This is a video to make you think about it. It’s not about me saying whether it’s right or wrong. One thing is for sure you can make valve seal worse by lapping badly!!
Even when I’ve built multi valve 500-600bhp engines I still manually lap valves by hand with a fine paste exactly the same way you taught me to do two decades or so ago when building mini engines in your workshop :) Good engineering is still good engineering and it frustrates me that for something that ultimately only takes a few minutes a valve people are looking for a short cut that isn’t needed.
@HREIRL
2 жыл бұрын
I think it’s completely fair to say this is one of the best videos available now on the internet regarding valve seat seat seal. There will be an order on its way in the new year for some of this valve paste. Top top job mister Dodd
@ACDodd
2 жыл бұрын
Thanks Paul, I must say I did spend along time working this out and some people still don’t want to understand it.
@fixpaana
Жыл бұрын
@@ACDodd Great video Mr.Dodd. I however didn't understand if you made the lapping paste yourself or bought it from the industrial suppliers. If you did make it yourself, how do you suggest one can do it themselves? Thanks for a great educational video!
@ACDodd
Жыл бұрын
@@fixpaana hi there, I simply purchased different grades and found what works best. For small quantities buy for the USA search for the clover brand
@misfitsa
Жыл бұрын
You sir are a genius 👌🏼💯 Nah fr though 😳
@brucebear1
6 ай бұрын
@@ACDodd An excellent demonstration, indeed. Now you young people wouldn't know but back in my day, we'd tilt the cylinder head so that the port was vertical, install the valve with a light spring, dust the valve seat area with talcum powder, and fill the port with kerosene or ATF. A beautifully lapped valve will leave the powder dry for hours, a good one will show you spots around the valve in a short time, and an ordinary valve installation will be dripping kerosene. It's all the same -- good sealing (valves, head gaskets, piston rings, etc.) is an absolutely fundamental feature of any good, strong-running engine. A head with valves not properly lapped is a poor head and it indicates a poor job.
@russellduffy
2 сағат бұрын
Great video! Thanks for the testing idea using the press and rubber mat. I was able to do that today and it's nice to know that it's going to be OK before going to the trouble to put things back together. Thanks.
@markgutter8443
2 жыл бұрын
You are the man. You are one of the two people on the Mini forums who's reply i rely on. Hourly rates for skill and good knowledge has always demanded a fair price. Thank you.
@ACDodd
2 жыл бұрын
Thanks for that Mark, I try my best!
@furyfantoo
Жыл бұрын
Excellent video showing different results from different lapping methods, and also showing how to verify your work. One thing to note - when watching the needle-sweep of leakage, be aware that the leakage/needle sweep is NON-linear, so make sure to compare the same range on the gauge (i.e. from 50psi to 40psi) when making comparisons. Obviously the 1000-grit valve is noticeably different across the entire range.
@anthonybennett1878
2 жыл бұрын
Spot on as usual, was doing this in the mid 70s when I served my time on jags, the garage had a name for head work, coarse paste was banned from the workshop as it would pocket the valve seats, a good valve job would cure most hot starting problems ,but not a quick job on a jag though.
@dobrowolskibartosz
Жыл бұрын
just found your channel and your videos are extremally valuable. Thank you very much for sharing your knowledge., I just got into the hobby of engine building and your content is pure gold for me.
@ACDodd
Жыл бұрын
Glad you find it useful it’s the culmination or more than 30th arms experience working on the classic BMC a-series engine, and also more than 30 years experience in manufacturing and machining.
@riadhch5643
Жыл бұрын
You're great mister the explanation was perfect and the amount of information you shared are countless please accept my full respect and thank you for you time and for every think you shared good luck in your job and on your life
@travisrichardson1292
Жыл бұрын
As a beginner, great video with easy to understand concepts.
@andyfry1970
2 жыл бұрын
Hi, I watched and listened and it all makes perfect sense given the results and comparisons between valve paste grades. These findings only ever come from someone like you who has done lots of homework! Great stuff 😊
@ACDodd
2 жыл бұрын
I did spend a lot of time a few years ago working this out. I also had to scrap everything I knew about lapping and re learn.
