Photos for Rohan

[HCA]

[rgh0]

Hi Hal

Can you post a couple of photos looking straight down from the top of the the retainer both fitted to the valve and not fitted.

Also what is the distance from the top of the collet groove to the top of the valve. This is is normally around 0.25mm. Make sure everything is absolutely clean and tap the valve stem down to make sure its properly seated in the collets and check again if the valve steams are still level or above the top of the retainer

You certainly cannot fit a normal shim with this assembly with the valve stems level or above with the retainer top and it was probably designed for valve stem cap shims. I do not use them as they need to be individually ground to achieve the correct clearance which is a difficult and time consuming process for an expert machine shop that has the right equipment to do it.

cheers
Rohan

[HCA]

Photos attached Rohan. Sorry for poor quality - old iphone.

First, the best I can measure the top of the collet groove to the valve top is a tad over 5mm - about 5.2mm. Certainly more than 0.25mm!

Second the retainer on its own and third with valve and collets.

Double checked the valve and collets are tight in the retainer and still the valve top is flush, or point something of a mm proud...

Race Engine Components do not - that I can see - give general specs for their valves on the website. Certainly I have their REC 225, race length, for the inlet and REC 227, race length, for the exhaust as they are clearly stamped thus. But I see in their catalogue that REC 244 is the same application but with 'std length' stem. Likewise for the exhaust it is REC 320.

Obviously Wilcox for whatever reason prefers using caps, but if as you say, they are a pita to size, I would prefer a simpler alternative.

Maybe in the morning I will call Race Engine and ask what the std length of the valve is, and then ask John to exchange? What do you suggest?

[HCA]

Thinking about this Rohan if I ask for an exchange, now that the UK has decided to leave civilisation, I am going to have all sorts of paperwork with customs to exchange the valves (if this is what I must/should do) - as the top of the valve stem is not, accourding to the GS catalogue, hardened, could I get the stem tops turned down to a size to accept shims locally..? Just a thought.

[rgh0]

The valves can certainly be modified to fit standard shims. The tips should be ground to get them smooth and square. i made a typo in my last post , should have said 2.5mm not .25 mm. The 5mm is to much when using standard shims and more typically what's used with caps in my limited experience with the cap style setups.

From the photo the retainers have a shallow recess in the top. Is that recess the diameter of a standard shim and how deep is it? It may be possible to use these retainers with standard shims but maybe not as the valve assembly does look like its been designed for stem caps.

Depending on the spring inside diameters it may be possible to source alternate retainers if the ones you have will not work with standard shims.

cheers
Rohan

[HCA]

The recess in the retainer is 15.1mm diameter with a depth of 1.14mm. What is the depth of a recess in a retainer designed for shims?

The depth of the top of collet (top of the groove) from the top of the retainer is 5.16mm.

If the diameter of a shim is 15mm, then it only needs 0.7mm shaving off the top of the valve stem for a shim to sit in the recess without pushing on the retainer...

[rgh0]

The retainer looks and measures the same as the QED race retainers I have. It is designed for using valve stem caps and the recess in the top while it may fit a shim is to shallow to adequately retain it in place.

Normal retainers designed for shims have the top recess around 4 mm minimum and the valve tip sticks up into that recess by around 2 mm

I need to do some measuring of the various retainers I have see what's suitable for the springs you have

cheers
Rohan

[HCA]

Thanks Rohan

I did some trawling of the internet and agree these retainers are not suitable.

Whilst everything is still new and exchangeable, and rather than make any irreversible changes, it might be prudent to call John Wilcox and see if he has a ready supply of caps or will change my valves and springs for the shim type.

I will let you know tonight.

Thanks again!

[rgh0]

Talk to John about your options, The stem caps come in only a couple of thickness and need to be ground for each valve to suit, Shims are much easier to work with.

I have previously used the QED springs with the Tony Ingram titanium retainer without issues when an engine build needed a different spring length and rate than what Tony offered and the QED race springs were better for that particular build and I did not want to use the QED retainers with stem caps

However given you will need to grind the valve tops and buy new retainers and maybe springs also to go to shims it is certainly worth talking to John first

cheers
Rohan

[2cams70]

For what it's worth I used top hat shims in my build and they weren't a problem. True they had to be machined to the correct thickness but getting that done wasn't a problem either or particularly expensive (admittedly that was when Crankshaft Rebuilders was still in business). You can use one shim of a known thickness and use that as a +/- reference on all the valves for working out the amount of machining required for each shim.

They are actually a better solution engineering wise being both smaller and lighter. It's only the part of the shim that contacts the stem that's functional. The rest is waste and not required.

If you do go down the route of getting some top hat shims machined it might be worth getting a few more done + and minus a few thou from what you have in case you need to adjust clearances further down the track. Probably cheaper to do it all at the one time than having another batch done later on.

[HCA]

Thanks for the reassurance!

All is ok now, since spoken with the supplier who has a good stock of these caps and will supply caps and followers to suit each valve after a dry assembly.

[rgh0]

Now that I have retired from full time work, I have time to go down some of these rabbit holes further than I used to and can provide some quantified data

True that caps are lighter than shims

2.9mm shim - 4 gm
2.9mm stem cap - 2 gm

However other components have a much greater impact on valve train weight

Standard Lotus and QED Q55 steel retainer - 27 gm
Lotus 907 retainer used for Bean special spring pack in twin cam - 20 gm
QED cap style steel retainers - 16 gm
McCoy and Bean cap style steel retainers - 11 gm
Tony Ingram shim style Titanium retainer - 7 gm

Standard lotus cast iron follower 5.5 mm pad thickness - 51 gm
Thin steel longer followers 3.5 and 4.5 mm pad thickness - 39 m

Valve design is also a source of significant variation at least as big as the above components.

Both cap or shim options can be made to work to 9000 rpm plus with the right spring loads selected and it is personal preference as to which one you use. The titanium retainers more than compensate for the shim versus cap weight and I know of no one making titanium cap style retainers though I am sure you could get them made to order at a cost. Shims also spread the bearing load on the follower to better match the pad on the follower and cam lobe pressure on the other side of the follower but this does not appear to be a major reliability advantage.

I have collected a stock of over 400 shims over the years at very low cost so I prefer to use shims. There is a local shim grinder in Melbourne who can grind stem caps to whatever thickness you want but that isa time and cost I prefer to avoid.

cheers
Rohan

[HCA]

Hi Rohan

Some more photos!

First showing number of coils of the Isky spring, second showing the note on the box and then a fuzzy one showing colour - yes, it could be orange indeed.

Compressed length of the outer spring = 18mm (open length = 43.5mm)

Wire diam = 3.72mm

IMG_4160.jpeg (67.61 KiB) Viewed 702 times

IMG_4161.jpeg (40.37 KiB) Viewed 702 times

IMG_4162.jpeg (52.66 KiB) Viewed 702 times

[rgh0]

Except for the paint as far as i can tell these springs look identical to the QED race springs i have which are painted red all over. It appears based on whats in the Isky manual and my measurements of the QED springs that both Wilcox and QED are sourcing their springs from Isky with part number VWE-005 / SP-006

The Tony Ingram rally springs also look very similar from his web site but I dont have a set of these to measure up to confirm that. I have a couple of sets of the Tony Ingram race springs and these are slightly different.

I dont know if Isky design and make their own springs or if the get them from someone else who may be supplying all 3. The Isky springs were originally intended for an early air cooled VW / Porsche application which may explain the link I have never been able to track down to early Porsche engine springs.

cheers
Rohan

[Hawksfield]

Hi
What a great forum, information is always available from the experts.

Well done