I was also concerned about that but was led to believe it would be ok. No marks on the lifter bore bushes but haven't seen anything over 4000 rpm.
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Solid rollers with off set push rod hole issue.
- Thread starter gg408
- Start date
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If I could I would run 3/8"pushrods but room is tight.I have never seen anything adverse from running offset lifters.
Like I said, when I see that I look at spring load and heat treating.
One other thing it could be is pushrod flex. The incredible loads generated by pushrod flex is real.
Spring pressure are both the same on intake and exhaust. Not sure if I should have little more on intake as it is boosted. Valves are 2.05" in & 1.65" exh , 11/32 stem with tool steel retainers and AFR/PAC springs. Waiting to see what cam company has to say.Assuming valve springs are set up the same, spalling on the intake only suggests it's an issue of the larger forces involved due to the heavier intake valve. I doubt the heat treat or core is any different intake vs exhaust so we're back to an insufficient heat treat or material for the stresses involved.
RAMM
Well-Known Member
I've looked through this thread and you have an out of control valvetrain. Hope the following helps.
That photo tells me "Why even run an offset lifter in a W2 at all!"
I'm going to share my thoughts on the W2 head itself as it is part of your problem.
The W2 is a great cylinder head and I have used them many times. The massive offset rocker arm carries its own set of problems and in your case creates or exasperates an additional one.
You should be using more spring pressure on the intake in comparison to the exhaust just because of the mass of the rocker and the offset of the arm itself. Just think of the side loading. I have used as much as 140lbs on the seat in a solid flat tappet build and all of the intakes floated (star pattern on valve tips) while none of the exhaust did. Not only are the valves heavier but so are the rocker arms and then add in the weird geometry and side loading forces. It's almost as bad as a Hemi. That big beautiful offset rocker arm needs its own considerations when it comes to set up. Once you use a paired shaft T&D system you will wonder why you didn't do it sooner. The T&D paired shaft system is really the only good answer for any offset rocker system. Oh and if you are running boost you need to calculate the area in square inches that your boost in PSI is acting on and add that to your spring pressure, you might be surprised that you might need 30-40? lbs (just a guess) more spring to control the valve. The offset rocker arm only adds to this problem.
Offset Lifter: The offset lifter comes from Smallblock Chevy Land and in my opinion--CANNOT ever be used in a 59* degree SBM. Why? A SBC can get away with it for much longer because the lifter bore is parallel with the pushrod and cylinder bank. I believe it would "work" in a BBM but have never tried it. I don't like offset lifters even in a SBC but have used them many times in DIRT engines that get rebuilt at least every year.
An offset lifter in a 59* lifter bore is a short term recipe for disaster--that pushrod is ALWAYS trying its best to make that lifter body rotate--It has lots of leverage and I don't care how BIG and BEEFY you make that lifter tie bar it WILL break. If it IS BEEFY enough it will manifest its unhappiness in other valvetrain unhappiness. If you add spring pressure it will stress the tie bar more, wear out your lifter bore, make the side loading on the rocker arm worse and bring you closer much much sooner to catastrophic failure. Think of a diving board as your tie bar and a 600lb morbidly obese guy standing on the end of it. Now think of the 600lb guy lightly bouncing up and down on it his big ugly feet never leaving the board--You should have about that much open spring force-Solid roller right? Now add lash--Yup you got it now that fat guy's feet are leaving the diving board as the diving board momentarily provides enough force to overcome his mass and make him weightless for a moment in time. You only have so many times before the diving board snaps. In short an offset rocker arm AND an offset lifter in a 59* SBM is in my eyes a perfect storm-**** STORM. If you take a look at your picture a normal non-offset lifter is not going to add much more angularity to your pushrod. IME&IMO completely unnecessary.
Related but not really relevant info: The W2 does not need or even perform well because of the big port inlet. The majic is in the deep bowls=tall S.S. and exhaust port design. If I were to do it again--I'd shrink the inlet with the sole purpose of straightening that pushrod as much as I could, and I would move the lifter over about .060"<<(I've done this) It wouldn't impact the almighty (CFM) flow rate at all but it would allow for higher RPM torque production which equals BIG HP.
