MTFCA Forum

What is the difference in diameter, length, and spring pressure of Model T, Model A, and flathead V8 valve springs? If a owner wanted slightly more spring pressure to run with a high lift cam, could A or V8 springs be used if they provided higher spring pressure and were compatible in size? Would using stock reproduction springs with shims be better?

I have seen A springs in a model T. I think they put too much pressure on the cam bearings which are much larger in an A. I use new springs and you can shim them if you want more pressure but I have not found it necessary. The valves won’t float until you are way past the rpm limits of most T engines.

years ago I did a valve job on a T that had crap for compression, all the exhaust valves where mushroomed out from have a heavier spring they looked like A's but might have been some thing else?? All I know once the valves and springs where changed out it ran well after?? I have asked about extra spring pressure for my Rajo and have never got an answer on that one. Hope this helps?? Joe

Overheads want more spring pressure because the weight of the pushrods, heavier valves, and higher rpm range can all contribute to valve float.

Thanks Erik and Joe. You answered my concern.

I built a T engine with a really high performance A cam and the T springs float at about 4300 rpm!! So a useful built in rev limiter on a flathead T engine