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Discussion Starter · #1 ·
hi all
right, ive got a set of 94mm heads, but currently building a 1835 with 92 mm barrels and pistons, could i modify the heads at all to use on the 92's? for example, a machined collar? that reduces the bore?

any help on this would be great

thanks alot

mei :D
 

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Nope.

92 and 90.5 share the same head and case cutting tool.

94 is another larger tool.
 

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It can be done but it depends on whether you want the grief. Is the chamber in the head opened to the same size as the inner edge of the 92mm cylinder? If it isn't it makes things somewhat easier. The other thing would be to make an ali ring that would go over the od of the cylinder, but inside the head to keep the cylinder stable in the oversize head opening. A decent machine shop should be able to do this for you.
 

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Discussion Starter · #5 ·
thanks for the help guys :), a ring seems to be my best option at the moment

mei :hangloose
 

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meislei said:
hi all
right, ive got a set of 94mm heads, but currently building a 1835 with 92 mm barrels and pistons, could i modify the heads at all to use on the 92's? for example, a machined collar? that reduces the bore?

any help on this would be great

thanks alot

mei :D
Yep you can modifiy the head by machining up an insert as you suggested to press fit into the 94mm head, JMR and I have talked about this before when only 94s were availible and I wanted 90.5s.

cheers

J..
 

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yep a alloy ring will work, this is how i ran my type 4 race motor for a while. heads cut for 103 mm and running 96mm barrels.

cheers rob
 

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Why not just egt some 94mm barrels and a case cut for them - 1914cc! :D

Machining alu rings may be expensive.

(I got quoted over £110 to bore out 93mm ->94mm barrels yesterday! :eek: Looks like machining is expensive! )
 

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Discussion Starter · #9 ·
thanks guys, looks like thats the way ill be doing them then, nice to have some more confirmation on the subject :D, ooh my bro's a machinst...so i get anything and everything i want in alloy wooo,

one question, should it be press fitted into the head, or just a sleeve over the barrel end?



mei :hangloose
 

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meislei said:
thanks guys, looks like thats the way ill be doing them then, nice to have some more confirmation on the subject :D, ooh my bro's a machinst...so i get anything and everything i want in alloy wooo,

one question, should it be press fitted into the head, or just a sleeve over the barrel end?

mei :hangloose
They need to be the same material as the head (so aluminimum will do the trick) so the rate of expansion is the same. I would also recommend a transition fit, not a press fit. I would also run a copper head gasket of 10 thou just to make sure you don`t loose any combusion gases.

Cheers

J..
 
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