Smoking Alfa - Valve stem seal replacement

Started by fazersix, December 28, 2019, 12:13:34 PM

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fazersix

Hey
Whilst changing my cams I took the opportunity to replace the valve stem oil seals to fix the puff of smoke when changing above 4000 RPM. I read a lot of posts ranging from the "rope method" to head off! Just thought that I would share my method using compressed air - if it didn't work then I would have to take the head off to retrieve a fallen valve anyway!
I bought an inexpensive valve removal kit from ebay for $40 that would suite the angled Alfa valves .

https://www.ebay.com.au/itm/vidaXL-Universal-Overhead-Valve-Spring-Compressor-OHC-OHV-Petrol-Diesel-Engine/232548559512?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

You also need the special oil stem seal removal tool - about $15
Follow normal procedure to remove the cams

I made up a couple of end brackets and bolted to the inlet camshaft cap bolts at the front and rear of the engine.
Then pumped the cylinder full of air at 60-80 psi - this was plenty. I did not rotate the engine, I left 2 & 3 at the bottom of the stroke so as not to mess up the timing etc (I have done this before on other engines)Give the val cap a share blow with a socket and hammer to loosen the collets. Then use the tool to leave and compress the spring and remove the collets - very fiddly.
Then remove the valve old black valve seals very brittle and came out in pieces - new seals are green!
Now no more smoke

bonno

Further to fazersix post, but using simple handmade tools and rope instead of compressed air and special tool from e-bay, I have attached a Youtube video on How to. Extreme care when removing and installing valve stem seals as not to damage/score valve.
https://www.youtube.com/watch?v=F54Z-9QJSXg

bonno

No!!! But in my opinion the method is sound, as long as care is taken using the rope and position cylinder at the bottom of stroke, then rotate crank to TDC so the rope is sufficiently compacted to hold valves from moving down. 

bonno

Hi Sportiva
The method is considered sound as I said, but anything may happen if sufficient care is not taken. Personally, I would have conducted a compression test first and if all is fine except for leaking valve stem seals, then I would have no hesitation in carrying out this or compressed air method (air compressor might not be available to all). 

carlo rossi

#4
brilliant cant believe only 60psi did the trick
can you post a link for the tool
current cars
red 83 gtv 2.0


previous cars
Red 76 1.2/1.5 alfasud ti
white 79 alfetta 2000
alfetta 74 1.8
escort Lotus twin cam
bikes
ducati 900 ss 1979
moto morini 3 1/2 sport 1975/6
Moto morini 3 1/2 valentini speciale 77 oh and a deltek rockhopper