Big Block Timeing Chains revisit?

[cj's mopar]

Hello, does anyone know if a B engine will run ok with a Hydraulic roller cam With Out a Torrington bearing behind the top timing gear ?
Thought I read once that this was not necessary for big block Mopar?

 

[gkent]

Stock hydraulic cams never had the roller bearings - this is something the aftermarket thought would be a good idea. The roller cam will put less stress on that area so in theory a torrington bearing isn't needed. HOWEVER ... its always advisable to use a cam button with any roller cam since there is no taper on the lobes to prevent forward cam walk. That said, if you don't properly fit the cam button's clearance it can put pressure on the sprocket and that surface WILL gall. Even with the torrington in there you still don't want crazy pressure on that area - clearance the cam button. DO NOT use an aluminum cam button.

 

[cj's mopar]

Thanks for the info I am using a nylon button do I need to weld an piece of square stock inside the timing cover to reinforce it or would the cover itself be fine?

 

[diesel_lv]

No bearing behind my roller cam, used nylon button, had to clearance it a little to fit between cam gear bolts, then put a bunch of putty where the button would go and put gasket and timing cover on and torqued. Removed and measured how thick it was and shaved nylon button down to spec. No issues.

 

[diesel_lv]

Thanks for the info I am using a nylon button do I need to weld an piece of square stock inside the timing cover to reinforce it or would the cover itself be fine?

They say the stock cover "can" flex. I used a 440 Source stamped cover, it's a bit thicker and say it won't flex.

 

[gkent]

Weld the piece to the outside of the cover. The general consensus is reinforcement is necessary on a stock cover. Anything close to .005" is a comfortable clearance for the button. Check with the gasket in place. If you have access to the valley you can check play by moving the cam back and forth. Otherwise you'll need to check with plasticene on the end of the button. If clearance is too tight, grind the button. If its too loose, shim behind the button - pieces of feeler gauge work. No worry of them falling out once the button is in place.

 

[RemCharger]

When you weld the washer on.... make sure to mock up the water pump housing with gaskets. I ground the pump and washer, then feeler gauged it to a few thou. Then if the cover does flex, the pump holds it there.

 

[cj's mopar]

So make a washer Sandwich with water pump and timing cover thanks for the info.
Never messed with this before .

 

[66Satellite47]

Thanks for the info I am using a nylon button do I need to weld an piece of square stock inside the timing cover to reinforce it or would the cover itself be fine?

I welded the flat stock on the outside of the cover. With my roller cams and roller thrust buttons. Proper adjustment is required. I used the hammer and multiple measurements.

 

[IQ52]

Friend of mine (Ford guy) was running a Big Block Chrysler with roller cam and a reinforced stock timing cover on his dyno and was watching the timing cover bulge in and out. He called me and asked about a solution.

This was my answer........http://arengineering.com/products/timing-chain-cover/

I run these on every one of my big block roller cam engines.

 

[cj's mopar]

Wow that's very interesting. I think I will try and fab up something to wedge against the back of the water pump so it can't move .I try and take some pictures of the process.

 

[gkent]

A big wad of epoxy will do the trick. wrap it in saran before wedging it in there so it doesn't stick to the pump or cover.

running a Big Block Chrysler with roller cam and a reinforced stock timing cover on his dyno and was watching the timing cover bulge in and out.

Someone needs to explain why a roller cam would move - particularly on a dyno run. Let's look at this ... a) the lobes are flat so there is no force on those to move the cam forward. b) the oil pump drive gear rotates CCW and the cam turns CW - the cam against the drive gear would drive the cam rearward - not forward c) the timing chain will have some influence on keeping the cam from moving forward.

So, I'm not denying that the cam will move, I'm just saying that having it move to significantly flex a timing cover is a little far-fetched.

 

[IQ52]

Aw shucks, yer right. He didn't know what the hell he was seeing and I don't know what I'm saying. Good thing we got you to straighten every far-fetched thing out. In fact my friend was so confused he called me back to thank me as it cured the floating timing issue he was having.

 

[66Satellite47]

A big wad of epoxy will do the trick. wrap it in saran before wedging it in there so it doesn't stick to the pump or cover.



Someone needs to explain why a roller cam would move - particularly on a dyno run. Let's look at this ... a) the lobes are flat so there is no force on those to move the cam forward. b) the oil pump drive gear rotates CCW and the cam turns CW - the cam against the drive gear would drive the cam rearward - not forward c) the timing chain will have some influence on keeping the cam from moving forward.

So, I'm not denying that the cam will move, I'm just saying that having it move to significantly flex a timing cover is a little far-fetched.

Back in the day my explanation was valve spring dynamics combined with the oil pump pulsation. True??

 

[cj's mopar]

That big wad of Por 15 epoxy would be easier! And it will smash in to the correct size when water pump installed and then painted to be not noticeable!
I think I will let it stick to the timing cover so it can not ever move . Seran wrap pump side .
I have used it before it is rock hard I am glad you mentioned it I forget stuff sometimes.
Lol.

Back in the day my explanation was valve spring dynamics combined with the oil pump pulsation. True??

 

[Gunner1]

All it takes is one lifter bore to be slightly out of square fore and aft with the cam centerline to impart a thrust on the cam. The more spring pressure you run the more it affects the problem. SBC's get lifter bores sleeved for exactly this reason. Across the block out of spec bores change the cam timing events. Using a bore fixture and bronze sleeves is done on lots of circle track and road race small blocks. Just learning Mopar blocks so I have no idea if they suffer like the GM blocks do.

 

[cj's mopar]

So I been trying to figure this out I fave a large 2 inch diameter washer wedged behind the water pump .the washer is .064 thou thick and cover still flexing with watep pump on
Flex is about .005 to 7 and the cam true clearance is about .004 .
I am worried about the flex.

 

[gkent]

Nah, nothing to worry about. .010 is acceptable and you're only .001 over. And all this is only "if" the cam walks.

 

[INTMD8]

Friend of mine (Ford guy) was running a Big Block Chrysler with roller cam and a reinforced stock timing cover on his dyno and was watching the timing cover bulge in and out. He called me and asked about a solution.

This was my answer........http://arengineering.com/products/timing-chain-cover/

I run these on every one of my big block roller cam engines.

I reinforced my stock cover and noticed how flexy it was -still-, when checking button clearance.

Didn't feel good about it and ended up with the AR engineering cover as well. Very nice

 

[cj's mopar]

This is what I ended up with .007 true clearance with .064 washer Wedge behind the cast iron water pump housing.
I will flex about another .010 if I force it .
I feel comfortable with it and going to run it .
It's going have to do for now .