We have a student in the shop most of the time from a local trade school. They spend 4 hours in the shop in stead of school. I LOVE IT. These kids are good real good and there minds are like a sponge when it comes to knowledge. Last week we got a new kid full of PISS & VINEGAR. So the new chap busted my stones when i was assembling the head for the 3.4. Planed to flatten it and i always hand lap the valves. I asked the kid to come to my work bench and lap in the valves with compound. The kid was very respectful and asked me why?? I said because that is the proper way to do it. He laughed and said OK RENZO IF YOU INSIST. So with that i let him explain to me what he thought about doing it?? He said it was a waste of time?? So my head mechanic Said ok kid watch out now you have dun it ??? With that i called him over as well. They both agreed that once the seats are ground and the valves faces it was a waste of time. Now my DAD always did it and me also. So does anyone feel i am wasting my time and this is not necessary any more. GO ahead pound me or correct these Two DUDES!!! lay it on me
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I do whatever extra work makes me feel confident about the job. I think you are right. The kid needs to learn to lap valves anyway!! After they are cut, I wouldn't though on my stuff. As the rednecks in the shop say:"Let 'er eat!"
"You can lead a horse to water, but only an arrogant man will try to make that horse drink.."
You know, I didn't really let it soak in, but 4-6 weeks ago I was looking into head work again since my new heads need some. I found a ton of threads on google that lapping is NOT something that one should do (that it's a "backyard mechanic" way of "fixing" things). Now I lapped my heads years ago before installing them, as advised by my father, but there were some very detailed explanations as to why one shouldn't lap valves. I think it had something to do with the heat and the metal expanding to provide a seal. If you lap it cold, the seal will be smaller after the seats and valve heat up. Now my question is how is this any different than how the seats and valves are cut? I'd assume they'd be cut cold also, so unless they are cut in a way that expects the expansion to seal them up, a perfect seat on a valve when cold would also have the same issue with expansion as lapped valves.
As a backyard mechanic, to save a few hundred dollars of machine work, I'd just lap them. Maybe there's advanced machining out there that can compensate for the expansion of the metal at temperatures, but I doubt it'd be common.
That is my thought on the issue. What is the difference when the seat and face is ground COLD. BUT then you have interference grinding like on the older chevy heads. You know 44* seats and 45* valve face. Then you have 30* face and seat. (BUICK) This combination flows the best and was the stepping stone for 3&5 angle valve jobs. So once again i am insisting on the chap learning valve lapping with compound. It sets the stage and checks for good valve contact. Now my DAD and me both feel this is necessary but it seems like the young techs are a little taken back by the procedure. With that i am headed down to the Social Security office to register for medicare. WOW where has the time gone!!! Maybe this is the problem and not the procedure!!!! There is an old saying.. YOU CANT TEACH OLD DOGS NEW TRICKS. I think it may be true. But there is another saying.. I may not be the sharpest Knife in the draw.> BUT I HAVE CERTAINLY CUT A LOT OF STAKE. Thanks for the replies guys very interesting at best. Keep the comments coming if you desire. I am all ears. Thanks Tom!!
Bottom line is it does not hurt to learn old procedures. Example like how to use a TIMING LIGHT. This CHAP does not even know what one is !!!!! Progress ain't it GREAT!!!
There's still a need for a timing light in everyone's toolbox....unless you're a chainsaw mechanic, lol.
We did some lessons on lapping valves in high school, never messed with it other than that, and if I have to have valve work done, I'd rather take the project to someone who has the equipment and the knowledge to do it.
My timing light has about an inch of dust on it. Other than the midnighter that no longer needs to be timed. That is one dar i used one on. I have not used a light on customers cars for many many years. Think about it how many cars need to be timed today. NONE
I just send that stuff out to the machine shop. We don't even HAVE that equipment in the shop. It got sold 2 or 3 years ago. I send them out and make money doing other stuff til they get back.
the kid is right~ dont do the good quality steps and the customers stuff will break sooner.
pull you head out of the sand,,, get programed!! start thinking like the rest of the tools.
seriously though, i cant see how one could just assume two different CNC machines with possibly different tolerances could match perfectly separated by different nasdac symbols unless they are milspec rated parts.
I am curious of the grind you saw transfer and if it was a perfect / even pattern on the first pass on all valves or not. as soon as the circle grind appears on the valve evenly all the way around , that would be something to show him.
better yet, grind one then clean and add the spring/keepers.
dont grind another , just add the springs and keepers.
flip the head then pour water on the chamber and see which one leaks the most water into the intake or exhaust port.