I know, long winded post but this is my .02 cents take it FWIW. J.Rob
P.S. Just calculated the area of a 2.055" valve and it is 3.317" so 10psi of boost is 33lbs of force trying to open your intake valve when it is trying to close.
Last edited:
Thanks RAMM, this should help a lot of ppl contemplating the offset game. Kim
Newbomb Turk
Well-Known Member
If I could I would run 3/8"pushrods but room is tight.
I have used both single taper (7/16 x 3/8) and double taper 7/16 x 3/8 x 7/16) pushrods to get them half assed close to rigid enough.
Ramm’s above post is 100 fact. He nailed it. Lots of good information in that post.
It’s my opinion (based on years of running W2 and W5 heads and even GM crap) that you can’t get a pushrod too stiff.
Overkill on pushrods is barely acceptable.
I went through a time where you could torque the rocker adjusters so tight they would snap and they would still come loose.
I forgot how I figured that one out but the pushrods were flexing so much it was like the adjusters were getting hammered on like they were getting hit with an impact gun (I apologize for the horrible sentence structure…) and they would come loose.
I’ve seen heads that had .150 clearance and the pushrods showed witness marks from bending that far and rubbing the head.
Can you imagine what that pushrod is doing if it is bending far enough to eat up .150?? That’s crazy. And who knows? It might have bent even more if the head wasn’t acting like a guide plate.
As Ramm said, offset rocker valve train is its own *****. You have far less room for error with offset rockers.
Thanks for that info. I will certainly rethink everything I was lead to believe when told to use them.I've looked through this thread and you have an out of control valvetrain. Hope the following helps.
That photo tells me "Why even run an offset lifter in a W2 at all!"
I'm going to share my thoughts on the W2 head itself as it is part of your problem.
The W2 is a great cylinder head and I have used them many times. The massive offset rocker arm carries its own set of problems and in your case creates or exasperates an additional one.
You should be using more spring pressure on the intake in comparison to the exhaust just because of the mass of the rocker and the offset of the arm itself. Just think of the side loading. I have used as much as 140lbs on the seat in a solid flat tappet build and all of the intakes floated (star pattern on valve tips) while none of the exhaust did. Not only are the valves heavier but so are the rocker arms and then add in the weird geometry and side loading forces. It's almost as bad as a Hemi. That big beautiful offset rocker arm needs its own considerations when it comes to set up. Once you use a paired shaft T&D system you will wonder why you didn't do it sooner. The T&D paired shaft system is really the only good answer for any offset rocker system. Oh and if you are running boost you need to calculate the area in square inches that your boost in PSI is acting on and add that to your spring pressure, you might be surprised that you might need 30-40? lbs (just a guess) more spring to control the valve. The offset rocker arm only adds to this problem.
Offset Lifter: The offset lifter comes from Smallblock Chevy Land and in my opinion--CANNOT ever be used in a 59* degree SBM. Why? A SBC can get away with it for much longer because the lifter bore is parallel with the pushrod and cylinder bank. I believe it would "work" in a BBM but have never tried it. I don't like offset lifters even in a SBC but have used them many times in DIRT engines that get rebuilt at least every year.
An offset lifter in a 59* lifter bore is a short term recipe for disaster--that pushrod is ALWAYS trying its best to make that lifter body rotate--It has lots of leverage and I don't care how BIG and BEEFY you make that lifter tie bar it WILL break. If it IS BEEFY enough it will manifest its unhappiness in other valvetrain unhappiness. If you add spring pressure it will stress the tie bar more, wear out your lifter bore, make the side loading on the rocker arm worse and bring you closer much much sooner to catastrophic failure. Think of a diving board as your tie bar and a 600lb morbidly obese guy standing on the end of it. Now think of the 600lb guy lightly bouncing up and down on it his big ugly feet never leaving the board--You should have about that much open spring force-Solid roller right? Now add lash--Yup you got it now that fat guy's feet are leaving the diving board as the diving board momentarily provides enough force to overcome his mass and make him weightless for a moment in time. You only have so many times before the diving board snaps. In short an offset rocker arm AND an offset lifter in a 59* SBM is in my eyes a perfect storm-**** STORM. If you take a look at your picture a normal non-offset lifter is not going to add much more angularity to your pushrod. IME&IMO completely unnecessary.
