Top Dead Center By Water Bubble

[Willit Stop]

Take an old spark plug from your box of spare parts that you "might need someday".Today is the day.Cut the crimp off just above the hex with a hacksaw.Cut the ground off and drive out the porcelain being careful not to damage the threads.Scrape the hole out clean.Now you'll need about 5'of clear vinyl hose (I used 7/16 o.d.x 5/16 i.d.)and a grommet to use as a seal.Slide the grommet onto one end of the hose and insert this into the large end of the sacrificial plug.BTW you can click on the photo to enlarge.






































Remove all of the spark plugs and place #1 wire close to a good ground ( you may have to pull the boot back a little).Turn the ignition switch on.Shift the transmission into high gear and slowly roll it forward by rotating the front wheel just until the spark occurs.Now roll it back a little.Turn the switch off.Screw the now altered spark plug and hose into #1 cylinder. You don't have to use a dying stain here.Snug will do.Next,loop and tape the hose to the radiator support rod.Pour just a little water into the open end of the hose so you have about a 4" bubble of water in the bottom of the loop.Grab the front wheel with your now greasy hands and SLOWLY roll the car forward a little at a time.Watch the bubble,it will return back to the bottom of the loop in a few seconds.The upstroke of the piston will force the bubble to the open end of the hose(BTDC) and the down stroke will draw it towards the cylinder(ATDC).Pretty simple huh? Roll the wheel forward just until the bubble decides to change direction.TDC. Done.With a little luck,George/Maine will respond with his directions on how to do the final timing.I tried it and it works great! Thank you sooo much George.

[V8COOPMAN]

Need to really emphasize that LOOP part of the equation, so as to keep water from reaching cylinder. Not a bad idea though, in theory. DD

[woodypecker]

I have done something similar overdid the down stroke and sucked water into the cyclinder and I now use oil instead of water.

[V8COOPMAN]

Not to steal any "thunder" from your thread, but the link below shows another somewhat similar idea currently floating around on the H.A.M.B. DD

http://www.jalopyjournal.com/forum/s...d.php?t=778434

[Willit Stop]

So do you use this before or after you uh...........Oh, never mind.

[V8COOPMAN]

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Originally Posted by Willit Stop

So do you use this before or after you uh...........Oh, never mind.

Depends on one's priorities, I'm guessing. Good one! DD

[Mart]

Like the water bubble idea, Willit, you have some good ideas.

Mart.

[George/Maine]

Originally Posted by Willit Stop

Take an old spark plug from your box of spare parts that you "might need someday".Today is the day.Cut the crimp off just above the hex with a hacksaw.Cut the ground off and drive out the porcelain being careful not to damage the threads.Scrape the hole out clean.Now you'll need about 5'of clear vinyl hose (I used 7/16 o.d.x 5/16 i.d.)and a grommet to use as a seal.Slide the grommet onto one end of the hose and insert this into the large end of the sacrificial plug.BTW you can click on the photo to enlarge.

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Remove all of the spark plugs and place #1 wire close to a good ground ( you may have to pull the boot back a little).Turn the ignition switch on.Shift the transmission into high gear and slowly roll it forward by rotating the front wheel just until the spark occurs.Now roll it back a little.Turn the switch off.Screw the now altered spark plug and hose into #1 cylinder. You don't have to use a dying stain here.Snug will do.Next,loop and tape the hose to the radiator support rod.Pour just a little water into the open end of the hose so you have about a 4" bubble of water in the bottom of the loop.Grab the front wheel with your now greasy hands and SLOWLY roll the car forward a little at a time.Watch the bubble,it will return back to the bottom of the loop in a few seconds.The upstroke of the piston will force the bubble to the open end of the hose(BTDC) and the down stroke will draw it towards the cylinder(ATDC).Pretty simple huh? Roll the wheel forward just until the bubble decides to change direction.TDC. Done.With a little luck,George/Maine will respond with his directions on how to do the final timing.I tried it and it works great! Thank you sooo much George.

That looks like a good way to find TDC.

[Mart]

Originally Posted by George/Maine

That looks like a good way to find TDC.

