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  #1  
Old 30th October 2018, 07:15 PM
I polished one off to a dude's Avatar
I polished one off to a dude I polished one off to a dude is offline
Buswald's Finest
 
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Question Custom shims

Anyone ever get custom valve/tappet shims made?
Recommend anywhere?
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  #2  
Old 30th October 2018, 08:30 PM
the landshark's Avatar
the landshark the landshark is offline
Quantum Mechanic
 
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Default Re: Custom shims

Why? If the valve is that far out of clearance that a standard shim set won't cover it you've bigger problems.
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  #3  
Old 30th October 2018, 09:21 PM
DavyH DavyH is offline
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Default Re: Custom shims

I'm sure you could find an engineering firm that can surface grind them, but they'd need to be case hardened again more than likely depending how much needs removing. Now if its the diameter that's a whole different ball game. They will need to be made from scratch. What's the objective, maximum lift? Or oversized valves and springs?
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  #4  
Old 30th October 2018, 11:55 PM
I polished one off to a dude's Avatar
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Buswald's Finest
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Default Re: Custom shims

my shim edges are eating into the walls of the titanium retainers. one almost made it completely out.
I noted the shims were sharp edged so replaced them with radiused/chamfered edge ones and same thing happens.

manufacturer of the titanium retainers said it looks like some kind of harmonic frequency vibration shit.

rather than trying to tackle that black box i was thinking of getting custom shims made.
the current setup is 1.75mm lower shims and 2.35 - 2.50mm upper shims. they both wear a ring into the retainer.

i was thinking make shims thick enough so i only need 1 instead of 2 per valve, and also shape them with a skirt that goes down around the valve tip almost to the collets. and radius the lower edge generously.

the aim would be to maximise surface area, remove the edges that start the wear, and use the valve tip as additional surface area holding onto the shim.
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  #5  
Old 31st October 2018, 12:40 AM
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chopper chopper is offline
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Default Re: Custom shims

something like a yamaha shim ? http://www.biker.ie/forum/showpost.p...9&postcount=83
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  #6  
Old 31st October 2018, 10:19 AM
Dave38 Dave38 is offline
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Default Re: Custom shims

Give Kent Cams a shout: http://www.kentcams.com/
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  #7  
Old 31st October 2018, 10:31 AM
the landshark's Avatar
the landshark the landshark is offline
Quantum Mechanic
 
Biker.ie Member No. 7493 from Mallow
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Motorbike: TLR,Z900,CB200,CD200,Pan
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Default Re: Custom shims

If they're wearing into the titanium I'd say that galling is the problem.
Can the shims move laterally across the titanium, ie can they slide from side to side, even a tiny amount, because if they can this is the reason for the galling, and titanium galls like a bastard.
I would look to see could the shims be made to press fit into the retainer.
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  #8  
Old 31st October 2018, 06:44 PM
I polished one off to a dude's Avatar
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Buswald's Finest
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Default Re: Custom shims

Originally Posted by chopper
exactly yes, someone has done it before. can you get them in 9.48mm?
or what yamaha they out of?


Originally Posted by the landshark
If they're wearing into the titanium I'd say that galling is the problem.
Can the shims move laterally across the titanium, ie can they slide from side to side, even a tiny amount, because if they can this is the reason for the galling, and titanium galls like a bastard.
I would look to see could the shims be made to press fit into the retainer.
new they are a transition fit, you have to get them exactly square or they jam and won't go in. after several thousand miles they loosen up due to this wearing
galling happen with the level of oil lube insides of tappet buckets get?
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  #9  
Old 31st October 2018, 10:05 PM
the landshark's Avatar
the landshark the landshark is offline
Quantum Mechanic
 
Biker.ie Member No. 7493 from Mallow
5,918 posts since Dec 2007
Motorbike: TLR,Z900,CB200,CD200,Pan
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Default Re: Custom shims

Originally Posted by I polished one off to a dude
galling happen with the level of oil lube insides of tappet buckets get?
Titanium is difficult stuff to lubricate, it doesn't deal with oils very well.
The main problem is that Titanium to Titanium has one of the highest friction coefficients of any metal. Now you will say that the shim is steel so why does that matter but the steel shim picks up a coating of titanium from the retainer so you have, in effect, two titanium surfaces sliding against each other.
Ordinary oils will do fuck all to reduce the friction and thus the galling.
In industrial applications Titanium is generally coated with another metal, gears or suchlike would be coated in nickel, Titanium is rarely used in high wear applications due to the fact that it's a right bastard to lubricate.
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  #10  
Old 1st November 2018, 12:04 AM
DavyH DavyH is offline
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Default Re: Custom shims

Originally Posted by the landshark
Titanium is difficult stuff to lubricate, it doesn't deal with oils very well.
The main problem is that Titanium to Titanium has one of the highest friction coefficients of any metal. Now you will say that the shim is steel so why does that matter but the steel shim picks up a coating of titanium from the retainer so you have, in effect, two titanium surfaces sliding against each other.
Ordinary oils will do fuck all to reduce the friction and thus the galling.
In industrial applications Titanium is generally coated with another metal, gears or suchlike would be coated in nickel, Titanium is rarely used in high wear applications due to the fact that it's a right bastard to lubricate.
Great info there Landshark, is it possible to get it shot peened to take the roughness off the surface?
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  #11  
Old 1st November 2018, 09:09 AM
the landshark's Avatar
the landshark the landshark is offline
Quantum Mechanic
 
