Valve laping with power drill?

[36tudordeluxe]

Leak down test on my '36 LB indicates air getting past the valves, this is on engine with a little over 500 miles on it since rebuild.
Saw video of suction cup attached to hand held power drill that seemed to work very well, but others say it would be very easy to damage the valve and seat; what do you think?

[rotorwrench]

Lapping is generally done with constant rotational direction changes to prevent streaks around the seat or the valve. Rotating one direction for a half turn then reversing rotation for a half turn and so on while lifting the valve off the seat every couple of cycles is the normal way most folks do it. This keeps the lapping compound moving around so that the grit doesn't set in one place.

If a person just rotates one direction, it tends to put grinding streaks or light scores in the seat and/or valve face. In effect it would be grinding the surfaces instead of lapping them.

Seats can be ground with angle grinder wheels or cut with cutters to get the angle profile then the lapping will polish the seating surfaces to a finish that depends on the coarseness of the lapping compound. It is basically just to insure that the valve is seating all the way around.

[SofaKing]

I've done it that way, it can work but is not considered orthodox. Don't overheat things by applying too much pressure or staying in contact for long duration. I go slow speed, light, short touches a few seconds at a time. Check contact with Prussian blue when finished. The caution about introducing valve lapping paste into your fresh rebuild needs mentioning as does duplicating your test results so your not fixing the wrong thing.

[tubman]

I have an old "manual crank" valve lapping tool. You turn the crank and it goes half a revolution one way and then half a revolution the other way. It also retracts once a revolution. That's the motion you want, not strictly one way like a drill would give you. I wouldn't do it. Hand lapping is fine on a one cylinder Briggs & Stratton, but can get tedious on an eight cylinder. That being said, it's probably a better way to go..

[Ole Don]

If you lap, wipe out the crud with a wet paper towel, then heavy oil on the seat and the valve, then turn the valve by hand to see how well you did. There should be a nice even mark all the way around, on both seat and valve. Then, double check clearance.

[Mart]

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I'm surprised you have valve seating problems at 500 miles. Are the gaps ok?

Mart.

[36tudordeluxe]

The consensus seems to be to re-lap the old fashioned way and thats what I'll do.
Am surprised that I have valve problems also but leak down test says that I do.
After pulling heads today I found these deposits in the water way passages, something I haven't seen before. I'm using a product called No-Rosion (aluminum heads) and a water wetter, is this why I'm seeing these deposits?

[cas3]

i have better luck with a black felt marker pen then the blue stuff, easier to see i think. also, i mark the valve and the seat in 4 spots, then lap, and then look at the contact marks in the black pen marks

[Ronnie]

What is the history on the valve job.Who did it and how

R

[flatjack9]

I've never used No-rosion,but I wouldn't be happy with my cooling system looking like that.

[36tudordeluxe]

This valve job was done by a machine shop over 25 years ago but the engine only has around 500 miles or so on it. Here's a better picture of the deposits in the block and heads.

[Mart]

Jeez is that supposed to be better than just normal (distilled) water and a good quality anti-freeze/summer coolant?

Factories don't fit the normal stuff to millions of vehicles worldwide for no reason.

Mart.

[Karl Wolf]

A good valve job does not need to include lapping.

Only MAYBE to show where on the valve the seat is.

I agree with someone elses idea of using black felt tip marker.
Better than lapping. Worked for me.

What tooling was used for the valve seats and grinding the valves?

How were the valve clearances?

Karl

[FlatheadTed]

It looks like you had copper gaskets with a Aluminium head that sets up a electrolyse action ,you also may have had a light film of rust on the valve seat after 25 years ,Ted

[Kurt in NJ]

Aluminum heads?, I have seen such corrosion on ones that have sat long times

[36tudordeluxe]

Yes, aluminum heads, copper gaskets after approx. one year.
Going to try the black marker pen, am I looking for the marks to disappear completely on the seats and valve bottoms?

[Ronnie]

Originally Posted by Karl Wolf

A good valve job does not need to include lapping.

Only MAYBE to show where on the valve the seat is.