@kathysarmcandy1992
Жыл бұрын
I like a swab of Dykem before lapping. Caught many seats not concentric that way.
@MiniMattTV
2 жыл бұрын
Always nice to learn something new, I’d only watched the first half of this before I saw you yesterday, definitely going to check what paste I have and find something better
@flinch622
2 жыл бұрын
I was gobsmacked to see the 4% meant roughly half of pressure was lost in just under a second. Granted, its only chamber volume - full cylinder would take longer. That makes an engine wheeze on down the road. The description of good valve seats making a running engine sound "digital" is pretty good: things are popping along with clarity and distinction.
@tonyjenkins7156
3 ай бұрын
Glad I found this. Just lapped valves into a Mini Cooper S. With the head upside down each pod of 4 holds water with no leakage after 2 hours. With paint thinner ever exhaust valve leaked. Permatex grinding compound is supposed to start at 120 and end up at 200. I've ordered Loctite Clover 280 and Wheeler 600. Only choices i could find. This video really helped in understanding how smooth is perfect and what to expect at 200. If i can make the jump from 280 to 600, i will do a leakdown test with oil in the piston and report back.
@OldRodder1964
Жыл бұрын
Excellent tutorial, answered all my questions.... thanks
@georgesanderson8050
Жыл бұрын
Amazing info and demonstration cheers!!!
@ApprenticeGM
Жыл бұрын
Great to see a guy become an expert in a specialised field through hands-on research and data collection. Particularly like building your own tools to test, and making your own paste. Thanks for sharing, it all makes sense to me!
@ACDodd
Жыл бұрын
Thanks for the feedback
@alistairrussell4562
2 жыл бұрын
Another great informative vide. Great to see you sharing knowledge and experience.
@ACDodd
2 жыл бұрын
Glad you liked it
@davidyendoll5903
2 ай бұрын
Thanks ! I never knew the fine paste I have used for years was not fine enough . Ta muchly . And vacuum testing .... damn , you are worth listening to !
@--OpT.OuT--
9 ай бұрын
One of the best videos on KZitem
@ACDodd
9 ай бұрын
Thankyou for the high praise!
@blacksoldierfly888
10 ай бұрын
great info. Thanks for the research
@johnholland4776
2 жыл бұрын
Brilliant article.
@mikedx2706
5 ай бұрын
Thank you for this informative video. It was a real eye opener.
@thelongranger55
5 ай бұрын
350 / 450 / 700 / 1,000 all 24 valves on my m113 engine rebuild. Runs like a champ .
@ACDodd
5 ай бұрын
Good effort!
@thelongranger55
5 ай бұрын
@@ACDodd I also ported them for performance. next pair of m113/m112 heads I get my hands on I’m going to go up even finer , spend less time on the begging grits so they don’t cut away to much to soon work my way up to 1.5k / 2k / 3k / 4k paste . It’s diamond paste btw . I’m very careful with it . Light pressure & use very little to get the job done . you can feel each grit cut down & when you feel how it gets smoother that’s when it’s time to switch grits & the colorful paste turns black quickly so that’s also a sign to stop .
@MarkShinnick
Жыл бұрын
Thanks, nicely done.
@ericgeber6145
Жыл бұрын
Helped me alot to get my valve seats DIALED! 😊
@chrismechanic2000
2 жыл бұрын
this guy is right, i have had a VW head back from the machine shop lately, the ones with the soft exhaust guides, it was badly leaking with new valves and fresh cut seats on more than 1 seat, i do a liquid test before i fit the head, the head is upside down the valves and springs are in and so are the spark plugs, now fill the head pockets up with a low viscosity liquid and if any valve leaks you will see which port it flows from. i have never fitted a head which i didn't lap all the valves in on, but who does that anyway?
