Installing Pushrods on 318 with 302's

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bschubarg

bschubarg

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Quick question, after tightening the stock rocker assembly, will there be the ability to rotate the pushrod when the lifter is at it's base? None of the pushrods I installed won't rotate at cam base but I was wondering if that is normal....
 
You might have something wrong.........are the heads milled?

Are you sure the ones you checked are closed?
 
Looks like there is interference in the pushrod hole on the head. heads been milled slightly, .004
 
So this is just when the lifters are on the base circle? That is when the pushrod should be easiest to spin. If you did not put any oil i the lifters, then they should spin, but if they have residual oil in them, or if you filled the lifters with oil, then it may be hard to spin the pushrods with the lifter even on the base circle.

So is the interference the answer? That amount of milling seems way too trivial to cause this. Is this the roller lifters?
 
I panicked...after looking closer I did indeed find it is interference. Interesting, I am putting hydraulic lifters in a roller block('87). Pushrod geometry is a bit difference...
 
Ground the pushrod holes and it is all fixed..... so the point is.... if you are attempting replacing the roller with a performance hydraulic cam, pay attention to pushrod clearance.....
 
The roller pushrod holes were bigger but the lifters were way taller too so thats probably why the holes were enlarged. Usually at rest you can turn the pushrods with your fingers, even with the .060 preolad as the lifter spring pressure is not that strong.
 
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How long are the pushrods? Roller cam pushrods are shorter.
 
bschubarg said:
Ground the pushrod holes and it is all fixed..... so the point is.... if you are attempting replacing the roller with a performance hydraulic cam, pay attention to pushrod clearance.....
Click to expand...


Good to check everything... but your issue is not caused by simply putting a flat tappet cam into a roller block.

You have either over size push rods or jacked up machining.

You dont even need over size push rod holes till you go roller...so how else would you end up with interference between the push rod and head. lol
 
MOPAROFFICIAL said:
Good to check everything... but your issue is not caused by simply putting a flat tappet cam into a roller block.

You have either over size push rods or jacked up machining.

You dont even need over size push rod holes till you go roller...so how else would you end up with interference between the push rod and head. lol
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Not true. It is a change in geometry that causes interference. OP more than likely has clearance issues like this. J.Rob

pushrodclearance.jpg
 
I'm not sure, but i think he is using a factory roller cam 318 block with #302 heads, roller cam and 7.50" pushrods. I could be wrong, but his last thread was that and he bent his pushrods and they were 7.50" length, not 6.75".
 
See post 5 and 6.... the term "performance hydraulic" seems to indicate that the OP is not using roller lifters but flat tappets. The info is not 100% clear...

OP, can you clarify: are these roller or flat tappet lifters?
 
RAMM said:
Not true. It is a change in geometry that causes interference. OP more than likely has clearance issues like this. J.Rob

View attachment 1715199089
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And the picture above would make sense if he was using a roller cam and some aftermarket rockers perhaps... But he's using a flat tappet and all stock parts and there should not be any interference unless he's using a 6000 lift cam.
I've never had to ground the heads like that for anything other than a taller roller lifter.
It's a roller block that he is using a flat tappet cam and hopefully 5/16 pushrods ...because anything bigger would be overkill for what he's doing.
Maybe the op is using pre bent pushrods.
Did he angle mill the heads, again? Lol
This point I feel bad for the guy, money's just pouring down the drain
 
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MOPAROFFICIAL said:
And the picture above would make sense if he was using a roller cam and some aftermarket rockers perhaps... But he's using a flat tappet and all stock parts and there should not be any interference unless he's using a 6000 lift cam.
I've never had to ground the heads like that for anything other than a taller roller lifter.
It's a roller block that he is using a flat tappet cam and hopefully 5/16 pushrods ...because anything bigger would be overkill for what he's doing.
Maybe the op is using pre bent pushrods.
Did he angle mill the heads, again? Lol
This point I feel bad for the guy, money's just pouring down the drain
Click to expand...

That picture is from the Cheepy build and that was a flat tappet cam with Magnum heads--There is an interference issue because of the longer pushrods required. J.Rob
 
I was thinking that the above pictured issue could occur if going to the shorter flat tappet lifters..... the bottom of the pushrod would move inward towards the center of the valley and move the pushrod closer to that cast web in the head. As for the other possibilities, I/we don't know; it's impossible to say when so many things are kept a mystery.
 
bschubarg said:
I panicked...after looking closer I did indeed find it is interference. Interesting, I am putting hydraulic lifters in a roller block('87). Pushrod geometry is a bit difference...
Click to expand...

Are you using roller hydraulic lifters?
 
If it turns out to be that you need 6.75" pushrods I just happen to have a brand new set of Smith Bros hardened ball to ball in that length.... measured 4 times and stil got it wrong ! Lol
 
hydraulic lifters in a roller block... and I finally found the culprit. Somehow I manage to get the timing chain mis-aligned. All my fault. Bought Comp Cams 7.55 pushrods with the new Voodoo cam and things are all better. Still slow with the 2.2 rear but no more bend pushrods.
 
We installed a new Comp Cam timing set in the wrong keyway on the crank. Bent pushrods when setting valves(while on stand). We had the crank gear installed in the retarded position.
Glad ya got it figured out!
 
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