Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Bolts either side of air filter

I seem to remember you made a lot of little improvements like this, which all seemed sensible and good ideas - do you remember where it was that you posted about that? Or have I got the wrong person

Got the bolts out easily enough, but they don't seem to be metric sizes which would make sense since they screw into the cylinder head.

The bolts are almost exactly 1 1/2" inches long but does anyone know the thread spec.?

They seem to be 'nearly' M8 metric but not quite (when I tried to thread an M8 nut on them to check before destroying the thread in the head!)

Local shops don't seem to know what I'm talking about...

Bolts are a UNC thread, sorry can't remember exact size offhand.

Thanks, Calum, glad I didn't force a metric thread in!

Anyone found a good supplier of stainless bolts? And the size of course...

I've used www.a2stainless.co.uk before. Don't seem to have any minimum quantities and had things in stock when I needed them.
John at RPM in Perth (01738 44 4004) should be able to tell you the size

I think from memory they are 5/16 UNC thread.

Any good Harley shop or fastner shop should have these, but imperial stainless fasteners are getting harder to find. I tend to buy job lots at autojumbles when I see them.

As the USA is still imperial, most of the engine bolts ar not metric.

All my posts should be in the M3W section.

If the metric size is M8, then 5/16 is my guess too as it's 7.9375 mm, ie very close.

UNC also makes sense for this application, 18 tpi. Same size UNF is 24 tpi.

I've got and suggest one is useful to a Morgan owner, a thread gauge. Sort of thing you ought to be able to buy cheaply from an autojumble, but I was given mine!

Yes, measured and seems to be 5/16" x 1 1/4" thread length.

Will order a couple via the internut and let you all know if it works.

Am going to go for 'socket button screws' which have a hex inner fitting but a domed head which I think will look better.

Thanks for this post or I might not have noticed the bolts which are now rusty and look ugly. Have you also noticed how parts of me chrome finished engine have acquired a dusty bloom? This is powdery to touch and my guess is that it is made from cast aluminium. It is likely that both problems have been caused by salt on our roads being applied in winter months, any ideas for cleaning this?

Salt will destroy the finish on the engine in no time. You need to get it polished ASAP.