Season over....tossed a rod...
08-18-2014, 02:25 PM
#42
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Full Force,
The PBM connecting rod is a Scat with either a 8740 or 2000 bolt depending upon how it was optioned.
Secondly if you look at the connecting rod, what’s left of the bearing in both the upper shell area and the rod cap exhibit extreme bluing from excessive heat. The considerable heat buildup in that area resulted in the bearing grabbing the crankshaft, at that point the rod and bolts failed as a result of the bearing seizing. It appears the connecting rod assembly may be collateral damage rather than the root cause the failure.
Looking at the second photo it also appears a fracture occurred right in the radius of the rod bolt seat which would be consistent with a connecting rod seizure at the journal.
It’s a bit difficult to analyze from just these two pictures, however it would appear that this may not have been a parts related failure. If you shoot me over couple more pictures I’d be happy to take a look at them for you.
Bob
The PBM connecting rod is a Scat with either a 8740 or 2000 bolt depending upon how it was optioned.
Secondly if you look at the connecting rod, what’s left of the bearing in both the upper shell area and the rod cap exhibit extreme bluing from excessive heat. The considerable heat buildup in that area resulted in the bearing grabbing the crankshaft, at that point the rod and bolts failed as a result of the bearing seizing. It appears the connecting rod assembly may be collateral damage rather than the root cause the failure.
Looking at the second photo it also appears a fracture occurred right in the radius of the rod bolt seat which would be consistent with a connecting rod seizure at the journal.
It’s a bit difficult to analyze from just these two pictures, however it would appear that this may not have been a parts related failure. If you shoot me over couple more pictures I’d be happy to take a look at them for you.
Bob
Would you use the pbm stuff in a budget situation like this? I am so wise about having mismatched parts want both same but other engine runs fine, don't want to buy new stuff there besides rod bolts, wanna reuse crank and rods (both pbm) the cost to buy new for both engines and re balance isn't able to be done this year, but I can afford easily to re ring and bearing other engine
08-18-2014, 04:44 PM
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I'd call it Beth, just because.
08-18-2014, 05:10 PM
#46
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Thanks guys I wonder like even with the pbm stuff in there who actually makes it? Stuff looks nice and is almost the same money as others .... Is there really much difference once it's all machined and checked? That's what I wanna research, I don't need crazy expensive parts as I have a 1985 35 cig I don't need 30,000.00 engines you know? Luckily the recipe parts are there just need to rebuild...
08-18-2014, 05:17 PM
#47
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Yup,
And it's About the metal itself and metal's certification process too.
Not everyone's 4340 is the same. No, nope, no way, nada.
On top of that, some companies have special ingredients to make the rod stronger.
And it's About the metal itself and metal's certification process too.
Not everyone's 4340 is the same. No, nope, no way, nada.
On top of that, some companies have special ingredients to make the rod stronger.
08-18-2014, 05:24 PM
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Yes, both were same parts, I added oil pressure and at that time looked all over them, 55psi was not enough for me, had issues in past with that...
08-18-2014, 05:25 PM
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true kinda, past owners did not beat them at all, and the issues I found when I took them out made me not too confident, I wont even bring up the lack of port matching... that will be addressed also, like I said I am in them cheap, but don't wanna reinvent the wheel with them either, just maximize what's there...
08-18-2014, 05:27 PM
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I get all that, I guess my question is are the PBM rods ok for my application? they don't look like Chitty rods, I mean they are upgrade to something no? they look as good as Scat, Eagle and such, going to see my machinist tonight to see what he says.... open late on Mondays...
its all in the forging process,,you can take a piece of steel and compress it 10 times to make it strong (eagle,scat,ohio,procomp)..then you can take the same steel and compress it 100 times to smash steel tighter to make them stronger (crower,lunati,) which is why some cranks are more expensive.. then their are cranks like winberg and bryant which go to another level to make them look like a show piece and rods like oliver which are also strong as hell compared to the cheaper eagle and scat..
