Valvespring height vs. daily driver
- Thread starter Doober
- Start date
There are two factors that are important. You need to have a minimum amount of clearance between the retainer and the valve seal/guide. Also, spring pressure is dictated by installed spring height. The spring manufacturer should be able to give you the specs on the springs. Then you can calculate pressure based on your actual installed height. Too low spring pressure and you will get valve bounce which will limit RPM's. Too much can destroy a cam and/or lifters.
The required spring pressure is determined by what type cam you're running (solid, hydraulic, roller, etc.). The cam vendor should give you the value you need for that specific cam.
HTH, or it may have confused you more.... :?
The required spring pressure is determined by what type cam you're running (solid, hydraulic, roller, etc.). The cam vendor should give you the value you need for that specific cam.
HTH, or it may have confused you more.... :?
Nope, already knew all those goodies 
I'm just trying to justify whether or not to invest in a valvespring micrometer. I have no problem calculating required installed height for springs, it's just I'll have to get shims, etc. if they're too far off. I'm looking at a Comp complete cam kit for the 383 project that includes the timing set, springs and retainers/locks along with the cam/lifters. The springs are (or should be, they're within the o.d. limits) a drop-in on the heads.
Is there any other way outside using a micrometer to measure installed height? I can get a close measurement using the digital caliper, but I know it won't be as accurate as the valvespring mic.
I'm just trying to justify whether or not to invest in a valvespring micrometer. I have no problem calculating required installed height for springs, it's just I'll have to get shims, etc. if they're too far off. I'm looking at a Comp complete cam kit for the 383 project that includes the timing set, springs and retainers/locks along with the cam/lifters. The springs are (or should be, they're within the o.d. limits) a drop-in on the heads.Is there any other way outside using a micrometer to measure installed height? I can get a close measurement using the digital caliper, but I know it won't be as accurate as the valvespring mic.
I've got a Valve Spring Height micrometer that I can mail you and let you use. You can send it back whenever you get finished if interested. Looks like this:
That, sir, will be awesome I'll have to let you know when it's almost time to get the retainers, etc. so I can measure.
I'll have to let you know when it's almost time to get the retainers, etc. so I can measure.The tolerance isn't that critical as the Shims come in .015", .030" & .060" thickness.
A Dial Caliper is usually within + or - .001"
I've used cut lengths of PVC pipe & feeler gauges many times to set Installed Height.
A Dial Caliper is usually within + or - .001"
I've used cut lengths of PVC pipe & feeler gauges many times to set Installed Height.
Ok. The springs I'm looking at are an installed height of 1.7", and they're basically a drop-in spring, I'm just not sure what my heads will come out at (stock 193... late model 350 TBI heads).
Well I can tell you my machinist uses a caliper when he builds a typical engine to measure spring height.
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