Spun cam bearing...

-

Miszny

Well-Known Member
Joined
May 24, 2012
Messages
846
Reaction score
566
Location
Warsaw
Hello

I am curious what could have caused my camshaft bearing to move?
Bearings are not new, they were installed like 12 years ago.
I was currently using solid roller billet cam, it was 4th different camshaft in this block. I was regularly spinning to 7000...
All other bearings are in place and look good, it’s almost a shame to remove them ;-)
I caught this early so cam was not affected. Rockers took the biggest beating but they can be reused.

I will be installing new bearings and wanted to know how to avoid this in future?

1794E173-4266-4E00-B771-CA4961A33E2B.jpeg
 
Do you have any #'s off the back side of these bushings to "I-D" whose brand they are? Just suggesting, 18$ units may not be up to the job where a race set is needed! Are you sure that is actually spun, some bushings have unused extra holes in them!
 
"Regularly spinning to 7000"

Well there you go. Lots of unusual things happen at those high RPMS. Too much heat? Not enough oil? Both?
 
Have a good machine shop install the new ones, they can also check for any misalignment in the cam bore. Are you thinking of re using the cam that was installed when you noticed this? Probably not recommended.
 
If you have low volume pressure at idle, you can snag a bearing. Especially when using roller spring pressures.
 
All 3 holes in this bearing are relocated abour 1/4" so yes I am sure it actually spun. ZERO oil to rockers also.
These are PD-17 bearings.

As for reusing cam it did not cross my mind not to. It looks like there is no noticeable damage to it. I will have it checked by machine shop to make sure its straight but thats about it. Why would I not want to use it?

As for low oil pressure at idle, seems to make sense, not long ago I used some thin oil with cleaning solvent and I got almost 20PSI at idle when hot. Normally with 20w50 I use I get 30PSI at idle when hot.
 
If they were removed after being installed, then re-installed, the retention force is reduced... Each time they are removed and re-installed, you loose some interference in the fit....

You need to install them only once for greatest retention force...
 
If they were removed after being installed, then re-installed, the retention force is reduced... Each time they are removed and re-installed, you loose some interference in the fit....

You need to install them only once for greatest retention force...

They were not reinstalled as far as I know.
 
Then check the cam for runout (axial straightness)..

Or else your revving it too high like RRR posted...

Yes I will check if it’s straight for sure.

It revved like crazy so I guess I went too far.
I will put 6400 rev limiter back in, cam specs say it works between 2800 and 6300 but it really revs so nice, or should I say used to rev ;-)
 
Was block pressure washed? I always replace cam bearings when I tear down and jet wash a BBM.
If cam journals are fine, I'd roll with it. Polish it up on the crank polisher, and go to town. S/F....Ken M
 
PD-17 bushings are for stock use only, not intended for a performance build. Request PDP-17 this time. My assembler tells me he can feel a difference in the force required to install the "P" or "P#T" series compared to the stock ones.
 
Was block pressure washed? I always replace cam bearings when I tear down and jet wash a BBM.
If cam journals are fine, I'd roll with it. Polish it up on the crank polisher, and go to town. S/F....Ken M

I hope it was washed many years ago ;-)
I have no idea why this happened and this low oil pressure idea seems to make sense.
It's not that I swapped cams yesterday or something.

Also camshaft really has zero marks on it. I will post a photo later this week. You can neither see or feel anything. Will have it checked for straightness just in case.
 
mikes motor 009.jpg

you drill into the main oil galleries then tread and plug the. the heads get full time oiling from the main gallery. the cam bearing doesn't share any oil.
you then turn the bearing so the holes don't line up to the head oiling passages.
 
Last edited:
Yes I was thinking about the oiling mods for a while now. Seems like a good opportunity to do it.

I have the PDP-17 bearings and PD-17 bearings, was curious what is the difference between them.
Also my machinist said that using some Loctite adhesive would be a good idea but there are different types and I need to check what I need before I glue the bearings in there for good ;-)
 
I snapped a cam in an aluminum OHC head that had no cam bearings. Oil starved and seized it up. Only think I can think is oil starvation to that journal. Possible?
 
