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Finding top dead center with Rajo B head
Posted: Fri Apr 30, 2021 8:59 pm
by jmemjr
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.
Re: Finding top dead center with Rajo B head
Posted: Fri Apr 30, 2021 9:48 pm
by tman1913
Dial indicator in the spark plug hole for absolute. The crank shaft pulley horizontally will get you very close
Re: Finding top dead center with Rajo B head
Posted: Fri Apr 30, 2021 9:50 pm
by tman1913
Crank shaft pulley pin will be horizontally
Re: Finding top dead center with Rajo B head
Posted: Fri Apr 30, 2021 10:33 pm
by bowerss2
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
Re: Finding top dead center with Rajo B head
Posted: Sat May 01, 2021 11:53 pm
by Dan McEachern
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.
Re: Finding top dead center with Rajo B head
Posted: Mon May 03, 2021 12:54 pm
by Dropacent
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.