Oh yeah, brilliant. Can anyone tell me how you can judge that No.s 2 and 3 pistons are at the same height in the bore? I can't think how to do it. I think a lot of methods people quote make the assumption the spark plug is over the cylinder, when as we all know, on a flatty the plug hole is over the exhaust valve.

Mart.

[V8COOPMAN]

Originally Posted by Mart

Oh yeah, brilliant. Can anyone tell me how you can judge that No.s 2 and 3 pistons are at the same height in the bore? I can't think how to do it. I think a lot of methods people quote make the assumption the spark plug is over the cylinder, when as we all know, on a flatty the plug hole is over the exhaust valve.

Mart.

Mart...Think FIRING ORDER.....15486372. After #3 fires, #7 will be the next to come to TDC. While #7 is at TDC, #3 has proceeded to exactly half-way down it's respective bore. Since #2 will be the NEXT to fire (while #7 is still at TDC), #2 will be EXACTLY half-way UP in it's respective bore. Half-way UP (#2) and half-way down (#3) equeal same height in respective bores. DD

[George/Maine]

Originally Posted by Mart

Oh yeah, brilliant. Can anyone tell me how you can judge that No.s 2 and 3 pistons are at the same height in the bore? I can't think how to do it. I think a lot of methods people quote make the assumption the spark plug is over the cylinder, when as we all know, on a flatty the plug hole is over the exhaust valve.

Mart.

This was writen in 1943 by Motors Factory Shop Manual
I have never done this test, but I would think it works.
First go out and buy two loly pops," Reds ones".
When they are about even thats TDC.
Now the angle of the dangle is not the same as TDC
The piston are even about 2" down plus 2" head.
If this method works let it be known.
George

[Ronnie]

Bin here since 2002 but still a good refresher. http://www.btc-bci.com/~billben/tdc.htm

R

[Hoop]

If you have a '36 engine with a "diver's helmet" distributor, it's easy to accurately locate TDC ... but you have to think about it a bit.

Many guys get thrown off by TDC discussions involving engines and ignition systems that aren't as slick as the earlier flatheads.

Still like seeing guys experiment.

[Binx]

[QUOTE=Hoop;598868]If you have a '36 engine with a "diver's helmet" distributor, it's easy to accurately locate TDC ... but you have to think about it a bit.


Well I'm wracking my brain too. Considering the slop provided by the gears and drive tang, you'll get close but not DEAD center -- '36 had two different distributors. Is that maybe a clue? Could it be a riddle that involves a company employee that "distributed" navy diver helmets?

See! I'm thinking way outside the box but not getting anywhere....

Lonnie

[Mart]

I'm not saying they are not in that position, just making the point that knowing this does not help locate TDC in a flatty because you can't measure the positions of the pistons in 2 and 3 bores.

Mart.

[V8COOPMAN]

Originally Posted by Mart

I'm not saying they are not in that position, just making the point that knowing this does not help locate TDC in a flatty because you can't measure the positions of the pistons in 2 and 3 bores.

Mart.

Mart...I must admit that I NOW understand YOUR point of the irrelevance of the positions of pistons #3 and #2 in this case. DD

[40 Deluxe]

Very possibly this was part of the engine overhaul procedure, in which case you simply set the timing BEFORE installing the head!

[Hoop]

I posted:

"If you have a '36 engine with a "diver's helmet" distributor, it's easy to accurately locate TDC ... but you have to think about it a bit."


That was a challenge.

(Bubbles, whistles, condoms, even cable ties, are not the way to find TDC on a '36 flathead.)

[Mart]

Originally Posted by Hoop

I posted:

"If you have a '36 engine with a "diver's helmet" distributor, it's easy to accurately locate TDC ... but you have to think about it a bit."


That was a challenge.

(Bubbles, whistles, condoms, even cable ties, are not the way to find TDC on a '36 flathead.)

i heard ya, and I love a challenge. I'm wracking my brains but nothin's comin'.

Mart.

[Ol' Ron]

I think Bruce Lancaster's method of using a large tie rap to find TDC with the heads on is very simple, quick and accurate.