Posted By: Armdropdart68
Cam walk? - 03/04/15 10:32 PM
Do you guys ever get cam walk from a solid roller with no cam button. Broke a link bar and trying to figure out why
Cam walk?
Posted By: AndyF
Re: Cam walk? - 03/04/15 10:53 PM
BB or SB? SB has built in plate so you should be good to go. BB or Hemi needs a button or else you'll bust all kinds of parts.
Posted By: jlatessa
Re: Cam walk? - 03/04/15 11:57 PM
Hope this is not seen as too dumb a question, but why are solid rollers prone to walk vs flat tappet??
And where is the button installed, front or back?
Anyone have some pics?
Thanks, Joe
OK, I looked up in the history and I saw the two reasons people think it does it; lobe taper, or lack of it, and gear thrust from the oil pump drive.
I can see the lack of lobe taper, but gear thrust is the same on all cams, no?
Does the skinny lobe width add a more important factor for restricting walk?
How does the button get installed??
Thanks again............
And where is the button installed, front or back?
Anyone have some pics?
Thanks, Joe
OK, I looked up in the history and I saw the two reasons people think it does it; lobe taper, or lack of it, and gear thrust from the oil pump drive.
I can see the lack of lobe taper, but gear thrust is the same on all cams, no?
Does the skinny lobe width add a more important factor for restricting walk?
How does the button get installed??
Thanks again............
Posted By: Stanton
Re: Cam walk? - 03/05/15 12:43 AM
Flat tappet and hydraulic cams have the lobes ground on an angle so as to make the lifter spin in the bore. The angle tapers to the front so the force of the lifter pushes the cam towards the rear - eliminating forward cam walk. A solid roller cam on the other hand has the lobe ground flat so the roller will make fill contact. The timing sprocket will prevent it from walking back but nothing is there to prevent it walking forward - unless you install a button.
Worth noting is that the button needs to be fit to the motor. A roller button can have some preload but a solid nylon button should have about .005" of play (opinions will vary).
Aluminum buttons should be avoided like the plague unless you like aluminum filings in your motor!
Worth noting is that the button needs to be fit to the motor. A roller button can have some preload but a solid nylon button should have about .005" of play (opinions will vary).
Aluminum buttons should be avoided like the plague unless you like aluminum filings in your motor!
Posted By: jlatessa
Re: Cam walk? - 03/05/15 12:48 AM
Are they fitted to the cam gear on a BB?
Do you measure by pushing the cam forward
with the timing cover on and no pump gear installed?
Thanks, Joe
Do you measure by pushing the cam forward
with the timing cover on and no pump gear installed?
Thanks, Joe
Posted By: Armdropdart68
Re: Cam walk? - 03/05/15 01:03 AM
Who makes one for a BB? How do you install one??
Posted By: Stanton
Re: Cam walk? - 03/05/15 02:19 AM
Most roller cams are 3-bolt cams. The button fits into the center hole of the cam gear. To "fit" it you install the timing cover and gasket then check fore/aft movement of the cam. If there is too much movement you can shim behind the button (I use a piece of the appropriate thickness of feeler gauge). If the button is too tight, its a whole different ballgame. You can grind down a nylon button until you get the desired clearance. If you're using a roller button then grinding is pretty much out of the question. In this case you can stack a couple timing cover gaskets and see if that helps. There are also a couple different thickness gaskets available from Superformance Gaskets.
Worth noting too is that nobody (that I've found) makes a Mopar specific button. They all seem to pass off another brand button as a Mopar. When shopping for a button you want to measure the sprocket hole size as these are not standard and you want do calculate an approximate length you need and then buy accordingly.
Worth noting too is that nobody (that I've found) makes a Mopar specific button. They all seem to pass off another brand button as a Mopar. When shopping for a button you want to measure the sprocket hole size as these are not standard and you want do calculate an approximate length you need and then buy accordingly.
Posted By: Stanton
Re: Cam walk? - 03/05/15 02:21 AM
Are they fitted to the cam gear on a BB?
Yes.
Do you measure by pushing the cam forward
with the timing cover on and no pump gear installed
Yes
Yes.
Do you measure by pushing the cam forward
with the timing cover on and no pump gear installed
Yes
Posted By: Stanton
Re: Cam walk? - 03/05/15 02:24 AM
Virtually every cam manufacturer makes/sells them ... Isky, Comp, Crane to name a few.
