Topic: lapping made leaks worse!?!?!

[USCG_C130]

oooookay! sorry its taken me awhile to get back on here but, i was at work for 30 straight hours and  only had me phone then i had to go help a friend pack up their house and garage, so i am just now getting back on here, also i wont be able to get back out to the  bike till tuesday or weds because i have a big test on tuesday morning. but to answer a few questions, no the seats were not cut before lapping, i was hoping a nice lapping would be fine and all they needed, also i gave them  a good wiggle in the guides and felt little if no play. and as for the bat drill i went very slowly clockwise and counter clockwise and even used the tapping method to keep the paste moving around plus light pressure as i have read on several threads. i am still really hoping i just didn't clean them out as well as i needed since all i did was towel the seats off but i did give the valves them selves a good spray off and a rinse in a cup of gas that i used for leak test and wiped them off.  but like i said i will be studying for the next 2 days but as soon as i get back out in the garage i will take them off again and clean them very thoroughly and leak test again and if they still drip i will be looking for a machine shop to get them recut and get the guides checked. Again this is my first motor rebuild of any sorts besides a c-130 so please forgive the novice and rookie mistakes i may make. thanks again for all the input and help for everyone!

[LesterPiglet]

How easy is it to get C130 carbs onto your workbench?   

[Blackhole]

Have you checked your valve adjustment after the lapping?

[lucky]

How easy is it to get C130 carbs onto your workbench?   

The C-130 is a turbo prop. Jet engine turning a gearbox.
It has a fuel system to use any fuel with any BTU rating from anyplace in the world.
It gets VERY complicated.

[USCG_C130]

well really the engine is pretty basic just like any other engine, suck, squeeze, bang, blow. and everything is just geared its not very hard to get the gist of it, BUT, the fuel control and temp control are some of  the most complex things ive tried to wrap my head around,m i actually got to go to the rolls royce school and tear everything down form the gearbox to compressor and turbine blades, to opening the fuel control and i was amazed at really the simplicity of the main part of the T56

[MCRider]

It's funny, there are many threads on how to lap using a drill with flex tubing. I've done on three heads with great results. To make the statement to never use a drill is just incorrect. If you do it properly with the correct speeds and rotation, you will have good results. To say never use a drill because something could go wrong is ridiculous. There are plenty of people who've used a drill with great results. It's the technique, not the tool the matters.

Yup.

[lucky]

I urge you to get the guides checked with dial indicator and not a wiggle by hand test.
Unless you can tell the difference between .004-.006 with your hands. LOL.

Then get the seats cut, and finally lap them by hand.

That is the right way to do it.

[USCG_C130]

i am still hopeful that it maybe just wasn't cleaned well enough but i have a feeling that lucky, u may be right, and its always better to do it right the first time, but like i said i wont be getting much done for the next couple weeks with being out of town for a weeding and work and advancement test this week so when i learn more i will be back to give you all an update!

[KJ790]

Dumb questions, but did you put the springs back on the valves to hold seat pressure before checking to see if the valves were leaking? If you just set the valves in the seats then they are gonna leak pretty much no matter what.

I don't know why people waste their time with lapping, it's such an old school way of accomplishing very little. Most of the top engine builders I know have never lapped a valve in their lives, it's not needed with today's precision cutting equipment.

[LesterPiglet]

Dumb questions, but did you put the springs back on the valves to hold seat pressure before checking to see if the valves were leaking? If you just set the valves in the seats then they are gonna leak pretty much no matter what.

I don't know why people waste their time with lapping, it's such an old school way of accomplishing very little. Most of the top engine builders I know have never lapped a valve in their lives, it's not needed with today's precision cutting equipment.

Because you can do it at home and it costs very little.

[Pat_at_APE]

Dumb questions, but did you put the springs back on the valves to hold seat pressure before checking to see if the valves were leaking? If you just set the valves in the seats then they are gonna leak pretty much no matter what.

I don't know why people waste their time with lapping, it's such an old school way of accomplishing very little. Most of the top engine builders I know have never lapped a valve in their lives, it's not needed with today's precision cutting equipment.

At APE we have some of the best equipment available and we STILL hand lap each valve in and inspect the marks on the seat and valve.  It is the only way to be sure your equipment did the job as it is supposed to....   Many times we end up re-doing a seat because we don't like what we see after lapping.

Cheers,
Pat at APE

[MCRider]

Dumb questions, but did you put the springs back on the valves to hold seat pressure before checking to see if the valves were leaking? If you just set the valves in the seats then they are gonna leak pretty much no matter what.

I don't know why people waste their time with lapping, it's such an old school way of accomplishing very little. Most of the top engine builders I know have never lapped a valve in their lives, it's not needed with today's precision cutting equipment.

Because you can do it at home and it costs very little.

Thanks Pat at APE:

Also it is very effeective for home brew rebuilds. It will really perk up an engine's compression. I'd say it accomplishes a lot for not much.

[KJ790]

If the seat and valve are cut correctly, lapping is completely unnecessary. Anyone building top race engines using coated valves (especially titanium) is not lapping them. Lapping can actually be detrimental to coated valves, hence why it is a technique that has gone by the wayside in the last 15-20 years.

