I have an 85 302 with the dipstick in the block instead of timing cover so I think it came out of a bronco or van. My problem lies with the push rod length, motor has been bored .40 over with srp flat top pistons the heads have been ported and a surface job was done, they have 1.94 intake valves that I was told were actually chevy valves, the cam is a comp cams 268H with .456 lift and 268 duration I got the complete kit wich included lifters and valve spring parts and timing chain.
I tried first to use the stock push rods that came out of the motor when I tore it down I have the style of rockers that you are supposed to just torqe down. When tightened to specs ther is wya to much play I can almost rotate the rocker off of the push rod. So I got a set that were 7.1" they seem to be way to long I can turn the motor over by hand but cannot spin the push rods weather they are up or down on the cam. I have another motor that is all put together and ran fine I can spin every push rod in that motor so that is why I think they are to long.
Any info will help if somebody out there has done this chevy valve thing before let me know it sounds crazy to me but I'm not an engine builder this is my first. I have found to more mesuments between what I have and the originals a 6.936 and a 6.950 one is $27.00 the other is $150.00 need to get the right ones this time.

 

If your comp is like my 252H comp, they advise .020" - .040" preload on the lifter.
I've not ever done it, but there are tools (or you can make one out of an old pushrod) to measure how long of a rod it takes to reach the preload that you are looking for.

Good luck! I'd like to here what you think about the 268H, I was afraid that aggressive of a grind would give up too much low end torque.

 

in the info that came with the cam and this is word for word
"268H this is a very versatile cam. It is a great high performance cam for small blocks and a powerful cam for big blocks. With its noticeable idle and great all-around power, the 268H cam is an ideal cam for pickup drivers who want major power increases. It also is good for big blocks towing heavy loads eguipped with optional rear and gears."
I chose this one to get the most aggressive idle without having to get an expensive torqe converter with a high stall.I got $5,000.00 in this thing and have been on it for five years, I have a push rod checker tool thats how I came up with the 7.1" measurment but obviously I did not do it right. I don't understand how to get the proper preload I just know that the stock ones are to short and the 7.1 when tightened down the rocker doesn't sit on the pedestal like it should. Also can't seem to get any compression out of it when I turn over by hand I think the pushrod is holding the valve open. I will not start this thing until I get this figured out cause if it breaks I will cry and never try to do this again.I was hoping someone on here may have done this combination before and could tell me the proper size.

 

There are people who know a lot more than me, but I say:

set the crank in such a way that the cam is closed on the intake valve for cylinder 1 (TDC if I remember right). Put your pushrod length tool in so that it is too short and not affecting anything. Bolt the rocker down to the recommended torque, then back off a half turn. Then, work your pushrod tool to a length that just takes the play out of the rocker arm. Make a mark on the pushrod tool in a way that the angle can be duplicated - I rested a putty knife across the valve cover flange and marked it with paint on the knife. After the mark is made, torque the rocker arm down to spec. Make another mark, then remove the pushrod and measure the distance between the marks.

This should get it in the ball park - fine tune your length from there to get your desired preload.

If after you get your pushrod your valve geometry is off, you may be able to shim the rocker to get it perfect.

 

I will give it a shot

 

can I check the geometry with the pushrod checker tool?

 

Yeah - just mark the valve tip with a marker, assemble the rocker arm, and wiggle it to see where the mark is. You want it more toward the intake side of the head (in that 3rd of the diameter of the valve tip).

Here's a good article on the subject:
Setting Pushrods Length, Quick and Easy- Car Craft Magazine

What length have you come up with so far? And by the way, what heads are you using?

 

I'll be honest I haven't messed with it yet my heads are just iron heads that have been ported out.

 

ok I did the sharpie trick on the valve stem. the longer ones made a mark on the outside of the stem so I put the originals in and the mark moved almost dead center. So I got a couple more questions. While I was turning the motor over with the different push rods in I noticed that the longer ones push the springs down a lot almost all the way compressed. The shorter ones seemed to compress the spring just a little. Are they supposed to be compressed a lot or a little? Im thinking I'm gonna go with the shorter ones they measure to be 6 and a hair under 7/8 all I have to measure with is a standard tape measure. As far as the pre load goes still trying to understand that I do know that when it is off of the cam the rocker is loose and can be wiggeld around if I push on the rod it pulls the rocker arm off of the valve is this normal? When the cam comes up everything is good and tight.

