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Sprint engine, Newman PH3 cam problem, etc

Posted: Thu Aug 02, 2018 11:35 pm
by dursley92
Just checking over a Sprint engine I have bought and found a few "issues".
The engine came from a rally car, said to be lightened and balanced with a Newman PH3 cam and running on twin 45DCOE Webers. First thing I noticed was no chain wheel support bracket or cam sprocket locating pin fitted. The straight chain guide only had one fixing bolt. Bit of a worry now because whoever built it was obviously not very particular. There are no markings at all on the cam that I can find so I measured the lift and it is approx 0.400" so that seems about right for a PH3.

I have an adjustable cam sprocket so thought it would be worth putting that on and checking the cam timing at the same time. When I tried to fit the cam pulley I find that the sprocket locating pin will not fit the hole in the end of the cam, it is too big. Not by much, maybe about 0.010"-0.015". I will get it turned down tomorrow but that presumably explains why there was none fitted. Too much trouble to get one modified.

Anyone else come across this problem before?

Re: Sprint engine, Newman PH3 cam problem, etc

Posted: Fri Aug 03, 2018 7:43 am
by xvivalve
Rather than turning the pin down and making it weaker, would it not be better to reamer out the hole?

Not come across that problem before, but shoddy build is common place!

I have a spare cam support bracket if you need one.

Re: Sprint engine, Newman PH3 cam problem, etc

Posted: Fri Aug 03, 2018 9:43 am
by trackerjack
Just a thought.
The lower straight bolt is in the middle of the front cover and is removed with the cover when said cover is removed.
I have fitted 2 Newman cams and the only issue was the first one that did not quite match a line up with the rocker fingers as some were over the edge. Recently however I fitted a Newman cam and they lined up much better.

The most recent cam I have just fitted was an STR91 from a genuine BL blank and its perfect.

Have never found a problem with the cam centre location though.