@classicminiworkshop
2 жыл бұрын
Very interesting, great video 👍
@daledavies2334
Жыл бұрын
Never lapped valves. Seats and the valve face are ground or cut with about 1° difference. Put the valve in the guide and hold off the seat with a finger. Give the valve a quick tap with a couple of fingers so it hits the seat. This will leave a witness mark around the valve face. It should be visible all around the valve face and will show how far up the face toward the margin that the seat is. A very thin smear of grease on the valve face and lightly pushed on the seat will allow measurement of seat width. When this indicates the proper seat position and width, wipe the valves and seats clean and dry. Install the valves with a bit of assembly lube or oil in the guides and the stems. Once assembled, perform a vaccuum test on the ports. With the stems lubed it should hold the vaccuum for a minute. If it does not, there is a leak on either the guide/stem or the face/seat. I never had an issue. Taking care with having good guides and grinding the seats and faces makes the difference. Most of this was on diesel heads that went 100's of thousands of miles.
@glensweeting9408
2 жыл бұрын
Great video, thanks for sharing 👍
@BrokeAsHellChallenge
9 ай бұрын
🔥 content! Thank you for post.
@vintagebikes4215
11 күн бұрын
Superb video...clear point...dead on
@BC-wg5pq
20 күн бұрын
Ty great video, truly helpful,was wondering about this.
@hamlet2554
5 ай бұрын
Very informative and thank you!
@deangaryjames
2 жыл бұрын
Really interesting, must admit in later years i lapped valves using a drill in both directions, naughty but quick!
@boskopavlovic5832
Ай бұрын
Superb stuff!
@Rein_Ciarfella
Жыл бұрын
I'm just learning about this process in my work on small engines. I'd very much appreciate a video demonstrating your technique using the drill press (pillar drill) and the oscillating thing you mention, as well as a link to the oscillating item and why you use that as opposed to mounting the lapping tool directly in the chuck. Is that tool oscillating or automatically reversing? Thanks! (Cheers, that is, from a Yank who lived for a year in Guildford and another year in London back in the '70's - I recognize that accent!) All the best!
@ACDodd
Жыл бұрын
IT’s oscillating
@ercost60
Жыл бұрын
Great info, thank you!
@oriancunningham
Жыл бұрын
Wow, brilliant content! Thanks mate
@ACDodd
Жыл бұрын
Glad you enjoyed it!
@Sternhammer89
2 жыл бұрын
Another great explanation, many thanks. P.S. could you link the oscillating attachment, cant seem to find one anywhere?
@ACDodd
2 жыл бұрын
Just type ‘valve lapper’ into ebay
@adamcolby805
2 жыл бұрын
Great video 👍🏻
@Joey-yj5ry
2 жыл бұрын
This video was awesome!
@TheAnonymous1one
Жыл бұрын
Damn this video is great. One of the best about valve lapping. Did you start with the 360 grit and work your way up to 1000?
@ACDodd
Жыл бұрын
Yes
@john2ndname
Жыл бұрын
thanks for uploading very interesting.
@nsummy
5 ай бұрын
Never thought I would watch a 20 minute video on valve lapping but here I am. Always good to see a science based approach instead of old wives tails or going by "passed down" knowledge. One question: This makes sense for new valves, but lets say I have a used Toyota head with the original OEM valves. If I take them out & clean them, and they are to spec, is lapping still necessary or is this something that would have been perfected at the factory?
@ACDodd
5 ай бұрын
Performing a leakage test informs you of the likely work needed.
@ofwofw2522
2 жыл бұрын
Woooowww... Very informative. Thanks for sharing and more videos. Happpppppy new year♥️😊😊
@nikolamasic7395
Жыл бұрын
Great video. One question regarding valve lapping paste: I was discouraged from lapping at one shop I worked at because the boss-man insisted that once you lap you can't completely remove the paste/grit and that causes problems. Is there a cleaning procedure you follow to ensure the valve and seats are perfectly clean?
@ACDodd
Жыл бұрын
Excellent question, I have only ever had issues using diamond lapping paste, in those cases finishing using normal silicon carbide paste cleaned the seats sufficiently. After all lapping I clean with thinnners or brake cleaner, both the seat and the valves
@Darlovo
10 ай бұрын
Perfectly matched surfaces after lapping are no longer the same in very high temperatures 600C plus. Valves grow up and just are out of the lapping position [pattern] obtained when cold. Race engine builders never ever lapping the valves. Modern valve seat cutting machines give perfect concentric surfaces without lapping.
