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Engine torque reactions
Nitrogeno25 - 7/9/05 at 03:05 AM

I was looking at a seven style chassis that has and arm attached the engine (one bolt that join the gearbox with the engine) and the other side to the chassis with a bush. The engine was a fiat with 100hp so no big hp figures.

Does it make sense to use something like this to avoid the engine trying to "twist" the chassis or the engine/gearbox mount are enough?

Thank you.

kb58 - 7/9/05 at 05:01 AM

Adding a stay will make no difference for the engine trying to twist the chassis. All the bracket will do is share the load from the engine into the chassis. It's probably there to protect the engine mounts from failing.

britishtrident - 7/9/05 at 07:30 AM

Torque tie bar links were a tradditional and quite effective way of rerstraining an engine BMC used them a lot in them durring the 1950s, there are two problems with them --- (1) they can transmitt a lot of vibration (OK not a problem in a Locost) (2) Then tend to fail due to metal fatigue.

[Edited on 7/9/05 by britishtrident]

Nitrogeno25 - 7/9/05 at 02:02 PM

quote:
Originally posted by britishtrident
Torque tie bar links were a tradditional and quite effective way of rerstraining an engine BMC used them a lot in them durring the 1950s, there are two problems with them --- (1) they can transmitt a lot of vibration (OK not a ptoblem in a Locost) (2) Then tend to fail due to metal fatigue.


You are right, the chassis I saw was very old, and I never saw it again in a newer one, so I think I can live without it

iank - 7/9/05 at 02:23 PM

Still see them in (classic) minis.
But then again they still use the 50's A-series engine.

britishtrident - 7/9/05 at 02:47 PM

Mini ones gave a lot of trouble until they fitted one underneath the gearbox as well -- after that they still gave trouble just not quite so much :-)

Nissan/Datsun used to copy a lot of BMC practice but improve it a bit so they used two on the Cherry -- they also used to sheer off bolts at the engine end, repairing them mean't attacking the cylinder head with a drill. :-(

andyps - 7/9/05 at 06:57 PM

With the Mini the only mountings for the engine were under the ends of the engine rather than the more conventional one each side - as such due to the rubber mountings the engine will move along way even pushing by hand let alone with the torque of the engine - the top steady bar makes a massive difference!

NS Dev - 7/9/05 at 08:00 PM

fiat and lancia used them a lot.

Funnily enough, many years ago we built a metro turbo powered go-kart (it was funny!! and some time before "the book" became!!) and used a lancia engine stay for the a-series in that!

Bob C - 13/9/05 at 04:14 PM

on FWD car the engine is being twisted by axle torque & that can be 1000s of ft lbs.
RWD car of the 7 variety this torque is divided by the diff ratio ('bout 4) SO you see these stays in FWD transverse engines & generally not in north/south conventional cars
Bob