Posted By: jlatessa
Re: Cam walk? - 03/05/15 02:49 AM
Thanks for the info Stanton, more questions if you don't mind;
Do/should you weld a thrust plate to the cover for better wear
and rigidity or is that not a factor with all the oil up front?
Your preference on nylon or roller buttons?
Thanks for the help, first solid roller for me.
Joe
Do/should you weld a thrust plate to the cover for better wear
and rigidity or is that not a factor with all the oil up front?
Your preference on nylon or roller buttons?
Thanks for the help, first solid roller for me.
Joe
Posted By: Stanton
Re: Cam walk? - 03/05/15 04:17 AM
Quote:
Do/should you weld a thrust plate to the cover for better wear
and rigidity or is that not a factor with all the oil up front?
Your preference on nylon or roller buttons?
If you're using the stock cover you need something to reduce the deflection. A plate welded on will work but make sure it clears the water pump.
I prefer a roller and I managed to find a roller button that fit. But I'm using a cast cover and a thick gasket. It took a lot of farting around to get the right combination. Its really personal preference, if the roller hadn't fit I wouldn't hesitate to use a nylon one.
To get "in the ballpark", I laid a straight edge across the top sprocket in the block and measured to the cover gasket face. I also measured to the bottom of the center hole and to the face of the sprocket. I then laid the straight edge across the timing cover and measured the depth where the button would be. I then used all those measurements to get an idea of the length of button I'd need. As it so happened the button was too long with a stock gasket so I used the thicker Superformance gasket and then had to slightly shim out the button.
Right about now Andy F. should be jumping in to promote the virtues of his billet timing covers !!
Posted By: AndyF
Re: Cam walk? - 03/05/15 06:16 AM
Posted By: jlatessa
Re: Cam walk? - 03/05/15 07:23 AM
Nice cover Andy, but a little steep for right now as I already have new std. stuff.
Stanton, I was thinking of welding the wear plate inside the timing cover, using an appropriately sized piece made up of a durable
enough material.
Think I can make this work with say a nylon button??
Thanks guys, Joe
Stanton, I was thinking of welding the wear plate inside the timing cover, using an appropriately sized piece made up of a durable
enough material.
Think I can make this work with say a nylon button??
Thanks guys, Joe
Posted By: Mr.Yuck
Re: Cam walk? - 03/05/15 05:02 PM
Well I can tell you what happens when the rear cam plug is not installed all the way in.... The cam walks until the cam lobe wears, then the valve gets hung up and breaks, sending it thru your expensive diamond piston, cutting your fresh block, then other pieces of carnage suck thru the intake and damage the intake valve/seat and piston #2 including the piston wall. When you drain the pan you'll find it full of water and beside having to fix 2 valve seats you will need 2 sleeves. 
Posted By: jlatessa
Re: Cam walk? - 03/05/15 06:02 PM
Posted By: Stanton
Re: Cam walk? - 03/05/15 06:07 PM
Quote:
Well I can tell you what happens when the rear cam plug is not installed all the way in.... The cam walks until the cam lobe wears,
Well that's really strange because the timing sprocket usually stops the cam from moving back!!
Posted By: Stanton
Re: Cam walk? - 03/05/15 06:12 PM
Quote:
I was thinking of welding the wear plate inside the timing cover, using an appropriately sized piece made up of a durable
enough material.
I'd weld it on the outside. I don't think there's enough room on the inside. The timing sprocket bolts will likely hit the plate.
Posted By: jlatessa
Re: Cam walk? - 03/05/15 07:32 PM
Outside it is then, thanks Stanton,
Joe
Joe
Posted By: BSB67
Re: Cam walk? - 03/06/15 02:43 AM
Quote:
Quote:
Well I can tell you what happens when the rear cam plug is not installed all the way in.... The cam walks until the cam lobe wears,
Well that's really strange because the timing sprocket usually stops the cam from moving back!!
Posted By: Armdropdart68
Re: Cam walk? - 03/06/15 04:03 AM
Will the AR billet timing cover work with the low mount alternator bracket
Posted By: AndyF
Re: Cam walk? - 03/06/15 04:37 AM
yes it works
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Posted By: Mr.Yuck
Re: Cam walk? - 03/06/15 07:44 PM
Quote:
Quote:
Well I can tell you what happens when the rear cam plug is not installed all the way in.... The cam walks until the cam lobe wears,
Well that's really strange because the timing sprocket usually stops the cam from moving back!!
Just going by what I was told by the guy who took the motor apart.
