Just wondering how many actually do a complete measurement of engine blocks and components when performing a rebuild? Certain things I always check-one is deck height and it doesn't matter the brand gas or diesel. I spent today getting a 855 Cummins BC-1 block cleaned up to go to machine shop along with rods, heads and crank. * Upon removing the liners I noticed someone didn't know what they were doing years ago. It had 3046325 liners, those are .010 X .020 over size upper press fit, Problem was a .020 shim was installed also. It was obvious the liners seeped constantly. Only one of the issues. * These are the measurements for Block/Deck Height measured from crankshaft centerline to deck/where main cap mates to block up to deck. Factory measurements are. Maximum deck can be cut wear limit-18.994 New minimum-19.003 New maximum-19.007. I measured 19.060 three times then had my machinist friend come over and measure it with his caliper, same. Now figuring .055 extra over a 5.5" bore that's a compression loss and low power running issue that no one would have ever found, performance was lousy with this NTC350, injectors and injector timing which is matched to compression ratio--all was off. The smaller hp Cummins not [Cummings} run higher compression ratios with faster injection timing. This block rolled of the machine line at Cummins in 1979, been running 44 years like that. * I can have the block machined correctly that isn't a problem. I own a Fowler 24" like below. Question--do you fellers critically check your engine rebuilds? *
do you bolt a measuring plate across the main bearing flats?
No need to. * * Lets see 78 views in 9 hrs--I guess the consummate Cat mechanic's/ Technicians never check. * What I really like about this problem-is the starting issue that it would cause/caused.
I've never measured deck height myself on any engine but have had many planed to straighten them up from warp, (usually). Same with heads. I do use a very good machine shop however and trust they are doing the measurements. I'm not versed in Cummins engines at all.
I always check liner protrusion but to be honest that’s the only measurement I know to check.
Crank line bore, stretched main caps, same with con rods. I learned never trust a machine shop to check it all, plus if it's a OEM recon they don't stamp castings with machine info.
I've always taken my stuff to a machine shop. I will check liner heights on assembly along with plasti-gauging the bearings. I've always left the critical measurements to the people that do it for a living. So far it hasn't failed me yet, but it seems like forever ago when I last did a full engine rebuild.
Machinists are like everyone else they make plenty of mistakes too, So checking their work is necessary. Look at it this way the manufactures make enough mistakes that get past quality control. A smart machinist has another check his work from time to time.
This right there is very true. Shop I use builds very high dollar race engines and second check quality control is standard practice for them. Tractor pulling engines are a secondary line too and I don't feel they miss much. They can be a bit expensive at times to be fair, but I've never seen, nor heard of mistakes leaving their shop.
If they did have some they would never let it out, it's quick death to a auto machine shop.
I tend to measure just about everything. I’ve got a drawer full of various measuring tools. I enjoy that part of the process. Some tools are easier to use than others. My dial bore gauge had a bit of a learning curve before I felt I could trust what I was getting. I’d always end up going back to the old school way of checking bore taper just to be sure. That particular Cummins would have drove a man crazy trying figure out why it wouldn’t run for ****.
Very true. Not many good machine shops left either. I had these guys machine one of my V8 Mack blocks and open the crank and cam bores to fit bearings from another application. Pistons from Arias Custom Pistons, Hastings moly rings, liners from their supplier, made it all work together well. I have everything balanced and weight matched as standard practice and the engine runs very well and sounds nice through the exhaust under throttle. I always liked the big V8 diesels myself as they are from a bygone era around here.
It is, always has been a fun part of the job for me. * Even if that were to take place on a todays engine-trouble shooting would never find it. Because no one would think to check piston assembled height installed in liner.
In all honesty, I can count on one hand how many out of frame, complete teardown overhaul I've done. Quick and dirty in-frames were always the way. Almost always for cavitation or reached a mileage threshold. I'd measure the deck with a straight edge, measure counterbores and final clamped liner protrusion. I'd also measure ring gap, crown height in relation to the deck, thrust, rod and main clearances. In my experience, it's always been cheaper for the owner to go with a reman exchange if the engine needed more than a works kit. Labor rates in Chicagoland take that out of the equation.
Trouble is there were/are allot of inframes completed with a crooked deck. I personally don't have much faith in reman/exchange units.
Agreed, but it takes the responsibility away from me and the swing labor is significantly less than the swing and rebuild. The fun part is where rebuildable cores are drying up and they aren't making more.
I’m in the same boat. I don’t trust reman but I also am leery of the liability. My dump truck customer has two he wants to OH this winter. They really need to be out of frame to be right. They’re Highway trucks that went 750k then became dump trucks. I know one had a backyard OH years back because I showed the previous owner how to spin the bearings in lol.
Actually the labor works out the same it's paid either way Reman or in house. And that's the reason to measure/check before sending to machine shop. And too it's a good thing it will force to buy new. * Years ago all shops rebuilt/out of frame. It was common practice to mic every item and expected. And now because the core pile is drying up, customers that want it rebuilt in house are going that direction and finding capable mechanics to do it. I tell people up front I'm not a major player-I do good work but I can't warranty stupidity so therefor there is no warranty, only thing I can say is work performed was done correctly. Take it or leave it.
I've had a head at a shop for like a month now, they are only just getting to it. Probably worse in this state though.
