360 j head valve stem diameter?

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63dartman

63dartman

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What size valve stem diameter do the stock j-heads carry? Is it 5/16 or 3/8? My 915 heads are 1.88 and 1.60.
 
Thanks BJR, just wanted to know so I can get some lash caps. I got my pushrods cut too short for a set of adjustable crane rockers and need to make up about .08, which happens to be the overall thickness on the caps. Alot cheaper than new pushrods. Any ill effects from doing it this way that you know of?
 
You really should get the right length push rods. Tipping the rocker back or forward more than it's designed angle is not good. Plus if you are running a hydraulic cam it would be very easy for a lash cap to be kicked out. If you had a lifter bleed down while it was sitting then when you started the motor before the oil in the lifter could take up the clearance the lash cap could fall out. Or worse get jammed sidways in the retainer or rocker. Lash caps should only be used with a mechanical cam.

Chuck
 
That's my plan, getting everything together for a mechanical cam swap. As far as the rocker movement, I thought that as long as the aduster is in the right place ( crane says 2-3 threads showing on the bottom side of the rocker) and the pushrod is the right length then everything is good? Since the rockers are shaft mounted the pivot point is the constant, So it shouldn't matter which side I take up the clearance on(ie. the lash caps) If I am thinking this wrong please straighten me out. So what is the intended use for lash caps? I thought they would give me a larger surface area and protect the valve stem? Without the lash caps I would have 6-7 threads showing, I tried running it this way but I took them back off because I was afraid of snapping an adjuster since it had so many threads showing. I will get the right pushrods if there is a chance of damaging parts. Thanks for the replies!
 
The problem arises when the rocker is at full lift, the pushrod will get a abnormal amount of pressure due to the spring rate and the deflection of the rocker arm, and try to push the pushrod through the intake side of the head. Also this puts a major strain on the adjuster and can cause them to fail. Useing the right pushrod is the best and only way to do this. I agree with 340mopar when useing the hyd. lifters and lash caps.
 
I guess that means I'll be making a call to crane for some custom length pushrods. Thanks again guys. I think I may be putting this off for awhile based on the cost. 300$ for the cam and lifters, 135$ for the pushrods, and probably another 100$ for gaskets and valve covers(I promised myself I was going to get some aluminum covers if I took my cheap chromies off). Santa has my wallet held hostage until after the first of the year:)
 
hi, lash caps are not made to fit on 7 degree locks/ they will not sit down all the way. they are made for 10 degree locks, that are machined for them.
i know of a 340, this senario was done on, 7 deg. locks, solid cam. the caps kept kicking out, plus valves had to be relashed after a few passes. the shop down town, did this ,so they wouldn't have to buy pushrods. as for pushrods, contact smith bros in bend, oregon. 1-800-367-1533. this is a lot faster and they probably make them for crane. they know pushrods!!
 
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