Hints and Tips - A7 Body Position on Chassis

From: Michael Lunch
Sent: 11 July 1999
To: British-Cars-Pre-war
Subject: Fw: Chummy body positioning on chassis

Further items:
1. How do I decide exactly where the body should sit on the chassis (fore and aft). I have a "spare" crankcase mounted with the real gearbox, but my engine block is away being "sorted out". e.g. What is the distance between the centre rear crankcase stud (which holds down the block) and the front of the bulkhead?

2. The floor pan is an EXACT fit with the gearbox - i.e. a tight fit on either side. This means it WILL be touching the gearbox all the time. Is this a good idea - should I "fettle it" so there is a slight gap - say 1/8" on either side? How? Probably easiest way would be to "hammer over a lip" on the edge of the floor pan using a brass drift so the edge of the floor pan dropped away parallel to the gearbox - pointing downwards.

Many thanks team...
Mike


From: David Cochrane
Sent: 12 July 1999
To: Mike Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning on chassis

> 1. How do I decide exactly where the body should sit on the chassis (fore
> and aft).
>I have a "spare" crankcase mounted with the real gearbox, but my engine
> block is away being "sorted out".
> e.g. What is the distance between the centre rear crankcase stud (which
> holds down the block) and the front of the bulkhead?

I have just measured one, and around 3/8 to 1/2 inch from the centre of that stud would seem to be OK. On my Chummy the block is practically touching the body, and I think on many cars there is a hole in the bulkhead so that you can get at the rear block core plug. If the body is too far forward it will touch the block, if it's too far back you can't get the starter on and off.

> 2. The floor pan is an EXACT fit with the gearbox - i.e. a tight
> fit on either side. This means it WILL be touching the gearbox all
> the time. Is this a good idea - should I "fettle it" so there is a
> slight gap - say 1/8" on either side?

No it is not a good idea for it to be touching, so I would advise fettling.

If it is any consolation, every time I take any bits of the body off my car, it is always a job to get them to fit back on again - you would never think they had been together for 75 years! And the bonnet has never fitted properly.

Good luck,

David C


From: Mike Lunch
Sent: 12 July 1999
To: David Cochrane
cc: british-cars-pre-war
Subject: Re: Chummy body positioning on chassis

Brilliant reply David. This is the stuff that makes this list incredible! Can anyone believe it is possible to get replies like no 1 below - overnight - free.

Thanks!
Mike


From: Guy Weatherall
Sent: 13 July 1999
To: Mike Lunch
cc: british-cars-pre-war; David Cochrane
Subject: RE: Chummy body positioning on chassis

This is OK if you're using a crankcase that is original to the car. There is a later coil crankcase that has the feet mounted further back that moves the whole engine forward. This later crankcase requires the use of the shorter fan spindle. I believe this came in with the 4-speed 'box. Pete Bishop should have chapter and verse on this if you are interested as he has been through it with his rebuild.

Guy


From: Mike Lunch
Sent: 13 July 1999
To: Pete Bishop
cc: British-Cars-Pre-war
Subject: Fw: Chummy body positioning on chassis

Pete, any comments on this!
My chassis is 108,000 (March 1930) my "original" engine is about 111,000 and is a coil unit, the "spare" crankcase I am using is 122,000 - however superficially the two crank cases look the same - and my three speed box sits nicely on back of the spare case - and all looks OK (apart from the fettling stuff!)

Should I now become paranoid that I am using the "wrong spare crank case"???

Mike


From: David Cochrane
Sent: 13 July 1999
To: Mike_Lunch
cc: british-cars-pre-war; Guy Weatherall
Subject: RE: Chummy body positioning on chassis

> This is OK if you're using a crankcase that is original to the car. There
> is a later coil crankcase that has the feet mounted further back that moves
> the whole engine forward.

I warned you that it was all probably all rubbish ! Although I didn't expect to get found out so quickly (Thanks, Guy). My measurements were for a magneto-engined crankcase. Having just measured this, the centre of the hole in the o/s rear mounting foot is 1 1/8 to 1 1/4 inches behind the centre of the centre rear crankcase stud (which holds down the block), so this should help you work out if the crankcase I am measuring is the same as yours, or to calculate the difference if it isn't.

Regards,

David C


From: Pete Bishop
Sent: 13 July 1999
To: Mike Lunch
cc: British-Cars-Pre-war
Subject: Fw: Chummy body positioning on chassis

No, those both sound like the early type crankcases to me. FYI I can just get the throttle control rod between the back of my block and the front of the bulkhead I guess that's a gap of about 1/4 - 3/8 inch. David also took some measurements from his car for me so lets hope his is straight and original!

As Guy suggested I have built my car to take any combination of early and late crankcases and 3 or 4 speed boxes so that I can try all the options in an attempt to beat Guy on trials!

