CB HD Springs

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Ark1
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CB HD Springs

Post by Ark1 » Wed Oct 12, 2016 9:46 pm

Hey guys! Started assembling my heads and the Cb HD springs I installed just didn't seem to fit into the head right. Is it necessary to clearance the base somehow?

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Marc
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Re: CB HD Springs

Post by Marc » Thu Oct 13, 2016 1:25 am

They may be "Chev" diameter which can be used but only after flycutting the spring seat out. Gene Berg used to sell 1.4374" (36.5mm); CB Performance sells some that "drop in" to the stock diameter seat as well as some that they say are 1.440".

Which CB P/N are they?

What retainers are you using, and do they fit snugly into the springs?

Ark1
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Joined: Wed Jul 20, 2016 11:17 pm

Re: CB HD Springs

Post by Ark1 » Thu Oct 13, 2016 3:43 pm

Cb 1490. Title Reads "1490 Single Hi-Rev Valve Springs - 40hp-later (set of 8)". The retainers/keepers are the basic chromoly one's offered on CIP1.

Ad says "Replaces original parts perfectly."

I'll grab some picture's of them installed for reference.

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Marc
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Re: CB HD Springs

Post by Marc » Thu Oct 13, 2016 4:47 pm

Those should be stock diameter (so "standard" O.D. retainers should fit them fine). OEM springs typically measure around 1.23" O.D., I think the "nominal" size of the stock spring pocket is 32mm (~1.25") - 1¼" O.D. spring shims fit snugly in them.
The inside diameter should come close to rubbing on the guide boss - that'll keep the springs centered, which is why some hacks have managed to fit "Chev" springs to unmachined heads and just let them chew their way in...not smart, especially without a full-flow oil filter ;)

If yours measure bigger than 1.25" O.D. it may be that CBP's supplier made a bad batch and they weren't caught before packaging - you want the retainers to fit snugly, if they can move laterally inside the spring I'd send the springs back.

It's good practice to always use a steel shim between the spring & the head, especially with stiffer-than-stock springs. Doesn't have to be very thick, say .015-.020".

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