Biker.ie Member No. 7493 from Mallow
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Motorbike: TLR,Z900,CB200,CD200,Pan
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Default Re: Custom shims

Originally Posted by DavyH
Great info there Landshark, is it possible to get it shot peened to take the roughness off the surface?
Yes it's possible to shot peen it but it won't help fuck all in my experience.
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  #12  
Old 1st November 2018, 07:01 PM
I polished one off to a dude's Avatar
I polished one off to a dude I polished one off to a dude is offline
Buswald's Finest
Original Poster of This Thread Topic Starter
 
Biker.ie Member No. 21188
4,697 posts since Mar 2010
Motorbike: same as my friend iano
Default Re: Custom shims

Originally Posted by the landshark
Titanium is difficult stuff to lubricate, it doesn't deal with oils very well.
The main problem is that Titanium to Titanium has one of the highest friction coefficients of any metal. Now you will say that the shim is steel so why does that matter but the steel shim picks up a coating of titanium from the retainer so you have, in effect, two titanium surfaces sliding against each other.
Ordinary oils will do fuck all to reduce the friction and thus the galling.
In industrial applications Titanium is generally coated with another metal, gears or suchlike would be coated in nickel, Titanium is rarely used in high wear applications due to the fact that it's a right bastard to lubricate.
so i suppose i should be looking for a steel equivalent retainer to put in instead then. makes me wonder why they make titanium retainers, is it just coz it sounds good sales pitch wise, lighter weight in the moving parts and all that?


not my pic but someone with similar issue in a busa;

Click the image to open in full size.

Last edited by I polished one off to a dude; 1st November 2018 at 07:03 PM.
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  #13  
Old 1st November 2018, 10:05 PM
the landshark's Avatar
the landshark the landshark is offline
Quantum Mechanic
 
Biker.ie Member No. 7493 from Mallow
5,918 posts since Dec 2007
Motorbike: TLR,Z900,CB200,CD200,Pan
Modifications: They sometimes work
Default Re: Custom shims

The one on the left seems to be showing a little galling, where the shim can wander about a bit, i assume that is the issue with yours,
the one on the right is plain jane fatigue cracking. To be exact it appears to be a shear failure. That's not good especially in an OE part. Without examining the part it's hard to be sure but i would guess that the step in the underside of the retainer has too sharp a radius in the inside corner and the stresses are concentrated in one spot.
As to why use titanium retainers in the first place i cannot imagine a manufacturer using them. The failure rate would, i would have thought, be unacceptable although these guys know a lot more about metallurgy than I do.
In a competition engine i can see the benefits of titanium valve train components, less weight equals less inertia equals more available power and as those engines are rebuilt regularly i can see why they'd do it.
Myself I would be looking for steel replacements or go back to Standard if they are an aftermarket part. The miniscule HP gain ain't worth it if it goes tits up.
Btw I'm not a metallurgist or anything and I'm just giving you my understanding of what titanium is like, I have worked on enough broken Industrial Machinery to have come across this stuff before.
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  #14  
Old 1st November 2018, 11:54 PM
I polished one off to a dude's Avatar
I polished one off to a dude I polished one off to a dude is offline
Buswald's Finest
Original Poster of This Thread Topic Starter
 
Biker.ie Member No. 21188
4,697 posts since Mar 2010
Motorbike: same as my friend iano
Default Re: Custom shims

"lash caps" is apparently what they use with titanium valves. i guess what i'm talking about are custom made lash caps to the thickness of my shims.

landshark i think you hit the nail on the head there, joys of running a race engine on the street, seems like you just have to replace these things every so often.
fuck that. wondering would it be easier/better to go with steel retainers or with customs made lash caps.

you see the stock engine is a shim over bucket design. but the head has been converted to shim under bucket (amongst other things) to permit aggressive race cams and 33% higher rev limit and not spit shims. so the retainers are apparently a propriety custom design.
my supplier will only sell me more, of course, there's no manufacturer mark on them but i did manage to sleuth out the manufacturer.
anyway custom propriety might mean it's difficult to get OEM steel versions the same critical dims as them.

i suppose there must be a reason they went to the trouble of getting these retainers made in titanium, maybe they were getting valve float issues and decided to lighten the load. they did also have dual spring setup but changed to a single spring.

Last edited by I polished one off to a dude; 1st November 2018 at 11:55 PM.
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  #15  
Old 2nd November 2018, 03:11 PM
chopper's Avatar
chopper chopper is offline
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Biker.ie Member No. 1841 from meath
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My Motorcycle Pics Motorbike: jap brit and euro
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Default Re: Custom shims

Originally Posted by I polished one off to a dude
exactly yes, someone has done it before. can you get them in 9.48mm?
or what yamaha they out of?




new they are a transition fit, you have to get them exactly square or they jam and won't go in. after several thousand miles they loosen up due to this wearing
galling happen with the level of oil lube insides of tappet buckets get?
Those are 7mm yamaha ones from some fzx/r 750s and some fzr1000s
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