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Engine(CC)mounting bolts - Printable Version

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Engine(CC)mounting bolts - Erich - 24-02-2021

Hi All,

I've found that my engine(crankcase) mounting bolts are incorrect with a couple of odd sizes. I have checked with a couple of the cherished suppliers who have said they are out of stock on these. Does anyone know of a source for these? I believe they are BSF.

Erich in Mukilteo


RE: Engine(CC)mounting bolts - Robert Leigh - 24-02-2021

Are you talking about the bolts for mounting the crankcase to the chassis which are BSF? There should be no need to go non-standard in any way on these because they don't fail in my experience.


RE: Engine(CC)mounting bolts - Erich - 24-02-2021

Yes, Robert, these are the ones I need. I have two which are correct and thread into the front chassis member, but the two at the rear are undersize and BW.

Erich in Mukilteo


RE: Engine(CC)mounting bolts - Andy Bennett - 25-02-2021

Wonder if they were replaced to be 'pegs' to provide location but also allow for some flex by not actually screwing in and so prevent foot breakage?


RE: Engine(CC)mounting bolts - Colin Wilks - 25-02-2021

My engine mounting bolts happened to be on the side in the kitchen this morning, so I measured them whilst making tea for the boss. All four are the same - 1 3/4" long and either 15/32" x 20tpi or, perhaps more likely, M12 x 1.25. The vernier measured .466" over the slightly tired threads. I assume the cherished suppliers were also out of stock at some earlier point in time when the chassis was being renovated, or is this another example of an unusual Austin original thread?


RE: Engine(CC)mounting bolts - Ruairidh Dunford - 25-02-2021

Solid mounted crankcase bolts are 3/8 BSF - I find optimum length is normally 1 1/2", but this can vary from car to car.


RE: Engine(CC)mounting bolts - Parazine - 25-02-2021

Agree Ruairidh, 3/8BSF by 1 1/2". No funny threads and no metric.


RE: Engine(CC)mounting bolts - Colin Wilks - 25-02-2021

That'll teach me to measure things while making tea. Measured .366 not .466. Duh!


RE: Engine(CC)mounting bolts - AustinWood - 25-02-2021

To prevent the rear engine mountings undoing I use Nylocs. They can then be left slightly loose to avoid stressing the crankcase.


RE: Engine(CC)mounting bolts - dickie65 - 25-02-2021

I use bolts on the rear with a extra nut welded to the head to stop it turning in the chassis channel, the bolts are fitted from underneath with nyloc nuts on the engine feet. 3/8" BSF