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To chassis mount, or not to chassis mount

Posted: Mon May 02, 2011 5:12 am
by Sunbmw
Hi all, in most Rally cars I have built (Talbot Sunbeams, Escorts etc), I have ended up chassis mounting the engine, this gives a few advantages regarding stiffness, ease of changing suspension components and also being able to mount the engine in a more suitable position.

I have just been weighing the job up when it occured to me that the Rover V8 block isn't the most stiff or strong of things (I do have an X-bolted block mind), and was throwing it out to you guys for opinions, good or bad idea?

I'll start, it maybe an advantage to have the engine as a "Stressed member" as it may add to the rigidity of the block.

I intended to use this kind of kit but replicate it myself.................

http://cgi.ebay.co.uk/Vauxhall-XE-16V-E ... 1c18d6f49e

Look forward to this one................

Posted: Tue May 03, 2011 4:39 pm
by Rossco
The Repco Brabham F1 used the engine as a stressed member without any problems.

Posted: Tue May 03, 2011 5:21 pm
by ian.stewart
I have my engine Chassis mounted in my Cortina on small box tabs on the chassis, works well, the only down side of it that I have found is, if you remove the X Member with the engine in situ, the rails spread a small amount, [2-3mm] making re-fitment of the X member a bit harder than I would like, But a big sash cramp takes it back without any effort,
Its probably more to do with the construction of the car from fords than any other reason, and Yes I would go that way again, it enables you to fit cotton reels almost direct to the chassis and keep the mounts nice and small, the cotton reels I use are HD Landrover items from Dingocroft

Posted: Tue May 03, 2011 10:36 pm
by Sunbmw
Cheers guys, I had been erring on the side of mounting to the chassis anyway, but just wanted someone else to say it was a good idea, now, wheres that welder............. :wink:

Posted: Thu May 12, 2011 8:33 am
by Sunbmw
Well, I did it, had a good day yesterday, positioned the engine and fabbed some mountings up, got the engine nicely back and down too...........

In position.........

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Tack on chassis brackets..........

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Tack tubes to bush mounts, I have used the V8 mounts but modified them and cut them down...............

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Fitted the heads and covers to check clearances..........

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Then take em off and weld them properly.............

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All done..............
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Then finish the chassis side of the job..........done!

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Posted: Fri May 13, 2011 9:36 am
by RoverP6B
That looks tops.. :D

You are a seriously handy fella!

Ron.

Posted: Fri May 13, 2011 9:44 pm
by stevieturbo
The concerns I would have there are how leverage is now acting on the mounts, and weight is hanging from them.

IMO it looks there will be more loads chucked through the tiny upper mount ( single bolt ), than the lower fixings on the block body.

Posted: Sat May 14, 2011 8:59 am
by Darkspeed
Stevie +1

Tubes should only carry loads in tension or compression they are not designed for bending loads.

Andrew

Posted: Sat May 14, 2011 3:08 pm
by stevieturbo
It's not even the tube I'm talking about. I'd say it's strong enough as does look fairly substantial.

More about how it interacts with the block fixings. It just looks wrong as all the loads will be distributed to the wrong places.


Although the actual rubber bits look good, what are they off ?