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Spring locator to guide fitment

General engine tech -- Drag Racing to Circle Track

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Ohio Rob
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Spring locator to guide fitment

Post by Ohio Rob »

Hello all.

I’m working on a set of Trick Flow twisted wedge R heads for a small block ford drag race project.

I had a shop put the heads together years ago and never used them. I’m changing the spring package due to the cam I’ve chosen being more radical than what I thought I was going to use.

I have stepped guides and the OD measures at .600. The locators that the shop installed have an ID of .635.

I can’t find any locators that are .600 ID in any of the catalogs I have. I’ve searched online as well.

I’m a hobbyist and sometimes I need to ask a question that is rudimentary to most here, so here goes....

I’m assuming that the setup was bad with .035 of slop at the locator. It seems that that would have the springs dancing around the spring pocket.

I’m also assuming I could buy a new locator set (I’ll have to anyhow to match the locating boss to the ID of the new inner spring) with an inner diameter of, say, .570.
Then use a cutter to reduce the .600 guide to for the smaller locators.

Is this correct logic?

Does someone make a cutter that locates on the guide and cuts the OD of the guide down?

The springs will be PSI 424’s which are 250 on the seat and 775 over the nose if I remember correctly.

Thanks for any insight,
Rob
rustbucket79
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Re: Spring locator to guide fitment

Post by rustbucket79 »

Why not get the .570” spring seats and bore them to the .600” on the lathe?
Ohio Rob
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Re: Spring locator to guide fitment

Post by Ohio Rob »

rustbucket79 wrote: Thu Nov 12, 2020 10:39 pm Why not get the .570” spring seats and bore them to the .600” on the lathe?
I figured they were hardened and would be hard or impossible to machine. Is that not correct?
KnightEngines
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Re: Spring locator to guide fitment

Post by KnightEngines »

They machine ok, case hardened, but still machine fine, just keep the speed down.
Ohio Rob
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Re: Spring locator to guide fitment

Post by Ohio Rob »

Ok, thanks. I didn’t know that.

So, the proper way to address this is to buy locators that are smaller than the guide and open them up?

Am I correct in thinking that the .035 clearance was not right and would have led to failure on an aluminum head with relatively stout springs, spinning 8000 RPM?

Thanks again for the help.
Rob
BillK
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Re: Spring locator to guide fitment

Post by BillK »

Rob,
I am surprised that the guide measures .600 That is kind of an oddball size. Almost all of the ones I have seen are .625 which works good with the .635 id spring seats. Is there a spring "pocket" cut in the head that would allow you to use an od type spring seat instead ?

I have had to cut spring seats in the lathe before and they are not too bad to cut. Like KE said just make sure you have a sharp tool and go slow.

I dont think anyone makes a "portable" type cutter for the guide that is that size. I have cut them down in the seat and guide machine with a long straight blade cutter but it is a very slow procedure.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
Ohio Rob
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Re: Spring locator to guide fitment

Post by Ohio Rob »

BillK wrote: Fri Nov 13, 2020 7:55 am Rob,
I am surprised that the guide measures .600 That is kind of an oddball size. Almost all of the ones I have seen are .625 which works good with the .635 id spring seats. Is there a spring "pocket" cut in the head that would allow you to use an od type spring seat instead ?

I have had to cut spring seats in the lathe before and they are not too bad to cut. Like KE said just make sure you have a sharp tool and go slow.

I dont think anyone makes a "portable" type cutter for the guide that is that size. I have cut them down in the seat and guide machine with a long straight blade cutter but it is a very slow procedure.
Thanks for the reply Bill.
The head has a spring pocket, but it’s much larger than the OD of the springs.

It sounds like the best course of action is to machine the new locators.

Thanks again
6.50camaro
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Re: Spring locator to guide fitment

Post by 6.50camaro »

Almost sounds like the heads are cut for cups that locate off the od of the spring.
BillK
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Re: Spring locator to guide fitment

Post by BillK »

Ohio Rob wrote: Fri Nov 13, 2020 8:05 am The head has a spring pocket, but it’s much larger than the OD of the springs.
If that is the case why cant you use a cup type locator that locates the springs on their od ? Like this one :

https://www.lunatipower.com/o-d-locator ... of-16.html

Measure the spring pocket in the head and see if you can find an OD cup to match.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
Ohio Rob
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Re: Spring locator to guide fitment

Post by Ohio Rob »

BillK wrote: Fri Nov 13, 2020 8:31 am
Ohio Rob wrote: Fri Nov 13, 2020 8:05 am The head has a spring pocket, but it’s much larger than the OD of the springs.
If that is the case why cant you use a cup type locator that locates the springs on their od ? Like this one :

https://www.lunatipower.com/o-d-locator ... of-16.html

Measure the spring pocket in the head and see if you can find an OD cup to match.
I’ll measure it when I get home and see what’s available.

Thanks for the link and suggestion
6.50camaro
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Re: Spring locator to guide fitment

Post by 6.50camaro »

Crower has a spring seat cup # 68933-16 that's 1.685 O.D. 1.540 spring seat .635 I.D. these would work nice with your 1.525 O.D. PSI 424 springs if the 1.685 O.D. fits and works for you. Dan
Geoff2
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Re: Spring locator to guide fitment

Post by Geoff2 »

Comp Cams has a number of 0.630" ID locators; probably other brands as well.
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