360 motors

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james a thompson sr

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ok guys need help we have 3 engines that have spin #3 rod bearings 2 were rebuit with stock parts in drag car and truck and the 3rd was all brand new except the block and crank new rods,pistons cam and all 3 have spun #3 rod bearing has anyone else had this problem and can anyone help us we only turn all motors 6000 rpms clearance on rods were .002 and could turn motor over with 1 finger and any help would be appreciated
 
Were these in same car? Balance problem? Bell/ trans misalignment? Balancer?

What is common to them? Same parts list? Were they balanced? Do the parts meet factory weight specs?
 
67Dart273 said:
Were these in same car? Balance problem? Bell/ trans misalignment? Balancer?

What is common to them? Same parts list? Were they balanced? Do the parts meet factory weight specs?
Click to expand...
ist 2 not balanced, 1-3 motor in same car, 2 in a truck and 3rd motor all balanced, only common thing is there 360 motors and yes parts meet all specs
 
being in a drag car
is engine up to temp before the run?
what weight oil?

I convert all my drag engines to full time oiling.
by blocking the oil from cam to heads, then
reduce the oil going to the cam.

next drill the lifter gallery for oiling to the heads
 
draginmopars said:
being in a drag car
is engine up to temp before the run?
what weight oil?

I convert all my drag engines to full time oiling.
by blocking the oil from cam to heads, then
reduce the oil going to the cam.

next drill the lifter gallery for oiling to the heads
Click to expand...
yes engines at 160 20-50 Kendell
 
20W50 is going to be hard to pump around when cold or cool. Especially with the first 2 engines rebuilt with stock parts... wear in the oil pump can make it hard to even pick up cold 20W50. Coolant at start reaching 160F will still leave oil temps low; oil temps lag well behind water temps.

If your pumps are not spanking brand new, you need to change to using new pumps every time. And go with a lighter weight oil; if you are just drag racing, it is not all that hard on oil, not like circle track, road race, or rally where the engines are run hard for long periods of times. Drag racing CAN be hard in that the oil cools then heats and cools then heats, over and over; unless you are using a synthetic, the actual viscosity will vary a lot.

DO you have any oil pressure readings?
 
nm9stheham said:
20W50 is going to be hard to pump around when cold or cool. Especially with the first 2 engines rebuilt with stock parts... wear in the oil pump can make it hard to even pick up cold 20W50. Coolant at start reaching 160F will still leave oil temps low; oil temps lag well behind water temps.

If your pumps are not spanking brand new, you need to change to using new pumps every time. And go with a lighter weight oil; if you are just drag racing, it is not all that hard on oil, not like circle track, road race, or rally where the engines are run hard for long periods of times. Drag racing CAN be hard in that the oil cools then heats and cools then heats, over and over; unless you are using a synthetic, the actual viscosity will vary a lot.

DO you have any oil pressure readings?
Click to expand...
only drag racing these motors no street and we use new high volume oil pump on every new motor oil pressure is at 70-80 lbs and 60 warmed up and the cars never see cold air under 40 degrees and why does any of this matter to #3 rod and not 1& 2 all other bearings are perfect main and rods
 
Ok good on the pumps. Pressures sound spot on. I'd still go with a lighter oil. I see no need to use 20W50 for drag racing. What oil filter?

#3 is fed from the #2 main and so is the #2 cam bearings as well as the drivers side rockers system. That is the point of draginmopars about blocking the feed from cam bearings 2 and 4 to the heads; it takes a bit of oil pressure away from main #2 and 4 and thus from rod bearings 2 and 3 (fed from main #2), and 6 and 7 (fed from main bearing #4).

Why #3 rod is the only bad one for you, I can't say. Seems like most I have read is of there being a problem is back at the #4 main, not the #2 main. Is the #3 bearing actually spinning in the rod?
- Have you had the older rods reconditioned?
- Were the new rods stock type rods?
- What rod bolts?
- Are you checking rod side clearance?
- Standard cam bearing types (not full grooved)?
- Have you checked lifter bore sizes? Loose lifter bores bleed off pressure the further you go to the front. Dunno why #1 & 2 would not be effected though, as you say....
- Are the rods being installed with the side oil outlets at the parting line pointing down to the cylinders (Numbers up with the engine flipped over)? These rods have a small sideways offset in the rod beam from bottom to top, and that needs to be in the right direction. Just wondering if something is side-loading the rods.

