I have Afr165's on my 308 and originally measured for a 6.250" pushrod. My package was from ED C. and he said that was right in line with what he's found also. I just pulled my intake off for Tmoss to port, and figured I would adjust the valves again (they always seem noisey to me) I looked at the contact patch of the rocker to the valve stem. There are a handful that are centered, a couple that are towards the header side, and the rest are wearing towards the intake side of the valve stem. What do you do in this situation? Some look like I need longer pushrods, others are ok, and then a couple need shorter pushrods?? The contact area measures approx .050 on the worst valve so thats not too bad. Any suggestions??? If i need to change anything, I would like to do it now with it apart.
Afr 165 pushrod issue. Need suggestions!!!
- Thread starter meangreen92lx
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Hard to tell from the description, but are all the contact patches about the same width? Being exactly cemtered is not a necessity, as long as the contact patch width has been minimized and the the patch is reasonably centered. If some patches are wider than others, you may want to do another PR length check on them and order some custom length PR - you can get them onesy-twosy to order at www.pushrods.net
Thanks for the reply Tom. When I mocked up the valvetrain when I first built the engine, I checked for pushrod length on #1 cylinder which is one of the best ones on the engine. It seems the drivers side head has more of them wearing towards the intake side. The wear pattern width is about the same on all the valves, just some are not as close to center as I'd like, which like you said is not totally critical. I recall a magazine write up in MMFF with D&D performance saying they prefer the rocker to favor the intake side a little. I've driven 10,000 or so miles so far this way and nothings gone wrong. Just trying to optimize the geometery while I have it apart. I don't think there is a fix all solution because if I opt for 6.300 pushrods, then some of them will shift off the center to the exhuast side some. Unless I custom order a bunch specially for each cylinder.
You also want to make sure that the rockers rolls first towards the header then towards the intake. Contact Patch should be under .080"
It is weird to have to use different sizes across the motor with everything square, however it is not impossible. Also check to make sure your lifters are moving the same amount...
Yes stock is 6.272"
Your also using a Stud mount head which can take up a little more of the tolerance as long as geometry is good.
It is weird to have to use different sizes across the motor with everything square, however it is not impossible. Also check to make sure your lifters are moving the same amount...
Yes stock is 6.272"
Your also using a Stud mount head which can take up a little more of the tolerance as long as geometry is good.
monte87 said:
I realize this. I mocked up the valvetrain on #1 cylinder and measured for pushrod length and came up with 6.250". You have to take into account I'm using a thinner headgasket than normal and other variables also. So 6.272 is not perfect for every engine. My rocker contact is perfect on #1 cylinder. It is not perfect on a few other cylinders like I have mentioned. I think the difference between a 6.250 and 6.272" pushrod would be unmeasureable. Maybe a 6.300" pushrod would help but only on a few cylinders.
Rick 91GT said:
Yeah, thats why I have those. #1 cylinders valves are perfect with that size, just some of the other cylinders are not. I looked at it again and noticed the exhaust valves seem to be a little worse than the intake. I'm starting to wonder if the valve stem lengths are not all identical? And I know my motor is 0 deck per DSS and I have the ROL headgaskets which I believe are .039 compressed like you mentioned. My heads are not milled and my cam is a Comp Cams blank. Do you know if Comp Cams have a different base circle?
i just recently bought a set of 165 heads, in the instructions it said to torque the studs down since they just screw them in for shippeng. i was going to lube them when torquing them down and noticed when screwing them out about half of them were bent. good thing the heads i was replacing had screw ins in them else i woulda been screwed till the big brown truck showed up again.
