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sam christie
United Kingdom
3051 Posts |
 Posted - 11/02/2016 : 21:35:04
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Terry, what I call "the J1 pattern" became standard issue on later J2's according to the J parts list. As I recall, this happened after J1 production stopped at almost exactly 600 chassis numbers before J2 production ended. (Would anyone care to cross check this?)
It looks as though the factory also used up about 600 J1 exhaust systems on the J2 at the same time. Since "the complex pattern"undertray was probably only needed to allow the Burgess silencer forward to clear the J1 rear footwells it was not needed on a two seater. I guess this was done simply to use up an existing overstock of 600 J1 undertrays.
Why do you state that the later J2 one had been fitted to J1's ? - I am simply going by the part numbers. The parts list is little confusing for not directly stating that '1965' was the J1 part number but it says '1965' commenced on 2-seater at chassis J3581 (already standard on the J1).
Part number 1176 was common to the D-type and the plain type.
Sam |
Edited by - sam christie on 11/02/2016 21:40:42 |
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Simon Johnston
United Kingdom
5983 Posts |
Posted - 11/02/2016 : 22:21:39
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Terry,
I guess having the joint a few inches higher may have made it less exposed to muck and road detritus which I suppose is why it was added for the P Type. And if it makes the seal easier to fit, then that's another bonus.
I'd certainly agree with Sam's interpretation of the Parts Lists: basically the J2 never seemed to have its own 'unique' undertray. It either had one the same as the D Type and then when the J1 was discontinued, the J1 undertray was used, presumably to use up stocks.
Simon J
J3437 |
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sam christie
United Kingdom
3051 Posts |
Posted - 11/02/2016 : 22:45:42
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This might also help - note the amazingly long silencer illustrated for the P-type but still clear of potential rear footwells.
The D-type is illustrated with a very different silencer which encroaches on neither the undertray nor the rear footwells.
Sam |
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tholden
United Kingdom
1624 Posts |
Posted - 12/02/2016 : 08:55:13
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Hi Sam/Simon
Afraid I cannot believe that MG were using up large stocks of unused parts. From what I was told by people who worked at the factory at that time there was usually an under supply rather than over supply of parts which were always ordered up in small batches. Also parts lists written well after the event have often been shown to have questionable accuracy.
I think it much more likely from what I have actually seen on cars over many years and from comments read in works files that they changed the layout of the exhaust and the design of the undertray to deal with problems that were occurring with the early J2 exhaust layout.
I have been involved with the three particular J1's over the years all of which I either stripped or helped to strip/rebuild. None of them had the late type J2 undertray although I know one of them does now because I made it for the owner. I have also owned, stripped, rebuilt,inspected and judged quite a few very original J2.s over a 55 year period and know what I have actually seen fitted to these cars.
So not sure if making assumptions from parts lists, or oiling charts or guessing what might have happened in the factory is the answer. What I would say is that it does not matter that much. If it fits, looks right and does the job intended then fit whichever one you like, or believe is correct - not many people are going to crawl underneath to check it !
TH |
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sam christie
United Kingdom
3051 Posts |
Posted - 12/02/2016 : 09:01:38
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It is of course possible all the oiling charts and parts lists are wrong and MG used the same part numbers for different parts.
Sam |
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tholden
United Kingdom
1624 Posts |
Posted - 12/02/2016 : 09:07:09
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Quite. Not necessarily wrong but not always accurately reflecting what was done on the cars.
TH |
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John Mee
United Kingdom
209 Posts |
Posted - 13/02/2016 : 18:03:20
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My F1 had its original, but very battered under tray fitted when I bought it in 1970.It has up stands at each end with felt seals riveted to the flange to fit around the bell housing , the rear up stand flange was fixed with screws to the floor boards, the silencer is fitted behind the under tray with a steel heat shield screwed to the floor boards, It had a bulge spot welded on to allow for the brake adjustment wing nut, it can be clearly seen in the original instruction manual for the F. Chris will know all these details, and I realise the J is different but as far as I know the F silencer was always behind the tray, it certainly makes everything easier to fit
John Mee |
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John Mee
United Kingdom
209 Posts |
Posted - 13/02/2016 : 18:37:06
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The F under tray
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