In order to fit the 4 speed box on the early crankcase I had to cut away part of the floor and turn round the front body mountings etc. Again this involved lots of test fittings.

Pete


From: David Cochrane
Sent: 13 July 1999
To: Mike_Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning on chassis
> I can just get the throttle control rod between the back
> of my block and the front of the bulkhead I guess that's a
> gap of about 1/4 - 3/8 inch.

I've just measured the Top Hat and there seems to be 1/2" between the back of the block and the bulkhead, but the bulkhead is nearly touching the starter. The gap on the Chummy is less than that. The Top Hat isn't entirely reliable as a standard as it is a 1950s bitsa.

Regards,

David C


From: Mike Lunch
Sent: 14 July 1999
To: British-Cars-Pre-war
Subject: Chummy body positioning - update

I am climbing up the "fettling" learning curve real fast now! Following all the excellent advice, have successfully bent the clutch pedal lever - actually whilst in car - using blowtorch and stilson as lever - fits perfectly with delightful and elegant slight bend.

Also discovered floor pan fouled handbrake - soon fixed with angle grinder, trimmed a bit off left side where it was intimate with gearbox, and a bit off where the left top mounting bolt for gearbox onto crankcase / clutch housing was a bit tight too. Quick touch up with file and spot of hammerite and "bob's your uncle". All pretty painless really.

I have spotted the "middle position" where there is still room for throttle rod to clear block - and also able to get starter back on - so I reckon I have THE spot. Now dare I DRILL the key holes to locate the tub that will be a start to the rest of the "fettling"? I think so...

Thanks all for the encouragement.
Mike


From: Ian Grace
Sent: 14 July 1999
To: Mike Lunch; British-Cars-Pre-war
Subject: Re: Chummy body positioning - update

Mike,

Why don't all you crazy Austineers sell your Sevens and buy a *real* small car - a vintage Morris Minor. They all had wooden floors, so you just take a hacksaw to the plywood floorboards and screw them back in - problem fixed!

They also have proper semi-eliptic suspension which works - and an overhead cam unleashing an extra horse up front - all within the same track and wheelbase as the seven.

Only joking - I love the Seven too,

Good luck with the rest of the rebuild,

Ian Grace


From: Mike Lunch
Sent: 14 July 1999
To: Ian Grace; British-Cars-Pre-war
Subject: Re: Chummy body positioning - update

Come on Ian, next you'll be claiming that it steers straight and stops too!!!!!

Mike


From: Pete Bishop
Sent: 15 July 1999
To: Mike Lunch
cc: British-Cars-Pre-war
Subject: Re: Chummy body positioning - update

Mike Lunch wrote:

>Now dare I DRILL the key holes to locate the tub that will be
> a start to the rest of the "fettling"? I think so...
>

Mike, just one more thought on body position. Have you had a look at the flitch panel / rad shell & bonnet fit? This was probably the area that caused me most grief. The position of the top of the rad shell is determined by the fixed length of the bonnet hinge tie rod, so moving the tub backwards and forwards can result in the rad shell not being vertical. As it moves out of parallel with the front edge of the tub bulkhead, so the fit of the bonnet changes. Unfortunately on my car the position that was good for engine location was not so good for bonnet fit, so I ended up making my own bonnet to fit the space available (the one I just damaged trying to fix the center hinge in place!) You might want to check this out before you "fix" the tub position. The bonnet fit is a lot more visible than a 1/4 inch difference in the gap between the engine block and the bulkhead. So you might want to compromise the engine/bulkhead position slightly to save having to fettle the bonnet fit.

My current problems are with windscreen fit. Having got my frame back from the nickel platers the scuttle seems to have mysteriously grown about 1/4 inch in width so the piece of glass I have had cut and polished almost falls through the frame when it is bolted to the car. I suspect that the ash frame has crept slightly, it was all new wood. So it seems that despite putting everything together first there is no guarantee things will still fit after everything is painted!.

Don't let me depress you though, its very rewarding bolting all the shiny pieces together! I have gone for using wing beading. The panel gaps although small vary considerably down the length of he car giving a rather untidy appearance. The beading gives a much neater look.

Pete


From: Mike Lunch
Sent: 15 July 1999
To: Pete Bishop
cc: British-Cars-Pre-war
Subject: Re: Chummy body positioning - update

>Mike, just one more thought on body position. Have you had a
>look at the flitch panel / rad shell & bonnet fit?
>You might want to check this out before you "fix" the tub
>position. The bonnet fit is a lot more visible than a 1/4
>inch difference in the gap between the engine block and the
>bulkhead. So you might want to compromise the
>engine/bulkhead position slightly to save having to fettle
>the bonnet fit.

