Do I need a bronze cam thrust washer with my hydraulic roller cam?

I just got my hydraulic roller cam and I was expecting to get a thrust washer with it, but I did not. I contacted TA and was told I don't need one. I'm confused because there website states they include one with every 455 roller cam purchase. Do I need one? If not, is it recommended to use one? My intuition tells me it's wise to install one. I just want to ensure I'm assembling this engine correctly.




Thanks,

Jim

 

I use thread ROL 150 shown in your post.

 

Thanks Gary.

I did buy the ROL 150E. However, I was under the impression the cam bumper and the thrust washer serve different purposes. The cam bumper prevents the cam from moving back and forth in the block and the washer prevents the block and cam from wearing on each other. It sounds like the bumper is not needed.

 

Thanks Larry. The links you shared helped me to understand what’s going on. The cam bumper will prevent the cam from walking and I drilled a small hole in the passenger side oil gallery plug, so lubrication shouldn’t be an issue. So the bronze thrust bushing (ROL 100, depicted in my original post) isn’t necessary.

No, I was not referring to the Torrington bearing. I’m using ROL 150E, which is the cam bumper TA recommended.

 

From my experience I would use both...bumper is required....bearing "optional "....but from the mess it made in my brother's 494..I would do both

 

My issue was mostly due to a completely INCOMPETENT builder....but still

 

In my last iron block build I always had alumn shavings in the oil. Wasnt until after it finally spun a rod bearing and the ensuing disassembly did I find the cause. The cam button was wearing on the timing cover and had pretty much eaten away that little stopper cast into it. My solution was to drill through that and tap threads then screw in a brass carriage head bolt . Add sealer to the threads and cut off the excess in the water pump cavity. sand / grind smooth.

 

Ethan - Is there any machine work required on the block to use the bronze bushing or does it just fit in the recess in the block? My short block, less cam, is already assembled.

Briz - Do you think your cam end clearance was set too tight or do you think this is just an inherent problem when using a cam button with an aluminum timing cover?

 

There shouldn't be a recess...if there is it's been eat into already. But no it would need to be machined to accept the bearing or washer as far as I know

I know JW done a few Tomahawks there was a thread on it....technically the cam shouldn't be pushed backwards but instead forward that why you use the button obviously...on my brother's engine with only a few hours run time eat a 90 thousand deep groove in the block and sent all the shrapnel thru everything I'm sure

 

Here's a picture I took of my block during the teardown. So you're saying this recess is actually a result of the cam wearing into the block and it's not supposed to be there?

 

Correct....although it appears to be machined in your case...i can see the chatter /tool marks...but a stock block is smooth

 

You may have enough room for the thrust washer it appears

 

Thanks!

 

It may be a roller cam thing as my hyd cam didnt do it and thats what these engines were designed to run.

 

I mean...maybe I'm wrong but there can't be any taper rite? ...I mean roller cams have square lobes.....so what keeps the cam goin forward....it would just float...and get pushed back under rpm??

 

I mean obviously the OE uses retainer plates to limit forward movement....idk....but all I know is the front of my block is fubarred as is the back of the cam

 

Ethan - I agree with you. The cam button is required to prevent the cam from walking. The bronze thrust washer seems to be more of an individual preference. I’m leaning towards install one “just to be safe,” but I still haven’t decided. Although, I may be forced to run one if the recess in my block sets the cam too far back and causes a misalignment with the timing chain gears or with the lobes and lifters.

 

So I threw the cam in the block today and took some measurements. The recess in the block (shown in post #12) is 0.050" deep and has a diameter that is approximately 0.100" smaller than the diameter of the bump out on the back of the cam. So the cam bump out actually rests on the original surface of the block with a bearing width of only 0.050" around the circumference of the bump out. In addition, there's a 0.025" misalignment between the cam gear and the crank gear with the cam gear being closure to the block. TA recommends a misalignment tolerance of 0.015" +/-. To perfectly align the gears I'd need to add a 0.075" thick thrust washer (0.050" recess depth + 0.025" misalignment). TA's thrust washers are only 0.040" thick and are too wide to fit in the recess. The only options I can think of are:

1. Buy two TA thrust washers, turn down the O.D. so they fit in the recess, and stack both of them behind the cam. This will put the gear misalignment at only 0.005".
2. Buy a custom made 0.075" thrust washer for $150. This will align the cam and crank gears.
3. I have no idea.

I'm inclined to bight the bullet and just buy a custom washer, but if there are no issues with stacking two TA washers, then that would be the cheaper option.

Any thoughts?

Thanks,

Jim