[ferrari_f50_2]

hi, i have a 1985 gtv 2.0 which burns alot of smoke out of the exhaust mostly when you go back onto the throttle after changing gears. I was advised to change the stem seals which could fix the problem but theres a possibility it may not i believe? I heard there was a special tool to do this job without having to remove the head which would make it easier and cheaper to do, does anyone know who has this tool? i live in melbourne
thank you

 

[tomgtv6]

Some cars it is posible to do this, but an Alfa engine would be quite hard to do. The seals would be a temporary fix. The big thing you have to do is keep the valve from falling in. I feed some rope into the cylinder just short of TDCthen rotate the engine by hand until the rope is pushing on the valves. You are giong to have to make some kind of pry system to push on the valve but with a hole in it to extract the keepers. Then you can change the seal. Then reverse. It would be easer to remove the head in my opinion and in the long term it would be best to change the guides.

 

[Gabor K.]

I really have done this job several times with the heads off, but not on. However I have heard som schetchy explanation using compressed air. If both valves are closed and one uses compressed air to keep them closed through the plug hole, one could probably compress the valve springs in order to remove the collets, springs and the stem seals. Maybe somebody has firsthand experience with such a tool ?

 

[papajam]

The only special tool I use is the Alfa valvespring compressor.

I start by putting the engine on TDC for cyls 1&4.
Remove intake cam, oil in the head galleys and the followers with shims (keep in order).
Install the valvespring compressor and open/close the valve a few millimeters three or four times (this helps to loosen the keepers).
Take a 1/2" piece of pipe (or similar), place it square on the retainer and give it a sharp blow with a hammer. This will dislodge the keepers from the valve stem.
Remove keepers, retainer and valve springs.
Using a sparkplug wire puller (pic #1), remove the seal.
Grab the valve stem with your fingers and attempt to rock it back and forth in all directions. If you can, the guides are worn.
Lube the valve stem (I use a bit of lithium grease).
Use a suitable piece of pipe (pics 3 & 4) and tap on the new seal.
Pull the valve all the way up (the new seal will hold it there).
Install springs, retainer and keepers (pic 5).
Install cam and rotate engine 90 degrees so cyls 2 & 3 are at TDC.
Repeat procedure for cyls 2 & 3.

Noting what the valve clearances are before starting will allow a valve adjustment to be done at the same time.

 

[tomgtv6]

I don't like compressed air because if the valve leaks the valve will fall. I have never seen the factory tool before; nice ,but probably hard to find. I worked at a cylinder head place just out of high school so we had more universal tools and we would make some too.

 

[brookstroutr]

Compressed air is common to change valve seals on a lot of motors. You're right about being careful about leaks and dropping. Just leave the air pressure on. Also, if there's that much air escaping, there's more than just the seals gone bad.

 

[brookstroutr]

Oh yeah. I forgot to mention that I discovered an easy way to do the intake valve adjustment w/o removing the cam. The BMW M88/3 '84 - '86 in like in mine has the same lifter shape. IIRC it's 30mm diameter and about 2mm deeper. These lifters have the shims on top of the bucket and are almost the full diameter of the lifter. The shims are retained by a vertical outer perimeter lip. A little grinding on the head adjacent the lifter and the BMW tool compresses the spring and pliers or compressed air blows out the shims. They're size ID'd on the bottom for differences. The VW same era motor has the same shim size and they're cheap and readily available. I must have 125 of them for my engines.

 

[ferrari_f50_2]

thanks for all the advice. im most likely going to get my mechanic to do the job and wanted to try to avoid removing the head because it would be alot more costly. it doesnt seem necessary to remove the head, are there alternatives to the alfa valve spring compressor? im sure thats the special tool he was talking about. cant seem to find it anywhere.

 

[Gabor K.]

Papajam: In your description I wonder what is holding the valve when you are using the valvespring compressor. Remember the head is on the block!

 

[papajam]

Gabor,
The new seal holds the valve closed.

ferrari,
I've only ever used the Alfa spring compressor so I don't know of any alternative. However, I recall a somewhat recent AlfaBB thread that discussed this. Perhaps a search will yield some results.

Found it. Click here.

 

[Gabor K.]

Some misunderstanding here, the seal itself cannot hold the valve.

When the head is off ,the valve is held from the inside by the valve compressing tool. On the other side the same tool is exerting pressure on the valve spring. Thereby compressing the spring and releasing the collets holding the valve. Illustration of the tool used when the head is off.

However when the head is fixed on the cylinder-block nothing holds the valve from inside when compressing the spring. The rubber seal itself has no power to hold the valve when compressing the valve spring. So could you explain how you do it without supporting the valve from the inside?

 

[GTV4EVR]

That part seems to be accomplished by:
"Take a 1/2" piece of pipe (or similar), place it square on the retainer and give it a sharp blow with a hammer. This will dislodge the keepers from the valve stem.".
It sound like the spring isn't compressed to remove them. The seal holds the valve in place and the spring is compressed when they are put back in.

 

[papajam]

Ken has it right. I use the Alfa valve spring compressor only to install the spring, not remove it. Spring removal is accomplished by using the impact method previously described. Hence, there's no need to hold the valve head from the inside.
Once the spring is off, the valve will drop a few millimeters and rest comfortably on the piston. Once the new seal is installed, the seal will hold the valve closed to facilitate spring installation. No need for rope, compressed air or any other widget to support the valve from the inside. (IMHO, of course)

FWIW, I replaced the valve seals on an S1 Euro 1750 GTV two weeks ago. Start to finish, with valve adjustment, was 1.5 hours.

 

[Gabor K.]

In my experience you can dislodge the springs by a sharp blow only when the valve is held back by the above tool from the rear side. Even when exerting full pressure from the compressing tool you have to give the spring a couple of blows to dislodge the spring. Giving the springs a blow without holding back the valve from the inside probably would result in nothing.

 

[papajam]

Giving the springs a blow without holding back the valve from the inside probably would result in nothing.

All I can say is to try it. I've been successfully using this method for decades.

 

[Gabor K.]

OK, point taken , still doubtful, but will try the method on my next engine to be dismantled. The original Alfa spring compressor is needed though.

 

[ferrari_f50_2]

ill have a better look for this tool and maybe try doing the job myself, otherwise i'll try one of the alternatives. That tool that was made up in the other thread seems quite good. thanks again

 

[r-mm]

This is a really old thread, but i'm wondering - with the "impact" valve spring removal technique, what stops the valve spring seat from flying at you once the cotters are dislodged?

All I can say is to try it. I've been successfully using this method for decades.

 

[alfavulcan]

i've removed valve springs with the sharp blow method. the springs don't seem to be under too much tension and when the keepers come out, the spring may jump a half inch or so, no more and certainly not flying across the garage