Kent crossflow - valve spring compressor - head in place

[brianmurray325hotmail.com]

My old crossflow is going to to be the beneficiary of massive investment over the winter, i'm investing in new valve stem seals. Instead of using the "roadside solution" for compressing the valve springs with the head in place (a 12" driver and bike tyre lever) I think that there is a tool on the market that can compress the spring with the head on, i've seen one for the later ford engine but don't know if it is good for the crossflow. Has anybody got info on this bit of kit for use on the crossflow.

[OliverSedlacek]

I've no idea about 12" driver and bike tyre lever method. The only way to take the spring caps off with the head in situ that I know of is to turn the engine so that both valves are closed and then to apply compressed air through the spark plug hole.

[Ian Macquarie]

There is a method that involves feeding string into the plug hole then rotating the crank until the piston compresses the string and holds the valves in place. (Similar to the compressed air but without the need for an air compressor and the risk of leaks.) A steel bar with suitable holes can then be used to compress the valve spring and remove the collets (Sp?).

I have done this successfully with a home made bar - I'm not sure whether there is a commercially available equivalent or not.

Ian

[virden]

 If your seals need replacing would it not be a good idea to take the head off to give the valve seats a light  lap and to check your bores?  Did you take a compression test?

[OliverSedlacek]

Bearing in mind that taking the head off is pretty easy on a crossflow seven, I would also question how much time you would save.

[simonpa]

Window sash cord is easier than string - the effect is the same.

Removing the head is really simple, though - especially as you will be removing the rocker assembly.
Use double (steel) nuts on the exhaust manifold studs, to remove the stud, rather than having to loosen the exhaust to get it far enough away from the head to lift the head.  The carbs/inlet manifold can always stay attached to the head.

 

[Gloucestershire AR]

Coincidentally - just taken my head off to do the same thing and found it needed new inlet valves and guides too. Incidentally, my head uses VW valve stem seals. Reckoned to be better than the Ford ones.

Also found the exhaust valves (no stem seals needed on those) needed a bit of a clean up, as did the pistons and valve seats so another reason to bite the bullet and remove the head! Ajusa head gasket reckoned to be a good choice and a lot less expensive than some. Burtons were very good and had everything in stock, including advice.

Good luck!

Andy

[brianmurray325hotmail.com]

Thanks guys, a lot of valuable input there, bits and pieces i hadn't considered. Generally speaking you all managed to talk me into making a project of it and whipping the head off. The VW stem seals are an interesting angle Andy, do you know which engine that they are from?

An interesting point i'd forgotten about.....no exhaust valve stem seal due to it  being always being under a compressive and any oil that does get down aids cooling i think. I believe that the maker,s still install them, though performance engine builders don't as a rule.

Thanks again for the input

BM

 

[OliverSedlacek]

Exhaust seals are useful to stop oil running down the guides after the engine has stopped running (classic symptom, puff of smoke when the engine starts).