ford 428 cam or valves or now both.

[1970 f250]

Ok so I just put new top end gaskets on a 428 when I started it the intake push rod bent and the exhaust valve is not opening I took the valve cover off to look and its not moving at all. WTF!!!!

[1970 f250]

Could it be a collapsed lifter on the exhaust side but then again what would cause the intake push rod to bend like that?

[34_40]

Sounds like it's coming back apart sadly. You'll need to verify / ensure the valves can move freely, same with the rocker arms. Also verify / inspect the camshaft for damage to the lobes. Also while it's apart and before re-assembly inspect verify each of the lifters are in satisfactory condition to continue using. Any gouges or damage to that lifter base means that cam lobe is probably in the same shape.

[rspears]

Mike's right, not much choice about taking it apart. You say, "...when I started it the intake push rod bent and the exhaust valve is not opening..." Did it start and run, or was it when you cranked it? Just trying to think what might have caused it.... What all was included in your "...new top end gaskets"?

[Dave Severson]

If you had the distributor off a few teeth it could cause a backfire resulting in this sort of damage.........??????

[1970 f250]

I put head and intake gaskets on it. Yes it did start and run fine. When it first started it sounded terrible but had a slow I mean very slow knock sound even with a little throttle it didn't speed up. Then the tick in the valve cover started. Would it be a safe assumption to plan for a new cam with lifters and rods?

[1970 f250]

oh and Dave yes it did backfire once before it started.

[rspears]

I'd suggest that you verify your distributor position before you take anything apart, just to know if that was the problem. Get it to TDC compression ( Finding TDC ) and double check that you stabbed the distributor right.

[1970 f250]

Can bad timing or a mis fire do this much damage.

[Dave Severson]

Yup, sure can!!!! Now please don't ask how I learned how much damage a backfire can do!!!!!!!!

[cffisher]

I wouldn't think so but I'm not a Ford guy.

[jerry clayton]

This probably came about because you didn't have the pushrods into the lifters AND into the rockers--Its much more complicated (not really ) in that with a shaft rocker arm set up you don't do individual rockers/pushrods at a time but the whole bank of cylinders on one side of the engine-and at least one cylinder will be on full lift of one valve and others at least somewhere on overlap----------


You need to remove the rocker shaft assy, and place a straight edge across all the valve tips to see that they are ALL at pretty close to the same height---a few thousands difference is acceptable but nothing more---if a valve is considerably down, it is probably bent and/or seized and will need to have that head removed for repair---


If all valves are pretty much at the same height, you can do a cylinder leakage test to determine if there are any problems-- since the valves are closed, you don't have to be on top dead center but be careful around the pulleys as the engine can turn---if leakage, listen at carb and/or exhaust plus crankcase for where the air is going (crankcase can just be ear down near the manifold/cylinder head joint--------


For the cam check----------take something (a long #3 or 4 phillips screw driver?) and push the tappet down against the cam and while holding down on the driver rotate the engine to see it the lifter goes up and down--A remote starter swirch works nice but anything to cross from main battery feed on the starter solenoid to the start position(small wire) will do to rotate engine--If both lifters go up and down a reasonable amount I wouldn't worry about the cam ------If you have a way of measureing the amount it would be nice and you could compare lift on all of them on that side----


As you install the rocker shaft assy you must watch to see that all the pushrod tips and rocker tips stay in proper contact as you tighten down on the bolts----just start the bolts and then tip all the rockers to the pushrods and with careful attention they should stay in place as you tighten the bolts---at least one set will be on the nose of cam and will cause those valves to be opened as you pull the shafts down




And the secret numbe r for a cam back in 428cj days----------C8AZ-6250-D--------

[1970 f250]

Ok so have the timing a tooth or two off probably caused this whole mess. The massive pressure build up caused the head gaskets to blow even tho they are only a day old? And likely a seized or bent valve. However I did look down into the push rod guides and they were indeed seated into the lifters. My guess from talking to you all is that I I have a bad valve and a will need to replace lifters and push rods as well as the valves

[jerry clayton]

I don't deal in guesses----------------if you want to follow my recommendations to solve what"s wrong, let me know

[34_40]

I'm not saying the dizzy being off a tooth or 2,3,4,5, whatever caused anything. What I will say (Again) inspect and verify, that the valves can move freely, and check the height across the valve stems as directed by Jerry above. Also inspect and verify the rocker arms move freely on the shaft without binding or any scratchy feeling. Checking the pushrod is seated needs to be on both ends of each! Not just the lifter, it's very easy for the top of the pushrod to be off center. And as Jerry said, check the length of those pushrods, and the ends can be worn and have a crushed or pushed down depression in them. If you see that, consider replacement if they all show damage. (my point oh two!)