I also managed to drop the oil pump shaft into the pan, do I need to pull the motor and drop the pan to get it out or will can it be left there and I get another? I know I should get it out but do I have to I'm really getting sick of working on this thing I have had the motor in and out twice now this time I have the headers on and drive shaft hooked up and all really don't want to do it all again if I don't have to.

 

DONT LEAVE THAT PUMP DRIVE IN THERE
ask me how i know

 

The typical procedure with adjustable studs is to grab the rocker and move it up and down through the gap while turning down the nut until there is no more gap. Then turn the nut down another 3/4 turn.

If you have non-adjustable studs, then you want to get the exact length specific to your setup. If you do not know what that is, you will have to go by feel. Again, pull and push on the rocker through its gap as you turn down the nut or bolt, and note when you close up all the gap. Now turn the nut or bolt down to where it tightens, and hope that it is no more than 1 turn. If it's more, then you need a shorter push rod. If you have any gap left after you've torqued down the bolt or nut, then you need a longer push rod.

I would NOT leave ANY loose parts inside the oil pan. Just imagine cruising down the road, and hitting a bump. The part bounces up and meets the rotating crank shaft... It won't matter what it is, it's going to cause damage.

And just a suggestion: a few more punctuations in your sentences would make them a lot easier to read.

 

I'd have to 3rd the removal of the pump shaft. Sorry dude.

If I'm understanding you right, the shorter pushrods, when the rocker is torqued down, is loose enough to remove? Doesn't sound right. XLT4WD90's method should work well, and you should end up with a pushrod seated lightly before the bolt is completely torqued down. Sounds to me like you aren't getting any preload at all with the short ones.

 

Ok I will remove the shaft. I'm gonna try to do it without removing the motor though. Sorry about my punctuations, I will try to be more clear.I do have non adjustable studs. So if I'm understanding xlt4wd90 right, I just set my checker a little longer than the stock rod and "go by feel" from there?

Does anyone know how to get a video on here, or maybe a link to one? I could take a short video of my problem. That way you can see, I am not sure if I'm explaining everything clear enough.

There is a set of rods at Jeggs that are .60 over stock. This may sound dumb but, is .60 over a lot?

To ilovemy60ford: the shorter rods are not so loose that they can be removed when tightened down, the rocker is just really loose and sloppy.

When I did the sharpie trick, how is it that the mark was in the right spot on the valve stem but the rods are still too short?

 

The contact point between the rocker tip and valve stem tip is determined by the position of the adjusting nut. Or, in your case, where it's not adjustable, it's fixed by the position of the rocker when the bolt is torqued down. As long as the length of the valve stem is the same as stock, and the length of the arm from the fulcrum to the tip is also same as stock, then that geometry is fixed. Your only adjustment is to change the push rod length.

This is why even with adjustable studs, the push rod length needs to be really close to spec; if the rod is too long or short, and you turn the nut to compensate either way, the contact point would end up too far inward.

A difference of .060 is a lot, but what you actually need depends on what's been done to the heads and block. On most builds, where you cut the heads and/or block, you usually need a shorter rod. But it sounds like your original rods may be just a shade too short. There should be no slack, and some pressure between the parts, even with dry lifters. See if you can achieve that with your adjustable rod. Then measure it with a vernier caliper; a tape measure is too coarse for the precision you need.

When you were turning the engine over, and the valves were being actuated, you probably had dry lifters, so you can't go by how much either rod was pushing down on the valves. They will be much different when the engine is running and the lifters are pressurized with oil.

 

I have manualy ran the oil pump with a drill to pre oil the motor, so my lifters should be oiled right? I can push the rod down on the lifter, when I let off the lifter brings it back up a little. Is that the pre load?

The heads have been shaved not sure about the block. It also has chevy valves which are a different length than ford valves I'm told. Other than that the cam is no longer stock, It is now comps cams 268H with a lift of .456.

Stock rods for this motor are 6.88 something. I also have a set at 7.1. So I know it has to be somewhere in between those two. I can only find ones at 6.936 which are .060 over stock. I typed it wrong yesterday, its not .60 its .060 my bad. The other size I found is 6.950.

6.950 cost $115.00
6.936 cost $27.00
The 7.1 that I have already purchased cost me $150.00
Does anyone know what a shop would charge to figure this out? I don't want to think its right I want to know its right.

If anyone reading this is from Oklahoma I would gladly pay for some help. Food and Beer on me too!