Finding top dead center with Rajo B head

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jmemjr
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Joined: Mon Jan 07, 2019 4:17 pm
First Name: John
Last Name: Memmelaar
* REQUIRED* Type and Year of Model Ts owned: 1912, 1914, 1915
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Finding top dead center with Rajo B head

Post by jmemjr » Fri Apr 30, 2021 8:59 pm

I had to replace the fiber timing gear on my Rajo head engine. It is equipped with a distributor. I have to find TDC to re time it. I want to make sure I got it right.

https://youtu.be/ivtvlMwcIAI

BTW the timing gear was replaced with a metal one and the fiber one came with the engine and head and I knew it was going to fail at some point.


tman1913
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* REQUIRED* Type and Year of Model Ts owned: 1913 Canadian touring, 1924 Roadster, 1926 Mercury speedster, 1927 Roadster p/u, 1920’s bobtail dirt track racer
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MTFCA Number: 21160

Re: Finding top dead center with Rajo B head

Post by tman1913 » Fri Apr 30, 2021 9:48 pm

Dial indicator in the spark plug hole for absolute. The crank shaft pulley horizontally will get you very close
IMG_3231.jpg


tman1913
Posts: 52
Joined: Sun Jan 06, 2019 12:30 pm
First Name: Mike
Last Name: Bender
* REQUIRED* Type and Year of Model Ts owned: 1913 Canadian touring, 1924 Roadster, 1926 Mercury speedster, 1927 Roadster p/u, 1920’s bobtail dirt track racer
Location: Tulsa OK
MTFCA Number: 21160

Re: Finding top dead center with Rajo B head

Post by tman1913 » Fri Apr 30, 2021 9:50 pm

Crank shaft pulley pin will be horizontally


bowerss2
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Re: Finding top dead center with Rajo B head

Post by bowerss2 » Fri Apr 30, 2021 10:33 pm

tman1913 wrote:
Fri Apr 30, 2021 9:48 pm
Dial indicator in the spark plug hole for absolute. The crank shaft pulley horizontally will get you very close

IMG_3231.jpg
That engine looks familiar :lol:


Dan McEachern
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Re: Finding top dead center with Rajo B head

Post by Dan McEachern » Sat May 01, 2021 11:53 pm

Make a positive stop out of an old sparkplug. Don't make it so long that you hit a valve- just long enough to stop the piston. Crank the engine clockwise until you hit the stop, mark your pulley, rotate the engine the opposite direction until the piston contacts the stop, make a mark. TDC is exactly between the two marks. Do not use a dial indicator and assume TDC is when the indicator stops moving, as that is a terribly inaccurate way to do it.


Dropacent
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* REQUIRED* Type and Year of Model Ts owned: 1925TT, 1926 Martin-Parry bodied wagon, 1927 mercury bodied speedster
Location: Norwalk Ohio

Re: Finding top dead center with Rajo B head

Post by Dropacent » Mon May 03, 2021 12:54 pm

I always use this simple trick on my cars. I think Ted Ashman shared this originally. I put a small chisel mark ( Dremel cutoff would do the same) at top dead center. I also but a little match mark in the pulley ( Dan’s pulley , of course!). Makes it easy peasy to just reach down to find TDC at the 3 o’clock mark with your fingernail.
E37D77DF-E17C-4609-AA21-9D581EE7C4AF.jpeg

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