235 DYI overhaul. In this process in my garage I’ve started the valve lapping process. Attached are videos and pictures of my very first valve lapping job. I’m using Permatex lapping compound and a stick/suction cup method. After lapping only the #1 cylinder I’ve applied a home made vacuum test concoction (shop vacuum cleaner, sanding foam, home made adapter.) The videos and pictures should show that potentially there are no valve to seat leaks. Your opinion matters. Having problems uploading videos, I’ll see if I can change the format the edit this msg. Can someone tell me why or how to upload videos. I can upload photos but not videos.
Last edited by TexasA&M48Truck; 08/26/20265:03 PM. Reason: Added problems with video
That seat contact area is way too wide and too high on the valve face. The intake valve will run too cool with a wide seat, and carbon deposits will build up quickly. Intake seats need to be around .060" (1/16") wide, and just above the center of the valve face. Exhaust seats should be .090" (3/32") and also just slightly above center on the valve face. I use three angles of seating stones to alter the position and width of the seat- - - -intake angles should be 0/30/45 degrees, and exhausts are 30/45/60 degrees. I haven't lapped a valve in over 30 years- - - -I check the seat width with Prussian Blue and rely on the precision grinding of the seat to establish a seal. There are sets of hand-turned carbide seat cutters available on Ebay for adjusting valve seat width and position at very reasonable prices if you don't happen to have access to seat grinding equipment.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Your video file is too big. Maximum file size is 5 MB so it would have to be a very short video to be allowed. You could put your video on a file sharing site and post the link here.
Example is in Greasy Spoon (so not to hijack your thread)
Seats get wider with wear. By lapping valves on a used engine, you only make the seats wider. I use three different stones on the seats, but possibly the things that Hotrod cited on eBay may work. But whatever you do, don't reassemble the engine before you get the correct width on your valve seats. I am in Germany at the moment so I don't have access to all of my books, but I think if you would buy about a 70 year old Motor's Manual off of eBay it would explain a lot of things. They can be bought for about $20 including shipping. They were written by mechanics out in the field compared to service manuals that were written by engineers at the factory.
Those carbide cutters are intended to be turned by hand, but they also work by using a cordless drill motor on them. I drilled and tapped the mandrels on my set for a short piece of all thread rod and clamped the drill chuck onto it. It's easier to get a smooth cut by running the drill motor at a slow, constant speed. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