@ACDodd
10 ай бұрын
The same applies when hot. I would agree with you if the the machining action was carried out with a hot casting. The point it both the centre and the diameters will change at heating, meaning both methods are flawed when done cold. I have yet to see an as machined seat that can get less than 2.5% loss on this seal check I use regardless who’s cuts them or what process they use. Valves are not lapped nowadays as the customers won’t pay for it.
@joecummings1260
5 ай бұрын
I've got an electric valve lapper made by Black & Decker. I'm guessing it's from the early 50's. I never used it I got it with a bunch of valve grinding equipment I bought when an old garage went out of business. It's in nice shape but it needs a new cord and a good cleaning, lubrication, etc
@user-el5cv1hc9k
7 ай бұрын
R.KO...fine work....result under ambient temps......which obviously transcends under heat or load.....now that leaves exacting surface material....expansion contractions.....after this polish method obviously is LEGIT.....that leaves material choice.YES not all LAPS are TIGHT.
@tomstrum6259
2 жыл бұрын
Well done on the modern " just machined Cut only" or the older, traditional finished, fine compound Lapped valve job controversy with Precision Leak down Measurments directly linked to valve job finishing techniques.....The 4 different valve job examples dramatically demonstrate how just the Slightest valve seat Irregularities produce measurable, significant Leakage differences.....Assuming, at hot engine running conditions, with valve & seat at Different but extremely Elevated temperatures, Is the Lapped, room temperature performed valve job sealing good as it could be ?? How can the hot, running engine valve sealing be Improved by changing to a temperature compensating procedure,...maybe using a slightly Larger OD valve for lapping & Leakage measurments ??
@pauliebots
3 ай бұрын
Hello, great vid. I was wondering your thoughts on a 3 angled valve job compared to just the 45⁰ being lapped tightly. Also I looked up the 1000 grit clover paste wheweee! That is pricey. They have a diamond tech brand with 600,800,1000,1200 grits. Any good? Cheap compared to clover. Anyway, great stuff and excellent food for thought.! Thank you for this.
@ACDodd
3 ай бұрын
I had a bad experience with diamond paste an now use silicon carbide water based product from Kemet. However it’s very expensive to purchase as it only comes in relatively large sizes.
@--OpT.OuT--
Жыл бұрын
Thank you sir
@danielward-allen9825
7 ай бұрын
Thanks for that. Excellent. How does this relate to 3 angle valve grind?
@ACDodd
7 ай бұрын
Same. The seal still needs to be as good as you can make it.
@user-mm1se7gy7e
Жыл бұрын
I find this video two weeks after I lapped my valves, apparently incorrectly.
@AquaMarine1000
3 ай бұрын
After grinding, check the valve seat with bearing blue applied with the lightest fingerprints of blue and a light tap of the valve. Cheers
@ACDodd
3 ай бұрын
I get a full seal reading after seat cutting, let alone after lapping the blue does not indicate how well the seat seals.
@CoreMaster111
Жыл бұрын
My cars workshop manual says that you can recondition valves by lapping them but if you need to use new valves then do not lap them under any condition and you must have the seats in the head ground to spec. Also valve seats on the valve are supposed to be at 45 degree angle and on the head at 46 degree angle. I assume this is necessary for proper seating once engine warms up? On top of this according to the workshop manual, actual seating area is supposed to be less than a millimeter in width.
@ACDodd
Жыл бұрын
Every engine differs in their requirements, this info was gathers on the Classic A-series engine.
@shanedeacon6548
Ай бұрын
Did you work down through the grits in order, or was each cylinder lapped in with the single listed grit? Also do you have any data on how a "broken in" engine seals? Would the freshly machined surfaces eventually mate together through run time to approach the leak down from a lapped in valve?
@ACDodd
Ай бұрын
Work down the grits, cylinder seal is never as good as valve seal.
@jonniejam-shovel6405
Жыл бұрын
With grateful thanks from a new subscriber.👍Cheers.
