Board Logo

Lapping/Grinding Valves
Quoll - April 7th, 2004 at 05:19 PM

G'day
I've got all the gear to lap/grind my vavles
I'm just wondering whats the best way of doing it, and how long should I do it for?
Thanks
Justin

Craig Torrens - April 7th, 2004 at 07:34 PM

so what gear do you have?
I'm guessing valve grinding paste and the rod with a suction cup ?

Quoll - April 7th, 2004 at 07:51 PM

Yep, Coarse and Fine Grit and four diff size suction rods I'm doing this on a set of stock 1600 tp heads

Craig Torrens - April 7th, 2004 at 08:18 PM

I assume all the valves have been removed?

With the valve removed start with the coarse paste, and coat the valve or valve seat with a small amount of paste. Insert the valve back into the head and push the rod and suction cup tool onto the face of the valve. Then turn the rod (and valve) clockwise and counterclockwise so the valve and seat are rubbing together. Every few turns you should lift the valve off the seat and then push back down again. Clean away the valve grinding paste, and check the seat as well as the valve. There should be a dull grey line around the valve and the seat, this is where the valve and seat are meeting. You need to keep grinding untill this grey line is uniform all away around and is about 1.5mm in width. Then just repeat with the fine paste to finish off. Clean all surfaces and repeat for all your valves !!!!

I would recommend replacing the exhaust valves.

I hope this helps

warb - April 7th, 2004 at 09:27 PM

i dont like those suction cup things, i'd rather jam a rubber tube over the back of the valves, and spinning them that way... just my 2c

also, remember to put the valves in the same holes, dont get them mixed up..

Quoll - April 7th, 2004 at 09:39 PM

yep have replaced all the exhaust valves with new ones.
cool thanks for all the info.

Craig Torrens - April 7th, 2004 at 09:53 PM

have fun !:)

count - April 8th, 2004 at 08:18 PM

And Lube the Shaft:)

Oasis - April 9th, 2004 at 12:27 PM

Quote:
Originally posted by count
And Lube the Shaft:)


My goodness......:cool:

Craig Torrens - April 9th, 2004 at 12:30 PM

always lube the shaft:P

tassupervee - April 9th, 2004 at 01:37 PM

Errr, I have a very nasty and quick way to lap 'em in. This is likely to result in the purists vomiting and spitting out their teeth but:

First, lube the shaft!!!!!!!!!

Wipe on some grinding paste onto the seat, insert the valve into the guide and grab the valve stem gently in a battery drill!!
Using your finger tip as a pressure guide on the head of the valve, spin up the valve and just keep lifting the valve off its seat every second or so.

Requires only slight pressure on the valve head and keep the bloody drill steady.

Very quick and as rough as guts but works surprisingly well if you are rather careful about it!!!

Sorry guys, I had to detail this one!!!! ready...set......PUKE!

L8tr
E

MickH - April 9th, 2004 at 03:06 PM

Quote:
Originally posted by tassupervee
Errr, I have a very nasty and quick way to lap 'em in. This is likely to result in the purists vomiting and spitting out their teeth but:

First, lube the shaft!!!!!!!!!

Wipe on some grinding paste onto the seat, insert the valve into the guide and grab the valve stem gently in a battery drill!!
Using your finger tip as a pressure guide on the head of the valve, spin up the valve and just keep lifting the valve off its seat every second or so.

Requires only slight pressure on the valve head and keep the bloody drill steady.

Very quick and as rough as guts but works surprisingly well if you are rather careful about it!!!

Sorry guys, I had to detail this one!!!! ready...set......PUKE!

L8tr
E




HeHeHe.....was waiting for someone to post this "method"!!!!:thumb:P:P

tassupervee - April 9th, 2004 at 03:45 PM

yeah sorry dude, I could not resist it. I gotta say I have employed this method on many occasions with remarkable success.
It seem I am not the only one to employ it then eh???

Muwaaaaahahahahahahah

L8tr
E

toplessbug - April 9th, 2004 at 09:18 PM

requirements
keyless chuck.reversable drill.30 secs per valve and a quick clean up instant valve grind!!!

toplessbug - April 9th, 2004 at 09:18 PM

requirements
keyless chuck.reversable drill.30 secs per valve and a quick clean up instant valve grind!!!

Kai.A. - April 9th, 2004 at 09:28 PM

i too have used the drill method, back when i worked in a motorbike workshop. it's really handy for the tiny valves in some bikes which are impossible to get a suction cup onto....

you've just gotta make sure you don't put any sidways pressure on the drill, could end up with the valve seating kinda off centre, and i spose it probably wouldn't be too good for the valve guide either.....

it's easy tho, and it works.

kai:cool:

Quoll - April 13th, 2004 at 11:07 PM

Lol
the same thought crossed my mind while I was lapping them in after spending ages getting one valve to seat properly, the rest took a lot less work tho
thanks for all the info dudes :D

helbus - April 13th, 2004 at 11:20 PM

I remember my dad doing the sidevalve Briggs & Stratton motors with the suction cup. When I would help him I would use the drill too. He didn't like it done that way as he was of the old school. I just wanted to go for a ride on my pushbike or for a swim, so I wanted to get it done as quick as possible. :)

primate - April 14th, 2004 at 11:16 AM

I think the 'drill method' could be refined by inserting the shaft end of the valve into a short piece of tight fitting rubber tubing then putting the other end of the rubber tubing into the drill chuck. Inserting a bolt shank into the rubber tube at the drill end will stop the chuck from collapsing the tube.
This method will reduce the tendency for any bending loads inadvertantly applied to the shaft whilst rotating your valves.

Cheers,
Ali ;)

tassupervee - April 14th, 2004 at 09:01 PM

Yep!
I like that.
Good one.
L8tr
E