How many valve springs should I have?

[Highwaylass]

I took apart a spare cylinder head for practice, and that had 2 valve springs per valve, a large and a small.

Now I've taken apart the one from my Lomax and it only has one spring per valve.

Is that correct?

[Geoff Ryall-Harvey]

Entirely possible - they came with either single or double valve springs. Ken Hannah would know the details of when and which... I suspect the earlier ones had double springs and then the accountants decided to go the cheaper route.

[Ken Hanna]

Earlier 602 engines had double valve springs, not sure when the changeover took place, but probably early 1970s.
Keep the valve spring parts for that head separate from any 'single spring' bits, as there are quite a few differences, not just in the spring rates but also the associated bits 'n pieces.

Entirely possible - they came with either single or double valve springs. Ken Hanna would know the details of when and which... I suspect the earlier ones had double springs and then the accountants decided to go the cheaper route.

[Highwaylass]

Thanks!

If they are that early, presumably they won't be unleaded-ready?

I was going to get them reconditioned and have them as a back-up, is that OK as long as I don't mix up the bits?

[Ken Hanna]

Unleaded ready?
As far as I'm concerned, all 602 engines are OK with unleaded, just as long as you take the simple precautions of setting the
valve clearances slightly wider than originally recommended*, then checking them every time an oil change is done.
* (* 0.25mm 'loose fit' for the exhaust valves, 0.25mm 'sliding fit' for the inlets.)

The rocker covers have to come off anyway to drain the oil that sits in there and also to clear away any sludge which settles
in the covers, so it's no real bother to let things cool while you have a cup of tea and dig out the feeler gauges.

Maybe have the head(s) checked over by someone who knows 2CVs before having a lot of work done?
Things such as the condition of the manifold studs, spark plug threads and oil feed threads need to be taken into account before
launching into work such as new guides and valves...

Ken

Thanks!

If they are that early, presumably they won't be unleaded-ready?

I was going to get them reconditioned and have them as a back-up, is that OK as long as I don't mix up the bits?

[Highwaylass]

ECAs sell this:

"Exhaust valve seat 2cv6 for unleaded fuel use. VERY difficult to fit, not DIY!"

So I assumed that in order to be "unleaded-ready" the heads had to have them fitted. My mistake!

[Ken Hanna]

More detailed advice on ECAS' site here...
http://www.ecas2cvparts.co.uk/info_page ... 7c01951d4f

Have to add that I'm not convinced by Citroen's claim that even harder valve seats were fitted post '86.
Not too long ago, I recommissioned a 1989 car which had been used for 12,000 miles, then stored for
20 years. The rocker covers had never been off and both exhaust valves had less than 0.05mm clearance,
so it was one long, fast trip away from burnt valve seats.
Regular checks and adjustment seem to me to be a better approach than adding chemicals with an unknown
effect on the environment as a substitute for one with known adverse affects...

[Geoff Ryall-Harvey]

I've stopped using the additives because I can't see that it's necessary. I do keep the valve clearances at .25 and have never had any issues.

This larger clearance makes the engine sound quite "tappetty" by normal standards and I think people coming new to 2CVs don't like that so they adjust them until they're quieter and then run into all sorts of problems.

The problems Ken mentions with threads (oil feed, studs and plugs) are very common and can lead to an otherwise good head being scrapped. In motorsport a lot of aluminium heads have steel inserts fitted as a matter of course. I'm thinking that I may have this done to my heads over the winter as I had an exhaust stud snap off recently and it was a real pain to sort out.

[Highwaylass]

Unfortunately one of the spare heads does have sheared exhaust studs, I am hoping to throw myself on the mercy of the machine shop and ask if they can get them out.

The valves are in much better condition than the ones that were in the Lomax heads. I am still learning but I am working on the basis that a thick coating of oil (right hand head) and a thick layer of charcoal (left hand head) are not signs of a healthy engine. One of the oil seals on the oily head came off in my fingers so I think the cause of that one is identified!