The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: Thomas on July 01, 2022, 07:39:43 PM

Title: Valve cap
Post by: Thomas on July 01, 2022, 07:39:43 PM
Hi all,

after a 200 miles run I noticed excess valve clearance at the exhaust side. I then discovered that the valve cap is significantly worn (see picture). Does somebody have an idea why that can happen? I followed Chris Odling's recommendation the lengthen the push rod. After I have installed a 2.5mm ring I now had to add another 2.5mm to get a nearly symmetric force application onto the valve tip. I have no idea what might have happened.

Cheers, Thomas
Title: Re: Valve cap
Post by: Thomas on July 02, 2022, 10:42:00 PM
I am in need of new 3/8" ID valve stem lash caps. Where can I get them?
Title: Re: Valve cap
Post by: singleminded on July 02, 2022, 10:43:19 PM
Was the valve cap hardened before it was fitted..If it was just ordinary steel it would wear quickly.
Title: Re: Valve cap
Post by: Thomas on July 03, 2022, 07:23:36 AM
Yes, it was hardened since I drive the machine for about 5.000 miles. I discovered this very problem after I worked on the rocker box and valve gears.
Title: Re: Valve cap
Post by: Thomas on July 04, 2022, 01:58:39 PM
GS Valves will make me four caps for 10 pounds each. Surprisingly, they quickly sent me a drawing (attached). Does the club know about this? Could be interesting for spare parts supply.
Title: Re: Valve cap
Post by: VicYouel on July 05, 2022, 09:19:06 PM
Thomas
That is very useful and I did not know that!
Vic
Title: Re: Valve cap
Post by: Thomas on July 21, 2022, 05:21:48 PM
The hardened caps from GS Valves arrived. They were so kind to send them as a private parcel! So, no trouble with extra tax and customs charge. :)