TR6 TR6 Crankcase breather/carb replacement questions.

[SpannerMan]

I have 1 3/4" SU H6's on my TR6- I bought these in a collection of parts I picked up a while back. I believe they were from one of the earlier TR's (TR3 or 3A). I have been happy with the way the car runs on these- the main issues being though that the floatbowls are tilted over to offset the manifold tilt on the earlier cars, and the marginal hood clearance on the front dashpot. The guy I bought them from swore by using them on his 6's - he may have rejetted/needled them, I am not sure. I seem to have stopped them from leaking too!... - the O-ring replacements for the cork jet seals seem to work well. I never could get the Strombergs tuned properly - I am not suggesting that they offer an advantage over Strombergs that are in good shape.

I have been using air cleaners for a Volvo Amazon 122 - they had the same size SU's. On those cars, the front filter has a snorkel tube for the crankcase breather pipe, and I have been running the pipe from the valve cover through a flame trap to that tube (recall that on the stock Strombergs there are ports on the carbs for the breather). Well, the aircleaners are ready for a change but I can't find those air cleaners this time- at the time I bought them they were a Beck/Arnley part for about $20 the pair but now all that is out there is Volvo NOS for $80 or so- too much for a pair of paper air filters in my book... I am looking for suggestions and advice on what to do to either (a) source similar air filters (b) modify/fabricate possibly by trying to put new elements in what I have or - or add the tube to new air filters (c) do something else with the crankcase breather. I really don't want to just put a long hose on it and send it down to the road though. I could take post a pic of the current setup if it would help anyone.

According to the ads, this comes up with other carb replacement options (e.g. Webers) but I am not clear what people end up doing. Appreciate any and all advice/suggestions!! Thanks a lot, Pete

 

[71tr]

Re: TR6 Crankcase breather/carb replacement questi

spannerman,
I'm also replacing my ailing ZS carbs with rebuilt SU H6's. As for air filter options there are actually quite a few. K&N makes some very nice setups, 1+3/4" up to 3" deep round filters or conical shaped filters for each carb. Piper Cross (a european firm I believe) makes some interesting single and dual filter options as well. I guess I'm just trying to find something different from the old sixes filter box.

 

[gbtr6]

Hi, I also have twin SU HS-6's on my TR. They are a whole lot easier to tune and I think offer great performance. As for the float bowls tilted, I took mine off and there is a spacer with a wedge section on it as I recall. If you turn that around, it will allow the float bowl to rotate to a more level position. It's been a while since I've don ethis, but if you pull the bowl off I think you'll see what I mean. As for filters, I still run the stock setup, but I have an early 6 housing with the little tubes in front and I attached 2 lenghths of aluminized hose to them, with screens over them for bugs and stuff, and routed them to the grill for better/cooler air intake. I then put a T fitting in a hole I drilled in between the carbs on the back of the filter housing and attached the breather there. A small filter helps with oil pickup. Perry

 

[SpannerMan]

Re: TR6 Crankcase breather/carb replacement questi

Hi there - Are you aware of any of those replacement filters having the breather pipe attachment? That is what I was hoping to find.

I know the TR4A had filters that had ports in the middles of the fronts. If those work with the SU carb, that would be an option for what I am looking for. There again they are a little pricey for a disposable filter though ($25-30 ea. if memory serves). I believe I have the 'splitter' fitting that was used with these, in my parts collection. Thanks, Pete

[ QUOTE ]
spannerman,
I'm also replacing my ailing ZS carbs with rebuilt SU H6's. As for air filter options there are actually quite a few. K&N makes some very nice setups, 1+3/4" up to 3" deep round filters or conical shaped filters for each carb. Piper Cross (a european firm I believe) makes some interesting single and dual filter options as well. I guess I'm just trying to find something different from the old sixes filter box.

[/ QUOTE ]

 

[SpannerMan]

[ QUOTE ]
Hi, I also have twin SU HS-6's on my TR. They are a whole lot easier to tune and I think offer great performance. As for the float bowls tilted, I took mine off and there is a spacer with a wedge section on it as I recall. If you turn that around, it will allow the float bowl to rotate to a more level position. It's been a while since I've don ethis, but if you pull the bowl off I think you'll see what I mean. [ QUOTE ]


Hi there- I actually have the earlier H6 carbs where the fuel flows through the cast float bowl arm. That arm has the twist built right into it to make the floatbowls level when you have the tilted manifold.

