tr8todd
tr8todd Reader
10/19/12 6:34 a.m.

I scored a set of dual weber 32/36 carbs for a TR7 off CL the other day. They look clean except for the throttle shafts and butterflies are stuck. What should I soak them in to free up the shafts so I can disassemble them for a rebuild. The shafts are right at the bottom of the carb, so I figure I can just soak them in an overturned frisbee. Mystery oil, magic elixer? Worried about damaging the brass bushings. I tried spraying them several times with some PB, but that doesn't seem to be working.

jmthunderbirdturbo
jmthunderbirdturbo Reader
10/19/12 6:58 a.m.

dont spray, soak. and if you have access to a ultra sonic, that filled with Pb will have them loose in 10 minutes. also, when soaking in said frisbee in PB oil or Aero Kroil or KREEP, set it in dircet sun, the heat helps.

i dont have any info on the the brass bushings, but i doubt the solvents will harm them as long they are not corrosive.

-J0N

DaveEstey
DaveEstey Dork
10/19/12 8:48 a.m.

I use Marvel Mystery Oil for things like that. In fact I keep a large coffee can with about 2" of the stuff handy for soaking things.

erohslc
erohslc HalfDork
10/19/12 12:34 p.m.

Not hating on anyone, but why is it that 'dual weber 32/36 carbs for a TR7' doesn't sit right?
Are the TR7 motors grossly under-carb'd?
If so, is the optimal solution to add two Weber downdraft carbs?

Curmudgeon
Curmudgeon MegaDork
10/19/12 2:10 p.m.

Just takes time. Shoot the shafts with carb cleaner to loosen the fuel goo, then follow with PB. This might take a day or two. Heat helps, but not big heat; a floodlight placed close for a few hours will be about right.

TeamEvil
TeamEvil Reader
10/19/12 3:39 p.m.

" . . . . but why is it that 'dual weber 32/36 carbs for a TR7' doesn't sit right? "

That would be my first thought as well, until you poke at it a bit, then it all makes great sense.

While not exactly undercarbed, the carbs used on the TR7 were a federalized version and suffered from all things 1975. The carbs were de-tuned Strombergs with an odd fragile water choke set-up, they were piped with an air pump and prehistoric emissions strictures, the worst possible solution for the times, and one reason why a fine engine in the Saab turned into such crap by the time it was finally up and running in the TR7.

The emissions strangled TR7 dual Strombergs had close to 40mm which should have been perfect, on paper, for the TR7 engine. The dual Webers, much MUCH better carbs, have 36 primaries, plus a progressive secondary with a 32. With a correctly tuned exhaust and nice aftermarket or Saab distributor (with a Pertronix module) the little strangled TR7 will truly come alive. NOT a street beast, but much more than what you would expect.

So, the answer, YES, the twin progressive Webers, though not as good as some, is better than most solutions.

BobOfTheFuture
BobOfTheFuture HalfDork
10/19/12 7:05 p.m.

I had the same carb on my MGB. If it worked on that, Im sure it would work on a TR7.

Google around, There are people who sell replacement bushings for the butterfly shaft... Known failure point, Seeing how you gotta tear into it anyhow, Might as well make it right.

Good luck.

Curmudgeon
Curmudgeon MegaDork
10/20/12 7:03 a.m.

A single 32/36 is good for driveability but is not necessarily a good performance setup. There's a fair number of dyno charts floating around which show that twin SU's make as much if not more power on a B motor than the single 32/36. Never seen the twin 32/36 setup for a TR7, I wonder if it's like the 'sink trap' setup for the Z cars?

If so, that 'bend' in the adapter KILLS airflow. That's fine for buzzing around town, but when trying to get as much power as possible it's going to be a hindrance.

tr8todd
tr8todd Reader
10/20/12 8:19 a.m.

That's what they look like. When did this become a discussion on whether or not they work well? I just wanted to know what to soak them in. New kits sell for over a grand. A used set needing rebuilds sold last week on Ebay for $575. I have no intention on installing these things, so I don't care how well they work. I just want to resell them so I will have more money to spend on my TR8s. As far as I'm concerned TR7s are parts cars, V8 swap candidates and or scrap metal, but TR8s are a totally different animal. Why would anyone mess around with a problematic 4cyl when the V8s potentially making 2 to 3 times more power with the almost same fuel efficiency are available?

Curmudgeon
Curmudgeon MegaDork
10/20/12 8:39 a.m.

When did this become a discussion on the relative values of TR7's and TR8's?

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