cam bearings

[Dave]

how many oiling holes are in each cam bearing.
In mine I have 2 in the #1, 1 in the # 2and #3, and 2 in the last one but the holes dont line up to the oil ports on the last one. Only one slot in the last bearing lines up to the oiling port not the other slot

DW

 

[Intercooler]

Thats fine and normal. Enjoy!

 

[Dave]

Trying to find out why the thrust bearing keeps wiping out. Then taking out the others because of lack of oil pressure.
Two times in 5100 miles , complete rebuilds.

DW

 

[TRENT THOMPSON]

believe me I feel your pain thats what I am going through

 

[Buick Mark]

There is no "thrust" bearing for the cam bearings, are you talking about the thrust bearing for the crank main bearings? The cam thrust is controlled by a flange cast into the front of the camshaft that rides on the face of the block, the cam button that goes into the nose of the cam, and the tapper ground into the cam lobes. As far as the rear cam bearing having 2 oil holes is fine as long as one of the holes lines up with the oil feed hole drilled into the cam bearing bore. All the cam bearings are the same except for the front, which has the 2 oil holes. Somebody must have had an extra front bearing and put it in the rear of the block which is ok. Mark

 

[Alky V6]

Are you talking about the crank thrust? If so, which trans are you running? What is the trans line pressure at WOT and idle? If you are running a 400, has the pump been modified to control converter pressure? I might have an answer for you.

 

[JDEstill]

I seem to remember that the #1 and #2 bearings are 1 dia and the #3 and #4 are slightly smaller? When I got my set of TA Perf cam bearings, 2 of them would slip right through the #1 hole, while the other two were an interference fit there. It seems really odd to me that the #4 bearing would have 2 holes in it. And if it was a left over #1 bearing, and the #4 hole really is smaller, then someone must have really crushed that thing to get it in there!

Whatever the case, a problem in the #1 cam bearing area can starve everything else of oil. All the oil to everything (except the turbo) passes by the #1 bearing. If it is hemorraging oil there, expect all the rods and mains and everything else to see less oil. One guy here went through 3 rebuilds before they found his problem, oil leaking between the block and the #1 bearing. They had to hone out the block and I think fabricate an oversize bearing to fix it.

John

 

[Intercooler]

My new Teflon coated Durabonds have two holes also. It will not hurt anything and may even help by holding a pocket of oil in the hole that is blocked off. What was your stab depth?

 

[Dave]

I am talking about the main thrust crank bearing and main bearings and rod bearings but the main thrust is the worst one.

I am running a BRF that was built by Jimmy in Mundeline, IL with a Precision convertor. It blew before the trans was done and after.

Still looking for the problem, maybe the block is bad, it was originaly done because of a bad main thrust bearing, this will be the third rebuild, cam bearings are also the Teflon coated type.

DW

 

[Alky V6]

Do you know what kind of line pressures your running at idle and stall? Also, tee into the top cooler line and let me know what pressure you have at idle and stall. All these previous crank thrust failures, had the trans been modified in any way? Valve body recalibration, pump work, etc. Pump work in particular. The trans cooler or lines aren't presenting a restriction are they? Are you using that fitting with the restriction in it that Precision has you use? When we install a Precision we NEVER use that modified cooler fitting. It builds up a back pressure in the converter that tends to push on the crank more than normal.

 

[Alky V6]

Another thing we learned about the restriction cooler fitting is that it will tend to plug really easy if any debris is coming out of the torque converter. A little debris can be considered normal as long as it doesn't continue to be generated. We learned this with TurboDave's car. Luckily no damage was done to the trans. Remember that the oil returning to the trans from the cooler supplies the lubrication circuit of the trans. Could be disasterous. Imagine starving your engine for oil. Same thing. Just takes a little longer for the damage to set in. To control crank thrust problems with a 400 we restrict the converter feed BEFORE the converter. Doing it after just invites hair pulling experiences. I can't imagine having to redo engines for that kind of reason. I feel for you.

 

[Dave]

Thank you!!
I will check it out after I get it rebuilt again and get it running

Dave