Very good thought - will do that - bonnet is at hand and easy to mock up before i power up that drill! Tell me, where - exactly (!) should the "underbody" reach on the rad cowl - obviously it has to go as far as the holes that scure the cowl. Should the under body line up with the bonnet edge?

>My current problems are with windscreen fit. Having got my
>frame back from the nickel platers the scuttle seems to have
>mysteriously grown about 1/4 inch in width so the piece of
>glass I have had cut and polished almost falls through the
>frame when it is bolted to the car. I suspect that the ash
>frame has crept slightly, it was all new wood.

Mine has a steel dash panel which holds the scuttle rigid. Only Ash in my tub is around top edge behind doors - and back. And of course in the dorr frames too.

>So it seems that despite putting everything together first
>there is no guarantee things will still fit after everything
>is painted!.

Oh heck!

>
>Don't let me depress you though, its very rewarding bolting
>all the shiny pieces together! I have gone for using wing
>beading. The panel gaps although small vary considerably
>down the length of he car giving a rather untidy appearance.
>The beading gives a much neater look.

I am also planning to use wing beading - how small did you manage to get your gaps? Did you have to use filler (shh - I wont tell!)

Mike


From: Pete Bishop
Sent: 16 July 1999
To: Mike Lunch
cc: British-Cars-Pre-war
Subject: Re: Chummy body positioning - update

Mike Lunch wrote:
>
>
> Tell me, where - exactly (!) should the "underbody" reach on the rad cowl - obviously it has to go as far as the holes that secure the cowl. Should the
> under body line up with the bonnet edge?

The position on mine was determined by the turned over lip along the top edge of the flitch panel. This sat exactly against the flange around the back edge of the rad cowl that takes the bonnet rubber. You can move the bottom of the rad cowl backwards and forwards but that does effect how much the engine nose piece projects through the cowl. I took all my measurements off Guys car with the addition of a few of David's figures so I now have sort of average!

Another fun fit area on my car was the clearance between the bottom back corner of the bonnet sides (when closed) and the front wings - have you had a look at that on yours yet? Are your flitch panels new as well as the wings?

> >Only Ash in my tub is around top edge behind doors - and back. And of course in the door frames too.

Mine has an ash frame that runs up in front of the doors and in an arch under the scuttle behind the dashboard. The wood defines the curvature of the scuttle (and windscreen frame) as without it the alloy panel edge that the dashboard hooks over can be moved up and down 1/4 -1/2 inch

> I am also planning to use wing beading - how small did you manage to get your gaps?
> Did you have to use filler (shh - I wont tell!)

The body and the panels do ultimately touch all along the car so the gap is really zero. The problem is the "corner" on the body tub is not a sharp right angle but a varying radius curve where I have been fettling, so there is not a neat line where panels join tub. As regards filler, amazingly for something I have worked on, the tub has almost none! just a little on the sills where the shape was wrong and very little on the scuttle where I had dented it dropping tools etc on it. I used a high build two pack primer which did an excellent job of covering minor blemishes .

The front edges of the front wings took a bit of work, where the shape was wrong and the bonnet..... well that's another story, I think I will be challenging for the heaviest and thickest A7 bonnet! - but its all my own work. (I don't think I will get that panel beaters job just yet)

Pete


From: David Cochrane
Sent: 20 July 1999
To: Mike_Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning

Mike Lunch wrote:
> Tell me, where - exactly (!) should the "underbody" reach on the rad cowl - obviously it has to go as far as the holes that scure the cowl. Should the
> under body line up with the bonnet edge?

Mine overlaps by about 1.25". there has been some discussion at our local A7 club as to whether the rad shell fits inside or outside the flitch plates. Both cars in my garage have it inside, but some people's seem to fit better with it outside. From a mechanical point of view I think it's better inside.

Regards,

David C.


From: Pete Bishop
Sent: 22 July 1999
To: Mike_Lunch
cc: David Cochrane; Guy Weatherall; Hugh Barnes
Subject: Re: Chummy body positioning

Mike, Following the the discussion on this I thought you might like to see what I am up to! The attached pictures were taken about 2 months ago before I stripped the whole car down to start the painting process. It gives you some idea of the panel fits I achieved. I fitted the flitch panels outside the rad shell as the majority of cars/pictures I had seen were done that way, including Guy's which has been my main reference

A7 Chummy Front

A7 Chummy Bonnet

A7 Chummy Back


From:Mike Lunch
Sent: 22 July 1999
To: Pete Bishop
cc: David Cochrane; Guy Weatherall; Hugh Barnes
Subject: Re: Chummy body positioning

Pete Loved it! I wondered what the huge 2meg file was that downloaded - just great. I will scan in some of my pics and mail them back. I can see you are well ahead of me - all that lovely primer and smart ali.

