Cam/Lifter uh-oh Part II

J

JHFORD51

Senior Member
Today, I pulled engine and tore it down. News is not good. All pistons have scuff marks on them, all bearings are shot, and rear rod bearing journal and rear main on crank are deeply grooved. I'm not sure of the cause, I can't see where all that metal came off one lifter. I'm almost wondering if there was machine shop shavings left in the block when the assembler put it together for me (I usually do my own work but I didn't this time, probably my first and last time letting someone else build my engines).

What a waste: Schnieder cam, Johnson lifters, Ross pistons, grant rings, NOS Ford main bearings, Clevite rod bearings, and 4" crank out of my dads 51 Merc...All of it had a nice balance job by the machine shop too.

Crank already turned 0.020; 0.030 won't get rid of the grooves and I don't want to go to 0.040. Pistons might polish out but I doubt it. Cylinders are ok-I think I light hone will make them happy.

If you look close you can see where the rear main actually is galling the babbit material from the oil groove.

Sad, frustrating, and expensive.
 

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Well - it sure looks like a bunch of crap went through the engine - but I also wonder about bearing clearances being correct? That rod bearing looks to have more issues than just junk in it. I know - it is hard to know . . . and you may never know . . . but I wonder what the root cause really was? The pistons can probably be scuffed out with 600 wet or dry and a semi-hard rubber pad (depending on how deep the grooves are). You may also want to have the piston skirts coated with a dry-film lubricant - by Diamond or somebody like that.

Like you, I don't like to grind the cranks to .040, but if you can find bearings, maybe not a problem. I just wonder how hard the journals are at that point . . . and I can't say that I know as I've never taken one that far.

Good luck - what a pisser this engine has been!
 
These crankpins are often offset ground to 1.999 to gain a 1/8th stoke increase (which is .040 under).
 
wouldnt worry bout .040 either.looking at that main bearing you might have a main bore alignment issue as well.no such thing as too clean when it comes to engines.
 
The pistons should be ok as long as they measure correctly for the bore. Might want to double check that too. Most os the work is done by the rings. A loose fitting piston can cause piston slap.
 
flatjack9 said:
These crankpins are often offset ground to 1.999 to gain a 1/8th stoke increase (which is .040 under).
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Good point! Recently I had a Merc crank offset ground, and then I had it hardened in a 'nitride' process. I just did this to see if the journals end up lasting longer (kind of an experiment!).

I'm not sure if you can find .040 main bearings - I normally see .030 as the biggest undersize (but I'm sure somebody has them). It is better than losing a crank - that is for sure.
 
JWL said:
I would be suspicious of a oil pressure problem.
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reminds me... my father bought a motor out of a car that was being street rodded.. pulled the heads and it was nice and shiny... fresh rebuild! well he pulled the pan and there was a rat nest in it so we had to completely tear the motor down, clean it and put it back together. during the teardown we found that the brand new oil pump shaft was broken in half... :eek:
 
Did the engine have a full flow oil filter system? Yes the last engine I built had .040" under bearings in it. They were hard to find and very expensive. Wouldn't worry about the pistons, Ross are usually fit with .003/5" clearance
 
What is in the oilrelief up in the liftergallery ??
Just so the shop didn´t put the 50lbs used spring back...or it broke ??
 
Ol' Ron said:
Did the engine have a full flow oil filter system? Yes the last engine I built had .040" under bearings in it. They were hard to find and very expensive. Wouldn't worry about the pistons, Ross are usually fit with .003/5" clearance
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I was wondering about your oil filter setup too. There have been a couple of people with ruined engines due to wrong hook up of the 95% filter. I know I checked mine many timed before started it.

John
 
If these were my pistons, I would look for a shop with an old time knurling machine.
Knurling pistons raises up the size a bit. this may help reducing the loss of size due to the marring of the skirt. Also produces a cross pattern to the wear marks.

It makes the piston bigger, I would size them to the bore by rolling a file across the skirt of the piston. This will reduce the possibility of the piston galling again.

Karl
 
Karl Wolf said:
If these were my pistons, I would look for a shop with an old time knurling machine.
Knurling pistons raises up the size a bit. this may help reducing the loss of size due to the marring of the skirt. Also produces a cross pattern to the wear marks.

It makes the piston bigger, I would size them to the bore by rolling a file across the skirt of the piston. This will reduce the possibility of the piston galling again.

Karl
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Hi Karl, that's something we've never tried, know about it very well, but never tried it! Actually owned the knurler about 50 years ago!

Building these units for a living there's no way any of my own customers would even consider this procedure today nor would I ever recommend it even if I could provide the service!

(Add) Many of those parts pictured in this failure above appear to still have some value, just kind of difficult to make a safe call from photos? Those pistons may respond well to some "glass-beading" with the ring lands taped up! Very small vertical lines/scratches will have no adverse effect on performance.

Thanks, Gary in N.Y.

P.S. Would really be interested in the outcome trying to knurl "2618" pistons, really curious.
 
Post morteum today. Noted several issues: general uncleanliness, inattention to detail in assembly (missing front oil slinger, poorly fitted valve guide shims, and random top and bottom coil placement on valve springs), and non-existent crankshaft endplay.

Front main cap was a 1BA unit which was rubbing on the journal to counterweight transition. Heavy marring and metal displacement on about %50 of the edge of the main cap.

Rear crank journal thrust edge and inside thrust/slinger edge had some rust shadows that didn't clean up when the crank was turned. You can see where this marred the thrust edges of the rear main.

I could detect 0 endplay when prying the crank back and forth (without seals). Smallest feeler gauge I had at the moment was 0.004 and it wouldn't even think of inserting. Crank doesn't free spin without seals very good either.

My diagnosis is improper fitment/assembly and it should have been caught before proceeding with the engine buildout. As I noted earlier I didn't assemble this myself.

For those that asked, it has stock filtration and there was plenty of flow judging by oil on all the bearings. I can't see where it was a cam and lifter issue at all, I just happened to catch it there first.

Thanks for all of the responses!
 
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Well that sucks . . . guess you'll be doing the next one, the right way. This is exactly why I only have one place that I trust with my machine work and why I assemble everything myself - it is all that attention to detail that matters in the end. Good luck going forward!
 
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