lost a rod bearing

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lost a rod bearing

Post  strokedmyford on April 8th 2014, 10:08 pm

Lost a rod bearing on the dyno yesterday trying to figure out why.
Build details
A460 block bore 4.530 (used bought from a forum member)
stroke ohio crank 4.6
crane cam .740 lift 280's dur.
trickflow A460 360cc heads New
single 1450 quick fuel (used bought from a forum member)
callies 6.7 BBC compstar I beam rods
King 3/4 groove mains
king rod bearings
diamond +12cc domes
Kaase oil pump
moroso drag race oil pan
10 qrts val. 20w50

When I had the assembly balanced I asked the machinist to check the clearances and he said use std.X brgs. on the rods and std. on the mains. I plastic gauged a couple rods and a couple mains clearances looked to be .003 on the mains and .0025 on the rods (I know plastic gauge isn't perfect but its all I have). I have been putting the parts together over the years for a personal project but lost interest and a fellow mud racer asked me for advice on a simple low maintenance 900 horse build. I saw an opportunity to get out from under the parts I collected and help a fellow racer out so he gave me a deposit to finish the build. Assuming the all the clearances were correct and assembled correctly. I posted some pictures of the ohio crank and a higher end callies crank has anybody had any trouble with the oil holes to the rods not being centered in the rod bearing being an issue.
It did look like it was wanting to run first pull was 831 torque @ 4700 894 hp @ 6800 then went south.





Last edited by strokedmyford on April 8th 2014, 10:50 pm; edited 2 times in total
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Re: lost a rod bearing

Post  dfree383 on April 8th 2014, 10:22 pm

Clearance is critical on bigger engines, did you measure for taper and out of round? What rods? Did you measure the Rods? Do you have enough piston to head clearance?

Did you prime it?
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Re: lost a rod bearing

Post  strokedmyford on April 8th 2014, 10:34 pm

I left the measuring up to my machinist I am more of an engine assembly man.
Rod are listed it the build details
When assembling domes were hitting the heads but after a little massaging I got the engine to turn over nice without a head gasket and used a cometic .045
After disassembly the only piston showing contact was the one with the bad rod bearing but with the rod bearing lying in the pan all evidence is gone if it was contacting before.
when I did prime it I thought way to much oil was going up top so i double check the restrictor plug it had a 5/64 hole in it and the rear inner plug was installed. I still could not believe that much oil could come through that small hole.
Another note the oil psi stayed at 64-62 lbs. untill 6400 rpm then dropped a little ending up 56lbs. at 6800 rpm


Last edited by strokedmyford on April 8th 2014, 10:52 pm; edited 1 time in total
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Re: lost a rod bearing

Post  cool40 on April 8th 2014, 10:49 pm

piston hit the head  Suspect i had the same deal last year.
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Re: lost a rod bearing

Post  strokedmyford on April 8th 2014, 11:04 pm

cool40 wrote:piston hit the head  Suspect i had the same deal last year.
I plan on adding some extra clearance when I go back together, just trying to rule out any other issues.
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Re: lost a rod bearing

Post  BOSS 429 on April 8th 2014, 11:20 pm

how much oil did you have in this engine, sounds like it ran low filling up the valve cover area.

when you were priming it what did it look like in under the valve cover?

also how long did you prime it for?
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Re: lost a rod bearing

Post  rmcomprandy on April 8th 2014, 11:28 pm

Getting correct oil clearance is not the only thing to be checked upon pre-assembly.

1. are all the rod big end bores STRAIGHT and ROUND?
2. do the crankshaft journals exhibit perfectly ROUND and very little tapper journals of the CORRECT SIZE with good surface finish? (You can't see minor chatter with the naked eye)
3. Are the main bores in the block STRAIGHT and ROUND"
4. are the bores perpendicular to the crankshaft centerline?