Water is quite viscous compared to other liquids. I'd think you'd want to use something with a lower viscosity to measure leakage. My heads didn't leak down, but the seal was pretty terrible. On a badly worn head, I'd assume water wouldn't leak down, but things like acetone, while having a much lower absolute viscosity, would also evaporate fairly quickly.
Honda is telling us the machine shops are upselling unneeded work on our heads, so don't send them out in most cases(short block replacements) We had a shop belt sand a head we asked to be decked!! I only cut valves in tech school(uh yeah loooong time ago). I don't recall temp being relevant to the quality of the job... As far as lapping, you can see the contact area, and I have had great results with it. I think it is a good follow up to a (sometimes) unpredictable sublet repair.
Thought you would ask that Jay!!! Text book pattern!!!
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This is what caused the damage
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@ ABIRD
Honda has a unique situation. Once the TB breaks some shops just replace the bent valves and send the car packing. But i have seen a couple of problems with the puppiesanese car maker. The guides sometimes break just below where they come out of the head. This has to be checked. And sometimes when the valve hits the piston it breaks the upper ring land. Depending on the engine as you say some shops sell up a job. But any shop that flattened a head with a belt sander should have there machinist stack shelves in Wall Mart. I totally agree that a lap with a suction cup stick is the final check of how good a job you did with the grinding operation. Foe the above post that A BIRD posted is prime example of how machine shops do py work. Using a belt sander. That is crazy. So as i put my name on every repair the customer does not go back to the Machinist with issues. He comes to me screaming his or her brains out. Bottom line never put your reputation on the line from a third party. That is not to say there are not good shops around. You need a good shop that you can trust 100% There are a lot of BEATER SHOPS OUT THERE. Just saying. Thanks for the responses and the ideas.
@ A Bird
It is funny Honda is the first ones to complain when warranty work has to be paid out. I am assuming you are talking about warranty work that Honda has to flip the bill for?? It boggles my mind how people think so highly about HONDA and working on them and dealing with warranty work they are no better than any other car BUILDER. They just have a reputation i think is BS!!
That is fine and that is the NORM. We do it all the time with starters and alternators. How many alternators or starters do we rebuild now . NONE Years ago me and my DAD rebuilt everything. From steering boxes to rear axles. Now all these shops R&R and do not know the basics as to how things work and or how to repair a defect. Many on this site have great ideas and mods. Jay rebuilt a circuit board on his headlights. That is fascinating to me as electronics is not my thing. Example how did ne know what transistor to use or even know it would work. I do relay stuff ETC. But designing a circuit Not happening with me. So each of us do great things like when you installed those auto down modules on your windows. That blew me away FOE as a great mod to say the least. So my main concern with this CHAP is to teach him things that were good practice and even if he never does it again he can say he was taught it and actually dun it. Thanks Tom
A good friend of the family has a shop and he laps the valves. He also told me to use gasoline to check the valves by flipping the head over and pouring the gas in the combustion chamber. It works much better than water.
Any jackass that does not want to learn something for free is an idiot. The kid needs to understand the gift he has been given and learn everything he can while in your shop. Passing up free knowledge...makes me worry about the next generation of mechanics.
Darren
I just always left some deisel in the heads over night to see if it was leaking.
That is what i use STACKS DIESEL!!!
Aerocoupe i thank you for your kind words. But here is some facts that these kids dont realize. They do not know how to TIME A CAR!!! They do not know how to install points and adjust them. They do not know anything about CARBS. And the worst thing is they dont care!!!. Check this out Last Wednesday me and the chap went out to pick up an early Porsche for a NO START!!! At the shop i let the kid trouble shoot it. Presto he checked for spark and NONE. With that he asked me where to get a new control module for the car. I asked why. Well it has no spark he replied!! I asked him if he checked the points?? WHAT IS THAT RENZO. Cars do not have points any more. Well this car does i replied. WHERE ARE THEYHE ASKED. I said under the cap!! Under the CAP. YES!! With that he removed the cap and all that was there was the ROTOR and the cover for the points. Once again where are the points he replied. WELL remove the rotor and the point cover and you will find them. So he DID. Is that the points RENZO. YES, How do you check them. So i cranked the engine over to get the points in the high spot on the cam lobes of the DIZZY had the kid key the car and i used my trusty screwdriver to shove between the contacts. Bingo the kig says hay the test plug you installed is sparking RENZO. Imagine that. Whats wrong with them. I explained they were pitted and dirty. With that i went to my tool box and got out a point file. This kid was in shock. A POINT FILE. Is there such a thing. YES now with a few strokes of the file between the points i told the lad to replace the cover rotor and the cap. Bingo the pride of the GERMANS CAME TO LIFE. I ordered a new set of points and installed and gaped them. The lad asked what is that butter knife used for . I asid to adjust the gap correctly. The kid was schocked as this car has a CD system controlled by old fashioned points!!!
