i just rebuilt my 351m to a 400 thanks to a donor block over the fall and winter of 05 and put it back in my 79 ranchero. here comes the story now. i appologize for it getting lengthy. when i built it and got it running, it ran just fine for the first few times that i started it. park, neutral, drive and reverse. but the first day, just driving it to break it in, not going over 3k rpms, i broke a rocker arm bolt and bent a push rod. i blame that on my ignorance for being my first build and not using new hardware on the valvetrain. my shim heigth was also off. when i installed the new pushrods, rockerarms and bolts i noticed valve spring travel. i think that it moved about 1/16 of an inch to an 1/8 of an inch. my intuition told me that ain't right. so i re-shimmed all of my arms and had minimal travel on them all. is there supposed to be any travel at all?? i also chipped a fulcrum and bent a push rod on a different cylinder a little later that month. i think that it was poor oiling. this was after the re-shimming. any imputs on that?? every bad thing that has happened to the valvetrain happened on the driver's side of the engine. i went on deployment back in march and i haven't started my car since. it ran ok if it was idling in park or neutral, but when i put it in drive it acted like it would die if i came to a stop and did not keep my foot on the gas. someone told me that it was my timing. and it also ran like it was running on 7 cylinders although i had everything connected, plug wires, coil wire. any help??

 

Run a vacuum test to see if it is missing then try compression.

See the valve adjustment and lifter preload section in the Ford engine service manual. Measure your valve spring assy compressed height and make sure you have adequate clearance to prevent spring bind with your cam lift.

 

well i think that i got it all figured out. i traded one of my buddies my holley 600 for an edelbrock 1406 650. that was part of the problem. the timing was just barely off and plugwires are fubar'd. the valve spring issue i figured out by lookin at a couple of junkyard motors that had their valve covers pulled off and looked at the ammount of play in the closed valves so now i just gotta shim some of my rockerarms down now. out side of that it runs fine and hopefully i can get the motor broke in and get the raunchy hoe sold. that's her name. lol

 

shimming under a stock rocker pedestal will raise the rocker, not lower it.

 

my rockerarms are already shimmed. its just that some of them are shimmed too high.

 

So...you shimmed the rockers to get the right amount of pre-load?

For example of pre-load you would tighten the rocker down gently until the vertical play in the pushrod is gone- barely- then you tighten the rocker (closely counting the turns) until it makes contact with the head/shimms-no torque- that should equal 1/2- 1 1/2 turns if i remember right. When I was messing around my roller lifters only had 1 1/2 turns until they (lifters)were pretty much bottomed out anyway.

Any shim (under the rocker) would be to get the rocker to center on the valve tip- ie geometry. If you need to shim for pre-load don't you then need different length push rods instead? I'm still going through this to make sure mine is right and had a heck of a long thread about it.

I think you might be using the shims for the wrong issue. In pedestal rockers the geometry is the centering of the rocker on the valve and that is what you use shims for- then get the right length pushrods to get your pre-load right.

From what you discribed it seems as though you are binding up somewhere which is yet another issue- installed spring height, spring capacity and lift.

So what parts are you using?

 

also- can't edit on this computer- you mentioned the valve spring moving maybe- ie like the valve beginning to open when your tightening the lifter...?

Man- I'm thinking you may be WAYYYYYY off in what your doing...been there...am there. ok...so if your comparing old engines and trying to figure this geometry stuff out your screwed. I bet your bottoming out your lifters when you should be doing the pre-load and thus you can put enough pressure on the valve spring to begin to open it- a hair maybe- which isn't good...in sooo many ways. call me and well talk this thing through as i really don't know what I'm doing either but have a couple of ideas.

406.273.9074 I'll be out tomorrow Sunday with my stick and string (longbow) chasing wapiti (elk) in the local hills (northern rockies). SHould be in by 8:00 mountain time (7pacific) and will be up until 10:00. Monday 4065310283

later

 

Click on the edit button in the post to edit your post. All users have an hour to edit their posts.

 

edited this one!!

 

can't from the computer i was using- the computer itself is screwed up- too lazy to relaod windows- It has a language issue and won't interpret java or something involved in extra windows. kids were on the good one. besides if i have to double post someday I'll be a super guru....surely I want to be one of those.

 

well your os prolly has a virus. i remember the last computer that i had got 2 wrapped around the os. well the rockies are my mountains. my home state is famous for them. can ya guess which one it is?? can ya?? WELL CAN YA?? hahahahahahahahaha. omg, its like 1:57 on the am side. well as a far as i understand the whole shim thing they raise your rockerarms up so you can get the propper preload without having to get custom length pushrods. i was only cross refferencing old junkyard motors against what i saw so i could see how much play is there. with the rockerarms shimmed the way they are they don't open the valves. but they also move side to side easier than they would be if i had the correct preload. as far as centering on the valve, i don't believe that they do. what i do know is they set the rockerarm higher. i'll prolly give ya a buzz next weekend. i work the nightshift in the navy and i usually don't get out till 12 on the am side when i am supposed to get out at 10pm

 

Keeping all of those add in apps for browsers etc working and up to date is a pain.

Always check for coil bind.
-Shim the pedestal or adjust the stud mounted rocker for proper contact patch on the valve tip.
-Collapse the lifter and measure the travel it takes to collapse it, record this measurement.
-Rotate the cam to position the lifter on the base circle.
-Insert a pushrod length checker and adjust it until it will not rotate.
-Remove the rocker and pushrod checker then measure the length of the pushrod checker.
-Subtract the distance it takes to collapse the lifter from the measured length, then add the amount of lifter preload desired to the previous result. This final calculated measurement is the length of pushrod needed.

You may have to make adjustments for standard lengths available tho. Remember pushrods have a small flat on the end due to the hole drilled thru the rod. The pushrod manufacturer can help you determine an allowance for the flat in your measurements.

 

well i took yet another look at the valve train a week or so a go. well come to find out i need custom lenght pushrods. but i don't have the expertise or know how to do it. all i know is that they have pushrod checkers, but i wouldn't know where to go to get the lenght that i need. one of my pushrods is way too short, even with outh the shims. i watched the valve train with the covers off and i saw little to no oil on most cyinders. any advice??