Oil Soaking Valve springs

[VaBeachZ]

I would like an education.

Some time ago, I was read/told before using new cylinder head valve springs, to do two events to them.

1. Compress the spring in a vice to coil bind and return to stress-relieve.
2. Oil soak the springs overnight.

Why would I oil soak a valve spring?

 

[evelrod]

I never heard the soak in oil deal. But since my DOHC engine design precludes visual inspection of the assembled valve train I typically install the retainer, spring and, seat in a vice and compress them to measure the assembled height at bind. I can then assemble them in the engine at near min compression height. I assemble at near min installed height, which gives me a 10,000 rpm+ capability even though I only use 8500 or so, to keep the valve springs out of a damaging harmonic that used to occur at ~8000 when the springs were assembled at "reccommended" specs. Otherwise, I can think of no reason to compress them unless you suspect a problem in which case I would replace them anyway.

Rod

 

[strokersix]

It's possible that if the outer fibers of the spring yield slightly at coil bind that fatigue life will be improved when operating at less than coil bind.

Oil soak? To prevent corrosion from your fingerprints perhaps?

Above are just my thoughts. Please do not accept them as facts unless others corroborate.

 

[richdubbya]

IMO it is a good idea to oil valve springs well. One reason is to prevent rust if it will be some time before the engine is to be used. One small rust pit can spell disaster for a spring. Another reason is to prevent wear and heat from the rubbing friction between the coils and/or dampners during initial start up. This is especially important on OHV engines that may have been modified to limit the amount of oil delivered to the valve train.

 

[evelrod]

I agree that keeping valve springs well oiled, even when doing trial assembly is important but---soaking overnight?

Rod

 

[richdubbya]

I don't know what soaking overnight would do. I do know that to oil them completely they should be submerged (especially dual or triple springs).

 

[R1100S]

I've soaked lifters to try and get the air out reducing the number of cycles before they are pumped up, but never springs.

 

[swall]

Many valve springs are cold set (compressed to solid) by the manufacturer as the final stage in the manufacturing sequence. This increases the yield strength somewhat and (favorably) rearranges the residual stress distribution. My only concern about using a vise would be that if you got the spring slightly cocked and squeezed it to solid, you could end up with a spring out of square.Oiling, of course is good.

 

[patprimmer]

Compressing to coil bind might help if not already done by the manufacturer, but be carefully, they can be damaged or fly out if simply done in a bench vise without adequate jaws.

Liberally coated in oil should do, for all the reasons of start up friction and corrosion creating stress risers as indicated by previous comments. I can see no advantage in soaking in oil for more than the time it takes to wet the surface.


Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[VaBeachZ]

To All,

Appreciate the answers given and more info is learned.

I did not know manufacturers compressed the spring as a final assembly procedure. Yes, A straight vise is a major concern. One could drill both jaws and insert a rod inside the coil to help keep the spring from becoming a projectile.

I personally don't think oil soaking has anything to do with changing the mech properties of the steel, but, I do agree it is a good practice for initial oiling to cool the spring upon engine startup and waiting for the oil splash to cool it later.

Everett

 

[evelrod]

As I said above, I find it necessary to compress valve spring assemblies on occasion to measure the OA at bind. In my opinion, if one cannot perform such a simple process as compressing a valve spring, retainer and, seat in a vice properly without breaking something or injuring himself he, truly, should do us all a favor and find another hobby.


Rod

 

[patprimmer]

Rod

I couldn't agree more, but I have seen valve springs being compressed in a small worn vice with the original steel jaws, with the springs well off centre. I left the room before anything happened.

Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[tbuelna]

VaBeachZ:

All good quality valve spring (or any quality compression type spring- helical coil, belleville, etc.) are "pre set" by the manufacturer. That means they are compressed to flat, or coil bind, conditions after heat treat. If you are buying your springs from a reputable manufacturer, it should not be of concern to you.

As far as "oil soak" is concerned, most engine valve springs are metal alloy, and therefore impermeable to oil.
Of course, you may have confused the term "oil soak" and "oil quench". Most high quality engine valve springs are chrome-silicon or chrome-vanadium alloy steel, which may require an "oil quench" during their heat treat process.

Good Luck,
Terry