I have a set of new shankle valve springs for a 4 cyl. purchased a few years ago.
I know this subject was about earlier.
These springs have a foil damper in between the inner and outer coils. It is advised this damper be removed before installing the spring set.
My concern is having the inner and outer springs wound in the same direction which is not correct.
After contacting various spring suppliers they advise having the springs both wound in the same direction is very wrong. There is the danger that if either of the springs break there is a good chance it can fall inside the other coil making it become solid creating engine damage. The chances of spring breakage increases with higher spring loads and high lift camshafts.
What interested me was that most spring suppliers have springs for various makes of engines in that the inner spring O.D. dimmension is the same as the outer spring I.D. making a slight contact. I was told this cancels or reduces spring oscillations.
Has anyone have any experience with this style of springs for the alfa engines?
Many years ago I used ISKY valve springs for the 4 cyl.They were aslo same side wound with dampers.
Thats how I used them ,correct installed height.
This motor was turbo`ed and spun to 8300 rpm.In 53000 km I had no probs at all.The head I sold to a chap in Israel and its still running today in a turbo spider.same setup as initially done by myself.
I know the latest is to remove the foil,I did not.(actually did not know about it.)
My 2c worth.
Thats how I used them ,correct installed height.
This motor was turbo`ed and spun to 8300 rpm.In 53000 km I had no probs at all.The head I sold to a chap in Israel and its still running today in a turbo spider.same setup as initially done by myself.
I know the latest is to remove the foil,I did not.(actually did not know about it.)
My 2c worth.
French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.
Valve springs
After contacting Performancesprings Australia, and Eibach springs, both confirmed the dual springs they supply for all engines have a friction fit.
Performancesprings were able to supply me inner springs wound left hand, same spring rate and height, and had the correct sliding friction fit
I noticed on the Kent cams web catalogue the springs they sell have a larger than standard inner spring I.D. which would suggest their springs may also be friction fit
I had something in the garage that I could check my curiosity. My Moto Guzzi LeMans 1000. A factory engineered hot rod engine that its engine specification is a good recipe for Alfa performance engines (except for being a vee twin air cooled push rod) it ingredients are similar to what is in a modified Alfa engine.
Its got 500cc per cylinder, hemi chamber, 10:1 compression, 47/40 mm inlet/exhaust valves, 300 degrees 0.400" lift camshaft, 40mm venturi delloto's. Pumps out around 90 HP and revs to 8,000RPM. Does this sound similar
Now for the valve springs, the workshop manual specs are 122 lbs @ 36mm seat height and 188 @ 26.5 mm open valve lift. This is not far from what Jim K and Shankle recommend. However the Guzzi springs do not seem to be friction fit but very close.
I could have just whacked these springs I had in the Alfa engine and be done with it just like most do but I had my concerns.
Performancesprings were able to supply me inner springs wound left hand, same spring rate and height, and had the correct sliding friction fit
I noticed on the Kent cams web catalogue the springs they sell have a larger than standard inner spring I.D. which would suggest their springs may also be friction fit
I had something in the garage that I could check my curiosity. My Moto Guzzi LeMans 1000. A factory engineered hot rod engine that its engine specification is a good recipe for Alfa performance engines (except for being a vee twin air cooled push rod) it ingredients are similar to what is in a modified Alfa engine.
Its got 500cc per cylinder, hemi chamber, 10:1 compression, 47/40 mm inlet/exhaust valves, 300 degrees 0.400" lift camshaft, 40mm venturi delloto's. Pumps out around 90 HP and revs to 8,000RPM. Does this sound similar
Now for the valve springs, the workshop manual specs are 122 lbs @ 36mm seat height and 188 @ 26.5 mm open valve lift. This is not far from what Jim K and Shankle recommend. However the Guzzi springs do not seem to be friction fit but very close.
I could have just whacked these springs I had in the Alfa engine and be done with it just like most do but I had my concerns.