The original post must have got lost but will try again.
Just stripped the head and just discovered the exhaust valves are hitting the block causing the tappets to snap.
Can somebody help , can it be resolved by putting a thicker head gasket on or has the cylinder head been over skimmed?
Snapped tappet adjuster
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rich@minispares.com
- 1275 Cooper S
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Re: Snapped tappet adjuster
is it a 12g940 on a small bore engine?
best solution is to pocket the block
if its a large bore engine, then something odd is going on, as the valves don't go near the side of the cylinder
best solution is to pocket the block
if its a large bore engine, then something odd is going on, as the valves don't go near the side of the cylinder
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Ryan67
- 850 Super
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Re: Snapped tappet adjuster
Hi
No it's a standard 998 cooper engine which came with the car and was supposed to have been rebult
No it's a standard 998 cooper engine which came with the car and was supposed to have been rebult
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mk1coopers
- 1275 Cooper S
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Re: Snapped tappet adjuster
As Rich has said above check the head casting number, if it's a 9 stud 12G940 it's a big bore head on a small block, quickest solution would be to fit an appropriately skimmed 998 Cooper head.
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Ryan67
- 850 Super
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- Joined: Mon Mar 05, 2012 8:20 pm
Re: Snapped tappet adjuster
Hi
It is a standard 12g206 cooper head
the strange thing is I've done about 200 miles since the engine was fitted with no problem and have now Broken two tappets in just over a week .so I stripped the head off today and you can clearly see we're the valves have been hitting the block .
It is a standard 12g206 cooper head
the strange thing is I've done about 200 miles since the engine was fitted with no problem and have now Broken two tappets in just over a week .so I stripped the head off today and you can clearly see we're the valves have been hitting the block .
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ianh1968
- 1275 Cooper S
- Posts: 1012
- Joined: Sat Nov 03, 2012 6:00 pm
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Re: Snapped tappet adjuster
The biggest exhaust valves you can fit into one of the 295-type
heads without problems is 1.040". (On as standard 998cc bore).
I notice that the 1.040" exhaust valves are the largest size that
MiniSpares Centre list for the small bore.
I had a 1.0625" exhaust valve setup quite a few years back and
this required cutouts. In theory, they only needed to be a few
thou, but by the time you've allowed for a bit of "movement" in
the system, the reality is that there needs to be a fairly sensible
amount of clearance.
If the block has been bored, say +0.040", there may possibly
be enough clearance for the 1&1/16" valves...
Is it all the valves, or just the inner or outer pairs? I found that
the cutout requirement was different on the centre two bores
than it was on the outside ones because of the spacing of the
bores compared to the head/valve centres on the small bore
blocks.
Ian
heads without problems is 1.040". (On as standard 998cc bore).
I notice that the 1.040" exhaust valves are the largest size that
MiniSpares Centre list for the small bore.
I had a 1.0625" exhaust valve setup quite a few years back and
this required cutouts. In theory, they only needed to be a few
thou, but by the time you've allowed for a bit of "movement" in
the system, the reality is that there needs to be a fairly sensible
amount of clearance.
If the block has been bored, say +0.040", there may possibly
be enough clearance for the 1&1/16" valves...
Is it all the valves, or just the inner or outer pairs? I found that
the cutout requirement was different on the centre two bores
than it was on the outside ones because of the spacing of the
bores compared to the head/valve centres on the small bore
blocks.
Ian