ta cam bearing

[sylvain]

hi everyone,
i will like to know if anybody have the instruction to install the TA 1557A cam bearing #1. because the speed chop install the hole at 10 oclock and 2 oclock in my fresh rebuilt block and i spun two set of rod bearins #1 after the first startup and the other one after only 20 min of runing in garage.
if anyone can help me!

thanks
sylvain.

 

[MSDGN]

T/A recommends installing the bearings with the holes at 3 and 7 'o' clock when looking at the engine right side up from the front

 

[FJM568]

That being said, it shouldn' t cause you to spin two rod bearings just because the TA cam bearings were installed wrong...I would have the rods looked at to make sure the big ends are in spec when torqued down...If you didn't resize the rods after the first bearing spun, you will probably keep spinning the bearings until you do...

 

[notched]

I am glad I found this post. I am currently having the engine rebuilt on my own car and had pruchased the TA cam bearings.
According to TA, the say to install them at 3 oclock and 7 oclock. The problem is ALL of them are at 2 oclock and 10 oclock.
My machinist felt that 2 and 10 would be fine. But I figured I would ask. Does anyone know why they would be different than what TA recommends?

 

[Six_Silver]

Originally posted by notched
Does anyone know why they would be different than what TA recommends?

The holes in the block are at 10 and 2 o'clock. Most cam bearings are not grooved on the back like the TA bearings. If you install a standard cam bearing at 3 and 7 o'clock (which covers the oiling holes), the oil would not get through to the cam. The TA bearings are grooved on the back which allows you to block the 10 and 2 o'clock holes, forcing the oil thorugh the grooves and out the holes in the bearing.

I would like to know as well if anyone has had problems installing the TA bearings at 10 and 2 to line up with the oil holes in the block instead of blocking them like TA recommends.

 

[JDEstill]

1. I'm thinking that with the groove in the 109 block, you can orient the holes in a standard bearing (not just a TA bearing) any which way and it should work. If someone sees a problem with that, lets discuss!

2. My cam bearing wear all occured in the 4 o'clock to 8 o'clock range. I suspect this true of everyone else. So it is much better to put the holes where they introduce oil into these critical areas. Which is why TA recommended 3 and 7. If your engine is not yet buttoned up, I would pull the cam bearing and reorient it.

John

 

[getchasum]

Food for thought.....

I wonder if the fact that the bearing, block and an after market cam being grooved, created a oil hemorrhage that depleted oil psi?

Was this the same rod that spun the bearing???

 

[Lee Thompson]

Having a little trouble with your wording. Is it # rod bearing that spun each time? I don/t see how your cam bearing has anything to do with feeding your mains which gets oil before the rods. # 1 cam bearing feeds oil to the cam journal and also feeds oil to the drivers side lifter galley. Does the eng. have good oil pressure? If so I would check the crank and rod carefully!!!

 

[JDEstill]

Re: Food for thought.....

Originally posted by getchasum
... created a oil hemorrhage that depleted oil psi?

I don't think that these factors together will cause an oil hemorrage. I think you need some bad clearances somewhere for that to happen, which I wouldn't expect on a fresh motor.

If the cam bearing gets really worn, then the increased cam-to-bearing clearance can bleed off a lot of oil, which will then starve everything else.

And one of the guys here in Houston several years had to go through several rebuilds before he found that his block was bit distorted, and he had a gap between the block and the #1 cam bearing. That bleed off a lot of oil, leading to his engine failures. He had to do a pressure test on his oil system with the block on a stand to find that one.

John

 

[sylvain]

spun number one rod bearing two time ,
and this weekend i restart the motor with a new seed pro #1 cam bearing and with another rod number 1 that came from my last year set up.
same thing happen after only 15 minute idle and 2 road milles.
cold start up oil pressure at 85 psi and hot idle pressure wen the sound came from the rod at 5 psi.

the clearance on the rod is at 0.0025" and on the main too.
all others rod bearings and the number 1 main bearing are like new.

time to pull the motor again and change the crank !