Does anyone know the bolt size ......

[mk1fan]

..... for the overrun valve on a 3.5 RV8? It is a flapper EFI so NOT stepper motor.

Need to swap the cap head bolt for button or socket as it is fowling the throttle cable.

Thanks.

[mk1fan]

phillpot said:

you'll obviously know the length from the existing bolt.

Diameter can be measured easy enough

Thread is unlikely to be metric as these engines are of American origin so that leaves unf or unc. threads into alluminium are usually unc.
It's fiddly but thread pitch can be counted (if you don't have a thread gauge), unc will be 18tpi whereas unf is 24, a very distinguishable difference.

I am away from the car ATM and wanted to order some in ahead of my return. I was going to pinch one of them but forget.

[mk1fan]

v8s4me said:

I have a 3.9 EFI plenum in the loft. If the overrun valve goes in the same mounting hole I can get it out this evening and measure it for you.

Thanks Joe. No rush though as I need to go to Spain this weekend so this 'quick fix' job will have to wait!

[mk1fan]

phillpot said:

Order a selection!



........... can't have too many spare bolts

There's already a large selection of metric 'spares'. Really don't want to start an imperial one too

[mk1fan]

Thanks.