Valve Shims

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Cliffords
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Valve Shims

Post by Cliffords »

Now it time for a complete set of valve shims . The valves have all been lapped or replaced so I am starting from scratch .
I can see them individually priced at the usual suppliers .

What I really need is a box of various sizes , did I read somewhere others had found alternative sources , Saab ? I may have got this wrong .
Any thoughts appreciated

Thanks

Pete Boole
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Re: Valve Shims

Post by Pete Boole »

QED have the widest selection of thicknesses - beyond the normal range, depending on the cam profiles that you are using - up to 0.200".

Pete

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Re: Valve Shims

Post by Esprit2 »

Lotus valve shims for Twin Cam and 9XX engines are the same. And both are interchangeable with shims for the Triumph TR7 and older Jaguar XK 6-cylinder engines (Moss Motors, Victoria British, The Roadster Factory... etc), Saab 99 2-valve, Cosworth, Coventry-Climax (vintage racing suppliers) and the Hillman Imp (faux Climax FW_).

Lotus TC & 9XX .. 0.060"-0.150", in 0.001" steps, 0.061, 0.062, 0.063... etc (best resolution)
Saab 99 2-Valve . 0.090"-0.120"
Triumph TR- 7..... 0.070"-0.120" in 0.002" steps, 0.070, 0.072, 0.074... etc.

Many Former SAAB dealers only service the newer cars these days. And even if they have a shim set from the old days, the parts counter guys may not know about it. I make a point of asking to speak with the most senior mechanic on staff (the old guy), then ask him if they have a shop-collection of shims. It's usually a dusty bin the mechanics have separate from the service parts inventory and it hasn't seen the light of day for quite some time. Most of the shims will be used, but that's okay, they work just as well. Deal with the Service Manager since the parts guys don't know, and the old mechanic thinks the shims are "his".

The former-dealer near me exchanges shims on a one-for-one basis for free. Bring in your 16 old shims, ask for 'the old guy', and leave with 16 different old shims that you need... for free. 'IF' their service kit doesn't have the size you need, then the 'Parts Dept' just down the hall will SELL you a new one... they have them in stock.

If you re-use shims (perfectly acceptable), note that the end of the valve stem has probably worn a depression in the center of the shim that can be anything from a polished bright spot to a pocket several thousandths deep... enough to frustrate your efforts to clearance the valves if you don't give it proper consideration.. The Lotus, TR7, Saab, Jag and Cosworth shims are all about the same in metallurgy. Case-hardene4d... ie, hard durface, but soft center... sot not immortal.

Don't go by the thickness markings engrved on the shim. It's important to measure used valve shims with a micrometer with it's anvil positioned in the center (ie, in the depression). That will give a true reading of the shim's thickness in the working portion (center) where the valve stem makes contact. Using a micrometer to measure the rim, or using a caliper (the blades will bridge across the depression) will yield larger readings than the shim's actual center thickness.

Make it a point of discipline to always install the depression-side down against the valve stem. Yes, you can be smart about installing them depression side up or down to get the desired result. However, if you install a used shim depression side up and wear a second depression into the other side, it then becomes more difficult to measure and install properly the next time.

For a shim with a depression on both faces... time to trash it and move on.

Back when SAAB closed, I went to a local dealership (which was also closing) to inquire about the mechanic's shim kit. They sold it to me (compartmentalized flip-top bin, a 'lot' of shims and a 0-1" mictometer for US$40. It's been a long time, but it wouldn't hurt you to ask a former SAAB dealer what happened to their shim kit.

Is there a Lotus Owner's Club near you? I'm in Minnesota, USA. Our local club is 'Lotus Owners Oftha North' (LOON... the Loon is the Minnesota state bird). Years ago, all the Twin Cam and 9XX owners pooled their individually meeger shim collections into one large, shared kit. All those meeger collections became one substantial kit in a canvas bag (gym bag), complete with individual trays of 10 bins (one each for .060", 0.070", 0.080".... 0.140", 0.150"), a micrometer, feeler gauges, a few minor tools, and instructions. Use whatever shims you need for your engine, BUT... put all the shims you remove from your engine back into the kit. Purely voluntary, but often a grateful user will buy a few new shims and add them to the kit. Everybody benefits. Just pass it on to the next guy.

Regards,
Tim Engel

Cliffords
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Re: Valve Shims

Post by Cliffords »

Fantastic reply. Thank you for taking the time to write
David

jeff.fenton
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Re: Valve Shims

Post by jeff.fenton »

If you search "shims", April 2018, I offered to exchange shims for members free, apart from postage charges, not heard a word since. Still stands if you're interested. Jeff.

HC180
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Re: Valve Shims

Post by HC180 »

The Shim Library Thread

I still have these from Richard; I would happily forward them to you if you PM your details.
Last edited by HC180 on Sun Nov 06, 2022 19:10, edited 1 time in total.

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bash
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Re: Valve Shims

Post by bash »

The shim library thread should be be a 'sticky' for such an important service, ( one for admin) well done Jeff.

Bash
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Cliffords
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Re: Valve Shims

Post by Cliffords »

I did do the search but I had no success. So I am not quite following what the shim library is .

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rbgosling
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Re: Valve Shims

Post by rbgosling »

The concept of the Shim Library is a supply of shims of different sizes. Anyone who needs to re-shim their valves borrows the library, takes the shims they need, and in return donates the shims that they have left over.

I have no idea how many shims are currently in the library, but I'm guessing it's not enough to be truly useful yet.

When I rebuilt my engine I made a "first guess" as to the sizes I need, bought them from LotusBits (not expensive), and they were happy for me to come back and swap them a few times until I got it right. But I then lived 15 minutes drive / 30 minutes cycle ride from LotusBits, so popping back and forth wasn't so much of a faff. Still, more of a faff than just being able to swap in and out at home until they were perfect!
"Farmer" Richard

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Cliffords
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Re: Valve Shims

Post by Cliffords »

That's great. Thanks for the reply. I can add a full set as none of mine will do . But I do need a few to find my start point before I just buy blind . I now understand the library that's great . Who had got them right now ?

Thanks

David

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rbgosling
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Re: Valve Shims

Post by rbgosling »

Mark / HC180 has my old shims at least, I don't know how many more he has...
"Farmer" Richard

1990 Lotus Excel SE (Lilith)
2022 MG MG5 EV (not due to be a classic for quite a few years...)
2011 Nissan Leaf (Ragly - EV pioneer, must be due to be a classic one day)

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Re: Valve Shims

Post by DavidOliver »

Just in case!
If you intend to Home In to clearance and wish to avoid using Loctite 504 every time you re-assemble, the adjustment to gap measurements when Dry is 0.0015 inches.
I do not know what adjustment is required for more modern gasket replacing goos.

Dave the cog.

HC180
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Re: Valve Shims

Post by HC180 »

I have sent these today, recorded delivery.

Pete Boole
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Re: Valve Shims

Post by Pete Boole »

DavidOliver wrote:
Mon Nov 07, 2022 12:28
I do not know what adjustment is required for more modern gasket replacing goos.

Dave the cog.
0.0005" for the latest recommended goo!

Pete

Cliffords
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Re: Valve Shims

Post by Cliffords »

They are on their way to my house that's absolutely outstanding thank you for all that advised and I await the start of the next job that I suspect will be quite time consuming and fiddly

David

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