High Tensile bolts?

[stag36587]

Hi, just musing on whether engine mounting bolts, propshaft to diff bolts etc are high tensile or not?

[MarkyB]

I'm not sure either but the numbers cast into the bolt heads will tell you for sure.

[katy]

Not sure what you mean by high tensile, but Grade 5 are probably adequate.

[autolycus]

"Grade 5" is a High Tensile grade across the pond. In the UK, if a UNC or UNF bolt has three radial lines on its head, it's HT. R, S, or T on the heads of BSF bolts indicate increasing strength, and all are High Tensile, though some would say that R grade is a bit borderline. Metric bolts may be marked 6.6 (not HT) 8.8 (fairly HT), or 10.9 (HT).

This is oversimplified, but a starting point. I'd certainly use HT for prop shafts. Not sure which ones you mean by engine mounting bolts, but if in doubt, use HT.

Kevin

[bmcecosse]

Are the prop bolts not special 'fitted' bolts anyway?? And the engine mounts don't have 'bolts' as I remember??

[autolycus]

Reaming the holes for fitted bolts would surely have been too expensive for BMC assembly lines? It's enough of a fiddle poking a 1 1/4" bolt through and holding it, let alone turning a reamer. Moss don't show the bolts as anything special in the Midget catalogue. I'd have to stand up to check a Minor parts list, and icba. Probably worth a reminder to use bolts not set screws, and new nylocs.

Engine mount brackets to body? Set screws, iirc.

Kevin

[bmcecosse]

Ahh the brackets - yes, but the mounts just need nuts. I just seem to remember the prop bolts are very snug in the holes - no looseness. I don't imagine they actually reamed them - just a well toleranced hole I suppose.