[Dave Holmes]

Hi all,

I'm replacing a crash damaged head on an O.S. .70 FS Surpass (not the Surpass II) and don't know how to get the valve retainers off the valves, short of the B.F.&F.I. method. (Brute Force and F**g Ignorance)

Then once they're off, how to get them back on again. Anybody done this before?

T.I.A.

[hillmanr2]

Me and a buddy removed/ replaced a valve on a saito 125 recently in about 6 minutes.
#1 Remove carb/ muffler, cylinder, valve covers, gaskets and glow plug. see special note A

#2 remove pushrods one at a time and marking said pushrods so they go back in the same holes

#3 Compress the spring using bf & fi method without moving the valve, pull of circlip with a hemostat or needle nose and spring retainer. Put these on a towel or magnetic container. see special note A .

#4Gently release the pressure on the spring. see special note A.

#5 RE & RE parts as necessary

#6 reverse steps to replace retainers lightly re oil gaskets but do not install covers or plug.

special note A Just letting go and /or putting stuff anywhere will produce language not suitable in all conditions as you hunt for the item that just landed in the only spot you will not look.

Make sure to measure the backlash (gap between the pushrods and rockers) at TDC. Be extremely careful not to rotate the motor if you feel any resistance. If you feel resistance loosen the rocker arm adjustment.
Failure do this can result in unsuitable language and the ordering of new valves and a repeat of steps 1-6. Ask how I know

[treecutter]

Hey just compress the valve spring a little and push the keeper down, the retainers will come out in 2 halves

[Dave Holmes]

Originally Posted by treecutter

Hey just compress the valve spring a little and push the keeper down, the retainers will come out in 2 halves

Hey, that worked, but I still had to use B.F.&F.I. to get it to release. I just could not for the life of me see how it was put together.

Thanks, Treecutter!

[Vulcan1]

Dave,
From the sounds of the explanation with the retainer in 2 pieces holding on to the valve stem and the spring cup sliding up around to hold them locked then it is the normal setup used in just about all engines. The normal way is compress the spring and and remove the clips. The valve stays in the closed position. If it goes with the spring then give the valve a little tap to return it to the closed position then the retainers usually fall out. There are several tools on the market for full scale engines which I have a few but have not seen any for a model engine. If you where doing lots I would make one from a wide pair of pliers ground thin in a U shape so they slip under the spring and compress the top with the valve stem in the middle. For a one off job I would use a pair of pliers opened up and using the sides push on the spring so the valve stem is released. You still have to hold the valve closed for it to work.
As you have repaired your problem it may help for the next time or for somebody else.
John

[Dave Holmes]

John, I basically did exactly as you detailed in the second half of your post. What had me buffaloed is the fact that this engine had just enough crud built up on the tiny bits that nothing wanted to let go. I took a couple of short pieces of popsicle stick and placed them under the head so that they supported the valve and then with the long nose pliers open slightly and pressing down on the top, whacked the pliers with my other hand and voila, everything came apart.

Getting it back together was an adventure of a different flavour, the split clips are so danged small it was a bear to get a grip on them, put them in place, and keep the spring compressed at the same time, but I managed it.

Now all I have to do is find out what the rocker to valve clearance should be; it looks to my untrained eye to be a bit on the wide side. I'll have to dig up a set of feeler gauges and check 'em at least.

In any case I feel a bunch more clever as I learned something from this.

[treecutter]

I'm glad it worked out for you Dave, I did kinda give you the Chilton manual version though, the BF FI is to be expected with any mechanical thing...but you knew that allready!

[Vulcan1]

Who says we are never to old to learn. The problem now a days is not how to do it. My problem is how do you find it when everything lets go. The old eyes with bi focals are a pain in the butt when looking for small items.Now I try to keep a clean floor and work area for my problem. A small magnet also comes in handy.
Glad you got it Dave. Somebody should be able to give you the clearance or does the OS web site have the info. The next question will be hot or cold for the settings.
John

[Teledog]

Not sure of THAT engine..but we always used to jam string or thin rope through the plug hole with the piston at almost TDC, then turn the crank to tighten things up to TDC... to essentially fill up the combustion chamber (or fill it from the side port, barring that) .
{Leave the end of the rope hanging out for later removal!}
The valves would more or less stay in as we removed the retainers while pressing down on the springs.
The rope trick also works for removing/installing crank end bolts, being careful that you don't shear a piece of rope off through the side port though.

Whenever I disassemble/assemble things that can fly away I always put the engine and my hands in one of those big ziplock bags.

Ed S