Push rod clearance.

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Ironmike

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Just mocked up my rocker geometry kit from B3 Racing. Man it is perfect. My swipe pattern is pretty centered and only .035 wide. I DID do the mock up with pushrods that are .200 shorter than I plan to use but have a wee bit of a clearance issue.

I put a layer of .005 masking tape on them and the intake side had the tape torn, not touching the rod itself.
Exhaust side didn't tear the tape, but did contact it.

It looks like the contact is limited to the top of the pushrod tunnel. I think I really only need ten thou or so clearance. Thinking about just using a carbide burr that I use to port intakes.

The tunnels were clearanced as part of Hughes full CNC deal, but not quite enough. It's gotta be pretty thin there near the intake ports....
Don't think I can use thinner rods. 605 pounds on the nose at .670 lift.

I outlined in red right where the issue is. Most of you know I don't make a move until I check here, so....any suggestions? Have to get this done tomorrow!
Also this is a big plug for the great work B3 does!
20170212_200604.jpg
 
I always clearance the push rod tunnels when using a roller on a build.
carbide bit. I'm sure you could talk to smith bros about a thick wall skinny push rod that would work, I use their thick wall 5/16 push rods in a lot roller cam builds of .600 and less.
 
The exhaust won't be an issue but it's pretty thin by the intake. If you stay by the top, take your time and measure every one seperately so you only remove the minimum you have to you should be ok.

FWIW, I have seen pushrods with .060 clearance rub. After fighting it for a while, I just let them rub. If it's not to the point you can't turn the PR then you need some clearance.

That B3 stuff is worth it's weight in gold. For YEARS I had to convince guys who had a centered pattern wasn't good enough and I fixed it by machining the stands off and using blocks. His stuff is way better. I CANT SAY ENOUGH GOOD ABOUT MIKE AT B3 RACING ENGINES.
On top of a great product he's a damn good guy. And yes, I pay retail and get no money for endorsement.

^^^^^^^^^^^^^^^^^^^That is what correct rocker geometry looks like^^^^^^^^^^^^
 
Ironmike said:
Just mocked up my rocker geometry kit from B3 Racing. Man it is perfect. My swipe pattern is pretty centered and only .035 wide. I DID do the mock up with pushrods that are .200 shorter than I plan to use but have a wee bit of a clearance issue.

I put a layer of .005 masking tape on them and the intake side had the tape torn, not touching the rod itself.
Exhaust side didn't tear the tape, but did contact it.

It looks like the contact is limited to the top of the pushrod tunnel. I think I really only need ten thou or so clearance. Thinking about just using a carbide burr that I use to port intakes.

The tunnels were clearanced as part of Hughes full CNC deal, but not quite enough. It's gotta be pretty thin there near the intake ports....
Don't think I can use thinner rods. 605 pounds on the nose at .670 lift.

I outlined in red right where the issue is. Most of you know I don't make a move until I check here, so....any suggestions? Have to get this done tomorrow!
Also this is a big plug for the great work B3 does!View attachment 1715017687
Click to expand...
What is that gob of goo under the headbolt? A deformed washer?
 
Ironmike said:
Just mocked up my rocker geometry kit from B3 Racing. Man it is perfect. My swipe pattern is pretty centered and only .035 wide. I DID do the mock up with pushrods that are .200 shorter than I plan to use but have a wee bit of a clearance issue.

I put a layer of .005 masking tape on them and the intake side had the tape torn, not touching the rod itself.
Exhaust side didn't tear the tape, but did contact it.

It looks like the contact is limited to the top of the pushrod tunnel. I think I really only need ten thou or so clearance. Thinking about just using a carbide burr that I use to port intakes.

The tunnels were clearanced as part of Hughes full CNC deal, but not quite enough. It's gotta be pretty thin there near the intake ports....
Don't think I can use thinner rods. 605 pounds on the nose at .670 lift.

I outlined in red right where the issue is. Most of you know I don't make a move until I check here, so....any suggestions? Have to get this done tomorrow!
Also this is a big plug for the great work B3 does!View attachment 1715017687
Click to expand...
Mike,

With the mock up pushrods being that short, the adjusters would be hanging out of the bottom of the rocker pretty far. That would cause excessive pushrod sweep at full lift toward the intake manifold side of the tunnel. Once the correct length pushrods are in place, it probably won't touch at all.

The sweep on the valve tip looks fantastic! Like yellow rose said, that is what good geometry looks like. With only .035" sweep for .670" lift, imagine how far off it is for someone running .500" lift and having .080-.090" sweep. I've seen that many times, and sometimes worse.

Thanks for the plug, and good luck with your dyno session.
 
Well there you go. Maybe o need to grind anything.

That would be, as the cool dudes in the 1980's said, bitchin'
 
Just for FYI remember that what you take off can generally not be put back. With aluminum I would use polishing rolls instead of a carbide bit. Less likely to go too far. JMI.
 
B3RE said:
Mike,

With the mock up pushrods being that short, the adjusters would be hanging out of the bottom of the rocker pretty far. That would cause excessive pushrod sweep at full lift toward the intake manifold side of the tunnel. Once the correct length pushrods are in place, it probably won't touch at all.

The sweep on the valve tip looks fantastic! Like yellow rose said, that is what good geometry looks like. With only .035" sweep for .670" lift, imagine how far off it is for someone running .500" lift and having .080-.090" sweep. I've seen that many times, and sometimes worse.

Thanks for the plug, and good luck with your dyno session.
Click to expand...
Ya know Mike, I was wondering how longer rods would affect this. Don't know why, but I thought it might get even tighter......Glad to hear I might be wrong.

Adjusters were hanging out the bottom about as far as they could be. Like I said, damn near a quarter inch too far. Going to call my man Ethan at Smith Bros tomorrow. I don't know if a 5/16 rod is even possible. Far as I know I have a bit too much pressure.

Maybe like you said, it won't be an issue. While I'm waiting I am going to very gently open up the top third of the tunnel. I mean VERY gently. Turn down the air...go slow...I have a nice dull burr I've been saving.

And a big thanks for the set up! I was shocked when I first looked at the sweep pattern. Man I didn't think it was even possible to get it that nice. Don't have a clue how you do it but keep on doing it.
 
B3RE said:
Mike,

With the mock up pushrods being that short, the adjusters would be hanging out of the bottom of the rocker pretty far. That would cause excessive pushrod sweep at full lift toward the intake manifold side of the tunnel. Once the correct length pushrods are in place, it probably won't touch at all.

The sweep on the valve tip looks fantastic! Like yellow rose said, that is what good geometry looks like. With only .035" sweep for .670" lift, imagine how far off it is for someone running .500" lift and having .080-.090" sweep. I've seen that many times, and sometimes worse.

Thanks for the plug, and good luck with your dyno session.
Click to expand...
Looks like you were right Mike. I heated the cup end of the mock up rod, and pulled out the cup .200. Let it cool down....threw it in there at TDC and it looks like I will have plenty of clearance. Obviously I couldn't turn it over with that rod, but it looks good. Ordered 3/8 , .120 wall rods 7.700. Done.

Won't make the dyno Wednesday, but it's coming soon!
 
Ironmike said:
Looks like you were right Mike. I heated the cup end of the mock up rod, and pulled out the cup .200. Let it cool down....threw it in there at TDC and it looks like I will have plenty of clearance. Obviously I couldn't turn it over with that rod, but it looks good. Ordered 3/8 , .120 wall rods 7.700. Done.

Won't make the dyno Wednesday, but it's coming soon!
Click to expand...
Cool! Let us know how it works out.
 
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