how to determine TDC

[Deleted User]

Here's another dumb question !!



Its been quite awhile since I did this, and never on a Hudson engine, so thought I'd better ask before bungling it.



How do you determine top dead center on a 308? By looking down the spark plug hole, all that showed me was the top of the valves, so that's probably not it, unless you "feel" in there until the valve begins to open, and if this is the case, which valve is right under the spark plug --- (probably intake I'm thinking).



Perhaps one goes by the crankshaft pulley, and if so does the hole in the outer edge signify where the pistons are? Maybe so if this pulley can only be installed one way, with a keyway, but I've never had one off, so don't know this either.



Is this "hole" what's used as a timing mark, or is there some other stampings used for this purpose? ( maybe the hole is just used to stick a bar in and turn over the engine ? )



Basically, all I'm doing is transfering a distributor from one engine to another, and don't want to put it in wrong, so that the timing is out of whack.



If I had a manual I'd find out this stuff quick, but since I don't, I'll rely on the vast knowledge here on the forum to keep me in line. Way better'n a manual anyway !



Thanks again,



silverone..

[Deleted User]

Ken -- this is all extremely helpfull, and I will do exactly what you say when changing the distributor over to the new engine. I appreciate your taking the time to type this all out.



However, the new engine has neither flywheel, nor bellhousing bracket installed yet, ( it came without these items ), so I have to get the number one piston to TDC without the help of the timing marks on the flywheel.



Also, since it looks like the flywheel can be installed in any position around the "clock", I want to be sure I get the right bolts in the right holes, so that the timing marks are accurate.



That brings me back to the hole in the front pulley. Is this balancer / pulley keyed in place? Maybe if I position the hole on mine the same as the hole on the old engine, the flywheel can then be installed with the timing mark right at the pointer ?



I don't think I have the 55-56 engine, so that shouldn't be an issue.



???



silverone.

Geoff

The flywheel will only go on in one position. The spark plug is over the exhaust valve, so you can gauge roughly where t.d.c. is by observing when the exhaust valve is fully closed, which is slightly after t.d.c. Best tested with a feeler between the tappet. If you have all the plugs out to relieve compression, and the fan belt real tight you should be able to run the engine over by the fan belt if it is an engine that has been in service. However if it is a freshly re-built engine it will be too tight for this, and you will have to use a socket on the front nut.

Geoff.

[Deleted User]

Ok = if the flywheel only goes one way, that'll simplify things quite a bit. Once I have that in place, and lined up with the indicator marks, then I can check the bolt hole in the harmonic balancer and see if its in the same place as the old engine. Then if I check the position of the valves on #1, I should be pretty sure I've got it right.



I'd like to do like Jay Leno did with his '51 Hudson. When it flashes up for the first time, everything does what it should be doing, and she runs like a Hudson should right from the get-go! Waaaay more satisfying than a whole bunch of backfires and the neighbours all looking out wondering where the gunfire is coming from !! :-)

[Deleted User]

I forgot to ask ---- what's the torque spec for the flywheel bolts ?

[Deleted User]

Geoff C., N.Z. wrote:

The flywheel will only go on in one position. The spark plug is over the exhaust valve, so you can gauge roughly where t.d.c. is by observing when the exhaust valve is fully closed, which is slightly after t.d.c. Best tested with a feeler between the tappet. If you have all the plugs out to relieve compression, and the fan belt real tight you should be able to run the engine over by the fan belt if it is an engine that has been in service. However if it is a freshly re-built engine it will be too tight for this, and you will have to use a socket on the front nut.

Geoff.

Yep - determined today the flywheel only goes on one way, and it appears Dave left the #1 piston at TDC. Couldn't bolt the flywheel down today because I need the copper washers that go under the nuts, but will find them tomorrow, and get the timing marks right on for the distributor swap, as per Ken's instructions.



This is soooooo easy, thanks to the help from you Guy's !!



Thanks again.



Ryan (silverone)

[Deleted User]

Ken U-Tx wrote:

They also used a sealer on the crank flange, btween the flange and the flywheel to keep the ATF from leaking there and flying off the perimeter of flywheel . Can't remember the name or brand. Has to be resistant to ATF .

Whooops ---- sure glad you mentioned that Ken -- I installed the flywheel with no sealer !!



Looks like it comes off again and gets some. I like Permatex or Loctite #2 non hardening gasket maker for a lot of stuff, but am not sure how it reacts to ATF. Anyone know of somehing better ?



Also will probably need some of same to help seal up torus to flywheel gasket when it arrives.



silverone.