cylinder head

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greenow
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cylinder head

Post by greenow »

after replaceing the head on my npm with a replacement the push rods now fowl on the head. any ideas what to do?

Nick
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Re: cylinder head

Post by Nick »

Hi, did you replace the head with another New performance head?
Oh yay, look, another seized bolt! Lets get a hammer.....and some kano.....and some cider!

scoobyjim
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Re: cylinder head

Post by scoobyjim »

what do you mean by foul on the head?

greenow
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Re: cylinder head

Post by greenow »

not sure what the head was of bought it at a sale years ago it does not have fl stamped at the front right which i think it should.
foul might not be spelt right what i mean is the push rods are rubing against the head and whould bend when the valves open

super6954
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Re: cylinder head

Post by super6954 »

Hi Greenow
I seem to remember that somewhere in production they changed the length of the rocker arms/ and possibly push rod length too :| so there may be a difference in clearance between both your heads, where the push rods come through the head to go under the valve cover :wink: .
you might need the complete rocker shaft assembly/ possibly push rods to match the head to get the clearance and valve travel right.
I remember this happening with me about 15 years ago, I think the head I had was either power major or last of the ordinary majors as this was the first blue orange super I worked on, and those where the spare heads around at the time.
I know I had a pile of used rockers and things here to get what I needed to make it work :) .
The other thing is have you checked to see if the push rods are straight :?: I have seen some that are very slightly bent and that will make them touch too, the clearance can be not that great at the start on some major motors ive worked on :eyes: .
Do you have the manifolds on yet as there is staggered and straight type head ports to, If your replacement head is the very early type your manifolds wont fit either :wink: . FL is an improved flow head too but I doubt you would ever know it lost a few HP with the wrong head on to have to worry about it :) .
Regards Robert
A Fordson is for life not just for Christmas !.

Pavel
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Re: cylinder head

Post by Pavel »

According to the 'good book' [Power Major; Super Major supplement] the rocker arms fitted to the Mk.3 engine [with the FL head] are different to those fitted to the early and Mk 2 engines in that the later ones are shorter in length from the centre of the adjusting screw to the centre of the rocker shaft. To accommodate this the holes in the FL head for the push rods were also re-positioned. Therefore fitting an earlier head, and coupling it with a later rocker assembly, will cause the push rods to foul against the sides of the push rod holes.
The cheapest remedy would be to obtain, and fit, the earlier rockers.

Pavel

greenow
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Re: cylinder head

Post by greenow »

yer been looking and found a differnt rocker shaft and they are slightly different not sure bowt the push rod length hadent thought bowt that, the longer rocker dident make a huge diffrence so il try and find some different push rods. never thought it whould be such a problem swaping heads, the manifoulds are correct i had them on the bench side by side and they looked the same. il try and put some pics up shortly

super6954
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Re: cylinder head

Post by super6954 »

Hi Greenow
I can't remember If I had to change the Push rods or not it was so long ago and many Majors have been apart here since :!: They could be close to touching the head anyway . As long as they are straight and not bent they will probably work as long as they turn when the motors running :wink: .
I just looked in my power major parts book. It lists 3 part numbers for push rods, before your tractor was made :cry: I don't have a newer book for your tractor so Can't check there number. Also don't have a clue what the differences are with the 3 numbers I have listed :cry: . I could maybe check the pile of parts and find out if I have any that are different lengths :idea:
Regards Robert
A Fordson is for life not just for Christmas !.

Pavel
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Re: cylinder head

Post by Pavel »

Before engine number 1425097 the push rods were 11.9inches [302.3mm] long.
From, and including, eng. no. 1425097 the push rods are 11.8inches [299.7mm] long.

Pavel

greenow
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Re: cylinder head

Post by greenow »

many thanks everyone i think the best option is to try and find a fl head it will be right then rather than cobbled. i might have to cobble it mind if i cant find a fl head, note use antifreez easier that way

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