There is a reason why valve faces and valve seats are shaped like they are. As they wear they begin to degrade. Lapping a valve on a worn seat is never going to restore the correct seat shape or sealing surface.

[MCRider]

If the seat and valve are cut correctly, lapping is completely unnecessary. Anyone building top race engines using coated valves (especially titanium) is not lapping them. Lapping can actually be detrimental to coated valves, hence why it is a technique that has gone by the wayside in the last 15-20 years.

There is a reason why valve faces and valve seats are shaped like they are. As they wear they begin to degrade. Lapping a valve on a worn seat is never going to restore the correct seat shape or sealing surface.

Who among us is using coated valves? We're talking garden variety valves and seats. We're talking bringing a 1970s machine back to life at least cost.

Gone by wayside in 15-20 years? Just Google lapping or go to youtube and see how many are still doing it.

It does work and is still in wide use.

[MCRider]

I have the absolute FINAL definitive absolute (did i say that?) video on the subject.  (Actually, its the comments that's the most enlightening)

Using a drill to Lap in the Valves on an old Austin A40 Devon head

Enjoy!   

[KJ790]

Who among us is using coated valves? We're talking garden variety valves and seats. We're talking bringing a 1970s machine back to life at least cost.

Gone by wayside in 15-20 years? Just Google lapping or go to youtube and see how many are still doing it.

It does work and is still in wide use.

I'm sure there are plenty of people here that have engines with coated valves in their garage. Most modern motorcycles come with coated valves, and they were never lapped. Most valves from companies such as Kibblewhite or xceldyne are coated, and plenty of people damage them when they try to lap them. Whether the valve is coated or not does not change the fact that lapping is not necessary if the surfaces are cut properly, nor does it change the fact that lapping worn out parts will never restore the correct valve seat shape.

As for checking youtube to see how many people are still lapping valves, there's plenty of videos of people trying to jump on excersise balls on there as well.

[MCRider]

Man do you know where you're at? This is a SOHC/4 forum, 1970s era. That's what we're talking about. Not people's other engines, or their modern bikes.

The number using Kibblewhite's is minor compared to the number just using the stock stuff (not necessarily worn out) over and trying to get back on the road.

I'll give you what you're saying. (To be nice) You're just saying it in the wrong place, IMO.

As far as exercize balls, many can use them very well.

[LesterPiglet]

I have actually cleaned up two heads by lapping, my 550 and a Sunbeam Stiletto. It works and is worth the effort.

[dave500]

not lapping valves on these types of of engines even if the seats have been cut and valve faces resurfaced is just dumb,,suggesting to others on this forum that you dont have to either is dumber.

[KJ790]

not lapping valves on these types of of engines even if the seats have been cut and valve faces resurfaced is just dumb,,suggesting to others on this forum that you dont have to either is dumber.

I'd like to know where you are getting your information from. Most top engine builders will tell you they haven't lapped valves in over 20 years. Here is a quote from Larry Widmer, who has built more engines than anyone on this forum, a few of which are world record holders:

http://speedtalk.com/forum/viewtopic.php?f=1&t=20642&start=15

"I didn't know that anyone lapped valves anymore. As far back as the Penske Nascar program in the mid 70's, testing proved conclusively that lapped valves and seats eroded much faster in use than precision-machined non-lapped surfaces...."

This concurs with David Vizard, Ron Hamp, Jesse Williams, Phil Burkhart Sr., etc.

Just because these are 70's technology does not mean that things need to be done as they were in the 70's. Afterall, they used to knurl pistons to make them fit clearances as well, how many people recommend that as a permanent fix now a days?

To some, telling people to do a half-@%# job with outdated methods is dumb. But to each his own I suppose.

[lucky]

Dumb questions, but did you put the springs back on the valves to hold seat pressure before checking to see if the valves were leaking? If you just set the valves in the seats then they are gonna leak pretty much no matter what.

I don't know why people waste their time with lapping, it's such an old school way of accomplishing very little. Most of the top engine builders I know have never lapped a valve in their lives, it's not needed with today's precision cutting equipment.

Who has that precision equipment set up for 33 year old CB750 head???

[lucky]

I have the absolute FINAL definitive absolute (did i say that?) video on the subject.  (Actually, its the comments that's the most enlightening)

Using a drill to Lap in the Valves on an old Austin A40 Devon head

Enjoy!   

You can see some of the dumbest stuff on the internet. It is very entertaining.

[USCG_C130]

pics are here, well i got outta work early and have been home tinkering a bit and checks some of my springs and the ones i checked were good, cleaning them out did fix a little bit of the drips, but i have on that i can see the dripping in a spot so ill be taking that back apart in a few but heres some pictures of 2 of my valves and seats

[USCG_C130]

so my question is can i lap these (this time by hand) anymore, i don't want to over do it, and i am really hoping i don't have to recut the seats, but i am open to more suggestions now that you all have pictures!

[Pat_at_APE]

Color the valve and seat surface with blueing compound or even a black marker and lap them again.  It's tough to tell from images but it looks like you still have some pitting which means grinding valves and cutting seats is needed.  The color will remain after lapping so you can see it better.  Clean it off with brake cleaner when you are finished... 

And, lap by hand.

Pat at APE