pushrods rubbing
Turbo Mini Forums

Here's the engine spec.

1275cc A+ fitted with a big valve and ported 12g 940 cylinder head.
286 cam.
3mm decompression plate with 2 head gaskets (obvisouly)
Standard metro turbo setup feeding the fuel.

Problem I have is that the pushrods are rubbing/binding on the front cylinder head side of the pushrod hole.
Have tried 3 sets of rockers including a 1.5 titan roller set.
Whatever I use the pushrods rub.

Any suggestions?

try it without the plate and only one gasket.


I suspect that because of the extra 3.8mm (3mm plate and .8mm gasket) you are having to wind the tapet adjusters down which inturn pulls the top of the pushrod forwards,

reprofiled cams wont help that either.

If i'm right you can...

get the chambers taken out so you only need 1 gasket as std,

file the push rod holes out longways (dont drill them! ask me how I know!)

you might be able to get a set of 8 port pushrods in there (theyre longer but I cant remember how much longer)

Thanks for the reply.

Was on the same lines as you with the 3.8mm, so this morning I took a set of rockers and machined 4mm from the base of the rocker posts. problem still exists.

Could well be the reprofiled cam, dont know how to eliminate that problem.

machining the rocker bases wont fix it as when the rockers come down they rotate.

Also, thought about drilling out the pushrod holes, but on a ported head it would end with hole!!

How 'ported' has this head been? Have the push rod holes been sleaved?

It has been quite extensivly ported, but no sleeving.
Also, I was thinking about the reprofiled cam. That should not make to much difference as its the follower that determines the position of the bottom of the pushrod, so thats unchanged.
Going to try a set of non A+ rockers this morning and if they dont work, i'll remove the head, try it with one gasket and failing that, i'll elongate the pushrod hole

Think about it.. machining the post just drops the pivoting point.. Machining the posts will put the rocker at a strange angle with the valve closed.. I have a feeling longer rods are the best fix

Edited by CR# on 20th May, 2011.

the follower drops, so the pushrod drops, that in itself dosent affect the geometry....

but you then have to jack the rocker adjuster screw out which pulls the top of the pushrod towards the valve.

Surely instead of reprofiling cams, machining things, spending money on new push rods and generally trying to make a 'bodge' work.

Wouldn't it just be easier to do it properly and enlarge the chambers on the head?

When you weigh up, time/money trying to get the decomp plate to work against whipping the head off for machining and slapping it back on (with 1 head gasket) its a no brainer...or am I missing something?

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1/4mile in 13.2sec @ 111 terminal on 15psi

what he said!

On 20th May, 2011 matty said:
Surely instead of reprofiling cams, machining things, spending money on new push rods and generally trying to make a 'bodge' work.

Wouldn't it just be easier to do it properly and enlarge the chambers on the head?

When you weigh up, time/money trying to get the decomp plate to work against whipping the head off for machining and slapping it back on (with 1 head gasket) its a no brainer...or am I missing something?

Yeah I agree what he said. lol

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1/4mile in 13.2sec @ 111 terminal on 15psi