And I am assuming the 360 LA engines, not Magnums.
 
Last edited:
nm9stheham said:
Ok good on the pumps. Pressures sound spot on. I'd still go with a lighter oil. I see no need to use 20W50 for drag racing. What oil filter?

#3 is fed from the #2 main and so is the #2 cam bearings as well as the drivers side rockers system. That is the point of draginmopars about blocking the feed from cam bearings 2 and 4 to the heads; it takes a bit of oil pressure away from main #2 and 4 and thus from rod bearings 2 and 3 (fed from main #2), and 6 and 7 (fed from main bearing #4).

Why #3 rod is the only bad one for you, I can't say. Seems like most I have read is of there being a problem is back at the #4 main, not the #2 main. Is the #3 bearing actually spinning in the rod?
- Have you had the older rods reconditioned?
- Were the new rods stock type rods?
- What rod bolts?
- Are you checking rod side clearance?
- Standard cam bearing types (not full grooved)?
- Have you checked lifter bore sizes? Loose lifter bores bleed off pressure the further you go to the front. Dunno why #1 & 2 would not be effected though, as you say....
- Are the rods being installed with the side oil outlets at the parting line pointing down to the cylinders Numbers up with the engine flipped over)? These rods have a small sideways offset in the rod beam from bottom to top, and that needs to be in the right direction. Just wondering if something is side-loading the rods.

And I am assuming the 360 LA engines, not Magnums.
Click to expand...
yes 360 la motors #3 motor had scat rods and one of the best bearings you can buy 1-2 rod redone and stock rod bolts cam bearing were great when took motor apart and yes all 3 motors #3 rod was the only one affected
 
Read all of thr guitar jones oiling system mod thread. If you are using hydralic lifters do the cross over mod. Otherwise do the tube mod on the drivers side oil passage.
 
draginmopars said:
being in a drag car
is engine up to temp before the run?
what weight oil?

I convert all my drag engines to full time oiling.
by blocking the oil from cam to heads, then
reduce the oil going to the cam.

next drill the lifter gallery for oiling to the heads
Click to expand...

Yes, to all of this, i had one let go myself, made the adjustments to the block, no problems since, 360 have that big main bearing and it just seems to be a problem at higher rpm's
 
Otherwise do the tube mod on the drivers side oil passage.[/QUOTE]


Said drivers side but the tube goes in the passenger side oil passage

Sorry about that. Read theGuitar Jones thread.
 
james a thompson sr said:
yes 360 la motors #3 motor had scat rods and one of the best bearings you can buy 1-2 rod redone and stock rod bolts cam bearing were great when took motor apart and yes all 3 motors #3 rod was the only one affected
Click to expand...

Scat rods do not have oil squirt holes like the stock rods do...
 
well found out that mopar screwed the oil passage way from rear to front they could not drill the main bearings all the way from rear to front , so they stopped just before #2 main cap and started drilling from front to rear and it is missed aligned so on 360s you have to finish drilling it out the step to get all the oil you need
 
james a thompson sr said:
well found out that mopar screwed the oil passage way from rear to front they could not drill the main bearings all the way from rear to front , so they stopped just before #2 main cap and started drilling from front to rear and it is missed aligned so on 360s you have to finish drilling it out the step to get all the oil you need
Click to expand...
This is not a 360 thing..... We found it in a '71 340 block just like that. And it is standard to drill from back to front halfway in several steps of drill sizes on each side, then drill front to back with several steps of drill sizes. One big long drill through from one end to the other would be breaking all the time.

But even then, the rough cast oil gallery passage should flow all the oil you need to the mains and rods, unless it was REALLY blocked up with casting flash. The finish drilling inside makes sure the openings in the sides of that oil gallery are full size for the lifter oiling. So, unless you had a big gob of casting flash inside the passage, I am not 100% convinced you have found your problem.
 
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