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Re: Not a Porsche… But air cooled and close enough
Posted: Sun Nov 23, 2025 7:21 am
by KS
Just another observation - looking at the number of threads showing on the valve adjusting screws, I would pay attention to the valve train geometry, pushrod length etc. Setting correct valvetrain geometry is critical on these engines to prevent, among other things, excessive valve guide wear, coil bind, etc etc. It's a time-consuming pain in the neck process involving dial gauges, adjustable (dummy) pushrod, rocker shims, etc, but pays dividends in the long run.
Re: Not a Porsche… But air cooled and close enough
Posted: Sun Nov 23, 2025 10:24 am
by Bruce M
Re: Not a Porsche… But air cooled and close enough
Posted: Sun Nov 23, 2025 11:49 am
by stevenery
Went through the process of valve geometry earlier this year. Very time consuming getting the pushrods down to size, but an enjoyable and satisfying one to learn. Unsure on compatibility, but Thorsten Pieper in Germany makes some really nice aluminium pushrods. I have a set aside for a Type 4 engine build.
http://www.tp-technologie.de/produkte%2 ... l%20en.htm
Re: Not a Porsche… But air cooled and close enough
Posted: Mon Apr 27, 2026 6:01 am
by Geordie71
Re: Not a Porsche… But air cooled and close enough
Posted: Mon Apr 27, 2026 6:05 am
by Geordie71
Not sure if videos will post here … but we were right. Left brass float had lots of micro holes in it and full of petrol … so assuming float never floated, needle valve was always open and loads of unburnt petrol seeping into oil around cylinders.
Very happy with investigative work …. and still lots to do
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