Hello all. I'm converting a pre war Hairpin head to B31/33 coil springs. Has anyone got a rocker box off that they could measure the height of the compressed valve springs, from the top cap to the floor of the valve chamber. ....PLEASE! Ron
I'll try to measure it tomorrow but I'll be away from Friday to Sunday afternoon so you might have to wait until next week before I have an answer.
Thanks Derek. I await your reply.
Cheers Ron
My head's off. It's from my built in late '53 M33, so same difference. Measurements from the top cap are:
Inlet valve: 36.8mm to floor/34.4mm to top edge of valve spring seat.
Exhaust valve: 33.7 to 35.1mm to floor/31mm to top edge of valve spring seat.
I'll be interested to see what Derek comes up with, as one of my measurements was a bit variable.
Excellent! Thanks Rog. I'll also be interested in Derek's findings to compare notes. Ron
I measured from the valve chamber floor which wasn't easy as it is circular machined recess which is largely taken up by the spring seat. Here's what I got :
Inlet valve: 40.8mm to floor/38.8mm to top edge of valve spring seat.
Exhaust valve: 38.5mm to floor/33.7mm to top edge of valve spring seat.
Since these are from the floor rather than the top edge of the seat they are larger values than Rog1's but seem to be consistent with them. I had imagined that the exh and inlet would be the same and was surprised that they weren't since the valves are the same length at 94.5mm
Thanks chaps. I just measured mine from the top cap to the floor, but getting varying measurements due to the un machine floor with an average of around 40mm. I am wondering if I should go back to my engineer and ask him to mill the floor?? Ron
PS. This is what I started with. Ron
I doubt of a mm or 2 either way would make much difference as long as the springs don't get coil bound at full lift.
Seeing your photos looks bit like how the B32A head that I have started. Here are before and after pics.