Expansion tank question

[krispy]

Hi people,
A quick question for you S owners out there. I'm trying to source a coolant expansion tank for my 1600M and am having major problems as all the usual stockists for M-bits are completely out. I've just spoken to Adrian Venn, however, who reckons that it's the same tank that is fitted to the S-series cars, in which case I can get it from the factory. Does this look familiar to any of you??



Any help gratefully appreciated,
Kris..
'75 1600M

>>> Edited by krispy on Monday 27th January 15:00

[krispy]

Cheers Dern, I went looking for some S engin-bay pix but didn't manage to dig any up. Thanks a lot for that.
Kris..

[krispy]

Psychobert said: Yup, just popped the bonnet and it looks the same as my S3C..

Except mine is full of a brown sludge.. Must look at that sometime..

>> Edited by Psychobert on Monday 27th January 15:11

tech tip: Brown sludge = not good

[krispy]

bigtone said:

Does this look familiar to any of you??

Erm, yep!

Still having problems getting hold of them Kris?

Tony

Indeed I am. It appears that you probably had the last one off the shelf at Moss! They don't have any left in stock and their ETA for more is, and I quote, '2005'. O joy. Nobody else claims to have anything like it in stock but I spoke to Adrian and he suggested that it was also an S part......which it appears to be. He contacted the factory and they've got some in, so fingers crossed I'll have one by the weekend .

What are you doing reading the S list anyway??

Kris..

[krispy]

dern said:

Given that it appears to serve no useful purpose, makes the engine bay scruffy and makes potential buyers wonder why there's so much sh*t in the cooling system I may well bin mine. Krispy, how much are these things worth

A very good point. In fact, getting rid of the thing would, in my case, free up a substantial amount of space on the bulkhead and allow me to relocate my oil catch tank somewhere nice and accessible (and high-up like it's supposed to be). Why did they fit them in the first place though? Easy reading of the coolant level sounds logical, but then the majority of M-series and earlier cars had brass tanks...not reknowned for their transparency.

Kris..

[krispy]

Paceracing said: It makes no sense having the pressure cap on the 'expansion' tank whatsoever, because for the pressure cap to work, the pressure below the seal or flange on the cap has to be greater than the pressure above it for it to vent excess pressure. The fitted 'expansion' tank has no lip for the cap flange seal to compress against, there for the pressure below the seal / flange is the same as above it. With the pressure in equilibrium, the cap will not vent! Simple really!!

Jas.

This makes perfect sense to me. My 1600M doesn't appear to have a pressurised cooling system however - the coolant reservoir is sealed with a plug and the expansion tank has a normal cap and an overflow pipe heading down to the ground. No other M-series variant ever had this arrangement and it appears that all subsequent TVRs, such as the S, have something slightly more conventional as well. I am somewhat perplexed.

kris..