it was eating a fair share of dust. It drives a monster compressor for the drill off the flywheel end and the front is coupled to a pump drive that runs a series of piston pumps for the drills hydraulic functions. It has a hard life, and as such, neglect will get spendy. The modern ethos of "I don't own a bolt in 'er." strikes again.

 

[absoluteyukon]

Hey all, been awhile since an update so here goes; right bank camshaft took over 2 months to arrive. . . I was prepared for delays, but that is getting excessive. I built as much of her as I was able to with the parts available and pieced the rest together as they came in. I believe our industry is going to be in serious trouble if the supply chain continues to be eviscerated in the name of "the science". I'm personally not one to load of the parts cannon and start firing away, but it was nice to at least have the option. At this rate we're gonna be splicing o-rings together from buna-n bulk stock just to try and keep the dinosaur squeezings off the yellow junk. Gluing everything together one tube of room temperature vulcanizing sealant at a time. I shudder to think... anyhow, heres a few more pics. I'm still waiting on the lhs turbo feed line but other than that shes ready to be sent south for a dyno run. Lemme know what ya think. Cheers!

 

[kenworth]

Looks like you did a great job.
Please give us a report after the Dyno run and is there any way you can get a picture of the machine that this engine lives in?

 

[absoluteyukon]

Thanks, will definitely share the dyno results once I have them. The machine is a MD6250, once it comes down for the overhaul I'll make sure to post em.

 

[absoluteyukon]

Hey all, the C27 arrived from its dyno run down south at Finning Power Systems, unfortunately, I haven't received the sheet yet, but will post it when I do. The drill itself arrived last week and I must correct myself on the model, it is a MD6290. I'll take some photos tomorrow and post em up. Happy New Year from the frozen north!

 

[absoluteyukon]

Hey all, we received the dynamometer results from Finning today, other than being a little light on data everything looks good. Here ya go.

 

[Nige]

A bit thin on info. Where are all the specs so that they can show the dyno test results are within the required parameters..?

 

[John C.]

Apparently all they did is run it for awhile and didn't do any real diagnostics.

 

[absoluteyukon]

I certainly expected more data as well. I was hoping to receive an as shipped engine test cell report. I was told she was being sent down for a full dyno run and break in. Oh well, the drill went into the equipment shop yesterday to begin the overhaul. I'll go take a few pictures and post em up.