I bent a pushrod today and went to get one to replace it. The standard length for my 390 is 9.59 but mine is barely a milimeter shorter. The shortest listed in Advance Auto is 9.62.
1. If I'm supposed to have shorter and put these longer ones in there, with hydraulic lifters, will the lifters compensate?

 

Are you running stock non-adjustable valve train?

It seems to me that you should be able to get away with .03" variation in a hydraulic setup. But, we should wait to hear from some of the more experienced FE Gurus.

 

I've been reading my post and realized that it doesn't make any sense, I apologize.
Advance lists a 9.56 available for my truck but not in stock. I bought 9.59 at another parts house and they are just a tad longer than what came out of my truck but the listing shows them for my motor.
I took two new ones and put the old one in the middle then made a "t". Doing the math shows me that what I bought is .030 longer than what came out, IF what came out was 9.56 or shorter. I have no way to measure them. I have hydraulic lifters and they are new. Stock cam. Is barely a millimeter longer going to hurt me?
I've asked around and being told that the lifers will adjust because that much is within tolerances.

 

Stock non-adjustable valve train.

 

I put the 9.59 pushrods in and the engine is running rough. I'm shutting down and ordering the 9.56. I guess a hairs bredth makes a difference. It doesn't make any sense to me why Ford would make 4, count'em 4, different lengths of pushrods for the same motor.

 

Judging from this and the other threads, sounds like .030" variation is enough to be trouble. There were previous discussions of engine dusing different pushrod longths within the same engine. Maybe a slight difference from intake to exhaust or such.

When you think about the preload being only .020-.060, .030 is significant. My hydraulic roller setup is supposed to be about a .060 preload.

 

I panicked earlier but I still have questions. When I put the distributor back in I put it in a little off so the timing was off, explaining why she was running rough. I fixed the timing and she's running fine now. The question is...should I hear anything at all coming from the inside of the engine? I have the slightest little knock.
What is preload?
Should I go ahead and change out the 9.59's with the 9.56's?
I know I'm asking questions that may be obvious to alot of you but I'm learning alot here and am very sincere about my truck being right.

 

To save you some time, there is an article here or somewhere else, that shows the proper way to adjust an FE non-adjustable-rockerarm setup ... (if the wording of that didn't confuse you, then you should be good to go!

The process is:

Make sure lifters are bled, as in compress them until they are bottomed out.
Assemble valve train on both sides with stock-length pushrods.
Check how much lifter can be compressed, check gap between rocker arm and valve stem. (this requies each lifter be on the backend of the cam lobe, etc. - long process to check all 16 valves).
Adjust up or down in pushrod length as necessary.
And most important - RECHECK from the beginning. This took me a week or so of part-time work to get this going.

Long and arduous process, but very fulfilling - I have a stock valve-train with a .554"/292 degree cam, and it holds together up to 6000 RPM no problem.

Any good book that covers the FE should have this procedure in it. Look around here with the search function, you should find the right link. Or, post back and I'll be glad to fill you in, if I can find the information.

Anything that effects the valvetrain geometry REQUIRES you to do this adjustment process. Head milling, valve job (seat grinding, valve stem grinding), block deck, new rocker shafts, new rocker arms, etc.

 

Forgot to mention... I have taken apart a few stock 360's, and found something like 4-5 pushrods were over OR under-sized... in almost every motor! I don't think even one of them had all "nominal"-sized pushrods.

 

Yeah, I think today I will change back to 9.56's in the parking lot at my parts house. I'm giving my lifters about .020 to work with and it's gonna mess up my valves.

 

I changed the pushrods back to 9.56 and got an instant increase in idle RPM by 100. The engine doesn't seem to be running as restricted as it was when I pulled up to the parts house. Whew.

 

I too bent pushrods recently on my 360 - suspect it happened because I only ran the motor a minute or so after an oil/filter change before parking for a week or so. Bent the pushrods when cranking to start after sitting for a week or more. Is this motor an "interference" motor (e.g. will valves hit pistons if the timing chain slips?)

 

Are you sure it's a 360? What exactly happened?

 

Yes, it's a 360 (Y door code) - I've had it since '79 when it was a fresh rebuild. Put on about 60K miles since then. Obviously don't drive it much - just when I need a truck. Oil change maintenance intervals based more on time than mileage obviously. It's always been a strong motor. A month or so ago I decided to change the oil and filter (that's all I did). Refilled and ran the motor about a minute (had other things to do) and parked it on the street. Total run time less than two minutes. Probably ran for a minute, shut down, restarted a couple of minutes later and parked.

Several weeks later, cold day - went to start it, cranked slowly and erratically - like the battery was low - but unevenly as I now recall. I chalked it up to the low temps and after several (say 4-5 cranking events of about 10-15 seconds each - without much encouragment - like no fire at all.... I quit and took another vehicle.

Last weekend I went out to start - used a jumper battery and it started fairly quickly but sounded terrible and had major misses.

Ran it around the block - actually probably 4 miles including down the interstate - no improvement (hoped it was a fouled plug - but the noise........) pulled the right valve cover and found three obviously bent pushrods. Tapped the associated valve stems - which were free.



(even survived running without any oil pressure the time I fail

 

Oops.. should have edited that last part about the time (probably 10 years ago) when I pulled the distributor - and failed to note that the intermediate shaft had come part-way out along with the dist. but fell into the oil pan (with a muffled sound as I recall thinking a screwdriver had fallen down). I put the distributor back in and fired her up - ran about a minute or so (maybe two) when I went to turn off the key and noticed the red light!!!!

So... it ran without any oil pressure for that time - didn't drive it but had run it up a couple of times....

Anyway, after fishing the shaft out of the pan - put it where it is supposed to be and .... no problemo as it turned out. I won't do that again.