Thread: machining for teflon valve seals

Tweet

I'd like to get Teflon valve seals for my 200 I6, because #1 there better than the umbrella seals and won't get hard and crack like mine did and #2 they are required to run the dual springs that classic inlines sells. what is machined to use teflon valve seals? also what is the diffrence between a dual spring, and a single spring?

here are the single springs, with dampers, they have a max lift of .700 so they should be good with the cam lift I want and the 1.65 rockers
http://classicinlines.com/proddetail...SC%2D200%2DSTY

and here's the teflon valve seals
http://classicinlines.com/proddetail...SC%2D200%2DTVS

Matt,

The outside of valve stem boss on the head is machined down so that the seal can slip over it.

I don't understand your question about the difference between dual springs and a single spring.

Not sure where you should look, but you can get Teflon guide cutters and do it yourself.
They're self-limiting and will stop when you get to the right place.

Only other thing you need is a 1/2" drill motor.

I did my own on the 462" Buick engine, didn't take long and no big deal.


You may want to check with an auto machine shop as well.
They don't seem to charge much to cut the head for Teflon seals when they do the valves & seats and perhaps that would be true when cutting for seals only.

The price may be favorable enough that you could have it done and skip buying what could be an expensive tool.

Originally Posted by C9x

Not sure where you should look, but you can get Teflon guide cutters and do it yourself.
They're self-limiting and will stop when you get to the right place.

Only other thing you need is a 1/2" drill motor.

I did my own on the 462" Buick engine, didn't take long and no big deal.


You may want to check with an auto machine shop as well.
They don't seem to charge much to cut the head for Teflon seals when they do the valves & seats and perhaps that would be true when cutting for seals only.

The price may be favorable enough that you could have it done and skip buying what could be an expensive tool.

we may have the tool to do it in the autoshop, I figured a mill was nessasary, and that we do not have

Originally Posted by Henry Rifle

Matt,

The outside of valve stem boss on the head is machined down so that the seal can slip over it.

I don't understand your question about the difference between dual springs and a single spring.

dual springs are 1 spring within another right? the 1's classic inlines sells are much stiffer than the singles with dampers, allow the same lift tho. so I'm going to get the single springs with dampers, don't need them that much stiffer for turbocharging.

where do you buy those?

the dual springs are designed to allow higher spring pressure while still allowing large lift..... the only thing is with higher pressure springs you can flatten out the cam easier.... the benefit of higher pressure springs is that they slam the valves shut quicker.... which is especially good if you have a large overlap..... gets the valve shut as quick as it can be allowed

You probably wouldn't run into rpm related harmonics problems with your installation, but you can when running single springs at elevated rpm levels.

Little brother runs a 500 cid DRCE engine in his 8.13 second Henry J drag racer.
Rpms are 6800 at launch and 9200 rpm when shifted. (4-speed Lenco.)

He ran single springs for a while and every run he broke one.

The breakage quit after he went to dual springs.
The inner spring - whether round wire or flat spring stock - act as vibration dampers and keep the main - outer - spring from doing weird things harmonics-wise and self destructing.

Originally Posted by C9x

You probably wouldn't run into rpm related harmonics problems with your installation, but you can when running single springs at elevated rpm levels.

Little brother runs a 500 cid DRCE engine in his 8.13 second Henry J drag racer.
Rpms are 6800 at launch and 9200 rpm when shifted. (4-speed Lenco.)

He ran single springs for a while and every run he broke one.

The breakage quit after he went to dual springs.
The inner spring - whether round wire or flat spring stock - act as vibration dampers and keep the main - outer - spring from doing weird things harmonics-wise and self destructing.

OH MY !!! SINGLE SPRINGS TRYING TO RUN 9,200 RPM'S ??? WHAT ??? CAN YOU SAY COIL BIND !!!

Originally Posted by erik erikson

OH MY !!! SINGLE SPRINGS TRYING TO RUN 9,200 RPM'S ??? WHAT ??? CAN YOU SAY COIL BIND !!!

And bent pushrods.

Originally Posted by erik erikson

OH MY !!! SINGLE SPRINGS TRYING TO RUN 9,200 RPM'S ??? WHAT ??? CAN YOU SAY COIL BIND !!!

Coil bind wasn't a problem.

Springs can do weird things when mechanically excited.
A good example may be a Slinky.
Hold it up so it's stretched out fairly well, strike it gently with a screwdriver or metal rod.
Take note of the oscillations produced.

It's especially interesting to press the upper end of the Slinky to your ear, strike it and listen to the jangling noises it makes.

High speed motion pictures have shown valve springs operated at high speeds do some weird things.
No small wonder they break.

I'm going to have the rev limiter kick at 6k, would the single springs be ok at 6k? the springs come with dampers and high strength valve locks.

the singles should work out just fine if your max rpm is 6000.... make sure to definately get quality springs rated at least .020 over your max life.... i like to make sure they're close to my max lift but still just a bit over... you'd be amazed what happens to the valve train at those kind of rpms.... you can get stuck with coil bind or valve floating.... even though floating valves wont leave you stuck on the road unless they float enough to hit each other

Spring harmonics can do weird things, as can resonant frequencies.

http://www.civeng.carleton.ca/Exhibi...rowsBridge.mpg