@angusnewman7782
2 жыл бұрын
Exellent video. I wish I'd had known this 9 months ago when building my engine! I'll be forever wondering what potential HP is wasted. I was told by the machine shop not to lap the valves but I couldn't help myself and used the bog standard fine paste. Next time I'll go all out. After the 1000 grit could you use something like autosol metal polish to finish?
@ACDodd
2 жыл бұрын
No point using finer
@martinfidel7086
10 ай бұрын
yes the smoother the better, as coke will stick to a rough surface easier, therefore your "tune" will fade away sooner if you leave it rough.
@pioneerpete8170
3 ай бұрын
Thanks for sharing
@gutrali
3 ай бұрын
I think what you mean to say is that there is a lot of fruit to be had, spending time to make it perfect
@thebenlyshop
2 ай бұрын
Very informative video. are these valve lapping compounds commercially available?
@ACDodd
2 ай бұрын
Clover brand from the usa
@ferrumignis
2 ай бұрын
In the UK a company called Brownells sell small containers of 600 and 800 grit lapping compound, though it's quite expensive IMO.
@ACDodd
2 ай бұрын
Thanks for that
@grjohn14
2 жыл бұрын
Hello sir, where can I order some of your valve cream? I thought your video was spot on and I really would like to have the lineup of the various grits for my current CR750 build.
@ACDodd
2 жыл бұрын
Sorry currently none instock
@jaybee5390
2 жыл бұрын
Thanks for your good video. Could you provide better pictures from the surface to have a better feeling of the the different grids? Would you tell us how you made your different paste's? When u scratch them with you nails, do you "hills" and "bottoms" greatings from GER
@ACDodd
2 жыл бұрын
I have no other pictures. The paste is purchased not made. You simply buy the grades I have mentioned. Look for suppliers in the US.
@jaybee5390
2 жыл бұрын
@@ACDodd thx! Can you still feel/see grooves with 380 grid? I tried "holts valve grinding paste" and the result wasnt good.. Found suppliers for 320/600/1000 and will try with these ones.
@DogbiteBob
Жыл бұрын
That's pretty interesting. Didn't expect to see such a difference, especially between different grits. What I wonder, though, and can't seem to find an answer to, is why do we need oscillating action when lapping valves? Why can't we just chuck them up in a drill and spin away?
@ACDodd
Жыл бұрын
Because it helps the keep the paste in between the valve and seat a little longer.
@jimgordon3274
Жыл бұрын
Hi, Do you sell your lapping pastes. A very good video with tons of information. Jim
@ACDodd
Жыл бұрын
Not anymore, the grade details are I. The video so you can make up your own.
@bsagreg
8 ай бұрын
Thanks proven information. instead of the usual repeating info over and over from sources with nothing to back them up.
@flinch622
2 жыл бұрын
Top notch. I always knew there was something wrong with average auto parts store "lapping compound" [which is always on the coarse side]. Grinding paste is a better description. Your test method shows why. Tricks learned from steam applications?
@ACDodd
2 жыл бұрын
No, tricks learned from trying to develop more low speed petrol Engine torque
@5angles114
Жыл бұрын
so chamber 3 sealing nice and tight was lapped with 360/600/then a final 1000, correct?
@ACDodd
Жыл бұрын
Yes
@jimgiordano2576
2 ай бұрын
Thank you.
@ACDodd
2 ай бұрын
You're welcome!
@juanrivera8566
Жыл бұрын
What is the outcome of using finer than 1000 grit? The more seal the better the sound of the engine? More power? I'm just curious because I'm gonna lap valves and since you have years of experience maybe you could know
@ACDodd
Жыл бұрын
Once you reach 100% seal there is no further benefit
@joshuanawrocki2994
2 ай бұрын
So do you start with a course paste and finish with a fine paste? or start with the fine paste from the beginning?
@ACDodd
2 ай бұрын
Start with the 360 grit and finish with the finest
@kevwills858
4 ай бұрын
Nice demo, thanks for sharing/teaching us knowledge ... Would be nice to see how you lap by hand and how to make a finer paste .. Its a wonder you dont provide a link to purchase your 3 home made grades ... Im sure they would sell ... 👍
@ACDodd
4 ай бұрын
Paste can be imported under the clover brand from the USA.
