John Bonnett
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| posted on 17/12/10 at 08:06 AM |
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To lengthen a chassis; advice please.
Well, after a lengthy period of inactivity on the car building front, I'm about to embark on a new project. It is still very much in the planning
stage but I do hope to have the donor vehicle early in the New Year.
What I'd like to do is to transform this;
[img]
 
Reliant Kitten
[/img]
into this;
[img]
 
MG TF Blueprint
[/img]
In order to maintain the proportions, the chassis will need to be lengthened by 10 inches.
[img]
 
Reliant Kitten chassis
[/img]
The chassis is made from box section and I can extend it without too much problem but what I am concerned about is whether it will spring out of shape
when cut and being quite stiff might be difficult to restore.I'm thinking along the lines of a jig.
I'd be pleased with your thoughts.
Thank you,
John
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MikeCapon
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| posted on 17/12/10 at 08:18 AM |
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Hi John and welcome back. Where are you planning to cut? Presumably where the chasis is reduced to just the two box sections where on the RHS it
turns from red to white?
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John Bonnett
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| posted on 17/12/10 at 08:27 AM |
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Hi Mike, good to hear from you and thank you for your good wishes.
Yes, I'm planning on cutting on the white straight portion possible about 6 inches rearward from where the two tubes meet. I can fold up a
sleeve to fit inside the box section and then slide on the 10 inch piece to extend the frame. The sleeve would extend far enough into the original
tube to hold it straight and to reinforce the joint. I'm just concerned that if the frame does move a bit after cutting, whether I'll be
able to slide the rear part of the chassis forward onto the sleeve. This is where I wondered about making a simple jig.
John
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britishtrident
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| posted on 17/12/10 at 08:27 AM |
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Might help if you had a picture of an actual TF chassis and compared to the Rebel/Kitten chassis a Scimitar SS1 would be a better start.
However MG TF replicas never look good when finished they all ways look like collection of parts that don't quite fit ------ even the
Naylor didn't look right.
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steve m
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| posted on 17/12/10 at 08:31 AM |
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The only way of checking is to cut oneside, if it flexs/twists then a jig will ne required
also what about bolting the chassis to the floor ?
Steve
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MikeCapon
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| posted on 17/12/10 at 08:38 AM |
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Rather than a jig why not weld in some temporary braces to avoid twist and lateral movement of the box sections than remove after sleeving. Like this
maybe? Obviously duplicated on the rear section too.....
 
brace
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dhutch
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| posted on 17/12/10 at 08:55 AM |
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quote:
Originally posted by MikeCapon
Rather than a jig why not weld in some temporary braces to avoid twist and lateral movement of the box sections than remove after sleeving.
This is certainly what they do on narrowboats when they lenghten them, even jsut a lenght of 2*2 angle between the rails both sides of the cut would
do a massive amount for you in terms of keeping the spacing right and the sections perpendicular.
Daniel
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John Bonnett
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| posted on 17/12/10 at 09:22 AM |
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Thank you Steve and Mike and Daniel for your helpful replies.
I like the idea of the braces Mike, easy to do and not nearly as much material needed as with the jig, so that's the way I'll go.
John
[Edited on 17/12/10 by John Bonnett]
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nick205
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| posted on 17/12/10 at 09:39 AM |
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Hi John,
Good to see you back on the forum and embarking on a new project. Are you still running the 205 engined trials car you built previously?
As per Mike's siuggestion, some temporary bracing should be sufficient and also efficient in terms of time and materials. Plenty of measureing
and checking required as you go, but perfectly do-able.
Will you be fabricating the body panels in ally again for this build?
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John Bonnett
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| posted on 17/12/10 at 09:54 AM |
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Hi Nick, thank you for the welcome back. Yes, the trials car has been on the road over a year now and covered over 7000 miles. In that time we have
taken two holidays in France in the car, a 2000 mile round trip to the Isle of Skye and competed in three Classic trials with awards in each one so, a
very good year. We are hoping that the Exeter on Jan 5th will not be cancelled because of the weather like the last one was.
I'm planning on building an aluminium body for the Kitten chassis on the lines of the MG Midget TF. It will not be a replica but will keep the
proportions of the MG which I think is a very pretty little car.
cheers
John
[Edited on 17/12/10 by John Bonnett]
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scudderfish
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| posted on 17/12/10 at 09:57 AM |
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Are those rear beams parallel? They don't look it in the photo and if they are not, you won't be able to just stick some extra length in.
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John Bonnett
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| posted on 17/12/10 at 10:17 AM |
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I hope you're wrong about that but until I get the car I've only this photograph to go on.
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PumaWestie
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| posted on 17/12/10 at 11:01 AM |
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They dont look parallel to me either but that could be an optical illusion (hopefully for your sake)
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mookaloid
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| posted on 17/12/10 at 11:41 AM |
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I think I would lengthen it just behind the front suspension turrets then put some cross bracing in between the extension pieces. like this - excuse
the rubbish drawing but I think it shows my idea.
 
