392 rebuild started missing

M

macktruck907

New member
This is my first corn-binder rebuild and it seamed to go well but after about 40 45 mins of run time it started missing bad. I ran engine for 20 at 14-1800 rpm s let cool and did it again. Cam break in seamed to go fine. I used an oil with plenty of zinc cant remember the brand but it was break-in oil. It ran great until I test drove it, after about 4 miles it started missing and ran like crap all the way back to the shop. Think the May have roached a lobe or maybe ignition prob. I have heard if the wires are close together they can cross fire. Any thoughts thanks
 
As recommended do a compression test. Let the engine idle and feel for colder ports on the exhaust manifold. Those will be the missing cylinders and the ones you should do the compression test on.
I have some suspicions but I'll wait until you give us the compression numbers.
 
So I did a compression test and nothing on cyl 6 pulled valve cover and fond no push rod. It was laying in the valley so I got it out with a magnet and found it was bent badly and the lifter was also laying in the valley... Not sure what happened to bend the push rod! Any thoughts... Thanks
 
Ok so got to looking at it alittle closer and seen the valve spring was stuck down and I could not pull it up even with channel locks. Compressed the spring and had barley enough room to get the keepers out. Found metal shavings on the valve steam where it goes into the head. The spring and keepers had lots of oil on them and before I started the engine I spun the pump with a drill and seen good oil supply to the top end. What could cause this, could the machine shop have miss installed the new guides? They all went in smooth and clean, im scratching my head on this one.
 
Once you removed the spring could you move the valve?
My guess is old fuel. The bent pushrod was an intake right?
This new crap goes in a couple of months to leaving a gummy residue.

I've had this happen to people I know on new builds where seals were installed. I always make sure the valve is lubed up real good including the seal...
 
Got the valve issue fixed. Machine shop did not properly ream the guides and they where way to tight, but now its going back together and I went to add coolant. It runs out between the block and head on passenger side. Disassembled and all looked good gasket was aligned and not creases , all clean and smooth. Put back together and leaks even worse. I dont know whats going on it was fine the fist time around when it lunched the valve. Any thoughts?
 
macktruck907 said:
this is my first corn-binder rebuild and it seamed to go well but after about 40 45 mins of run time it started missing bad. I ran engine for 20 at 14-1800 rpm s let cool and did it again. Cam break in seamed to go fine. I used an oil with plenty of zinc cant remember the brand but it was break-in oil. It ran great until I test drove it, after about 4 miles it started missing and ran like crap all the way back to the shop. Think the May have roached a lobe or maybe ignition prob. I have heard if the wires are close together they can cross fire. Any thoughts thanks
Click to expand...
same symptoms and failure here.
Mine was bent push rods caused by not lining up the timing marks before torquing the rocker stands.
See section e, page 53, paragraph 27, figure 157 -> binder planet forums
 
Maybe I'm a bit slow but I can see no reason why the crank position makes any difference at all.. The crank and cam are synchronized no matter where they are positioned.
You'd need to explain in detail the mechanism that could damage the push rods by not indexing the timing marks... I believe IH was wrong in their statement. :ihih:
 
I am interested in the final answer to this also. Even though my engines already done I had a hard time finding the right way to do per book. My old repair manual said just throw the rocker stands on and go, didn't even list a torque spec or special crank position. Just said to use original bolts and that was that. Other places I read say to use the crank position and then my neighbors Travelall manual says nothing specific once again. Soo I installed my rocker arms with no push rods in, got them sealed and torqued, then compressed the valves one at a time to put the push rods in just to be on the safe side. Lol maybe it was just extra work but just in case I thought it was best to do it that way.:icon_confused:
 
tiny yokum said:
I don't.
Click to expand...

We need to think about the mechanism that would create forces to damage the push rods.
Assuming the valve and piston crash it the only possible one. At the #8 tdc location #8 is on tdc of the compression stroke so no lift is to be expected but 1/2 way thru the firing order there is one other piston at tdc on overlap. There you could assume the position recommended by IH is faulty. In fact any other position could create the interference until the lifters collapse/bleed down. It is a bogus theory that lining up 0 will somehow be any amount safer than any other.
 
Robert kenney said:
we need to think about the mechanism that would create forces to damage the push rods.
Assuming the valve and piston crash it the only possible one. At the #8 tdc location #8 is on tdc of the compression stroke so no lift is to be expected but 1/2 way thru the firing order there is one other piston at tdc on overlap. There you could assume the position recommended by IH is faulty. In fact any other position could create the interference until the lifters collapse/bleed down. It is a bogus theory that lining up 0 will somehow be any amount safer than any other.
Click to expand...
thanks but I'll still go with the fsm.
How hard is it to rotate to tdc anyway?
 
tiny yokum said:
thanks but I'll still go with the fsm.
How hard is it to rotate to tdc anyway?
Click to expand...

Look closely at the figure 157 in the IH fsm. You do not Rotate the engine to tdc on #8, you align the forward edge of the balance weight with the "0" Mark on the timing indicator.
Quite different from tdc, enough of a difference for IH to provide a figure in the manual.
 
1975ih200 said:
look closely at the figure 157 in the IH fsm. You do not Rotate the engine to tdc on #8, you align the forward edge of the balance weight with the "0" Mark on the timing indicator.
Quite different from tdc, enough of a difference for IH to provide a figure in the manual.
Click to expand...

Thanks for clarifying. This location leaves no piston at tdc and would only be applicable to the engines with contoured pistons... The e series have tons of daylight..

Another clarification is that this is not what caused the failure in the op's engine as he already stated..
 
I have lined up the timing marks on the gears, and installed the push tubes....nothing bent. On another engine I indexed the edge of the counterweight on the pulley as recommended by IH, either way works.
 
Ok I got a new set of gaskets and they are way different. Ic and non ic im guessing. The guy at the parts store said if the lines from the water pump go to the head it is ic but I thought it was the other way around. Either way I messed up and should have seen that the gaskets didn't cover the cooling ports correctly. Im on my way to put it together again and read the post before about lining up timing marks on 0. Now im worried. Should I do this? I don't understand how it would make a difference either way but like I said new to IH engines. Thanks for the help.
 
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