You'll be looking at the green loctite. They have some that wick in if applied after the bearing is installed, and they have some that will set up while you're still installing.

Wasn't there someone that was Dowel pinning the cam bearings in place?
 
You'll be looking at the green loctite. They have some that wick in if applied after the bearing is installed, and they have some that will set up while you're still installing.

Wasn't there someone that was Dowel pinning the cam bearings in place?
you could if it was grooved, or make a very short pin to fit in the bearing thickness.
 
I snapped a cam in an aluminum OHC head that had no cam bearings. Oil starved and seized it up. Only think I can think is oil starvation to that journal. Possible?

Well it was rather my stupidity that added a lot to it. I was taking the pan off to look at the main and rod bearings, I put assembly lube on them after inspection. I was a smart *** and did not prime the engine after. Ofcourse my oil gauge did not show oil pressure right away...
Now I'm having all the fun. Just realised that these two things are linked. Prime your engines after you do stuff like this, learn on my mistakes.
I should be back on the road next week but I feel like an ***.
 
OK final update for this thread:

I decided that it wont stop me that easy so I made a cam bearing puller and pulled all the bearings with engine in the car. Tool is very simple, I used lathe to make size matched pushers made of aluminum for each bearing, and cut every single one to 4 pieces so they spread out and match the bearing size after they go past the bearing. Used rubber bands to keep 4 elements together and pulled one bearing after another spreading each tool to size with sized wedge. I made a puller using threaded rod with big washer welded on the back and piece of aluminum with a hole as locating part the size of 1st front cam bearing. Had to push the wedge from the front using some tube to be able to pull the last bearing mostly. I was using a wrench on a nut to pull each bearing out, worked great.
It took me like 15-20 minutes to pull all the bearings out.
I tried to use this tool to push the new ones in but it was not going that smooth so I used lathe again to make size matched pushers... Using threaded rod with washer welded on I pushed new bearings in place. Very easy and smooth process. This worked like magic, all was done very fast, again 15-20 minutes and all the bearings were in without using hammer once. This works great because using nut on a thread you can control bearing location very precise.

Bearings 2 and 3 were too tight, so I used old cam with grooves to size them. Took me a while to make sure no bearing shavings go to the windage tray and pan. After some gymnastics I made it.
Took me two beers to size the bearings, but they came out really smooth and nice looking after.

Car is on the road for a while now. I changed oil and put new oil filter just in case but it runs like crazy again. You don't need to pull the engine to swap cam bearings, it just takes some work and beers...

Cheers and remember to pre oil your engine to avoid this kind of gymnastics :)
 
Oh and my cam turned out to be straight and in very good condition so I used it again. I was tempted to advance it a bit but decided not too as the car run great before it happened.
 
You certainly are dedicated! I'm glad it turned out for you.

I don't know how so many hot rod guys live without a lathe and a mill at the shop. If I need something I make it. Saves time and money.
 
View attachment 1715183470
you drill into the main oil galleries then tread and plug the. the heads get full time oiling from the main gallery. the cam bearing doesn't share any oil.
you then turn the bearing so the holes don't line up to the head oiling passages.

I did this, thinking it was a good idea. It turned out bad, I have had to figure ways out to over come the flood of extra oil, which lowered my hot oil pressure at idle. I think I`ve finally got it . The trick was to overcome it w/o pulling the motor apart !! I still have full time oil, but restricted a bunch !
I wont make that mistake again!-----JMO

440`s (I hear are notorious for having cam bearing bores out of alignment from the factory, they supposedly checked and corrected the bad ones, (I heard).
The guy that did my machine work said the same thing, and he fitted the bearings to make up for it, by honing the out of line ones , w/ the cam I was going to run , that I took in to him. I t evidently worked , no problems.
 
Last edited:
-
Back
Top