Related but not really relevant info: The W2 does not need or even perform well because of the big port inlet. The majic is in the deep bowls=tall S.S. and exhaust port design. If I were to do it again--I'd shrink the inlet with the sole purpose of straightening that pushrod as much as I could, and I would move the lifter over about .060"<<(I've done this) It wouldn't impact the almighty (CFM) flow rate at all but it would allow for higher RPM torque production which equals BIG HP.
I know, long winded post but this is my .02 cents take it FWIW. J.Rob
P.S. Just calculated the area of a 2.055" valve and it is 3.317" so 10psi of boost is 33lbs of force trying to open your intake valve when it is trying to close.
Dale Davies
Well-Known Member
Is the cam bearing bores completely paralell vertically and horizontally to the main bearing bores? Are the bushed lifter bores completely perpendicular to the camshaft?Hey the peeps.
Have a set o BAM solid roller lifters in my SBM with .180"offset pushrod hole on the intake.
Recently damaged 2 intake lobes and the other 6 intake lobes have the same witness/wear marks.
Was wondering if the pushrod offset could be causing this issue.
Has anyone use offset lifters and had issues.
Thx.
View attachment 1716246118
A fellow had a real nice Mercury Cyclone with a 429. He had the cam tunnel bored to use the roller cam journal bearings with a roller cam. Did not run long as the shop got the bore off center and the lifter rollers working on the lobes were trying to screw the cam out of the block. Had to get another 385 block and this time just used the std bearings. Costly error.
Dale Davies
Well-Known Member
I would venture that the 0.0028"lifter clearance with the offset lifters is causing the lifter to tip in the bore. This will put extreme load on the contact area of the lifter roller and cam lobe on the opening ramp. The spauling is metal fatigue from the extreme contact point pounds (tons) of force. Properly set up with full width roller contact across the cam lobe, you have the spring load multiplied by the rocker ratio and then the acceleration or inertial load along a fine line of contact. Now it the lifter has a bit excess clearance and some force can push the lifter offset in the bore or the bore is not 100% perpendicular, the load contact is reduced from a 3/8" line to a 1/32" or 1/64 contact point. If we consider the 1/64" point width, the loading is 24× what it should be. Metal will fatigue very quickly in that circumstance.Thank you all for the replies.
The damage on the lifter is on the opening side of the ramp just before the top. The lifter bores where bushed for flat tappet solid lifers that measured .904"and these BAM lifters measure .903", so the clearance is about .0028" atm with the BAM's.
Spring pressure are 255 lbs on seat and 560lbs over the nose.
Cam specs are 255/262 deg @ .050", 112 lobe sep, lobe lift .399'intake .409'exhaust with 1.5 rockers.
All intake lobes have same wear pattern , runs on one side lobe , runs flat across the top then runs on the opposite side of the lobe going down. its as if its trying to turn twist the lifter.
This has me stumped
I would get the block inspected very carefully. You may need to rebush the lifter bores with a tighter tollerance and go to centered lifters.
Dale Davies
Well-Known Member
Boosted you normally need more spring force to offset the boost pressure working to blow the intake valves open.Spring pressure are both the same on intake and exhaust. Not sure if I should have little more on intake as it is boosted. Valves are 2.05" in & 1.65" exh , 11/32 stem with tool steel retainers and AFR/PAC springs. Waiting to see what cam company has to say.
Boost pressure × valve head effective area gives pounds force on the valve head. Remember the stem diameter area can be deducted from the valve head area. This pounds force is added to the required spring force for the intake valves.
Dale Davies
Well-Known Member
Yes you did. And after looking at the other comments and the information given by the OP, I believe you are correct.What is in post #34.....I stated back in post #6.
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