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

Jim, will the shoulder (bump out) on the cam safely center two of the TA 100 ROL bronze thrust washers stacked? I can't think of any issues having two in place rather than one if it lines things up for you, as long as that shoulder can handle two.

Cam needs a forward limiter too, so use your TA ROL 150E. (would like to know what that one looks like)

Seems to me a roller cam should be set so rollers are centered on the lobes. Not knowing about how deep the cam plug sits in the back of the block, don't rely on it. Instead limit rearward with thrust washers, frontward with the bumper.

As long as rollers are near center on lobes, and cam bearings cover the journals close to center too, and timing gears are aligned the 0.005" you mentioned, sounds good!

Get a few more folks to agree with me before you go for it, though!

Devon

P.S. Always wondered which direction, forward or rearward the oil pump resistance pushes the cam. If I had parts in hand or looked at a few photos, could answer my own question.

 

Devon,

Thanks for your thoughts.

The washers will center on the cam. I measured the journal size on the cam and the diameter of the bump out and then called TA for the washer dimensions. The washer I.D matches the journal size and the washer O.D. matches the bump out diameter. Although I (meaning my friend) will have to turn down the O.D of the washers so they fit in the recess, but that shouldn't affect anything.

Yep, I plan to use both the cam button and thrust washer now that I realize I have an issue with the block.

I'm building my engine at a friend's house and I just took the cam button over there today. I probably won't be back there until early next week, but the next time I'm there I'll take a picture and post it so you can see the cam button. It's pretty nice. The portion that touches the timing chain cover rotates independent of the portion in the cam.

When I had the cam in the block I looked through the lifter bores and it looked like the lobes were centered. Stacking the washers will move the cam 0.030" forward. I don't think a 0.030" shift in lobe position will adversely affect the lobe/lifter performance. I'd think the lifters will still be well within the lobes' footprints. (IMHO)

Good question about the oil pump. It's something I didn't think of ... and, like you, would need parts in hand to figure it out.

And one last thing I just thought about ... If others feel stacking the washers is a bad idea, I could do a combination of ordering a thinner than 0.075" custom washer and milling some material off the back of the crank gear to align the gears and keep the lobes closer to the center of the lifter bores.

Jim

 

We're on the same page, Jim. I was also thinking that if in the end, putting roller/lobe alignment in jeopardy for the sake of timing gear alignment, I'd go after the gear(s) if need be, either a shim here, or some surface machining there. Seems like measurement-wise it's looking good based on what you've seen so far.

Keep us posted!

Devon

 

The load by the oil pump pushes the cam backward into the engine, and pushes the distributor gear upwards

 

My first engine built by a shop, had way too much oil pressure, the result was the cam ate into the block big time so yes the oil pump pushes the cam back, in my case to the extreme. Just to know it didn't take long to dig in to the block. Symptoms besides high pressure included timing changes, shearing roll pins on distributer gear. Tear down revealed the damage and shop not building to given specs.

 

That kind of sounds like the oil pump was dragging, or bound. Bummer.

 

That's what Mike at TA had said and I know the HV HP pumps would accelerate gear wear...the oil psi on mine was 60ish on average forvthe short time it ran...

 

Mine had the HV pump with well over 100lbs cold pressure with 30 w oil. Tight bearing clearances and minimal rod side clearance no place for the oil to go.

 

Here are some pictures of the cam button I'll be using:

 

Also, I talked with Mike at TA. He couldn't think of any concerns with using two thrust washers for my situation; however, he did say that it's best to keep the cam gear as close to the block as possible. TA's thrust washer is 0.040" thick, so two would push my cam gear 0.030" away from the face of the block (I have a 0.050" recess in my block). This is probably doable, but something was still giving me a little hesitation about using two trust washers. So ... I started looking for a thicker thrust washer, but no luck. So I bought a small block of aluminum-bronze and had a friend machine it into a 0.060" thick thrust washer. This will put the cam gear 0.010" from the face of the block and then we'll mill some material off the back of the crank gear to ensure the gears are aligned properly. Note: there are a bunch of different bronze alloys and they all have their purpose. Not all are suited for being a thrust bearing. What I've found is aluminum-bronze is typically used for thrust washers.