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-   -   Just what should a 'complete chassis' consist of? (http://www.haynes.co.uk/forums/showthread.php?t=2351)

fabbyglass 19th July 2009 10:09 PM

Watch this space then matey....;)

HandyAndy 19th July 2009 10:19 PM

Quote:

Originally Posted by Eddy (Post 18233)
Found this post interesting because it talks about exactly what I'll be looking to buy in 5 months time.

I think that a complete chassis should require no further welding, but would anticipate certain aspects to be made universal (such as the slotted engine mounts mentioned)

Hi Eddy,

may i ask where are you located?

andy:)

mr henderson 19th July 2009 10:28 PM

Quote:

Originally Posted by Eddy (Post 18233)


I think that a complete chassis should require no further welding, but would anticipate certain aspects to be made universal (such as the slotted engine mounts mentioned)

That could be done, of course, bt is not necessarily the best solution.

If I was buying a ready made chassis I would prefer no drilling of the engine mount plates, and would drill them to suit my own set up. It's not unknown for engines to move where slots allow them to

HandyAndy 19th July 2009 10:35 PM

Quote:

Originally Posted by mr henderson (Post 18239)
That could be done, of course, bt is not necessarily the best solution.

If I was buying a ready made chassis I would prefer no drilling of the engine mount plates, and would drill them to suit my own set up. It's not unknown for engines to move where slots allow them to

this is then where the discussion with the customers "wish list" & donor engine choice can be incorporated into the building of the chassis can come in .

andy

Bonzo 19th July 2009 11:07 PM

Quote:

Originally Posted by mr henderson (Post 18239)
That could be done, of course, bt is not necessarily the best solution.

If I was buying a ready made chassis I would prefer no drilling of the engine mount plates, and would drill them to suit my own set up. It's not unknown for engines to move where slots allow them to

I have to dissagree with that one !!??

Many production cars use oversize engine mounting holes. with the use of the correct fixings & tightened correctly, there is no reason for the engine to move ??.
In any event, it would need both fixings to become loose in order for the engine to move ;)

If it were an unsafe practice to slot holes, it would not be allowed under the IVA regulations.

Remove a Ford Escort subframe & inspect the clearance holes in them :eek: :eek:

They require the use of large temporary locating pins to allow the correct alignment of the subframe.
I would say that a subframe is under a lot more stress than an engine !!??

That's my thoughts for what they are worth.

les g 19th July 2009 11:20 PM

wow a bit of a lively subject this one.........
well done everyone for provoking a bit of dialogue .....
as for slots and holes.......
i,m with Ronnie !!!!
slots are ok ..........its the clamping force that provides the security and retention of the bolted together bits
cheers les g

Bonzo 19th July 2009 11:26 PM

I would imagine that in your line of work Les, you must come across some hefty MF slot fixed components :eek: :eek:
I have seen some beautys on some of the agricultural stuff ;)

mr henderson 20th July 2009 08:19 AM

Quote:

Originally Posted by Bonzo (Post 18249)
I have to dissagree with that one !!??

Many production cars use oversize engine mounting holes. with the use of the correct fixings & tightened correctly, there is no reason for the engine to move ??.
In any event, it would need both fixings to become loose in order for the engine to move ;)

If it were an unsafe practice to slot holes, it would not be allowed under the IVA regulations.

Remove a Ford Escort subframe & inspect the clearance holes in them :eek: :eek:

They require the use of large temporary locating pins to allow the correct alignment of the subframe.
I would say that a subframe is under a lot more stress than an engine !!??

That's my thoughts for what they are worth.

I'm very well aware that many production cars use a good many slots in their engine mountings and oversize holes for subframes, Ford Mondeos certainly do and presumably all other similar cars.

However, and to be fair, this discussion does have a context, and the context is the Haynes Roadster. With the type of engine mountings used in the book I would not use slots if it could possibly be avoided.

Reasons-

How much torque should this type of rubber mounting be subjected to? I don't have any workshop manuals featuring this type to hand, but basically it's a flat plate bonded to rubber, and surely should not be tightened beyond a moderate amount.

If just isn't necessary. In a production situation makers are working to tolerances and need to be sure that any slight variations in the different components can be compensated for by lining up the parts and then tightening the fixings wherever they happen to be in the slots. But in our situation we are fitting a specific engine to a specific chassis. Much better to offer up the engine, mark the mounting plates where the bolts make contact, then drill the plates and get the exact fit, and keep it! without having to tighten the nuts to provide the clamping force that would be needed to resist any possible movement.

Anyway, I did say "not necessarily":)

Eddy 20th July 2009 08:59 AM

HandyAndy - I live in East Kent, close to Margate.

I didn't mean that I would want slotted engine mounts, its just what I would have expected from a completed chassis. I think the person selling their completed chassis would want to appeal to as many people as possible, so would try to allow for the widest range of engines possible without the need for modification.

mr henderson 20th July 2009 09:07 AM

Quote:

Originally Posted by Eddy (Post 18262)
HandyAndy - I live in East Kent, close to Margate.

I didn't mean that I would want slotted engine mounts, its just what I would have expected from a completed chassis. I think the person selling their completed chassis would want to appeal to as many people as possible, so would try to allow for the widest range of engines possible without the need for modification.

Simply not possible, I'm afraid. A nice idea but impractical in reality, there are far too many variables.

Much better for the maker to modify the design to suit a particular power unit, which either they might have to hand, or which the customer would have to provide.

Having made engine mountings for various cars, and modified chassis to suit, I know that there is no way of providing a 'universal' chassis. Slots alone would be nowhere near enough, the mountings would have to be able to move in 3 dimensions and by a considerable amount.


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