Cylinder Head 105 - Valve Job Basics

Valves not sealing and they're not bent? This is one way to fix that problem.

Once you've completed this work, you can clearly see the size, width, and consistency of the valve mating surface on BOTH the valve, and the seat. Should any distortion appear in the mating surfaces, you will need the help of a machinist to fix this properly.

I outline the cleaning and inspection techniques to help determine whether or not you need to pay a machinist to perform an actual valve job. If you find after performing these steps that your valves don't seat properly, or that your valve seat or valve margin measurements are out of spec, only then would you need a machinist's help.

Here I cover the inspection process start-to-finish. All of these same procedures would be used by your machinist, usually with better equipment... but you can still do the same thing in your garage. These techniques work exactly the same way for just about every non-rotary combustion engine. It takes patience and perseverance, but anyone can do it. Reference your service manual for your engine's specifications and service limits. Everything else that's not in your service manual is in this video.

If you have bent valves, you will discover it quickly once you chuck one up in the drill. You'll see the face of the valve wobble around while it spins. You'll see evidence of this damage on the valve seat. If it's bad, you may see damage on the valve guides in the form of cracks or missing pieces where the valve guides protrude through the head ports. Give all that stuff a good visual inspection.

...and if you doubt yourself, never hesitate to get a second opinion or consult a machine shop. They will have access to expensive tools that you wont find in your average gearhead's home garage. Tools that will give better, faster, more accurate answers than someone could determine with their eyeballs when they don't own those expensive tools.

Lastly: The oxidation found on these valve seats were caused by 110 octane leaded race fuel. Some kinds of race fuel are corrosive to hardened steel valve seats. This head had only about 30,000 miles on it since its last valve job. These techniques will not fix damaged valves without causing a different kind of damage. I'm sorry I had no damaged parts beyond corrosion to show you in this video.

[TurbosAndFPS]

10 years later and still one of the best tutorials on YouTube for doing such an important task

[woody]

I’ve been doing this for 40 years, you nailed it kid.

[joemikos]

One of the best automotive videos I've watched! Your expierience and knowledge is obvious but you also have a gift for teaching.
I was ASE cert with 25 years expierience. I owned an auto and truck repair shop and employed 15 full time techs.
My shop was 25k square feet and had a machine shop and a partitioned body shop. I owned a separate Corp that was a H D and light duty towing Co.
Also had Volvo, White, GMC dealer affiliation authorization.
I started in a 2 car garge at my childhood home.
I lost it to leukemia but only mention it, 1) because it was a source of pride and 2) because you mentioned health risks when using chemicals. I was proud of you for that. For all those that don't take it serious, my leukemia was likley caused by siphoning gas as a kid when I worked for a bus co. On several occasions I swallowed a bit. I have been suffering the effects for 35 years of which the last 12 included bone marrow cancer. My leukemia was a precursor to BMC so I knew that day was coming. If your reading this, DONT DO IT! BTW your video brought back memories, good ones. I too was a perfectionist, (Of coarse didn't always succeed). I used the exact method you did and was taught by a master machinist.
Thanks

[martinwilliamson]

Thank you so much for this video . With limited mechanical experience I was able to rebuild the head on my food truck and get back to business - deeply obliged .

[richardbennington]

There are people with knowledge and experience, but produce lousy, unedited videos. There are those without knowledge or experience that produce nice looking, edited videos. Both are not worth watching, in most instances, and can sometimes lead people astray. You, on the other hand, have knowledge and experience and produce quality, edited videos that are worth watching. Well done! I hope others are inspired by you to do better.

[nickkaplan]

This is one of the best how-to videos I have seen.  It's in focus and you can see the important parts perfectly, fast forward was great, thoughtful and useful commentary, awesome tips based on real experience. Thanks for a great lesson and not wasting my time!  Excellent tutorial!!!!

[mrarmy]

I'm about to make my first lapping attempt, and was considering the drill method. You convinced me to start by hand and get a 'feel' for it. Thanks for the great info!

[Glenn]

Done this a couple of years back on a spare 4 cylinder head i had after watching this vid. All in all it took me around 6-8 hours, took my time, no rush, had the little pots of course and fine compound you mentioned. Head went on my car and is still on there now and holding up fine.

[michaelboyle]

I thought this job was above my skill level. Like anything I've ever encountered, it's all about knowing the procedure. Thank you very much!

[Impossibilty]

Thanks man done this on my yz 450 5 valve head it had 3 leaking valves and now every one of them is fixed thanks!!!

[steveconyers]

This video is a life saver! This is the most informative straight-to-the-point video about valve lapping. I just went from apprehensive to confident in 15 minutes. I knew the basic procedure for lapping valves, but had never done it myself. He shows you all the tips and tricks that I never would have figured out. He also makes it clear what you need to watch out for, and how to tell when the valve is correctly seated. No doubt, I would have messed something up on my own engine If I hadn't watched this video. Thanks!

[GeordietheJoiner]

I haven’t done a valve job for about 25 years and about to do it for a diesel motor I’m rebuilding, I found this video awesome to brush up on a few skills and ideas that I haven’t used for so long, thanks man 👍

[lorsauto]

Hands down one of the best How to video on the internet. Great quality video, perfect audio, clear and to the point, fast forwarding!, everything. Keep up the awesome work.

[ProductionsProduce]

this is easily one of the best automotive instructional videos I have ever seen. informative, no skips getting people of less experience lost just speed up and quality information

[petertrast]

9 years later, still a very high quality video! Thanks!!

[stevecbr]

Your vids have rebuilt my Talon 2 times, diagnosed countless issues & tricks, several clutches & are going to get me through a 6-bolt swap into my 2g starting tomorrow. Thanks so much for all your help - hit me up next time you're in Monterey & I'll buy you some doughnuts

[forbeskenneth]

Ken Forbes
Great instructions I suggest making.lead pencil marks all around valve seat inserting valve into stem then turn seated valve half a turn .If all pencil marks get rubbed off you are done.If some pencil marks remain keep on lapping

[MrTaffiny]

i like this guy. He does everything right...has a good head on his shoulders.

[ryanharker]

Just blew my mind some people are made for this youtube stuff where clear didn't over complicate it . Can't thank you enough

[sethroberts]

I watch these automotive videos all the time, but this is the first time I’ve taken the time to comment on one. This is hands down the best how-to instructional video I’ve seen. Well done!