@blakenorman4822
Жыл бұрын
So do you go from 360 to 600 to 1000 when reseating, or do you just use 1000?
@ACDodd
Жыл бұрын
You need to use all 3 if you want perfect seats
@janhoogesteger4789
3 ай бұрын
I think the idea that cut seats and modern accurately made and super-finished valves can seat well is formed from dealing with multi cylinder engines with electric starters... Once the engine has fired, the hammer action over the first few minutes of running will form a working seal. This was exemplified by say the Sykes pickavant system usind say 46deg seat with a 45 deg valve seating surface....my experience with this and single cylinder diesels (Petter engines used by artisanal fishermen) did not allow us to start at all, the valves HAD to be ground. Now, many years later I rebuild Velocette motorcycle single cylinder engines and exactly the same applies, despite replacement unleaded seats being much softer than the original austenitic nickel iron. I have developed a vacuum system which shews near perfect sealing on the inlet, only determined ny the presence or absence of a stem seal, obviously a 2 thousandth inch clearance lets quite a lot of air in! You have produced a logical and sensible account which all home mechanics should take note of, and not be influenced by some of the quick fire b.s. spouted by some across the pond... Best Regards Jan Hoogesteger ( Velocette Toolroom Services)
@ACDodd
3 ай бұрын
Thankyou for those wise words
@_.-AAA-._
3 ай бұрын
At least on the intakes, I can imagine that an imperfect seal is more forgiving as the liquid fuel serves to help the seal between the seat and valve.
@shawnd567
Ай бұрын
@@_.-AAA-._ Not anymore with direct injection.
@Machines253
2 жыл бұрын
Nice
@Gemodaboss
Жыл бұрын
👏🏾👏🏾👏🏾
@therealspixycat
10 ай бұрын
Do you have a video on how to build a diy leak down tester?
@ACDodd
10 ай бұрын
No Sorry
@blacksoldierfly888
10 ай бұрын
And the next question what is a good brand of lapping compound or does someone have a tried and trusted recipe!!
@ACDodd
10 ай бұрын
Clover
@MrGsxr10001
3 күн бұрын
So do you work your way down to 1000 grit or just do it with 1000 grit from the get go ?
@ACDodd
3 күн бұрын
You have to work your way down the grits.
@sidds2004
8 ай бұрын
How do you lap the exhaust valve seat Do you make a full contact Or Do you make a line contact Your thoughts?
@ACDodd
8 ай бұрын
Full contact
@sidds2004
6 ай бұрын
@@ACDodd Dear Sir, The exhaust valve seat will have an expansion during operation because of high temperatures. If the contact is full contact, then the contact profile will be different during operation due to heat load. Hence, in my opinion a line contact will suffice.
@proFFGaming2
5 ай бұрын
Marvellous video, i haven't seen anyone explaining this deep knowledgeable stuff about valve lapping. Great video sir i am eager to know how you made lapping compound of 1000grit
@ACDodd
5 ай бұрын
I purchased the lapping compound.
@proFFGaming2
5 ай бұрын
@@ACDodd ooh i thought you diy 1000grit can you share where you bought it from?
@mikedx2706
5 ай бұрын
@@proFFGaming2 I just bought some om Amazon. It's from China.
@proFFGaming2
4 ай бұрын
@@mikedx2706 can you share me a link to it ?
@5angles114
Жыл бұрын
what is the pressure gun with the optional release there called AC? I can't locate one
@ACDodd
Жыл бұрын
It’s homemade
@michaelengebretson9186
Жыл бұрын
@@ACDoddyou must have got that pressure gun from something ? Paint gun ?
@ACDodd
Жыл бұрын
@@michaelengebretson9186 it’s a cheap eBay tyre inflator repurposed
@alro2434
Жыл бұрын
Shame the seats are soooo wide. Not that you need performance/narrow seats and that the heat transfer with wide seats is better, but wide seats don't crush out the carbon deposited.
@ACDodd
Жыл бұрын
Narrow seats last 10mins in an a-series. No use for road work.