I agree with someone elses idea of using black felt tip marker.
Better than lapping. Worked for me.

What tooling was used for the valve seats and grinding the valves?

How were the valve clearances?

Karl

Yup x2!!! ^^^^ 25 years ago "yikes" maybe a poor job at best. Lapping only really shows where the seat is in regards to the valve face,and the width also.

R

[Ronnie]

https://www.google.ca/search?hl=en-C...pe=&as_rights=

Some info here that will get you going.

R

[rotorwrench]

Check closely to see if you have any bent valves. It's not common to have bent valves on a flathead V8 but lots of things can happen in 25 years. If the heads show no signs of contact in the pockets then they should be OK unless some were already bent the last time they went in. Also see if there are any loose seats in the block. If someone didn't get a good interference fit upon replacement, they can come loose. I've also seen those old seats start to crumble if they get too much corrosion going on.

[Kurt in NJ]

Since you did a leakdown test you sould know which valves are problems, most likely if it just had the seats cut, valves refaced 500 miles ago the most likely cause of leakage is the valves and or the seats are not concentric, something lapping won't fix

when you remove the valves take pictures of the valve, seat that have leakage and post

[36tudordeluxe]

Just went to a site Ronnie suggested, do I understand that the intake and exhaust valves are not interchangeable because they're cut differently, if that's the case no wonder they're leaking?

[cas3]

i agree with Kurt, you should know which ones to look at, and also many shops dont have the real flathead ford pilot that is long enough that it centers in the lifter bore, and also the guide bore so its all straight. i know of two "engine rebuilders" that have a home made tapered thing that only fits the in guide. they tell me it works, done tons of flatheads, but i dont buy it. your laping will just show what the problem is, but it wont fix it if things are not straight and cut right to start with.

[flatheadmurre]

Originally Posted by 36tudordeluxe

Just went to a site Ronnie suggested, do I understand that the intake and exhaust valves are not interchangeable because they're cut differently, if that's the case no wonder they're leaking?

Seat angle and size are the same it´s the material they are made of that is different.

[cas3]

intake and exhaust are generally only different materials due to high heat on the exhaust valve. race motors could have all kinds of other things goin on, not my area to discuss.

[cas3]

murry beat me!

[flatheadmurre]

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Originally Posted by cas3

i agree with Kurt, you should know which ones to look at, and also many shops dont have the real flathead ford pilot that is long enough that it centers in the lifter bore, and also the guide bore so its all straight. i know of two "engine rebuilders" that have a home made tapered thing that only fits the in guide. they tell me it works, done tons of flatheads, but i dont buy it. your laping will just show what the problem is, but it wont fix it if things are not straight and cut right to start with.

Your valve guide is only centered in the upper bore...so why shouldn´t your pilot be the same ??
More of the factory buillt pilots are short then long...the most common long ones are B&D...kwik way, Sioux are short.

[cas3]

in my thinking, using a pilot that is only in the upper bore, you could be crooked and not in a true line with the lifter, which would then cause premature wear on one side of the guide. but...i am no expert engine guy. when i bought my old black and decker super service valve machine a few years back, it came with 3 long pilots for fords. i sold the two extra on ebay and nearly got the machine paid for!

[BUBBAS IGNITION]

Originally Posted by 36tudordeluxe

The consensus seems to be to re-lap the old fashioned way and thats what I'll do.
Am surprised that I have valve problems also but leak down test says that I do.
After pulling heads today I found these deposits in the water way passages, something I haven't seen before. I'm using a product called No-Rosion (aluminum heads) and a water wetter, is this why I'm seeing these deposits?

Thats stuff is terrible! Clean it up add a good brand of antifreeze and a small bottle of bars leak. That will give you the proper additives you need....

[36tudordeluxe]

My valves are all S.S. so they're interchangeable, when I saw SPEEDWAY cuts the their intake and exhaust differently, I thought maybe that was the problem.
Will post pictures of seats and valves in the next couple of days.
Will flush cooling system and get rid of the NO-ROSION, try and sacrificial anode. would dis-tilled water be a good idea to help reduce erosion?
Thanks for the help guys.

