Well, finally started diving into the valve problem I was having with a freshly rebuilt 360. It never ran right from the getgo. 5 of the 8 cylinders had really good compression. #4, #7, and #8 did not. #4 was 73, #7 was 0 and #8 had a very slow pump up. We popped the valve cover off to start by looking at #7.. we found this:

<img src="http://members.aol.com/james1787/pushrod.jpg" alt="ouch"></a>

It was the pushrod to the exhaust valve on cyl 7. We turned the motor over by hand a full cycle to see if the piston was hitting the valve, it wasn't. I wonder what might cause this on a brand newly rebuilt engine? Looks like this week I'll be pulling the heads off and taking them to the machine shop. Ugh, not fun.

 

First guess, heads decked and wrong length push rods. If the heads were milled they may need to have adjustables put in. Also a really bad lifter could do it. Depends, new lifters or old? same cam or new? Rocker shaft pedestals milled? Different heads?

 

Since we looking a pics of bent pushrods...


There was a good article posted a while back about pushrods bending on new FE builds. Might try a search. Mine happened when the end of the rocker shaft broke off. My guess is that you don't have the right clearance also. First install a new pushrod. Rotate the engine until the intake valve on the number 7 cylinder is all the way open. Then take a wrench and slowly rotate the exhaust rocker backwards until the lifter is completely colapsed. See how much clearance you have between the valve stem and the tip of the rocker.

 

Those pictures are gross, I don't even want to think about that.
I am having my heads rebuilt next week, guess I'll double check that my machine shop is not run by a moron.

have fun!

 

at:

http://64.90.9.168/cranecams/pdf/214e.pdf

On page 6, Crane cams had this to say:


Might want to take a look.

 

Many a pushrod has been bent when the machinist doesn't check the minimum compressed height of the valve spring in the head and the actual cam lift.

Don't FE's use a 1.7:1 rocker arm? I seem to remember that whatever it was, the FE's had a higher rocker arm ratio than your standard SB Ford/SB Chevy, so the machinist would check for a 1.6:1 max lift, not realizing the FE was a 1.7:1

Anyway, something bound up or ran out of give. That means either the valve stuck in the head, or the rocker arm encountered resistance somewhere else.

Sounds like a head QA problem to me ...

ak

 

The article mentioned is in the tech articles section of this website, it is the first one in the 1998 section, entitled :

"FE’s That Bend Push-rods, A Dirty little Secret"

 

I would look the head without rocker install and see if of all the valve stems are the same height or use a straight edge and check . Then I would check all of the pushrods and see if they are the same length ( I believe there 3 differents sizes ) Then I would reinstall the correct pushrods making sure they where seated in the lifter correct . Then roll motor over by hand and do a leak down test. Sort of where I would start GWB

 

All I can say is HOLY COW!
Id hate for that to happen to my motor
I think Id cry

 

Mechanical interference. The valve was going down and the piston coming up and that unfortunate pushrod was caught in the middel. Adjustable rockers have more ratio, zero deck is not always good, valve reliefs are a good thing, high lift cams do have high lifts, and Ford push rods come in different lengths. Did you fiddel around with the timing chain notches? Did you use a degree wheel to find TDC? You must pull the heads and check for piston damage. Do this; put a quarter size ball of clay in the valve relief, put the gasket and head back on install the push rods and rocker shaft, turn the engine over slowly. Pull all that stuff off and look at the marks the valves made on the clay, see what your clearence is. Setting a valve lash to tight in combination with one or two of the conditions mentioned above will cause that pesky mechanical interference. I like em loose, adjustable and 0.005 down the hole. Sorry for your difficulties. Please post back with the cause if you determine what caused this. Others here need to know.

 

I will do the first of the removal work tonight. Since I am in an apartment complex, I have to do the dirty work under the cover of darkness (remove antifreeze, etc)... If I can find my sockets I'll pull the preliminary stuff off.. carb, exhaust manifolds, distributor, etc. Depending on how fast it goes, I may get it all apart tonight if I can. A friend of mine who is an expert with this stuff will have a look and we'll get a determination of what went wrong. I will be sure to post the results here when we find out what happened and why. Many thanks for all the useful replies... more info to be posted soon..

 

Well, I got most of the motor ripped apart. Of course I added another thing that now must be removed - the oil pan. Stupid drive shaft for the distributor keeps falling in everytime I take it out. (ANY ideas here?)

Ok, here is what I found so far - the reason I had low compression in the #4 cylinder was a bolt that was too long, never got the rocker shaft tightened down.. it was off by 1/16"!! How I missed this gaping gap is beyond me!!

What is the correct size (length) and grade that the rocker arm shaft bolts should be? I think I have grade 5's in there now and they have a washer on them.

The bent pushrod was in 7.. thats the one that had the stuck valve. I still have yet to pull the head, because I can't find my sockets (took everything apart with wrenches only). Looks like a trip to sears might be up and coming if I can't find them soon. Hide the credit cards..

I'll see the extent of the damage once I pull the head probably tommorrow. Hopefully it won't be too bad.

Now when we first first started it with the motor, it had a valve tap or bad lifter. I'm thinking that was probably #4 due to the non-tightened portion of the shaft (it was the bolt closest to the firewall that was too long). We're gonna check all the lifters as well and measure them, check for damage, test, etc. Tommorrow I'll know the extent of the damage. Then the process of learning why it happened starts.. then goes the repairs, and finally PROPER reassembly. Hopefully in a week or so I'll be up and running. More to come soon..

P.S. Did I mention it really sucks lifting the intake manifold off. Really really really really sucks.

 

The bolt that was too long is the one that should have gone in the oil gallery to the rocker shaft hole. It is necked down to allow oil up into the rocker shaft. The rocker shaft will be bent, not to expensive and available at NAPA. Stuck valve must be resolved, new pushrods and reassemble. I would include a set of ARP head studs, rocker shaft studs are also available but I'd use the bolts. Washers go on top of the rocker bolts. These washers are thick, (make nice spacers for lining up brackets).

 

Well, the thing about that bolt is that it's a grade 8 and the others are grade 5. I'm not sure where it was supposed to go. There were so many mixed and matched bolts when I got this thing. I actually had to order an arp engine bolt set for the intake, timing cover, pan, valve covers and a few other misc things when I put the motor together.. nothing matched. I'll probably order arp bolts for the rocker arm shafts. I will now also order one, maybe two rocker arm shafts. Since it's a new rebuild (less than 100 miles on it), should I just go ahead and order new rocker arms along with the new pushrods?

 

I would check all the pushrods for straight and length. I like the ARP rocker shaft bolts but good ones from the junk yard will be okay for a regular use engine. The shaft with the loose bolt is bent for sure. After that just replace the bad parts and put the motor back together. Look for the necked down bolt it is special. Grade five or grade eight bolts with the correct length will work to retain the rockers and you can double up on the standard flat washers if the thick ones are missing. Be careful to install the rocker shaft with the holes down. Good luck!