@januaryonenineteenseventy4195
Жыл бұрын
Where do you post these creams for sale?
@ACDodd
Жыл бұрын
Currently not available
@eddiecalabro7265
Жыл бұрын
👍
@1crazypj
6 ай бұрын
If you want better performance I suggest you do some reading. Service manual will give correct seat width and usually position on valve head (top one third is a reasonable generic setting) For racing you can actually work out correct valve seat width, it will be narrower than production specification. Every single seat you showed is far too wide for good sealing A good generalisation for automotive use, 1.5mm (0.060") for intakes and 2mm (0.080") for exhaust seats. Seats too wide are likely to get a carbon build up and cause a leak, particularly if your valve guides are a bit worn and don't have seals. The vast majority of 'modern' engines (since at least 1980's, probably earlier?) don't have valves lapped because they use interference angles, often 45 degree valve face and 46 degree seat. May not be 100% seal if you check before starting engine but it will be 100% after first start. There is a lot, lot, more to know about valves, 4 months watching You Tube video's won't tell you an awful lot of useful information. I've watched way too many video's where people don't know what the hell they are talking about (forget name, mushroom, tomato or something weird) was going on about high revving Honda car engine but didn't even know valve springs were fitted upside down (that's bad and severely limits max rpm) David Vizard has several video's, mostly on small block Chevy, but, the information on valves and porting is applicable to any engine that uses poppet valves. Personally, if I need to lap valves I feel I cut something wrong, width or position. Solvol Autosol works fine to get an accurate measurement of width and position on valve head if everything is right, there are also several 'classic' tuning books you should probably own. Oh, since I retired, I really don't have anything better to do 😂
@ACDodd
6 ай бұрын
Thanks for the post, but having cut heads before that have passed the 130hp mark using only the stock exhaust valve sizes, and having many customers who have had heads cut by me can vouch for my experience with porting 5 port castings.. As for seats being too narrow, the a-series runs at high seat temps and will simply pound the seats out when used for typical road mileages. The narrowest I use is 1.7mm inlets and 1.8mm on modified heads. Any less than that will deliver unacceptably short service life. For further information, you might want to watch this 6 part series on rebuilding a 1275 cylinder head; kzitem.info/news/bejne/uaqIl5qFkJaZamUsi=PWAmOZ6cSeqOxzWZ
@1crazypj
6 ай бұрын
@@ACDodd Haven't worked on Mini's since I was 17 or 18, quite a long time ago. Never said anything about seats being too narrow, 1.5mm in. and 2mm ex. were generics that work on just about everything. I only said the ones you showed are too wide. Have you read Vizard's book on tuning the A-Series? He is an engineer who wrote tuning articles in many publications in the 1970's (probably before your time?) He did development work for many car companies. Here'sa You Tube video, it's actually much older than 12 years kzitem.info/news/bejne/0K1ryXuMcJSJdqwsi=bQhkJWFtzT3msiCZ
@ACDodd
6 ай бұрын
@@1crazypjI am well read and am fully aware of MrVizard and many others. I am also aware that a lot of information in books is old. The idea of this video is to give my view, nothing else. Things have moved on a lot since the information that have been written by many authors on the subject of A-series tuning, especially camshafts and cylinder heads. Thankyou for taking the time to write an extensive answer it is appreciated.
@ninacossetto2283
2 жыл бұрын
Top🏁🏆!
@iancooper5615
2 жыл бұрын
I really don’t understand how people can say that two parts machined separately, albeit to tight tolerances can expect them to seal anywhere near as good as if they were lapped together correctly. The internet makes my wee wee boil 🤣
@brianfrancis2862
2 ай бұрын
is the bigger one intake or exous
@ACDodd
2 ай бұрын
Bigger is intake.
@Aceman597
5 ай бұрын
Great video. What about tooth paste?
@ACDodd
5 ай бұрын
Try it!