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Re: lost a rod bearing

Post  Wheelie58 on April 9th 2014, 1:34 am

Is there evidence of "radius ride"?
If the journals fillet was touching the bearing, it will definitely cause early failure.
Easy to overlook.
Keith
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Re: lost a rod bearing

Post  c.evans on April 9th 2014, 2:21 am

Dennis,

Well of the two different cranks you have pictured, I'd much rather be using the one with the gray colored cheeks and counterweights, than the one with the black colored cheeks and counterweights. The gray colored one has a much bigger and nicer fillet radius than the black colored one, and I believe will prove to be the stronger crank.

I do think you have an oiling problem, that is related to the clocking and location of those oil holes in the black crank.

Another thing I noticed on the black crank is, that on it's main journals, I see that they chamfered BOTH the leading and trailing edge of the main oil hole. IMO that's wrong on the mains and allows the main to bleed off oil pressure. Only the leading edge of the main oil hole should be chamfered, as this helps capture and maintain oil pressure going to the rod bearings. I could not see the main bearing oiling hole on the gray crank, however if we could see and study it, I suspect it only has the leading edge chamfered.

Did the rod bearing that went south occur on cylinder numbers 3, 4, or 7?

Charlie

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Re: lost a rod bearing

Post  supervel45 on April 9th 2014, 7:26 am

No expert, but I do not like the black crank. It looks like it would only oil one side of the rod bearings, the way the holes are spaced. You did not mention how much side clearance you where running on the rods, but if it is on the loose side, it would seem like you would loose alot of pressure between the center of them, and not oil evenly across the bearing?

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Re: lost a rod bearing

Post  strokedmyford on April 9th 2014, 8:59 am

BOSS 429 wrote:how much oil did you have in this engine, sounds like it ran low filling up the valve cover area.

when you were priming it what did it look like in under the valve cover?

also how long did you prime it for?

10 qrts
plenty of oil up top it was a concern mentioned in earlier post
primed until all rocker arms had oil, I turn the engine over while priming


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Re: lost a rod bearing

Post  strokedmyford on April 9th 2014, 9:10 am

rmcomprandy wrote:Getting correct oil clearance is not the only thing to be checked upon pre-assembly.

1. are all the rod big end bores STRAIGHT and ROUND?
2. do the crankshaft journals exhibit perfectly ROUND and very little tapper journals of the CORRECT SIZE with good surface finish?   (You can't see minor chatter with the naked eye)
3. Are the main bores in the block STRAIGHT and ROUND"
4. are the bores perpendicular to the crankshaft centerline?

I know the block is spot on engine systems done the machining
The rest of the parts were new but I relied on my local machinist to check over.
















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Re: lost a rod bearing

Post  strokedmyford on April 9th 2014, 9:15 am

Wheelie58 wrote:Is there evidence of "radius ride"?
If the journals fillet was touching the bearing, it will definitely cause early failure.
Easy to overlook.
Keith

I was careful on disassembly to make sure the upper and lower rod bearing were correct but the one that spun all evidence was lost.
I did install the bearings incorrectly to check if that could have been an issue, even incorrectly the radius didn't touch the bearing.
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Re: lost a rod bearing

Post  strokedmyford on April 9th 2014, 9:44 am

c.evans wrote:Dennis,  

Well of the two different cranks you have pictured, I'd much rather be using the one with the gray colored cheeks and counterweights, than the one with the black colored cheeks and counterweights.  The gray colored one has a much bigger and nicer fillet radius than the black colored one, and I believe will prove to be the stronger crank.

I do think you have an oiling problem, that is related to the clocking and location of those oil holes in the black crank.

Another thing I noticed on the black crank is, that on it's main journals, I see that they chamfered BOTH the leading and trailing edge of the main oil hole.  IMO that's wrong on the mains and allows the main to bleed off oil pressure.  Only the leading edge of the main oil hole should be chamfered, as this helps capture and maintain oil pressure going to the rod bearings.  I could not see the main bearing oiling hole on the gray crank, however if we could see and study it, I suspect it only has the leading edge chamfered.

Did the rod bearing that went south occur on cylinder numbers 3, 4, or 7?

