Measuring

[Truck Shop]

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.
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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.
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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.
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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?
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[skyking1]

do you bolt a measuring plate across the main bearing flats?

 

[Truck Shop]

do you bolt a measuring plate across the main bearing flats?

No need to.
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Lets see 78 views in 9 hrs--I guess the consummate Cat mechanic's/ Technicians never check.
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What I really like about this problem-is the starting issue that it would cause/caused.

 

[1693TA]

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.

 

[Mike L]

I always check liner protrusion but to be honest that’s the only measurement I know to check.

 

[Truck Shop]

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.

 

[Vetech63]

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.

 

[Truck Shop]

I've always left the critical measurements to the people that do it for a living.

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.

 

[1693TA]

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.

 

[Truck Shop]

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.

 

[Junkyard]

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 ****.

 

[1693TA]

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.

 

[Truck Shop]

That particular Cummins would have drove a man crazy trying figure out why it wouldn’t run for ****.

It is, always has been a fun part of the job for me.
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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.

 

[funwithfuel]

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.

 

[Truck Shop]

Trouble is there were/are allot of inframes completed with a crooked deck. I personally
don't have much faith in reman/exchange units.

 

[funwithfuel]

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.

 

[Junkyard]

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.

 

[Truck Shop]

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.

Actually the labor works out the same it's paid either way Reman or in house.

The fun part is where rebuildable cores are drying up and they aren't making more.

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.
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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 don’t trust reman but I also am leery of the liability.

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.

 

[Birken Vogt]

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.

 

[OzDozer]

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.