@Aceman597
5 ай бұрын
@@ACDodd I tried 3m compound for car surfaces. Yellow squeeze bottle. Not sure the grit . I lapped all 16 valves with normal lapping compound . Then cut with oil and lapped again. Then cleaned off all surfaces and used the 3m compound. I even did another final lap adding tiny bit oil again. Deff noticed a difference in the steel looked more shiny like yours. Redoing heads and 350 for 72 c20 step side. Just a driver . But want to practice lapping for my GTO. Will test soon when the valve o rings come in .
@mcplutt
16 күн бұрын
Or metal polish like Autosol?
@allenhafner7795
7 ай бұрын
General Motors quit lapping valves in the fifties.
@ACDodd
7 ай бұрын
Most engine shops did too.
@marianajaldin2757
8 ай бұрын
Heart shaped? Really?
@ianqv
6 ай бұрын
WOW - what a great video. How can I contact you please?
@ACDodd
6 ай бұрын
Fb messenger
@0120raptor
2 жыл бұрын
I have to disagree. If you leak test any modern road car engine you`ll find around 4% leak from the rings.Nothing at all from the valves and they have ZERO lapping. We also have a similar test rig to yours whereby we turn off the air supply on our race heads but use vacuum down the ports. If your seats and valves are concentric and the angles are the same they will seal 100% WITHOUT SPRINGS FITTED just a bit of grease on the stems.You have to remember when the engines at full chat those exhaust valves are around 600*C and have grown in diameter. That perfectly lapped valve is no longer the same diameter and so wont seal when hot.There will be an imperceptible ridge on the valve from lapping which will no longer match the seat. We did however have to modify our very expensive seat cutting machine to achieve perfectly concentric seats .
@ACDodd
2 жыл бұрын
I never said it was better
@andrewleonard9257
2 жыл бұрын
How do you differentiate leak from the rings, from leakage from the valves? Are you suggesting that exhaust valves operating at working temperatures, do not seal properly, even onto perfectly concentric seats? Why can't the very expensive seat cutting machines compensate for the thermal expansion? What would you suggest the DIY engine builder does, in regard to valve seats?
@shimon2476
Жыл бұрын
@@andrewleonard9257 No reply guess he didt see the reply!
@martinfidel7086
10 ай бұрын
Can you show test data ? Most of the heat from the valve is going out through the valve and seat contact patch, so they both heat up and both expand, also expansion will not suddenly stop the system from sealing it will just move the position at which it seals at ! also if you understood the lapping process you would also understand that the grinding paste adds a thickness that raises the valve away from the seat. that reduces as the grind paste wears, ie no lip/step or whatever
@martinfidel7086
10 ай бұрын
@@andrewleonard9257 you don't need to compensate for heat, it is automatic within the system, ie a cone (valve) within another cone will simply move in Z (along centreline) but will still seal.
@martijnvangemeren9639
Жыл бұрын
This hole procedure far too expensive in commercial engine rebuild
@ACDodd
Жыл бұрын
Yes you are correct
@brianfrancis2862
2 ай бұрын
exhaust
@LabiaLicker
3 ай бұрын
The problem here is your not properly taking into account thermal expansion. Your engine runs hot, not at room temperature and certainly not at 85 degrees. Your "engine temp" is just your coolant loop temp and engine coolant relative to aluminum is like a insulator (very low Wm − 1K − 1) . With aluminum block and steel valves your getting a different temperature coefficient between the two materials. Your exhaust valves will be around 900 degrees Celsius and your intake will be ~500 degrees. So saying "the valves are going to be potentially hotter" is just flat out wrong and ignorant.
@ACDodd
3 ай бұрын
Thanks for the feedback, I am well aware of thermal expansion and the head here is not aluminium it’s cast iron. The good thing about the internet is we can share opinions and experiences, just because mine are not the same as yours does not make my view ingnorant, it just means in my experience with the subject I have not seen what you have.
@_.-AAA-._
3 ай бұрын
The material make of the head is irrelevant when the valve makes contact with the SEAT and not the head.
@LabiaLicker
3 ай бұрын
@@_.-AAA-._ Yes thanks for that, I meant to say block. Not head.
@_.-AAA-._
3 ай бұрын
@@LabiaLicker No... the valve does not make contact with the block either, it makes contact with the seat, which is inserted into the head. The seat is a hardened steel like the valve.
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