Description
"That thing you're thinking - it wont be that."
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John Bonnett
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| posted on 17/12/10 at 12:15 PM |
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mookaloid thank you very much for the thought and trouble you have taken to help me. I'd not thought of lengthening the frame at this point. In
order to keep the proportions in line with the TF it could be critical where the extra length is put in because the position of the bulkhead can
really only go in one place. So an extra 10 inches in the front might make the bonnet too long or conversely, extra length in the passenger bit might
make it too long there. This is starting to get complicated. I'll have to wait until I get the Reliant before I can make any decisions but
thanks to your contributions I'm starting to clarify in my own mind how it must be done.
The great thing that I really appreciate about the people on this forum is that they are never short of original ideas and apply themselves to every
problem thrown up. So thank you.
John
[Edited on 17/12/10 by John Bonnett]
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adithorp
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| posted on 17/12/10 at 01:21 PM |
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Welcome back John. can't wait to see how it turns out.
Do you have any pictures of the trials car? Last ones I saw were about half done and I wondered how it turned out. I had your old Pheonix around at my
workshop the other week. Now owned by FFTS off here but with a K-series engine in it.
adrian
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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John Bonnett
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| posted on 17/12/10 at 03:47 PM |
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Thank you Adrian, good to hear from you. I'm glad that my old Phoenix is still within the forum and that it now has a suitable engine in it. The
Cosworth YB was far too heavy and made what should have been a very nimble car handle like a lorry. I think the K series engine will be ideal and do
hope at that FFTS enjoys it to the full.
I'm really looking forward to doing another body particularly as this one will be along the lines of a traditional British sportscar rather than
the quirky looking trials car. With this body there will be plenty to get my teeth into with the reverse curves on the scuttle, faired in headlights
and beautiful flowing wings. I hope I can do it justice.
Here are a couple of YouTube clips of the trials car crewed by my son and his wife on the October MCC Edinburgh Trial.
http://www.youtube.com/watch?v=X6nEmCs5GJc
http://www.youtube.com/watch?v=X6nEmCs5GJc
I'll certainlt post some pictures of the trials car as soon as I can access the file but at the moment the system is fighting back and getting
the better of me!
[Edited on 17/12/10 by John Bonnett]
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Volvorsport
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| posted on 17/12/10 at 06:58 PM |
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do you want me to have a word with an ex reliant engineer ? he was on the development team- he works in our test house .
www.dbsmotorsport.co.uk
getting dirty under a bus
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John Bonnett
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| posted on 17/12/10 at 07:59 PM |
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quote: do you want me to have a word with an ex reliant engineer ? he was on the development team- he works in our test house .
Thank you very much that would be really good.
As I mentioned this morning, I now realise that I may have to put a bit in the front and a bit in the back (ie either side of the front bulkhead) but
I'll not know until I have the measurements of the Kitten chassis and compare them with the TF. There's not much more I can do until I get
the car.
Thank you for your help
John
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John Bonnett
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| posted on 18/12/10 at 07:32 AM |
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I've found some more pictures of the Kitten chassis which do seem to indicate that the rails are parallel from the bulkhead backwards so looking
promising for shortening in that area.
[img]
 
Reliant Kitten chassis2
[/img]
[img]
 
Reliant Kitten chassis4
[/img]
[Edited on 18/12/10 by John Bonnett]
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