[ QUOTE ]

As for filters, I still run the stock setup, but I have an early 6 housing with the little tubes in front and I attached 2 lenghths of aluminized hose to them, with screens over them for bugs and stuff, and routed them to the grill for better/cooler air intake. I then put a T fitting in a hole I drilled in between the carbs on the back of the filter housing and attached the breather there. A small filter helps with oil pickup. Perry

[/ QUOTE ]

Interesting - I didn't know the old ZS setup would fit. Thanks for the info! Pete

 

[Andy Blackley]

Re: TR6 Crankcase breather/carb replacement questi

Pete: Those old HS-6 carbs do not have any provision for crankcase ventilation like the later ZS setup used from '70 onwards, i.e. a line from the valve cover to ports on the back side of the carb body. I would retro fit the PCV setup used on the TR250 and 69 TR6 with the carbs you have now. Refer to the Emission Control page in the Moss catalog.
BTW just connecting the valve cover directly to the air cleaners will not provide the positive crankcase ventlation that the engine needs. Some sort of PCV is needed. I like the old fashioned Smiths "mushroom" PCV valve. It works very well as long as the rubber diaphram inside is not torn. All you need to do is plumb the valve to the large port on the intake manifold, and run a fresh air hose (no.9 in the Moss catalog) to the stock air box. On my car the PCV is threaded directly into the manifold, but on the earlier TR4/4A is uses a hose betwen the valve and manifold (I think).

 

[SpannerMan]

Re: TR6 Crankcase breather/carb replacement questi

[ QUOTE ]
Pete: Those old HS-6 carbs do not have any provision for crankcase ventilation like the later ZS setup used from '70 onwards, i.e. a line from the valve cover to ports on the back side of the carb body. I would retro fit the PCV setup used on the TR250 and 69 TR6 with the carbs you have now. Refer to the Emission Control page in the Moss catalog.
BTW just connecting the valve cover directly to the air cleaners will not provide the positive crankcase ventlation that the engine needs. Some sort of PCV is needed. I like the old fashioned Smiths "mushroom" PCV valve. It works very well as long as the rubber diaphram inside is not torn. All you need to do is plumb the valve to the large port on the intake manifold, and run a fresh air hose (no.9 in the Moss catalog) to the stock air box. On my car the PCV is threaded directly into the manifold, but on the earlier TR4/4A is uses a hose betwen the valve and manifold (I think).

[/ QUOTE ]

Andy, Thanks for your reply. I have been traveling for a few days and away from email. I started looking at the possibility of back-fitting the PCV system, as well as trying to work out how the various types work. There do seem to be two distinct types on the TR4/A and the 250/early 6. The TR4/4A has the PCV between the valve cover and the manifold port. The TR250/early 6 has the PCV threaded into the manifold, and a hose connecting to the PCV is teed into a hose that runs between the back of the aircleaner and the valvecover.

Anyway, it turns out that a previous owner has blanked off the manifold port (welded). I do have a spare manifold of the same type which probably isn't blanked like that, but I don't really want to start on something that major at this point.

I will do a little bit more reading and think about what I can do with what I have. Always open to suggestions... Thanks again, Pete

 

[SpannerMan]

Re: TR6 Crankcase breather/carb replacement questi

Wanted to followup and let you all know what I ended up doing. I bought 2 inexpensive replacement paper airfilters (Indian made), and ported them using some pipe fittings from the hardware store. I am shooting the crankcase vent into the front side, like the TR4 setup. I'm attaching a pic of what I have- nothing fancy... Anyway the car seemed a lot happier with a fresh set of filters- it was definitely time. I am thinking about exploring PCV options some time. The grey piece in the line is just a gauze flametrap.
Thanks again for all the insights. All input welcome! Pete

 

[SpannerMan]

Re: TR6 Crankcase breather/carb replacement questi

'nother pic.

 

[SpannerMan]

Re: TR6 Crankcase breather/carb replacement questi

Oops!