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Push rod legnth
Posted: April 29, 2010, 8:55 am
by "Whitey Ford"
So Ive been putting a buy list together for my rebuild and looking at push rods. Im staying iwht hydraulic lifters and non adjustable rockers. I want a mild build. Anyway when looking at push rod legnth, what does it mean when it says +.060" or -.040" and so on. I understand its a unit of measure in inches but from what? Stock size? Also, whats the benefit? Tighter springs/vavles? Is there a time to use smaller or bigger or is it up to the builder?
Posted: April 29, 2010, 9:01 am
by ebentraywick
I think thats the width measurment. ???
Posted: April 29, 2010, 9:05 am
by jakdad
It's overall length. Talk to your machine shop guy. He can tell you what you need.
Posted: April 29, 2010, 9:11 am
by "Whitey Ford"
yeah Im sure he will I just wanted to know for sh*ts and giggles. Just wanting to know what it was. Whats the stock length for FE 390?
Posted: April 29, 2010, 9:39 am
by ebentraywick
9.59 If i can remeber right???
Posted: April 29, 2010, 9:41 am
by ebentraywick
Posted: April 29, 2010, 11:18 am
by "Whitey Ford"
Thanks eben....see those rockers are made in china....do you have those? I think Im going to stay with the non-adjustable stock ones...trying to keep it a simple rebuild. Not sure if thats good or bad though.
Posted: April 29, 2010, 12:02 pm
by ebentraywick
no never owned a 390 but I rebuilt my freinds 390 and I installed those rockers they work great,,,
Posted: April 30, 2010, 7:29 am
by 64 f100
Main thing to remmember on the rockers and push rods, is that there was no adjustments for the stock hydraulic lifters. Only way to adjust these are by changing the push rods. You have to install you push rods and check the clearance and see what you've got. Thus, the oversize push rod length in different sizes. If you go with a cam kit, get the whole kit with lifters, as these should be replaced anyway. Otherwise, be sure to take the lifters apart and clean the inside bores out. the buildup of hardened oil and particles inside th e bores may cause problems othewise, when you reinstall these and go to check for clearance. You have to colapse the lifter to check and see if you have enough or not enough clearace. When forced bakc down inside the hole, the pluger may not come back up. Pain getting these back out thru the tiny hole the push rod goes thru. They used to make a special tool to do this as Ford lifters commonly went bad.
Rich
Posted: April 30, 2010, 12:12 pm
by "Whitey Ford"
Yeah i think that was problem to begine with, the lifters that is. I will get the entire set when gettting the lifter, rods, cah and all. Hey any info on the pm I sent to ya 64??? Thanks for the info as well.
Posted: May 19, 2010, 12:49 pm
by "Whitey Ford"
OK so I hate to bring up an old post but just found some more info on this pushrod question. So I did get the entire comp cam set which included the push rods and I noticed that they are 9.350 in length and the cup and ball style. Is this correct? I have non adjustable rockers in case that info is needed.
Posted: May 19, 2010, 8:29 pm
by Garbz
They will only work if the distance is correct. Was the head milled, was the block faced? All this is where the .040 comes in as it makes up for the material removed. You also need to know the thickness of the head gasket as it needs to be compensated for.
In a stock engine it can be a little loose but in high lift and high spring pressures it will spit them out and bend them.
Cup and ball style rods are for mechanical cams and adjustable rockers. The FE with hydraulic cam uses ball and ball type. You have the wrong push rods.
Garbz
Posted: May 20, 2010, 8:04 am
by "Whitey Ford"
The blcok and heads are at the machine shop but I dont think any of that work has been done. I only had it dipped and bored and balanced. I have the gaskets so i can find that out. Im doing a stock set up more or less. Nothing hi po but i purchased the whole valve train set up together. This makes me worry in that if I get new push rods will it match the cam and all. OI looked at the box the push rods came in and I noticed soemthign say "adj" and I knew nothing on my truck is adjustable so thats why i ask. Damn I wish I had someone on this engine that knew what they were talking about. It seems like Im the manager of this entire process communicating to 4 different parties what and how an FE works and thats not good. Hell Im learning myself. OK well Im going to bring these back and get some new push rods in.
Just for info my cam is
Comp Cams
Advertised Duration - Int: 256 Exh: 268
Duration @ .050 - Int: 212 Exh: 219
Valve Lift - Int: .487 Exh: .493
Lobe Separation: 110.0
The previous cam which was in it was a
Part No. M-6250-A411
Duration 204* / 214*
Lift .493” / .519”
Lobe Center 107* / 117*
I got one quite similiar to the old one so shouldnt the push rods be about the same size as the previous ones?
Posted: May 20, 2010, 5:25 pm
by Fanatic
..............why not just get a set of adjustable rockers and save all the hassle -plus you can dial in the clearances to optimize the set up.
Someone correct if need be but......I believe most older 352s and such from the late 50s all came with adjustables.
Posted: May 20, 2010, 7:11 pm
by "Whitey Ford"
No i got it corrected now. Sorry i was going to post about it tomorrow. The box was wrong that the rods came in. I noticed it and it said "adj" on them so I ran the part number and found what it really was. Thank god cause i could have been in the middle of the build and them say that. Anyway hydraulic cam and lifters get ball and ball. The previous set was not only wrong size but style. He found the correct one. It was under one of those " here are 2 tpyes of setups for the FE 390. Im good. My god I have learned my ass off on this rebuild. Other than the radiator thing Im good....I think it will start falling into place in a few weeks. Machinist is SLOW and parts havent come in.