Hand Lapping
 

Anybody have a good procedure for hand lapping a new engine? And what lapping compound do you use?

Yes, I do. I use lapping technics for about 25 years for now.
I use Clover Silicon Carbide compaund 2000 grit and made different sizes tool for differnt diameters.
I will put pics of my tool later today.
Edward

Thanks Edward
 

I would be interested in this.

Here is pics of my lapping tools for .12, .21 and .15 engines.
It made out of garolite LE, clamp type.
Procedure as follow-you apply small ammount of laping compaund inside the tool, then stick piston inside the tool and tighten the side screww untill if you turn piston you will feel that metall is laping. Next step is turning piston and mooving it forward and backward ( 1 turn-2mm move). After about 3-4 turns you need to check piston for fitting in sleeve. I know your next question-how far to go-well here is personal preferences, like for Novarossi .12 I stop when piston stack from the top of sleeve 2.3-2.5 mm, but this is in my piston/sleeve sets, for novarossi original I really doen't know-neber deal with them.
After you finish lapping, make sure you wash piston and sleeve really good-laping compaund stays there badly and it really need full attention. If some of compaund left-you set will gone in seconds after you started. I use strong soap in hot water-boiled and then aceton or laquier thiner.
If you have more questions, please feel free to ask

hi edward,
is it better to lap the piston to 2.3 or 2.5 mm bevore break in the engine
dieter

Lapping
 

I've seen a process where taking some aluminum polish like Mothers and placing a small amount on the piston skirt and putting that into the matching sleeve. Then working that up and down afew times like you do with your garolan sleeve. It seems to work very well as well.

Hi Ray.
I heard people do it to lapping pistons by sleeve, not by tool and this is wrong!!! Sleve has a taper inside and if lap piston by sleeve you piston will became taper too and it will not work properly. It doesn't mean engine will not work, it means will not work propely-the tapers one of the most important keys of power.
So if you want to use lapping procedure, I will sugest you to order in mechanical shop make for you the tool, get some lapping compaund and you will be good to go. If you go for it, please rememeber, this procedure required a lot of patients, specialy on the beginning ( no feelings for 3-4 first times) then will be much easier.
One more thing-never use "diamond compaunds"-they are not washing out from AL alloys, the good for Chrome plating, but not for pistons.
Edward