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Posted: Wed Jan 30, 2008 9:31 pm
by M_Temple
That didn't seem to work so I'll try again - think I missed the last bit of the URL

this is another view of the engine as was

Below are some pics of its friend in the same barn for 25 years before and after (getting carried away now.....)


It's a '62 948cc, but with no V5 I had to get it re-registered on a new plate. I am planning to change the grille surround back to Rose Taupe and transfer the OEW one onto the '69 which is being done in Snowberry White.
Anyway back to the servo - I hope you can see what I was suggesting - that I use the connection on the inlet manifold that goes into the base of the 'top hat' thingy in the first two pictures with a tee-piece - vertically into the 'top-hat' as now, with a side branch for the servo pipe.
Also anyone any idea why the pics come out in different sizes - they all came from the same camera and file system on my computer?
top hat
Posted: Thu Jan 31, 2008 5:01 pm
by Willie
I can see the pipe entering the top hat in your pic but cannot see a pipe
exiting it on the other side? It should exit into an inlet on the carb(which you say you do not have) OR,rarely,into the inlet manifold itself. If neither of these connections are there then you have the wrong carb for that particular car. If that is the case you could use the rocker cover in your second pic with a pipe into the AIR FILTER, a solid oil filler cap,
throw away the top hat assembly, and use the now vacant hole for the servo connection, or plug it and have a new hole tapped for the servo.
If not then you must obtain the correct type of SU carb for that engine.
Posted: Thu Jan 31, 2008 5:40 pm
by M_Temple
There is a short (~50mm long) pipe from the inlet manifold into the base of the 'top hat', just visible in pic 2 above, and visible in pic 1 if you can get it big enough! There is then a connection (~ 200mm long) from the side of the top hat and into the top of the dashpot connected into the front crankcase side plate - this pipe is the one most visible in the photos. Sound like I have one of the 'rare' configurations.......
Hope this clarifies what I've got! I'm going to make a tee piece from the inlet manifold into the base of the top hat to replace the 50mm pipe, but with a side connection onto which I'll plumb the servo.
Posted: Thu Jan 31, 2008 5:43 pm
by bmcecosse
It does look ike it goes into the inlet manifold - so throw away the top-hat, use the connectin in the manifold for the servo (if you really think you NEED a servo) - and then connect the pipe from the side vent 'chimney' to the inlet hole on the filter casing. If you find it is oiling up the filter, then it is possible to make a new hole in the filter mounting plate and put the pipe in there. This draws the oil fume directly into the carb and not through the filter.
Posted: Thu Jan 31, 2008 6:33 pm
by Packedup
The top hat is a valve that sits on the inlet and hooks up to the breather. It's sprung inside, so you don't suck all the oil out the sump and dump it into the cylinders when the vacuum is too high.
It's expensive to maintain, over complicated and generally naff IMO. It was fitted to early Midgets, and I'm fairly sure the reason it wasn't on later ones was more down to complexity and fragility than cost...
So the simple answer is to hook up the breather system in a more conventional way, and use the connection on the inlet manifold for the servo. No need to start trying to mess with T pieces, just a nice straightforward valveless breather and straight to inlet servo would do absolutely fine

Posted: Thu Jan 31, 2008 7:31 pm
by bmcecosse
I see where some of the confusion arrives - you are calling the breather filter canister on the side of the engine a 'dashpot' - which it is not! The dashpot is the bell shaped top part of the SU carb.