Downey has the heavy duty springs --- http://downeyoff-road.com/EngineComponents/CamsValve.html
2F valve spring issues (1 Viewer)
- Thread starter Dave-T
- Start date
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You set spring pressure, not height as you originally stated. Of course you could have coil bind if the springs are weak. Both height & pressure must be within spec. Get new Toyota springs & install them to both height & pressure specs.
- Thread starter
- #23
Definitely the easiest and most intriguing option. What is valve float?
What's the most amount of bind that is acceptable? I think I've heard you should be able to stick a 60 thousandths feeler gauge in between the coil when it's fully compressed.
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Valve float happens at high RPM where the cam is spinning so fast that the valves don't get all the way seated before the valves open again. Stronger springs (higher spring rate) will close the valves more quickly allowing higher RPM without valve float.
I don't know about your bind question, but it seems unreasonable to be able to have .060 between each coil at full compression. If the spring has five turns on it, .060 between each turn is 0.3 inches--you will never get that back by removing your .060 & .090 shims. The crane web site recommends a total .060 safety margin between the height of the valve spring when it's compressed by the valve train and the coil bind height. If you've got coil bind with .060 shims, then remove the shims. If the springs don't have sufficient free length (51.5mm) then replace them.
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- Thread starter
- #25
Here is a pic of the coil bind and the specs of the cam regrind from Delta.
- Thread starter
- #27
Yeah that caught my eye as well, but are valve lash and valve clearance the same thing?
matt.mcinnes
2F-ETI
The Downey springs look just he job
- Thread starter
- #29
Those do look like a sweet setup
pull the shims out, shaved mine 100 and had no problem with adjusting the valves without shims.
Yes, valve lash is the same as valve clearance.
- Thread starter
- #32
Learned something new today that makes a lot of sense. The reason they make the clearance larger on the exhaust valves is to compensate for heat expansion since they are subject to higher temps then the intake. They did that mostly on older engines. Sounds like on newer engines and race engines etc. they do them the same now.
Thats why a lot of people will coat the face of the exhaust valves with that heat reflective paint, it keeps a lot of the heat from building up in the valve. It also can help prevent detonation, because the edge of a really hot exhaust valve is a good place for pre-ignition to start.
- Thread starter
- #34
Update! Issue resolved
Swapped over the springs this morning to some older SBC springs that were in great condition. Using a special tool, we were able to do it without removing the head! We now have proper installed height and seat pressure, and plenty of room before coil bind.
Swapped over the springs this morning to some older SBC springs that were in great condition. Using a special tool, we were able to do it without removing the head! We now have proper installed height and seat pressure, and plenty of room before coil bind.
