Technical valve-guide seals for the 652cc engine

[the hobbler]

I am in the process of rebuilding a 652cc engine for a colleague (the guy resurrecting my 500--got to help offset the cost one way or the other!) and I needed to find new valve guide seals. This engine had seals on all 4 guides, but most of them only have seals on the inlet valves (as does the Panda30 head). Being that these engines stopped being built some years ago/not imported to the UK, there is no listing for them. Having spent a couple of evenings trawling through a wide variety of sites I pinned it down to "Elring" or "Corteco". The 'Elring' type 197-378 fit perfectly and match all 3 criteria ---valve stem size (8mm), valve guide external diameter where they are 'reduced' to allow for fitment of the seals (10.8mm) and external diameter of the seal (14mm). The seals have to have an external diameter of less than 15mm in order that they will fit inside the inner valve spring.
"Corteco" have 3 seals that match the required criteria:---12014584 (8 seal kit---19018251), 12014265 (8 seal kit---19018249) or 12017061 (8 seal kit (8 seal kit---19034026). I haven't tried the 'Corteco' seals, but they are a company with a very good reputation so I have no doubt they will work as well as the 'Elring'--it's just that my 'engine shop' got me the 'Elring' to try, and at 70p per seal it was well worth trying them.

 

[Toshi 975]

I have only ever seen one picture of a very late Panda 30 head that had the step on all 4 valve guides that take the more sophisticated oil seals as opposed to the simple O-ring on the inlet valves of 500 and most 126 engines. May or may not have been original but I put it down to being more emissions aware. This is a 1986 126 head that has the step just on the inlets.

 

[AndrewHarvey]

Tom - when you say resurrect your 500 - what's happened to it?

 

[the hobbler]

It went into a local (small, but very good) restoration body shop to have the front spring mis-alignment rectified. The more they got into the job, the more totally crap previous repair they found. It seems that at some time it may have had a crunch at the n/s front---whoever repaired it had no welding skill, but this was compensated by his great skill with a pop-rivet gun and coach-screws!! The whole front has been re-built along with 2 new floors--and the (new) jacking points are now welded on!

 

[AndrewHarvey]

Wow!
I think mine still needs a pull....ive written about this but I still have an issue.
Although I run independent front suspension that I can adjust....u still have the tyre on the previously damaged side rubbing on my extended wheel arch.

 

[Toshi 975]

I need to replace the valve guides on a Panda 30 cylinder head but I can't seem to find the valve guides with the step on top to take these later seals. Any ideas you guys?

 

[the hobbler]

I had a fairly technical answer all written out--but because I was finding info out as I did it, the whole lot got blown out when I tried to put it through--AAAAArg! I will try again in the morning, now that I have the info to hand.

 

[the hobbler]

I had a good troll through all the main 500/126 sales sites, and it would seem that almost nobody sells the correct size, let alone the correct shape valve-guides. Almost everybody is selling guides (steel) with an outside diameter of 14.2mm---the correct outside diameter for a 652cc '126') is between 14.040mm and 14.058 for a standard size guide and between 14.060mm and 14.078mm for the 'oversize. To fit a 14.2mm guide, the valve-guide bore (in the head) which should be between 13.950mm and 13.977mm would need a fair bit of opening-up.
I found one exception re. guide size---that is WWW.PASSIONE.IT. Their part number "MOT37" is for valve guides with an external dimension of 14.02mm---their MOT36 series has other valve guides with an increasing external diameter. All are for 8mm valve-stems. However, none of these guides have the 'step' to allow for the fitment of 'proper' valve-guide seals, although it shouldn't be beyond the wit of a competent machine shop to machine the seal-fitment 'step' (diameter of 10.8mm with a length of 6.3-6.5mm, which allows 'Elring' 197-378 seals to be used).
Another option is to contact Franco at "Ricambi International" in south-west London---he sells new Panda30 heads.
The final option is to think outside the box---find an engine that uses valves with 8mm stems, and see if their guides can be made to fit/adapted. Whatever you do end up doing, please keep us informed--some of us might be pleased to hear the outcome!

 

[Toshi 975]

Thanks for the efforts there Tom. I will probably end up getting on a lathe and machining some down