GarageStudios Posted July 23, 2016 Share Posted July 23, 2016 Members.. So with your help we identified my engine... since the cleanup the distributor was removed before marking. We got the fire order captured but lost TDC. I'm not that mechanical savvy so please correct anything I may get wrong.. I searched online to read on advice to get Top Dead Center on a 235. I found posts on the finger test in spark plug 1, TDC tools, ball bearing on fly wheel.. I wanted to share how I "may" have found my TDC. I welcome any corrections. I purchased a squeaking dog toy at a dollar store. Found some misc tubing and cut the squeaking part from the toy and put it in the tubing and placed tube into spark plug 1. Removed starter... I cleaned the the flywheel with decreaser and light sandpaper. I found a triangle marking and a ball bearing with additional markings. I took the valve cover off to watch the valves move as I turned the engine slowly. The air started to squeak the tube. I saw the triangle pass.. then the squeaking stopped... at the same time the pin on the bell housing was over the ball bearing.. Just to make sure I turned the engine a few times. Partly because this was my first TDC discovery I wanted to watch a few times as the markers passed. Each time the squeaking started the first 2 valves were up. When the squeaking stopped.. the valves were down and the pointers matched up each time... I think the number 5, is 5 degrees of TDC? Now at this point I'm not 100% sure.. when the housing pin is at the ball bearing.. did I find TDC? Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 23, 2016 Share Posted July 23, 2016 Top dead center should be when the ball is on the pointer. That is assuming(?) that the flywheel can go on only one way. On my '15 truck and many other Buicks of the time the fly wheel could be bolted on any number of ways as the bold holes were evenly spaced. Found out the flywheel on my truck is the equilvalent of one cylinder off. I have put paint on the flywheel to identify #1. One way that I found TDC is on my truck I put a long straw in the spark plug hole and watched it go up and down (without falling into the cylinder if it was not long enough) and when the straw was the maximum up position that would be TDC. Good luck. 3 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted July 23, 2016 Share Posted July 23, 2016 (edited) CDN if I may call you by your first name I have done something similar. I have an old spark plug with a 1/4" pipe welded to it. I screw it into the #1 cylinder and put a balloon on the end. Turn the engine and the balloon blows up, go past TDC and it deflates. TDC is when the balloon is fully inflated. This is not totally precise but allows me to find the timing mark and know I am timing #1 not #6. Edited July 24, 2016 by Rusty_OToole (see edit history) 1 Link to comment Share on other sites More sharing options...
cahartley Posted July 23, 2016 Share Posted July 23, 2016 3 hours ago, Larry Schramm said: Top dead center should be when the ball is on the pointer. I'm not sure if the ball IS TDC or the running timing with the vacuum disconnected and plugged. Regardless it's close enough. Once running you might want to put a timing light to it and advance the timing ball until it appears at the right edge of the inspection hole (with the vacuum disconnected and plugged). 1 Link to comment Share on other sites More sharing options...
Larry Schramm Posted July 23, 2016 Share Posted July 23, 2016 The ball at the end of the ball has to be top dead center. The other hole is for the starter. When the engine is together that is the only place to see the timing mark. If my memory is correct, that is the same set up that Buick used on the '63 Special that I had. Ball & pointer. Link to comment Share on other sites More sharing options...
hchris Posted July 24, 2016 Share Posted July 24, 2016 Watching the valves is a good indicator, given the firing order is 1,5,3,6,2,4 when #1 is at TDC both valves will be closed and the valves at #6 will be rocking, ie, inlet will be opening and exhaust closing. Using this method eliminates all the possibilities of timing marks etc. being out, and will certainly be close enough to get the distributor in the right position, with rotor arm pointing to #1 spark lead. 1 Link to comment Share on other sites More sharing options...
Rusty_OToole Posted July 24, 2016 Share Posted July 24, 2016 That is a good method if the valve cover is off. Link to comment Share on other sites More sharing options...
JACK M Posted July 24, 2016 Share Posted July 24, 2016 I took an old spark plug and put an extended rod thru it. Take out all of the spark plugs and put this tool in #1 plug hole. HAND TURN the engine to where the piston hits this tool and stops.. Make a mark on the crank pulley or flywheel. Then HAND TURN the engine in the opposite direction until the piston hits the stop again. Make a mark on the crank pulley or flywheel. TRUE TDC is mid way between these marks. 1 Link to comment Share on other sites More sharing options...
GarageStudios Posted December 17, 2020 Author Share Posted December 17, 2020 Thanks to all that chimed in, I'm starting to work on engine again and all tips will help.. will post final results to maybe close thread Link to comment Share on other sites More sharing options...
Oldtech Posted December 17, 2020 Share Posted December 17, 2020 (edited) Almost guys! The ball is the timing indicator with a timing light. It's 5 degrees advance. The line with U C is Upper center. Yes your gizmo is kind of neat, but watch the valves. When number 6 exhaust ( the back end one) is just closed and the intake is just going to open (second from the back end) then number 1 is on firing position. Edited December 17, 2020 by Oldtech (see edit history) 1 Link to comment Share on other sites More sharing options...
George Cole Posted December 23, 2020 Share Posted December 23, 2020 1 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now