I managed to find a position that the bonnet, rad and scuttle were all pretty happy, and have now FIXED the tub! Imagine my surprise when I drilled through the centre of the two brackets either side of gearbox (from below), to discover that my holes came out right in the middle of the brackets on top! What a shock! Anyway, with the tub fixed, everything else has to be fitted with it!

Now that I have worked out that the "flitch plates" are those steel bits that stick out as part of the tub and floor, and sit below the bonnet - things are becoming clearer.

I mocked up the rad cowl and bonnet and discovered that the flitch plate is about 1/2 higher on one side than the other! What is the solution - add 1/2" to one side of bonnet - or raise the flitch plate 1/2"??? Is this the kind of trouble you had?

I am also having to cut the lower portion of the front wings to get them to sit nicely along edge of tub at running board level....

Mike PS Meantime, just for the record - I am looking forward to fitting "Davids silencer", and "Howard's radiator"


From: Pete Bishop
Sent: 23 July 1999
To: Mike Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning

Mike, I had exactly this problem, but only about 1/4" difference As I made the bonnet sides anyway I just made one longer than the other. The longer one is very tight fitting onto the cap between the bottom corner of the tub bulkhead and the back corner of the front wing. I have just yesterday fitted new bonnet catches (not shown in the pics) I screwed the base of these to the front wings rather than the flitch panels as they were originally I think. This seemed to pull the bonnet bottom edge done closer over the flitch panels.

Sorry about the size of the picture files - Guy has explained a way of compressing them to JPEG format so I will do that if I send any more.

Pete


From: David Cochrane
Sent: 23 July 1999
To: Mike_Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning

Pete,
Thanks for the pics
> I wondered what the huge 2meg file was that downloaded - just great.

So did I.

Mike,
> I managed to find a position that the bonnet, rad and scuttle were all
> pretty happy, and have now FIXED the tub!
> Imagine my surprise when I drilled through the centre of the two brackets
> either side of gearbox (from below), to discover that my holes came out
> right in the middle of the brackets on top!

A-M-A-Z-I-N-G !!

> I mocked up the rad cowl and bonnet and discovered that the flitch plate is
> about 1/2 higher on one side than the other! What is the solution - add 1/2"
> to one side of bonnet - or raise the flitch plate 1/2"??

Is it 1/2" higher all the way along (which suggests that the body tub is distorted) or just at the front? If the latter, you should be able to fiddle how it is attached to the cow horn to slide the front down. It will also affect how the front wing is fitted. Are you sure it is one side being too high rather than the other side being too low (or maybe a bit of both)? The cow horns should be identical (mirror images of course) so should be good reference points. I have measured a couple of cars, and the top of the flitch plate is 5/8" above the tip of the cow horn.

Hope this helps.

David C


From: Mike Lunch
Sent: 26 July 1999
To: Pete Bishop
Subject: Re: Chummy body positioning

Status tonight:
Off side front wing fitted (needed a bit cut out of back edge to fit body tub) cowl also now fitted - still with some bonnet troubles... All looks terrific!

Mike

In response to Pete's note:

>Mike, I had exactly this problem, but only about 1/4"
>difference

Now that I have looked at it much harder, I find that they are pretty well equal, the problem is that one side of the bonnet seems deeper that the other..

>As I made the bonnet sides anyway I just made one longer
>than the other. The longer one is very tight fitting onto
>the cap between the bottom corner of the tub bulkhead and
>the back corner of the front wing.

THIS is the problem I now have - on one side there is a gap between lower edge of bonnet and flitch plate, on the other side it overlaps, particularly at the back corner. I think the only solution will be to trim the bottom edge of bonnet there!

>I have just yesterday fitted new bonnet catches (not shown
>in the pics) I screwed the base of these to the front wings
>rather than the flitch panels as they were originally I
>think. This seemed to pull the bonnet bottom edge done
>closer over the flitch panels.

Mine were fitted to the wings anyway - not flitch plates - so I suspect that is where they are meant to be!

>
>Sorry about the size of the picture files - Guy has
>explained a way of compressing them to JPEG format so I will
>do that if I send any more.

Yup, JPEG is the answer - about 1/10 the size of BMP files!


From: David Cochrane
Sent: 26 July 1999
To: Mike Lunch
cc: british-cars-pre-war
Subject: Re: Chummy body positioning

> >I have just yesterday fitted new bonnet catches (not shown
> >in the pics) I screwed the base of these to the front wings
> >rather than the flitch panels as they were originally I
> >think. This seemed to pull the bonnet bottom edge done
> >closer over the flitch panels.
>
> Mine were fitted to the wings anyway - not flitch plates - so I suspect that
> is where they are meant to be!

No, they should be on the flitch plates. Not that it makes much difference, it's just easier to clean the wings if the catches aren't in the way.

Regards,

David C.


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