Just curious. Has anyone made a camshaft thrust plate foe a slant 6?
Camshaft Thrust Plate
- Thread starter RustyRatRod
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bcschief
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I have heard of using a thrust screw in the timing cover in fact I think they used a rocker arm adjuster screw with a nut welded to the timing cover.
MadScientistMat
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Yes, that's what I have seen too. Not using one myself.
Yeah, not a brilliant idea with a stamped steel cover. I guess it could be reinforced.
Charrlie_S
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Personally, I don't think one is necessary. With the taper on the lobes, and the load of the oil pump that should keep the cam from moving forward. Now if using a roller cam and external belt drive oil pump, we have a different ball game.
Absolutely and I agree. I was wondering about keeping a roller camshaft from walking.
MadScientistMat
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In that case, I would expect reinforcing the timing cover would be easier than rigging a needle bearing setup and cover on the back of the block.
And why would it need to be a needle bearing setup? The small block only has a flat plate.
MadScientistMat
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The options are to have something simple push the cam in from the front, or replace the freeze plugs at the back of the cam with some sort of contraption to pull the cam in. The "pull the cam from the back" option just seems a bit Rube Goldberg no matter how you set it up. Roller bearings may be overkill, but the whole adding a plate on the back of the cam to push against the block seems like more trouble than it's worth to begin with.
I was talking about a thrust plate on the front. I see no reason it would need needle bearings there. Have you made this modification to a slant 6 before?
MadScientistMat
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I have not used this myself as I am fairly confident the oil pump drag will pull the cam in without any need to push it from outside. It might have been a different matter if I had the budget for a dry sump. And I don't see a need to a bearing at the front of the cam. I had not meant to suggest it would be needed; there's a decent amount of oil in the timing cover and minimal force that would push the cam forward.
The bearing idea was meant to be the only way I could see a pull arrangement working on the back of the cam, but that wasn't meant to be a practical suggestion as much as an illustration that any alternative to pushing from the timing cover would be way too complicated.
The bearing idea was meant to be the only way I could see a pull arrangement working on the back of the cam, but that wasn't meant to be a practical suggestion as much as an illustration that any alternative to pushing from the timing cover would be way too complicated.
I went through the whole cam walk dilemma went I was turning crazy rpms also. Put an aluminum thrust button from a single bolt big block cam on it and my oil pump gear wear and timing related meltdowns went away.
CNC-Dude
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I've looked at adapting several different factory thrust plates from other engines and it's very doable with little effort. The cam gear will need to be clearanced to create the end play, but its a minor thing. No roller bearing thrust button will be needed if you use a plate....
Right! That's what I was wanting to avoid, the thrust button. I knew the cam sprocket would need clearancing. I was just wanting to figure it out now, even though I'm not using a roller yet, I may want that option down the road. What my thought was, was to clearance the cam sprocket more than needed and have some shims made so that I could adjust the end play as needed, as each cam core may be a little different. Heck, it might not even work, but I'm just spitballin. lol
vitamindart
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any reason why your against the button ( other than the thin cover ). always ran one on my big blocks, never had an issue and they didn't have a roller bearing. just curious
Mattman’s mopars on eBay makes a very nice cam button that goes onto the front of the Cam Bolt. It is file to fit made from black Delrin.
If you need more strength, I suggest using this button along with reinforcing the front of the chain cover with some 3/16” plate.
If you need more strength, I suggest using this button along with reinforcing the front of the chain cover with some 3/16” plate.
Yes sir. I have two.
I'm simply looking at other options is all.
A thrust plate would require;
1) Machining the front face of the cam journal to a reduced dia. the thickness of the plate plus any bearing if employed.
2) Machining a recess in the block face the shape & thickness of said plate.
3) A counterbore the depth & diameter of any thrust bearing employed beyond the plate recess . This may require narrowing the frt. cam brg.
4) A concentricity spacer ring to center the cam gear on the reduced diameter cam nose.
Since the cam has a .060-.070" deep chamfer from the sprocket/gear face, & the sprockets have a .250" pocket, that leaves less than .200" for a thrust plate & reliable centering of the sprocket/gear by machining the rear face(the easiest way).
Honestly, reinforcement of the cover & a simple thrust button is the best solution, JMO.
Jim K6
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There is this style used on asian OHC's, I think this is a Hyundai/Kia, but You get the idea. They aren't subjected to any real thrust loading, but do locate the cams well, just;
1) Machine recess in block for plate
2) Cut the receiver groove precisely in the cam journal.
Dave999
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method as specified in a chrysler Australia tech bulletin for Hemi 265
https://www.geocities.ws/drhemi.geo/camfloat.html
I didn't bother with the screw. too much hassle. things have moved on since 1976.
I used a 3 bolt cam, machined a Nylon? big block cam button and stuck it in the end. just cut it down until you can just fit the cover, then a bit more so it just just touches. the cover has not cracked and its been in there 10 years.
aftermarket aluminium covers come with a bolt already fitted....
1 bolt cam used a retainer as per the style shown above on these motors...but after market and all before about 1977 cams are all 3 bolt.
presume you could apply the same to a slant if you so desired. both motors use similar set up for dizzy and oil pump drive. i.e cam set up is similar.
and rely on the slope of the lobes and the profile of the lifters to keep cam in place.
the aftermarket doesn't get this quite right.
the hemi 6 suffers stupendous cam walk when its done 50,000+ miles in a police car or taxi on original style sprockets and chain.... hence the factory bulletin
modern double roller chain not so much.
timing set with torrington flat bearing on back of sprocket is a nice addition Romac/Rollmaster used to be the place to get that.
few other A body specific bulletin extracts here https://www.geocities.ws/drhemi.geo/techpage.html
Dave
https://www.geocities.ws/drhemi.geo/camfloat.html
I didn't bother with the screw. too much hassle. things have moved on since 1976.
I used a 3 bolt cam, machined a Nylon? big block cam button and stuck it in the end. just cut it down until you can just fit the cover, then a bit more so it just just touches. the cover has not cracked and its been in there 10 years.
aftermarket aluminium covers come with a bolt already fitted....
1 bolt cam used a retainer as per the style shown above on these motors...but after market and all before about 1977 cams are all 3 bolt.
presume you could apply the same to a slant if you so desired. both motors use similar set up for dizzy and oil pump drive. i.e cam set up is similar.
and rely on the slope of the lobes and the profile of the lifters to keep cam in place.
the aftermarket doesn't get this quite right.
the hemi 6 suffers stupendous cam walk when its done 50,000+ miles in a police car or taxi on original style sprockets and chain.... hence the factory bulletin
modern double roller chain not so much.
timing set with torrington flat bearing on back of sprocket is a nice addition Romac/Rollmaster used to be the place to get that.
few other A body specific bulletin extracts here https://www.geocities.ws/drhemi.geo/techpage.html
Dave
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