When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I think the old school machinists way was to cut the spring pocket deeper until you achieved the desired spring height. I don't know that I've ever heard of anyone having to cut the pockets on LS heads though.. Maybe try a different set of springs?
You can't go off of someones word that that step is 0.100", you MUST measure how deep that step is in the Mic. Just because a box of springs says 1.810" IH doesn't mean that is where it MUST be installed. We need way more info. What is the springs? How much valve lift, what will you be doing with the car, what rocker arms.....
You can't go off of someones word that that step is 0.100", you MUST measure how deep that step is in the Mic. Just because a box of springs says 1.810" IH doesn't mean that is where it MUST be installed. We need way more info. What is the springs? How much valve lift, what will you be doing with the car, what rocker arms.....
I had some pistons smack a couple valves. I am assuming valve springs were weak but I also want to make sure everything is in spec for when I get it put back together so I have no more issues.
the car has a tsp tsunami cam (235/240 .629 .615) with scorpion 1.7 rockers
this is just a street car I drive around quite often.
I had some pistons smack a couple valves. I am assuming valve springs were weak but I also want to make sure everything is in spec for when I get it put back together so I have no more issues.
the car has a tsp tsunami cam (235/240 .629 .615) with scorpion 1.7 rockers
this is just a street car I drive around quite often.
I would ditch those scorpion rockers for some stock ones with a trunnion upgrade, that should help with valve float.
Something I think a lot of people are forgetting is that installed height is to get the proper spring pressure. Whether you cut that spring pocket deeper, or even if you added .25" of shims, the actual position of the valve in the head has not changed; it is not any closer or further away from the piston - or the rocker arm, for that matter.
I always err on the tight side, because that spring is going to loosen up after the first few hours of operation. If you have access to a valve spring tester, you might be surprised how much a box of springs can vary.
Do you have the specs on the springs (spring rate, seat pressure at 1.810, and coil bind)? With you running 1.780 versus 1.810 just means you'll be running a touch more spring pressure and be .030" closer to coil bind. With those spring specs, it will be easy to calculate where you will be at with the new installed height.
If you want to raise the spring height, you can get valve locks that are advertised as "+0.xx," which means the locks will raise the spring height by that much. However, it has been my experience that you need to play around with those locks and retainers to get close to the height, because there is a tolerance that can push you too far in the opposite direction. But first, I would calculate where everything sits at the lower installed height and see if it even is an issue.
Do you have the specs on the springs (spring rate, seat pressure at 1.810, and coil bind)? With you running 1.780 versus 1.810 just means you'll be running a touch more spring pressure and be .030" closer to coil bind. With those spring specs, it will be easy to calculate where you will be at with the new installed height.
If you want to raise the spring height, you can get valve locks that are advertised as "+0.xx," which means the locks will raise the spring height by that much. However, it has been my experience that you need to play around with those locks and retainers to get close to the height, because there is a tolerance that can push you too far in the opposite direction. But first, I would calculate where everything sits at the lower installed height and see if it even is an issue.
I actually went with a BTR spring this time around. The specs are as follows
I actually went with a BTR spring this time around. The specs are as follows
Well, they give you the seat pressure at the height you measured, which is 155. Without the spring rate, it makes it harder to know exactly what your open pressure will be, but your intake lobe will have an open spring height of 1.151 and the exhaust lobe will be at 1.165. So, you'll be between 380 and 400lbs, probably close to 390 on the intake and 385 on the exhaust. You're also .081" away from coil bind on the intake and .095" away on the exhaust.
If 1.780" is your verified measurement, I would roll with it.
05-18-2022, 12:44 AM
Valve spring installed height HELP - TSP 2.5 LS6 heads 
