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Uprated valve springs

H One-Twenty

H One-Twenty

Donation Time
Does anyone have a source for uprated valve springs for a 1725? I have tried Delta and Isky without any luck.

The uprated specs I need are:

Inner 28 lb (standard spec is 21.2 lb)
Outer 52 lb (standard spec is 50.2 lb)

Thanks,
Stuart
 
R

RootesRacer

Donation Time
Unless they have put together a package before, they will not have an off the shelf kit. Isky at one time DID have a package to compliment their cam grinds.

4 things you need to know before trying to get springs.

1) free height of the spring.
2) force (lbs) at installed position and installed height.
3) spring rate.
4) coil inner and outer dimensions.

I got my springs from crane, they have a good selection, but you need to choose your own.
 
H One-Twenty

H One-Twenty

Donation Time
RootesRacer said:
4 things you need to know before trying to get springs.

1) free height of the spring.
2) force (lbs) at installed position and installed height.
3) spring rate.
4) coil inner and outer dimensions.
Click to expand...

Thanks for the info

I currently have a set of springs that used to be to the spec I want (sadly no longer available new), however they have weakened through use and old age. The only spec I don't know from your 1-4 list is the "spring rate" for the inner and outer springs. Any idea how I could determine what it should be? The original specs for the springs I have don't include rate.
 
R

RootesRacer

Donation Time
If you know or measure the spring loads at two known heights, you can calculate spring rate (lbs per inch).

The static spring load only tells a small part of the story, the force on the seat that is. The spring rate is important to make sure that the springs have enough force to close the valve mass at a given RPM.
 
H One-Twenty

H One-Twenty

Donation Time
I will attempt to measure the rate using the healthiest springs I have (the ones closest to the original static spring load spec).

Thanks again
 
B

Bill Blue

Platinum Level Sponsor
Wouldn't it be best to start with the desired over the nose pressure and look for a spring that gives acceptable closed pressure? How can you determine proper springs without inserting valve lift into the equation?

Bill
 
R

RootesRacer

Donation Time
Bill Blue said:
Wouldn't it be best to start with the desired over the nose pressure and look for a spring that gives acceptable closed pressure? How can you determine proper springs without inserting valve lift into the equation?

Bill
Click to expand...

He apparently is trying to duplicate the springs (which are NLA, but for which he has the specs on) and finding replacements.

My guess he is duplicating H120 springs am I correct?

I'll warn you on the spring selection thing when it comes to holbay setups.
The H120 springs are not the same springs as you would want with the E128/tornado grind. I mention this becuase many of the folks that think they have a holbay H120 cam in fact have the holbay aftermarket E128 cam which is totally different with higher lift and rev potential.
 
H One-Twenty

H One-Twenty

Donation Time
Yes I am looking for H120 spec springs as I am using the original Holbay spec cam (and head and flat tops) as fitted to the Rapier H120 and Hunter GLS. This 'standard' Holbay set up gives very good torque and this is what I want for my SIV
 
R

Rootes 66

Donation Time
While looking for Jarrids pistons I noticed valve springs listed on Speedy spares for the H120. Part No 5221358.
Pete
 
R

RootesRacer

Donation Time
H One-Twenty said:
Yes I am looking for H120 spec springs as I am using the original Holbay spec cam (and head and flat tops) as fitted to the Rapier H120 and Hunter GLS. This 'standard' Holbay set up gives very good torque and this is what I want for my SIV
Click to expand...


Did you actually get the cam from an H120 engine or have it ground?
 
RootesRooter

RootesRooter

Donation Time
You may want to think twice about using stock Holbay springs. If you look up the part number, the same springs were used on one of the Mk Minx'. Both inner and outer are a LOWER rate than the Series Alpine springs.

I think the reason Rootes used these springs is the high lift on the Holbay cam. When I installed a cam ground to Holbay specs a few years ago using stock Series V springs, I shortly ended up with bent push rods and busted rockers from the spring bind-up.

Rootes apparently didn't have anything else available in their existing parts bin that would accommodate a high lift cam, and didn't want to spend the money on new designs, so they went with an older, softer spring. Sorta like they recycled the Mk VIII Husky headlight rims to late Alpine V's and Mk II Tigers. I haven't read of people complaining about Holbay springs floating, so I suspect they're adequate until you get near the normal redline.

Dick Sanders
Kent, WA
 
H One-Twenty

H One-Twenty

Donation Time
All the parts I have including the cam came from a factory built genuine 'standard' Holbay engine. I was rebuilding the head with new guides and new Holbay spec valves when I discovered the springs were weak, hence my search for replacements.

I have owned a few Holbay engined cars and I have never had a problem with valve float even at and beyond the redline. The only details I have for the standard Rapier/Alpine v.s. Holbay spec springs are the "static spring loads" listed in my previous post. I'm surprised to learn that the "spring rate" is lower than stock Alpine.

The reason I want to replicate the Holbay spec as closely as possible for my SIV is because it has proven to be a powerful yet tractable set up and also because my standard H120 Rapier has been incredibly reliable over the past 10yrs (never requiring any tuning of the Weber DCOE carbs).

Thanks for the heads up on speedy spares listing, I'll call them on Monday and see if they actually have them
 
H One-Twenty

H One-Twenty

Donation Time
I now have a set of the correct Holbay spec valve springs on their way to me from Speedy Spares (apprx $45)

Thanks to everyone for their input

Stuart
 
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