Lapping Valves, yea or nay?

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dana
Posts: 951
Joined: Mon Oct 14, 2013 8:54 am

Lapping Valves, yea or nay?

Post by dana »

I have been cleaning up the valves and ports on my TDI. (dumb hippie women+veggie oil+EGR=mega carbon). Everything is covered with this rock hard veggie oil fossil crap. The only way to remove it is to carefully chip and scrape and burn it all away.

Everything is coming out well, but I am wondering if I should lap the valves in while I am in there. I have been really careful not to scratch up any of the mating surfaces on the valves or the seats. Would a light lapping be a good idea, or just run it as is?
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
DE80q
Posts: 2572
Joined: Mon Mar 04, 2013 9:25 am
Location: York PA 17403

Re: Lapping Valves, yea or nay?

Post by DE80q »

I dont know TDI engines, but in my opinion I would give them a quick lapping. This way you know they surfaces are mating properly. I mean, you already have them out.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
User avatar
dana
Posts: 951
Joined: Mon Oct 14, 2013 8:54 am

Re: Lapping Valves, yea or nay?

Post by dana »

nothing really special about the TDI valves vs. other VW/Audi stuff.

my methods of lapping are either this:
Image

or this
http://forums.vwvortex.com/showthread.p ... -Lapping...

I've done both with success in the past.
current:
-mk4 tdi wagon with some mods
-TDI b3 90q, holset turbo, be strong little connecting rods!
-the turbo tractor
past:
-11 second 90q junker
-20vt swapped 90q winter beater
-efi 20vt 4kq
-way too many other long gone urs's, 200's 4000's, b5's
DE80q
Posts: 2572
Joined: Mon Mar 04, 2013 9:25 am
Location: York PA 17403

Re: Lapping Valves, yea or nay?

Post by DE80q »

I do it by hand. Use a sharpy on the seat or valve to let you know you got the whole thing, and call it done.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
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