Charlie
The gray colored crank is the callies the bad thing is I'm stuck with the Ohio 4.6 stroke to keep in budget They had a new crank I stressed to them  I need this to be right. I know of a few guys running this crank making north of 1000hp with success.
It was #2 that spun
the callies crank only has the leading edge chamfered
I'm beginning to think maybe I didn't clearance the dome enough and after warm up it came in contact with the head
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Re: lost a rod bearing

Post  strokedmyford on April 9th 2014, 9:52 am

supervel45 wrote:No expert, but I do not like the black crank. It looks like it would only oil one side of the rod bearings, the way the holes are spaced. You did not mention how much side clearance you where running on the rods, but if it is on the loose side, it would seem like you would loose alot of pressure between the center of them, and not oil evenly across the bearing?

I never measured the side clearance I just know that the rods moved freely side to side.
On the new crank I had them add a some chamfer to the oil hole toward the radius side.
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Re: lost a rod bearing

Post  IDT-572 on April 9th 2014, 10:28 pm

If a piston hits a head it will kill the bearing.
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Re: lost a rod bearing

Post  powerstrokeace on April 9th 2014, 11:18 pm

I know for a fact that the OHIO cranks are fat and out of round and need to be machined before any thing else. these are not plug and play. I happen to have one that my crank grinder said finish the rods and the align hone first. Install the bearing and give him the measurements. from that he finished the crank and its spot on. As for the piston hitting the heads i have a whole nother comment i'll keep to myself. But since you lost the bearing it had extra play so it would hit the head. So the delema is what was the real failure? did the piston hit befor the rod failed or after








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Re: lost a rod bearing

Post  Lem Evans on April 9th 2014, 11:20 pm

Were the 360 cnc heads the 85cc chambers? If so, they take a bastard dome. I do not use them.

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Re: lost a rod bearing

Post  strokedmyford on April 10th 2014, 8:48 am

Lem Evans wrote:Were the 360 cnc heads the 85cc chambers? If so, they take a bastard dome. I do not use them.

they are the 85cc
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Re: lost a rod bearing

Post  strokedmyford on April 10th 2014, 11:28 am

powerstrokeace wrote:I know for a fact that the OHIO cranks are fat and out of round and need to be machined before any thing else. these are not plug and play. I happen to have one that my crank grinder said finish the rods and the align hone first. Install the bearing and give him the measurements. from that he finished the crank and its spot on. As for the piston hitting the heads i have a whole nother comment i'll keep to myself. But since you lost the bearing it had extra play so it would hit the head. So the delema is what was the real failure? did the piston hit befor the rod failed or after Ace

I did pay to have the crank that failed checked out and tuned up if necessary but I can't verify if he did his job, being a tight ass and saving some money on freight and using a local guy probably bit me in the ass Embarassed

I'm not one to make accuses I just like to find the problem and move on, being my error or someone else's.

They actually called me and said ''to be quit honest they should not be going out the door this out of shape'' The new one they tuned it up on the grinder and clearances should be good with a std. bearing.


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Re: lost a rod bearing

Post  supervel45 on April 10th 2014, 11:37 am

powerstrokeace wrote:I know for a fact that the OHIO cranks are fat and out of round and need to be machined before any thing else. these are not plug and play. I happen to have one that my crank grinder said finish the rods and the align hone first. Install the bearing and give him the measurements. from that he finished the crank and its spot on. As for the piston hitting the heads i have a whole nother comment i'll keep to myself. But since you lost the bearing it had extra play so it would hit the head. So the delema is what was the real failure? did the piston hit befor the rod failed or after It should not be too hard to install a new bearing on the suspect rod/piston, and mock the engine back up and check clearance on the head. Did your Ohio crank have the oil holes drilled like this one does? Randy also mentioned checking the rod big end for roundness, and that needs to be done now since the bearing spun on it anyway. Hope you get to the bottom of it.








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Re: lost a rod bearing

Post  supervel45 on April 10th 2014, 11:40 am

The above quote went wrong. The top part is from Powerstrokeace, and the bottom was mine. Don't know what went wrong, sorry, abot that.

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