After many dozens of engine rebuilds, I like to ensure that all measurements that the manufacturer has produced a specification for, are checked. To that end, I either check them myself or use a trusted engine reconditioner. One time, when I owned/ran 55 items of earthmoving equipment, I employed a head mechanic who had been one of Cummins local top engine reconditioners - and that guy was absolutely anal about checking specifications. If he rebuilt an engine, he would measure every factory part to make sure it met specs. When he rebuilt an engine, you could guarantee it would go for 12,000 hard hrs without missing a beat. Unfortunately, despite this guys great engine building skills, he wasn't real good on ethics. After he left my employment, he got involved in defrauding big clients with false invoicing, and went to jail. He should've known better, I don't know how he got caught up in that kind of stupidity. One thing I have learned over many years is to avoid taking someone elses block, crank or head unless you can prove up its authenticity. Too many blocks and heads get core-exchanged with major hidden damage - pulled out of fires, hidden major repairs, crack repairs, all sorts of shonkiness. I only rebuild engines that I know have good component history - and as much as possible, have been under my ownership.
It would be nice to operate that way but it's really not very practical, especially these days. I believe it's the reason for inspecting, the risk is low if you know what your doing. * But one thing I have gained out of this thread so far--------------There really isn't that many on HEF that do major rebuilds, or have completed very many, or maybe too shy to respond.
Now I have heard the term Honky before, Red Fox used it all the time.
"Honky" is my tractor's name. It is a "White Farm Equipment" brand and named after a "Red Foxx" character. We call it the "White Honky"; and as Lilly Tomlin used to say, "and that's the truth".
I just had a head take me twice that long. First shop was over two weeks, and they didn't do anything but lay a straight edge on it, and tell me "good to go!". It was a 3406 head and too big for their tank cleaner and their hone I believe. Which they could have just told my guy when he brought it in, but didn't. Second shop took just over a month. As far as all the measuring, I'm not nearly a precise enough individual, and "close enough" just doesn't cut it in engine work.
And sometimes it's just hard to beat someone at their own game. I've worked with literally dozens of skilled craftsmen and engineers over my career and many times it's best to lay down the cash than expend the effort to save a few bucks.
And that brings up a good point-I deal only with shops that perform diesel machine. Most automotive don't have the equipment to handle large engines plus they don't have the expertise to go with it. Look for a Industrial Machine Works. * If you enter a shop that's full of billy-bob chevys and fords-----your in the wrong place.
Back when i was working on a lot of engines and it was thier first overhaul i didnt check much but now a lot of stuff has been apart multible times i check more but getting older i about need a list of what to check. I have had great luck rebuilding engines for other people but i had one i did for my self that drank oil . I had it apart 2 times and couldnt figure it out. I put it back together and used it a lot hard but it used a quart of oil in less than 500 miles. I still have that engine along with 4 others but i dont know buy looking witch one it is.
If you hear an Australian or Kiwi start to talk about "a shonk", "some shonky business" or a "shonky character", you know straight up, there's some highly suspect goings-on, around the individual or the operation, and the trust levels are extremely low. I guess "crooks" or "scammers" is your equivalent. We even have "Shonky Awards" for businesses and products that don't deliver what they promise. The Shonky Awards | CHOICE CHOICE's annual awards have been running since 2006 to name and shame the shonkiest products and companies taking advantage of Australian consumers. www.choice.com.au
When i do an engine, the amount of measuring depends on several things. If i know the recent history of it and it ran well, then for an in-frame, just the basic upper end stuff, counterbores and all con-rod measurements along with crank endplay and plastigage the oil clearance. Also oil pump if re-used. On a bare block rebuild, all of the above, then all the lower end, main bearing bores and alignment. Also cam and all related stuff gets checked as well as complete crank measurements. If its an unknown engine or core, then i check everything there’s a measurement for and anything else that may be suspicious. After all, its a core engine for a good reason, otherwise it would still be running. I probably missed a few but I haven’t done a bare block rebuild for years
Completes for me are my favorite-I guess that's why I've done over 400 engines, gas, diesel, inframe out of frame. Working auto machine for five and building long blocks for machine shop-you end up doing a few. I remember late 80's I rebuilt 9 454's/440's, for motor homes in 7 weeks. The Cornwell tool guy use to sell me a 3/8 drive air ratchet every 3 months-burned them up. I was known to have to grab the cranks out using rags because those were still hot. I guess I always liked internal work best.
I know in my case I've done many.......too many to keep track of. ...............but its been quite some time ago now. Today's technology seems to be well enough to shut down a powertrain system in more than enough time to quell a major disaster before it happens. The older stuff is another story...............I just don't see a lot of older equipment anymore.
I was always afraid that something would happen taking a engine apart hot. I would do 2 gas engines a week . I would try to have a vehical at the shop Sunday and pull it that afternoon so i could get to block heads and stuff to the machine shop early monday morning.
Throw away industry.
I've learned the measure the parts the hard/expensive way. The first possibly second n844t I rebuilt (17 years old) just put the rods in that came out. Well after about a hour it spun a rod bearing and I got to buy a crank and all the other goodies to get it back together again luckily it didn't trash the block. Now I have a fellow check the rods. I need to get a bore gauge so I can one of these days. I never have checked deck height on the engines I get in to. Alot of smaller diesels I ever get in to they want you to check piston to head clearance and you adjust to spec with different head gaskets. I'll have to start tho for all the more time it takes. Probably spend more time finding the spec.
The simple one hardly anyone checks on 855's is cylinder head thickness. Max new is 4.380, minimum is 4.340, most of the old cores have been cut to minimum. Allot of heads are rebuilt that are beyond using. The Cat B model head has the same issue, cut too many times.
Found out the hard way. Piston protrusion bit me once…never again ! One rod fooked it up.