81 GS550T Full Rebuild...In Ohio

[cowboyup3371]

Thanks DMac. I'll work a little more on them. When you did the tops of your valves, did you have to be careful about going too far or is that easy to do?

[Nessism]

The dome where your valves live is the top of the squish area. The roof, if you will. Of that speaking I was. (in my best Yoda voice.)

Nope, sorry. The "squish area" is around the very outside of the combustion chamber, as Steve said, where the piston and head almost touch.

Scott, when you lap the valves don't go to hard on them. The only thing lapping does is clean the seats. Your engine looks really clean inside. When you are done it will be like new again.

[Mekanix]

Stem bearing.
Skip to 4 minutes
video


To the best of my knowledge, Squish can be thought of any area where the piston is within 0.060 or less to the cylinder head. Its an area where gases are expelled at high velocity "squished" and that movement of charge causes turbulence. This helps in mixing fuel and air with the ignition source as well as assisting propagation of flame fronts for a better and more complete burn. Like fanning the flame.
On flat top its obvious where the squish bands are because they are any flat area between the head and piston and usually around the outside.

With the dome pistons like yours, I don't know Could be anywhere

[koolaid_kid]

While technically we agree, then name the area I am discussing. Besides, it is not really an area, it is a volume if you want to get technical.

[Dogma]

Stem bearing.
Skip to 4 minutes
video

+1 to the Dremel and cold chisel. Skip any kind of heating. Here's a relevant post from my 1000G's thread.

I didn't mention it in that post, but putting the new bearing on is just a matter of driving it on with a hammer and some kind of punch that's longer than the stem. Move around the bearing to make sure it goes on evenly. A piece of pipe that slips over the stem is ideal, though. I used the old, split bearing race to protect the new bearing. New bearing, split race on top of that, then a pipe. Hammer into place. A chunk of wood directly under the stem will protect the lower triple.

[cowboyup3371]

Thank you Dale that will be much easier and something I can try tonight or tomorrow

[Shwartz]

I'm almost there

I finally figured out my best counterweight of all.

My great counterweight idea...and it worked beautifully

Your going to give that poor girl a complex! Years from now, I can see her in therapy.

[cowboyup3371]

Valve Lapping Compound

I'm going to pick up some valve lapping compound this weekend to try starting on the valves next week. As the service manual calls for the Prussian Blue or Red Lead, I thought I should get,

http://www.oreillyauto.com/site/c/detail/PER0/80038/N0408.oap?ck=Search_assembly+lube+%26+valve+compound_-1_2121&keyword=assembly+lube+%26+valve+compound

and this

http://www.oreillyauto.com/site/c/detail/PER0/80036/N0408.oap?ck=Search_assembly+lube+%26+valve+compound_-1_2121&keyword=assembly+lube+%26+valve+compound

Will I be okay? Or do I need something else?


Which one should I use first?

[Dogma]

I think I'd start with Blueing the parts to see where you are before you start. No point in lapping a valve that already seats well.

I have a vague memory of machinists being wary of Prussian Blue. I'd give the safety warnings a good look. If I recall correctly, the guys at our shop like Di-chem. Or maybe that was the nasty stuff. I'm sure either is safe if you take appropriate precautions.

[cowboyup3371]

I removed the lower race from the steering stem but not without some drama tonight sadly. Everything started off great when I locked it into my woodworkers vise and started cutting, which went off without a hitch.



I managed to get a decent notch set into it to start with





But because I haven't completely attached my vise to the owner's workbench, the whole setup fell on the ground once I started hitting on the notch. Unfortunately, my valve parts were right below it that area on the floor in their tins ; fortunately nothing busted except for the fact I can't find one keeper. I'll keep looking tomorrow but I already found a replacement just in case.

So, I pulled the stem out of the vise and laid it in my lap but couldn't get anywhere at first until I decided to start pushing it up using my chisel. I guess this will add another way of getting it off as I was able to pry enough of it up to start hitting it from the bottom. After a few minutes:



And then finally everything off. I'll have some sanding to do to clean up a couple of scratches though. I just will be glad to get a better place to be staying in so I can put in MY workbenches.

[Mekanix]

I think I'd start with Blueing the parts to see where you are before you start. No point in lapping a valve that already seats well.

I have a vague memory of machinists being wary of Prussian Blue. I'd give the safety warnings a good look. If I recall correctly, the guys at our shop like Di-chem. Or maybe that was the nasty stuff. I'm sure either is safe if you take appropriate precautions.

What about a Sharpie?


You need to find out if you have any high or low points first, So I'd say the blue first as well.
Put it on with a light coat and see where it rub's off after a turn or so.
I use a sharpie pen with the same result.
Don't go overboard while lapping or you could score the seat and valve.

To find that keeper, try a hand full of magnets on a stick

[duaneage]

I put a 550T back together again from scratch, here is a thread on it

http://www.thegsresources.com/_forum/showthread.php?t=82482&highlight=thebigred&page=2

An interesting project for sure. Ask me questions if you need help.

[koolaid_kid]

Valve lapping compound normally comes in 2 cans, coarse and fine, paired up. Please study up on this before you do it. It is a simple procedure and will help you seat the valves correctly if done properly. Beats the heck out of having a valve job done, IMHO.

[Nessism]

Repeating myself again...but lapping compound is only for cleaning the seats, it's not for making a new seat. You need cutting tools to do that. If you lap too hard a ridge will form on the valve face so please go easy. Oh and that general purpose valve lapping paste will work fine.

[wedoo2]

Following this with interest. I have a question, was wondering what a new set of valves would cost, and if that would cause a problem or just more things to buy?