Aluminum l98 spring height?
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Teching In
Joined: Nov 2013
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Aluminum l98 spring height? gonna ask another newbie question here...
I took apart my aluminum l98 heads for porting a while back and now I'm ready to reassemble them. But I can't remember where all the shims go and that's stopping me. There are 16 of them all from the exhaust valves. Do I need to buy a micrometer and measure it out? I don't want to just assume that it's two each. Oh and the springs are stock.
Thanks for the patience if I typed anything real stupid sounding
I took apart my aluminum l98 heads for porting a while back and now I'm ready to reassemble them. But I can't remember where all the shims go and that's stopping me. There are 16 of them all from the exhaust valves. Do I need to buy a micrometer and measure it out? I don't want to just assume that it's two each. Oh and the springs are stock.
Thanks for the patience if I typed anything real stupid sounding
Mods will likely move this as its in the wrong section but let's see if you can be helped quickly
Have you had a valve job done, what are the intended camshaft specs, and do you have corresponding springs to match..???
Have you had a valve job done, what are the intended camshaft specs, and do you have corresponding springs to match..???
Stock springs and that can, plus 1.6 rockers would probably self destruct while the starter is still engaged.
When you change the cam you have to change the springs to match the cam.
Tell us more about the whole setup, sounds like a lot of duration if this is a TPI car.
Might consider just getting the right springs, taking the heads to a shop and letting them do a valve job and the assembly.
When you change the cam you have to change the springs to match the cam.
Tell us more about the whole setup, sounds like a lot of duration if this is a TPI car.
Might consider just getting the right springs, taking the heads to a shop and letting them do a valve job and the assembly.
So what you are saying is that each exhaust spring had two shims under it? Personally, I would buy the spring micrometer and check things out. The spring height is critical to seat and over the nose spring force. Although the TPI won't spin that high with the stock intake, I would still be concerned with not knowing how the valve train is set up.
Yeah making that camshaft lift .530/.540 with the 1.6 ratio is just not something you will accomplish with stock spring height or even +0.050" valvelocks. You will need +0.100" longer than stock valves which will give you around 1.75 to 1.80 inch installed height range which is what you're looking for when selecting valve springs.
Competition Cams 941 is one of the best and most versatile 1.26" diameter springs available. I use them all the time on stock car applications as they work for so many different setups and seem to last a long time since they are the pacalloy type wire.
A budget version is sold by Competition Products in Oshkosh, WI under the number 98215 (electro-polished).
Competition Cams 941 is one of the best and most versatile 1.26" diameter springs available. I use them all the time on stock car applications as they work for so many different setups and seem to last a long time since they are the pacalloy type wire.
A budget version is sold by Competition Products in Oshkosh, WI under the number 98215 (electro-polished).
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Teching In
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So what you are saying is that each exhaust spring had two shims under it? Personally, I would buy the spring micrometer and check things out. The spring height is critical to seat and over the nose spring force. Although the TPI won't spin that high with the stock intake, I would still be concerned with not knowing how the valve train is set up.
I've run that exact camshaft in a few different 383s but those heads have very small intake runners (restrictive) and the 58 cc combustion chambers will most likely put your compression ratio well beyond 93 octane. If going E85 or race fuel then you are fine.
Basically they are a great head for a 350 but so many better choices for the extra cubes.
Basically they are a great head for a 350 but so many better choices for the extra cubes.
Thread Starter
Teching In
Joined: Nov 2013
Posts: 28
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I've run that exact camshaft in a few different 383s but those heads have very small intake runners (restrictive) and the 58 cc combustion chambers will most likely put your compression ratio well beyond 93 octane. If going E85 or race fuel then you are fine.
Basically they are a great head for a 350 but so many better choices for the extra cubes.
Basically they are a great head for a 350 but so many better choices for the extra cubes.