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944 Tappet Refurb?

barks944

New member
Can the 944's tappets be taken appart and cleaned, or maybe soke them in a solvent or something? Is it worth doing anything with them at all while they are on the bench?
 
Whether this works or not I have not tried but I found this guide a while ago about overhauling tappets and will be trying it on some spares I have for my S2 when I get chance.

http://jenniskens.livedsl.nl/Technical/Tips/7/MyTip795.htm

 
Just had a look at the 944's tappets in closer detail. Unfortunately I do not think removal of the piston is feasible, they have pressed indents into the tappet housing to prevent the tappet piston from escaping. I have however exercised the tappets while immersed in oil and a lot of black gunk has come out! I think the best option for the 944 is to place the tappets in a heated bath of oil and exercise them using a metal rod or something to try and get all of the nasty oil and gunk out of them and get some nice fresh oil in there. Going to try it out tonight on one of the spare tappets.
 
Clean them in valve train restorer you normally add this to your oil and it works ! around 7 squids from a motor factors, think the stuff i used was Wynns but Forte also do it.
 
This approach sounds totally reasonable to me. Back in the day (1960s Canada) virtually all vehicles had hydraulic tappets. Back when people would get a valve job rather than scrap the car, mechanics would regularly clean them and reuse rather than replace so long as the cam side had reasonable wear. The procedure I've seen used was to soak them in a solvent bath overnight and then dismantle for a good scrub. The style of tappets used in NA vehicles were usually assembled with snap ring retainers so dis-assembly was quite easy.

Even if they don't come apart - barks944 and Frenchy are on the right track - dissolving the varnish and removing the sludge will make a big difference - and even if the pistons are a little worn and you are not getting full valve opening because they can't hold full pressure - its better than having the valves not closing completely or on-time due to gummed up action.
 
Has anyone tried using an ultrasonic cleaner on the tappets.
Small ultrasonic cleaners are available quite cheaply these days, and there are many companies offering ultra sonic cleaning of injectors so it sounds as though it could work.

Mike

White 2.7 automatic
 
I have a set of 944 S2 tappets same as later 928 and 968 ones I will have a look if I get chance to see if the piston can be removed as in the procedure as I think that originally came from a 928 website so maybe different models use different types of units.

Found this on Pelican Porsche and it seems 928 units can be dismantled so maybe those of us with 928, 944S2 or 968s can split the tappets, the same article also makes comment about ultrasonic cleaning so this could be a easy option.

http://forums.pelicanparts.com/porsche-928-technical-forum/551007-hydraulic-lifters-cams.html
 
Looking at that thread it seems that the indents that hold the piston in failed and the piston popped out. Looks like you would have to mechanically remove the indents to get the piston out.

I think before doing anything you would need to get the existing oil out of the tappet. When you take them out of the cam housing the pistons are rigid due to the oil in the piston. I have managed to get the oil out of a couple of spare tappets such that I can move the piston by hand. I guess then it would be worth soaking it in solvent. However I'm not entirely sure how you would get the oil back in after if you can't get the piston out. Aren't you supposed to re-prime the tappets before you re-fit them?
 
Got a small ultrasonic cleaner from work and a syringe and small extension tube. Going to try cleaning them with the ultrasonics and then injecting fresh oil in with the syringe.
 

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