Pushrod Length

[Marvel]

Re-assembling the top end again after stripping a head stud when re-torquing it and I note the pushrods seem a bit short. They are early type with the cup at the top. They are the correct length to the drawing at 5 7/32" but the pushrod only engages with the cup by about one diameter and leaves about 1/4" of exposed thread. The valve seats in the bronze head have been welded so the pushrod will be at maximum length but it still looks wrong.

 

[delboy]

Just from the top of my head [not much there]
If the motor was previously assembled okay and all that's changed is the valve seats, therein lies the answer, but not if assembling from scratch.
If it's any help, I measured a couple of old E44, the adjustable cup bit. They seem to be 15/16" long with about 1/2" of thread up the spout.
Some new components in the system might not help, and add to the problem. A taller cylinder barrel, different camfollowers, valves, collets and sleeve, etc. I've encountered bits [old and new] with different dimensions so you can't take anything for granted.
At the end of the day maybe a custom E44 might be the way forward?
Cheers,
Delboy.

 

[Marvel]

According to the drawing of the pushrod cup it should be 29/32" long with 1/2" of 1/4" x 26tpi full thread. One of mine is a bit longer and the other a bit shoter. As you say the best way would be to make some pushrods a bit longer.

 

[Marvel]

Found some late style pushrods which are about 1/2" longer. One has the early diameter thread the other has the bigger late thread. Both can be modified to make some extra long early style pushrods.

 

[Stanley Chappell]

I had the problem tony Maugham welded up familiar crack between the plug hole and
exhaust seat and this altered the dimensions slightly not enough thread to keep
the cups secure so I made longer push rods jobs a good un hopefully!
I need to make some E44 but I don’t know what metal to use the works drawing says cast steel any ideals asstance required or please help

 

[delboy]

Stan,
I would take "cast steel" to mean Silver steel.
Bob Stafford mentions it at the top of page 233 of "Back to A".
cheers,
Delboy.

 

[Stanley Chappell]

Stan, I would take "cast steel" to mean Silver steel. Bob Stafford mentions it at the top of page 233 of "Back to A". cheers, Delboy.

I had the problem tony Maugham welded up familiar crack between the plug hole and
exhaust seat and this altered the dimensions slightly not enough thread to keep
the cups secure so I made longer push rods jobs a good un hopefully!
I need to make some E44 but I don’t know what metal to use the works drawing says cast steel any ideals asstance required or please help

 

[Marvel]

Back together and running sweet as a nut. I only took it apart as the head gasket was leaking. The nut next to the plug hole was only finger-tight as the stud had pulled out of the crankcase. Now heli-coiled and torqued to 30ft/lbs. Does this sound about right?

 

[greg brillus]

Sounds way too much to me.......... I can't imagine the thread in the cases handling that much torque........A 3/8" diameter stud/nut like that more like 18 to 20 max.......the case threads are only 7/16" BSF post war studs in the cases are 9/16" much bigger and much longer studs to boot........Folk/experts out there who know much better than the designers and torque them down to 45 to 50 Ft lb's find out sooner or later the hard way when the threads pull out of the cases.........Be careful with this one......The pre war bikes, the castings are fragile........

 

[Marvel]

Actually it was a bit less than that as it was a 30lb load on an 8” spanner so 20ft/lbs. it felt about right and doesn’t leak.