Tee Dee 0.020 Carb Body at an angle - is it normal?

steveod21 Fri Mar 15, 2019 8:10 pm

Hi Everybody

Could I ask for some help regarding a Tee Dee .020?

When replacing a cracked red plastic throttle body, I noticed that the crankshaft window in the crankcase appears to be machined at an angle, so that the carb body,
and venturi, leans to the right looking from the front.

Has anyone seen this before? Is it normal that some engines are like this?

Tee Dee 0.020 Carb Body at an angle - is it normal? P1030310

JennyC6 Fri Mar 15, 2019 8:40 pm

LArger engines with the carb mounting boss cast integral to the crankcase don't have that, but I can't imagine it'd affect anything here. The induction timing is set by the position of the port in the crank relative to the crankpin, so as long as the A/F mix can make it from the venturi to the crankshaft when the port in the crankshaft is facing upwards it should run just fine.

I can't imagine there's a way for that port to 'walk', so if it was running fine before the old retention ring cracked itt'l run fine with the new one.

aspeed Fri Mar 15, 2019 8:59 pm

I would say the machinist was in a hurry and didn't put the case on the fixture straight. It will affect the opening and closing of the intake timing. It looks like less than 2 degrees, so no big deal. At most it will like a bigger prop.

steveod21 Sat Mar 16, 2019 5:21 am

Thank you for your help. I was surprised to see this and thought 'well it must be right as Cox engines are so well made'!
You would think that quality control would have picked this up and scrapped the part!
I haven't run it yet but will keep the forum informed.

Many thanks once again.
Steve

gkamysz Sat Mar 16, 2019 8:53 am

steveod21 wrote:Thank you for your help. I was surprised to see this and thought 'well it must be right as Cox engines are so well made'!
You would think that quality control would have picked this up and scrapped the part!

The only parts that were held really tight are the piston to cylinder fit. The rest has general machining tolerances, which of the era weren't great compared to what we see now. Very likely there was no machinist involved in the part above as things were highly automated. Without today's automated inspection, spotting defects like this would be near impossible.

It's definitely more than 2°, 6-7° but still not enough to matter, much.

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Tee Dee 0.020 Carb Body at an angle - is it normal?

Tee Dee 0.020 Carb Body at an angle - is it normal?

Re: Tee Dee 0.020 Carb Body at an angle - is it normal?

Re: Tee Dee 0.020 Carb Body at an angle - is it normal?

Re: Tee Dee 0.020 Carb Body at an angle - is it normal?

Re: Tee Dee 0.020 Carb Body at an angle - is it normal?

Re: Tee Dee 0.020 Carb Body at an angle - is it normal?