Now we had to adjust the VALVES. REALLY RENZO> NEVER HEARD OF THAT. WOOPS WHEEEEEEEEEEEEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!
Here is the car with the mistery ignition system and complete with CARBS!!! The kid was MYSTIFIED!!! But he is a great kid and never complains. I LIKE HIM A LOT!!
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Some of the schools just dont touch on any of the old school stuff anymore. I actually went back to school here and am still in. I had to learn how to adjust the old school valves and what do ya know about a week later we had an early 90's 1/2 ton chevy come in that needed head gaskets. My boss hadnt done it since he was in school, so guess who got thrown into that one!!! Ive even had to do a basic learn on points for school, not sure Ill have something come in that runs them. But it sure helps to have a bit of a clue if I ever do.
The whole process of an engine rebuild is actually being fazed out at most schools, because everybody does send the work to machine shops anymore. My class was the last one at my school that got the full coarse. After mine they are learning the basics like head R&R and stuff like that. Its kind of a shame to its so much easier to diagnose I think if youve had a few engines torn down and actually known the parts. Ive been wrenching since I was 16 on my stuff(32 now) so Ive had a few engines torn down for repairs in my time.
The head on my TC I actually did all the work to in my class, including the mild porting and polishing. Its perfect!!!!!
That is 100% true i can buy a GM or Ford engine cheaper than we can rebuild them. And they come with a great warranty. Even the GM performance engines. You just cant beat the price. I have an old SUN DIZZY machine collecting dust in the back room and finally i sold it. We never Re-Curve a dizzy any more THOSE DAYS AS YOU SAY ARE GONE FOREVER!! Nice talking about it with you. You know it"s funny the kid was looking for a tool the other day in one of my boxes and he came across a tool that was funny looking to him. He said HAY RENZO WHAT IS THIS ??? Turned out it was a VEGA timing belt tension-er tool. Fancy that. All the old obsolete tools in my box just shows one thing. I AM AN OLD I TOLD THE LAD!!! I really like this kid a LOT!!
one sure way to learn all you need to know about points,,,,,,,,,,,,,,,,,
just buy an old tractor that wont start while looking at 2000 feet of driveway that needs plowed.
my tractor was made in 47,,
the point sets i purchased that "fit the best" were 73 continental.
they're not that hard to set, i just hate it when they try to move when you tighten them up. i pull my gaper out and they seem to come closer together,, then i started using something thicker so i end up at about .015 there abouts. thats prob why you use a butter knife,,
another thing is to make sure to use that lubricatant or the felt will were out and you'll be n there too often adjusting again.
oh well,, i suppose "how things work" isnt so important anymore.
what is this kungfu you speak of?
also,, did you have a chance to do that test on the valves, see if the ones you lap cut in sealed better than the ones you didnt?
Tom,
if you had someone verbally explain transitors to you,,, it would open up a whole new world of "relays" that you probably wished you learned 20 years ago.
especially the large power transitors that you bolt down... very reliable even more so than a mechanical relay.
think of this for a minute,, when you stuck that screw driver in betweent the contacts of those points, you bridged a gap that allowed a circut to be completed,,,, you simulated what transitors do for a living,, your triggering a small input to "allow" a larger one to be controlled.
Honda vehicles are generally very reliable... As I'm sure you're aware, warranty times are shrinking at an alarming rate. Honda squeezes every tenth out of us that they can. They call back on all warranty parts, and will debit a claim if all your stuff isn't in order. Guess it's a result of the "new" economy.
Speaking to new "parts changers": we used to change seals, rectifiers, solenoids, etc. Now the flat rate isn't worth the hassle and the parts are getting lower quality it seems. Throw a part in it, roll the next one. This business ain't fun anymore...
BTW, jcassity, I love transistors!!