Lotus Elan

Valve shims Question with Photo

PostPost by: hbferrariguy123 » Mon May 13, 2019 10:53 pm

img_4134.jpg and
While going through my Elan's engine parts I came across 2 different types of valve shims, 2 are flat discs and the remaining ones are sort of bowl shaped. (See photo) Also, I measured them and they run from .160 to .197. Looking at the parts manual the shims listed are much thinner then the ones I have. What's up with this?
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PostPost by: hbferrariguy123 » Tue May 14, 2019 1:17 am

Here's what I've gathered so far, the thicker shims are used when installing reground cams, which I happen to have. The cams are from Kenny Harman with .380 lift and 274 duration. I was told that the flat shims are factory and the cup shaped ones are/were Cosworth used on reground cams. So with that I think I'll start assembling the valves back in the head as they were when rebuilt a bunch of years ago just to see where they set the valves to. I can only hope that after my checking they fall into spec of inlets at 005 -007 and the exhaust at 006 - 008. That would make my life real easy!
Any input, suggestions, recommendations before I start the tedious task?
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PostPost by: StressCraxx » Tue May 14, 2019 5:19 am

First off, take your time. Put on some music, preferably some mellow surf music or jazz. If you put on Dick Dale and the Deltones, you will hurry and quickly get frustrated. Pour a glass of your favorite beverage.

I started with no shims and measured the gap for each valve and wrote the measurements down for each.

Then I subtracted 0.010" from the gap and installed the closest shims I had, writing down what I used.

Measured again with a feeler gauge and wrote the gaps down again.

Repeated the process with desired gaps on the high side of the tolerance.

Be glad you are not installing shims on a Cosworth DFV.
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PostPost by: el-saturn » Tue May 14, 2019 5:42 am

i love the suggestion: some jazz and a favourate drink - could that be some billie holiday and a bit of chardonnay?? .............................that's my ball park fellas! sandy ps - i own 6000 jazz lps: from satchmo to sun ra!
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PostPost by: 2cams70 » Tue May 14, 2019 8:34 am

Those shims have been discussed before on this forum. Just search under "top hat shims". If you are using a non-standard cam it's best to get information on clearances from the cam manufacturer.
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PostPost by: rgh0 » Tue May 14, 2019 1:09 pm

There are retainers designed for only top hat shims as they do not have the geometry to retain the biscuit style shim in location on the top of the retainer. These are typical some of the race supplied retainers. Top hat shims only come in a couple of thicknesses and need to be ground to achieve the required dimension when setting the cam clearance which is a pain to do when building an engine, especially if you have a couple of hundred biscuit shims in all the required thicknesses already. That's why I generally stick to springs and retainers that i can use biscuit shims with

However top hat shims can normally also be used as a substitute on retainers designed for biscuit shims but not visa versa though why you may want to do that is not obvious except for you may save a couple of grams in the valve train weight with the top hat shim.

Unless you building a 9000+ rpm engine and you want it to be based on a top hat shim spring pack you don't really need to worry about them as an alternative and should stick to the standard biscuit style shim.

cheers
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PostPost by: rgh0 » Tue May 14, 2019 1:15 pm

In terms of rebuilding your existing valve train you appear to have a somewhat compromised modified setup. Not easy to advise on what to do now from this distance except to say i would start from scratch.

I can advise on how to measure up what you have and how to determine what you need but it is a somewhat complex process with lots of variable and some judgement is required. Warnings of "your mileage may vary... " apply in this process

cheers
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PostPost by: StressCraxx » Wed May 15, 2019 3:40 am

el-saturn wrote:i love the suggestion: some jazz and a favourate drink - could that be some billie holiday and a bit of chardonnay?? .............................that's my ball park fellas! sandy ps - i own 6000 jazz lps: from satchmo to sun ra!
Wow, that's a lot of vinyl!

Billie Holliday, Stan Getz, Dave Brubeck.. Of course. Chardonnay is good, I'm partial to Cabernet or Pinot....

I used the surf music since HBferrari is from Huntington Beach, CA. I used to surf with my friends at Bolsa Chica and Huntington Cliffs...

Perhaps you could post some photos of the head with the valves installed. That might indicate which shims you need. Evidently some retainers will allow both shims. YMMV

Tony Ingram at http://www.lotus7.com/LOTUS_ENGINE_PARTS.html

Or Ken at Dave Bean can steer you right.
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PostPost by: el-saturn » Wed May 15, 2019 5:43 am

that's where my brother dex used to go (**) - he lived in carslbad and all day long he and his buddies were waiting for THE SWELL! sandy ** he moved to baja, mx
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PostPost by: JJDraper » Wed May 15, 2019 6:30 am

Valve clearances do change from the initial set up on the bench, to the initial head torque down and settle down period. After getting my paper calcs wrong (too much favourite beverage perhaps?) a couple of times I put together a simple spreadsheet to try and automate the process and eliminate brain fade. It is also useful to keep a record of how your valve clearances have changed over time. May help someone.. Feel free to modify, change and comment.

Jeremy
PS had to save it in the old Excel format as this site does not allow the latest file format.
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PostPost by: nmauduit » Wed May 15, 2019 8:58 am

el-saturn wrote:that's where my brother dex used to go (**) - he lived in carslbad and all day long he and his buddies were waiting for THE SWELL! sandy ** he moved to baja, mx


Dude... when I lived in Solana Beach I used to go surfin just a bit south, at Swami's, or next to San Elijo's state beach where they had a shower... brings back memories...
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PostPost by: hbferrariguy123 » Thu May 16, 2019 4:13 am

Thanks to all who replied with some great recommendations. To start, I disassembled the head last week and marked, bagged and tagged every part including the shims and retainers so I'm good there. As was suggested, I will slow down and take my time. My wife has some things I need to do before I will get time to mess with the engine. (Happy wife, happy life!)
When I do get back to working on the engine, hopefully over the weekend, I'll put on some classic rock, Eagles, Dobbie Brothers... and grab a Diet Coke, I'm not much of a jazz fan and I gave up drinking in 1995. Ugh! Plus, I don't surf so there will be no Dick Dale or Beach Boys. I was born and raised in Northern New Jersey where surfing is non existing. Just snow shoveling and working on cars was what I did often.
Meanwhile I will think about a plan and how I will progress and look forward to continuing on. Thanks again!
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