Posted By: Stanton
Re: Cam walk? - 03/07/15 12:39 AM
Quote:
Quote:
Quote:
Well I can tell you what happens when the rear cam plug is not installed all the way in.... The cam walks until the cam lobe wears,
Well that's really strange because the timing sprocket usually stops the cam from moving back!!
Just going by what I was told by the guy who took the motor apart.
You should find someone else to put it back together. He clearly hasn't got a clue!
The timing sprocket bolts to the front of the cam. The sprocket rides against the block so there's NO FRICKIN WAY that the rear core plug falling out has anything to do with a cam walking out the back of a block. Maybe the bolt(s) fell out of the sprocket but even so, you can't put any blame on the plug as its simply not designed to hold the cam in.
Posted By: 6PakBee
Re: Cam walk? - 03/08/15 02:26 PM
Quote:
Hope this is not seen as too dumb a question, but why are solid rollers prone to walk vs flat tappet??
And where is the button installed, front or back?
Anyone have some pics?.......
This explanation from Iskendarian is probably the best I've ever seen.
http://www.iskycams.com/pdfcatalog/2004-05/page192.pdf
Posted By: jlatessa
Re: Cam walk? - 03/08/15 06:01 PM
Thanks for all the info guys, I understand the physics of the problem now.
I've ordered both the Comp. Cams buttons; nylon and roller, to see which we prefer, and have polished the area where they will contact the cover, (standard sheet metal).
It seems pretty stout with no deflection when I give it a substantial push so I'm not sure of the need for one of the cast covers outside of the timing adjustability feature.
I may weld a reinforcement plate on the outside of the cover if your consensus agrees it would help.
I'm using a Comp Cam's cam and rollers and timing set so compatibility should work when it comes to adjusting end play.
Getting close to installing the cam so stay tuned for more questions, You guys are a big help to all of us needing your expertise and I know I appreciate it!!
Joe
I've ordered both the Comp. Cams buttons; nylon and roller, to see which we prefer, and have polished the area where they will contact the cover, (standard sheet metal).
It seems pretty stout with no deflection when I give it a substantial push so I'm not sure of the need for one of the cast covers outside of the timing adjustability feature.
I may weld a reinforcement plate on the outside of the cover if your consensus agrees it would help.
I'm using a Comp Cam's cam and rollers and timing set so compatibility should work when it comes to adjusting end play.
Getting close to installing the cam so stay tuned for more questions, You guys are a big help to all of us needing your expertise and I know I appreciate it!!
Joe
Posted By: JohnRR
Re: Cam walk? - 03/08/15 07:30 PM
Quote:
Thanks for all the info guys, I understand the physics of the problem now.
I've ordered both the Comp. Cams buttons; nylon and roller, to see which we prefer, and have polished the area where they will contact the cover, (standard sheet metal).
It seems pretty stout with no deflection when I give it a substantial push so I'm not sure of the need for one of the cast covers outside of the timing adjustability feature.
I may weld a reinforcement plate on the outside of the cover if your consensus agrees it would help.
I'm using a Comp Cam's cam and rollers and timing set so compatibility should work when it comes to adjusting end play.
Getting close to installing the cam so stay tuned for more questions, You guys are a big help to all of us needing your expertise and I know I appreciate it!!
Joe
I plan to put the reinforcement on the back of the waterpump.
Posted By: jlatessa
Re: Cam walk? - 03/08/15 08:47 PM
John, do you plan on measuring the gap then welding the same thickness onto the pump?
I guess that would result in a substantial back-up to the cover.
It would entail at least a couple of assembly/dis-assembly
routines though.
Joe
I guess that would result in a substantial back-up to the cover.
It would entail at least a couple of assembly/dis-assembly
routines though.
Joe
Posted By: Stanton
Re: Cam walk? - 03/08/15 09:41 PM
Quote:
John, do you plan on measuring the gap then welding the same thickness onto the pump?
I guess that would result in a substantial back-up to the cover.
It would entail at least a couple of assembly/dis-assembly
routines though.
The back of the pump isn't the best way to go but I guess he doesn't want to mess up his pretty chrome timing cover!
The spacer doesn't have to be a perfect fit, it can have some gap and the cover may deflect some. As long as it doesn't allow the cam to walk enough that the lifters fall off the lobes it should be ok. There would be some defection in the timing chain too but that wouldn't matter.
I hope its an aluminum pump, welding a spacer on an iron pump would be a b!tch.