Wedge SU on TR7 Float Level Engine Angle

[Alabama_Hokies]

Got the SU's mounted to the car (replacing the Strombergs) and they.

Now for tuning. I wanted set the float level. Appears to be two methods.
1-The measurement of the float with the bowl lid upside down. For that they are both nearly identical. Higher than the 1/8 or so but the same.

2- The other method, wicked I think is more accurate, is the fuel level relative to the bridge. They are WAY off. The front carb appears about right just below the bridge (not measured yet) and the rear appears to be about 3/8 or more below the bridge.The amount they are off is equal to the tilt angle of the engine. If I crank the rear end three feet in the air... perfect.

BTW- No tabs and both needle valves are at the top with no shims.

Anyone have experience with SU's with external bowls on tilted engines?

Thanks,

Dave B

 

[Marvin Gruber]

Dave
Are the fuel bowls tilted? The carbs can be tilted but not the bowls. Bowls must be sitting level, if not the engine will never run very good.

Marv

 

[Alabama_Hokies]

The answer is sort of both. The bowls are not exactly vertical. Not exactly sure how to explain and cannot post pictures until tonight.
The engine itself is tilted. The front is higher than the rear. The bowls follow that same tilt.
The body of the carbs and the bowls are not tilted in the other plane. That is the other surface of the carb (where the filter attaches) is vertical and so are the bowls in that plane.

Make sense?

 

[waltesefalcon]

How many degrees is the front of the engine raised? I am not the most experienced guy with SUs on here but I do believe that having the carbs on a tilt like that could cause problems with the floats.

 

[Alabama_Hokies]

Engine angle (tilt) is probably between 6 and 10 degrees. As I said, to get the carbs level the rear end has to be elevated about 3ft.
If the bowls were built in, like strombergs this would not be an issue. But the bowl on the front carb is forward and the aft carb bowl is aft.
So with the front carb bowl being higher, the fuel is higher in the carb, with the aft carb bowl being lower, the fuel level is lower in the rear carb. I can't find anything that speaks to this in the tech manuals etc or anywhere else on the web.

Does seem to be an issue to me. But would love to get some advice on how to address.

 

[waltesefalcon]

Put big wheels in the back. Seriously though I might consider filing the mounting bolt holes enough that you could rotate the carbs the six to ten degrees towards the front that it would take to make them level. Its a pretty low tech solution but one that should be effective.

 

[Alabama_Hokies]

Interesting thought. The filing not the big wheels. Although, I am in Alabama so a lift kit and gun rack... never mind.

I already fad to file the linkage to make these carbs fit. I really hope there is another solution as that does seem a little radical and I can't believe they did that to all the TR7's with SUs (Cars not exported to the USA.)

Thanks,

 

[waltesefalcon]

The big problem with my solution would be that by making them level to the ground they will no longer be perfectly inline with each other, meaning you'd have to fab a new linkage to make them work in sync.

 

[Alabama_Hokies]

My first thought was that they would be ok because the linkage would rotate with the angle change. But unfortunately the linkage is of course mounted to the manifold so the linkage mounting would have to rotate as well. Yea, starting to create a bunch of work. That can't be right...

 

[waltesefalcon]

Its been awhile since I worked on a 7 but I don't seem to remember the front of the engine being higher than the rear. Could you say be missing the rubber between the transmission and its rear mount?

 

[Alabama_Hokies]

All the mounts (engine and transmission) are intact and new.