Engine questions

[john charlton]

Still have not got the head off my hotrod swapmeet engine but have decided to put it in a frame and fire it up with the the head nuts backed off a bit. Took the pan off and found it looks like a recent (hours wise) rebuild. Pan was mostly clean but evidence of been run hot, caramalised oil in the dipper tray etc etc . The bores from the bottom side look good with still evidence of horizontal boring marking in the bores. No trace of loose babbitt anywhere. The big ends are tight with shims in place .The engine is stiff to turn with crank handle when the pistons are mid bore so I hope nothing nasty just not broke in yet. Question,how many hours running after a rebore/new pistons will the engine "rock back" on a compression stroke ??? Also the drain tube is missing from the rear main cap, the threads in the cap are semi stripped. Just wondered should I try to fudge a new drain tube in which might fall out or will it run OK without it ???

John in cool damp nearly midnight my son has just bought a nice solid 29 pickup he has always hankered after one so he is a happy bunny England.

 

[MikeK]

. . . Also the drain tube is missing from the rear main cap, the threads in the cap are semi stripped. Just wondered should I try to fudge a new drain tube in which might fall out or will it run OK without it ???

Without the drain tube it will look like the Gulf of Mexico in your garage. (oil everywhere, not shrimp!) Most guys either braze the tube in the cap or tack it with an arc welder for security. Also check that the new tube doesn't partially obstruct the crank slinger groove that the threaded hole intersects. You may need to notch the tube to keep the groove free.

 

[CWPASADENA]

Also the drain tube is missing from the rear main cap, the threads in the cap are semi stripped. Just wondered should I try to fudge a new drain tube in which might fall out or will it run OK without it ???

I would consider trying to replace the rear main drain back oil tube. Clean the threaded hole and the end of a new tube really well with Lacquer Thinner or Acetone and use some J B Weld to re-install it. I think it helps to keep the rear main oil leak to a minimum and I do not think it would hurt anything if it did come out.

Good Luck and keep us posted,

Chris

 

[Ice man]

The tube is designed to be in place, below the oil surface. This eliminates crankcase pressure from pushing oil back to the rear of the crank and blowing all over the fly wheel, and one the floor.