[Mart]

Not on it's own. Just use it with some good quality anti-freeze/summer coolant, like in your modern car.

Mart.

[SofaKing]

Originally Posted by 36tudordeluxe

My valves are all S.S. so they're interchangeable, when I saw SPEEDWAY cuts the their intake and exhaust differently, I thought maybe that was the problem.
Will post pictures of seats and valves in the next couple of days.
Will flush cooling system and get rid of the NO-ROSION, try and sacrificial anode. would dis-tilled water be a good idea to help reduce erosion?
Thanks for the help guys.

Have you determined if that sludge in your water jacket is water soluable? I am speculating that no-rosion and water wetter are incompatible judging from that photo. You can expect that sludge to be everywhere, radiator, heater core, water pumps, block, etc. You might try testing what will dissolve it before you button things up and attempt a flush.

I am also curious why folks prefer a marker to check their valve margin, seems like the ink would be too thin, and dry too quickly, to transfer and be a useful indicator.

[FlatheadTed]

You need composite gaskets with Aluminium .observe the use life of anty freeze it becomes corrosive after a while .I prefer soluble oil .Ted

[scooder]

I'm lead to believe that the proper modern red antifreeze can attack the lead soulder in our old radiators and heater cores. So I use older type blue stuff.
Martin.

[36tudordeluxe]

So heres a few pictures of my leaky valves, (90 over 75) on leak down test on my worst cylinder # 4.

I had very recently honed the cylinders and installed new rings and am surprised to see this ridge line at the top of all the cylinders, any thoughts on this?

Anything about the valves or seats that jump out at you?

[Mart]

Are the valve/seat angles mismatched? The contact seems to be a single thin line(???).

I'd grind/lap em in and reset the gaps and start running it again.

The gaskets look reusable to me too. (I'm a cheapskate).

Mart.

[JWL]

There is no assurance the tappet bore and the valve seat are concentric. I stopped using my long pilot when I noticed the fresh cut seats were running well off center from where the valves had been operating. I think a good, snug fit into the valve guide bore is the proper place for piloting.

Lapping of the valve/seat must be done with a minimum of compound spread evenly. It must not be allowed to vary in thickness or allowed to "stack up". Using the back and forth, lifting and shifting locations method is my recommendation.

Are the valve spring pressures and the tappet clearances correct?

[cas3]

JWL, its interesting that you quit using the long pilot. i too have seen valves that seemed off center from the pilot, but always assumed it was because the guy before me used a short pilot. you dont think the factory had that all straight when they did it?

[supereal]

At our shop we replace all valve seats eliminating lapping in rebuilds. If your engine needs valve lapping, it is probably due to seat erosion or previous poor installation.

[flatjack9]

My tool pilots in the both the lifter bore and the guide bore.

[36tudordeluxe]

Thanks for responding everyone, I value your opinions.

As far as seat pressure, the springs are a stock type and I have gone through the valves twice to confirm clearances.

In the picture I posted,. does anyone have an opinion as to what the ridge at the top of the cylinder is and should I be concerned?

Will proceed by hand lapping the valves, some have mentioned success in using a black marker pen rather than the blue stuff, what should I look for when using the black marker.

Mart thinks the head gaskets are re-useable, I was hoping that would be the case.

[rotorwrench]

Did you turn a ridge reamer in the cylinders before honing them before? It's normal for the rings to wear a ridge in there but it usually takes a while to get much wear. Boring the cylinders and putting in new pistons takes care of the ridge. If you get much more that .003" of wear out or round or .006" taper on the walls then boring is usually a good idea.

[36tudordeluxe]

Originally Posted by rotorwrench

Did you turn a ridge reamer in the cylinders before honing them before? It's normal for the rings to wear a ridge in there but it usually takes a while to get much wear. Boring the cylinders and putting in new pistons takes care of the ridge. If you get much more that .003" of wear out or round or .006" taper on the walls then boring is usually a good idea.

Soon as I get a bore gauge will see what that ridge measures, didn't use a ridge reamer before honing.