Quote Originally Posted by Itoldyouso View Post
Sorry Pat, I thought Dave was a BBC guy. There are tools you can buy that allow you to change valve springs with the head installed. You pump compressed air into a cylinder, then you use the tool to release the valve keeper. You can shim the springs to get some more tension on them, or replace them with new ones. Pat can advise better on that though.

Don
On old airplane recip's in the Navy we had to pull the rockers and springs for inspections - had a length of heavy nylon rope, the woven kind, that we fed into the cylinder with the piston down, then rotated the engine to bring that one up toward TDC to fill the space with compressed rope and hold the valves. Liked it better than air, as on those big old cylinders you could sometimes overcome the compressed air charge breaking the keepers loose. Never done it on a car engine, but some 1/4" rope should work fine, I would think.