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PostPosted: Thu Feb 10, 2011 12:30 pm 
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1360cc
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drmini in aust wrote:
The inlets won't hit the block, as they clear the bore. But the exhausts overhang, more so on a 1275 head as the valve centres are greater.
`Notching the block' as yours has is a recognized procedure when fitting a 1275 head and a hi-lift cam, to a smallbore block.

[edit] Maybe a valve was stuck in its guide after standing 30 years, that can bend a pushrod... :lol:


Hey Doc

He was asking about the valves hitting the piston, not the block :wink:

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PostPosted: Thu Feb 10, 2011 3:00 pm 
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Panthersteve wrote:
drmini in aust wrote:
The inlets won't hit the block, as they clear the bore. But the exhausts overhang, more so on a 1275 head as the valve centres are greater.
`Notching the block' as yours has is a recognized procedure when fitting a 1275 head and a hi-lift cam, to a smallbore block.

[edit] Maybe a valve was stuck in its guide after standing 30 years, that can bend a pushrod... :lol:


Hey Doc

He was asking about the valves hitting the piston, not the block :wink:

he was asking about inlets hitting the block... hence my 1st sentence.
Read my other post re the pistons. :wink:

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PostPosted: Thu Feb 10, 2011 4:59 pm 
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I was referring to the valves hitting the pistons. I know drmini mentioned that it was unlikely because the pistons are half way down the bore on full lift, but I was reading Vizard big yellow book and he suggests that with the smaller engines with high lift cams the pistons can require valve cutouts. I know that the camshaft in question does not have super lift, but still 328" or about 410" lift with 1.25 ratio rockers.

All of the pistons have been ground, but only on the exhaust side. Piston number 2 hasn't been ground as much as the other 3 pistons and it could be my imagination, but it looks like there maybe a slight mark on the piston and valve in question.

The valve did get stuck in the guide as drmini mentioned, but I dont know if that was the problem or a result of the problem.

Now if the cam was timed slightly wrong or the factory marking were used to time it would this make a difference to the timing of the valves/pistons?

I was trying to check how much had been skimmed off the head or how much thickness is left by sticking the vernier caliper down the small oil hole on the top of the head, however it seemed to be blocked? Why would it be blocked? How could I fix this?

Thanks for all of the advice guys!


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PostPosted: Thu Feb 10, 2011 5:12 pm 
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It is quite easy to have an Inlet Valve kiss a piston, when running a bit of a cam. I've got a pic somewhere.

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PostPosted: Thu Feb 10, 2011 6:11 pm 
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Well, my old 1220 (1098 bored to 68mm, Imp flat top pistons) back in 1968 ran a 1275 head, C-AEA544 cam, and it revved to 8500. Block was notched on exhaust side as this one apparently is, and the valves never ever hit the pistons... :P
It was retired at 20,000 miles for other problems though (a circlip broke up). Great motor until it happened. :cry:

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