Head/valves problems 1950 Panhead

[bonham3]

Description: After warm up rear head exhaust starts puffing (light gray/white smoke) as well as a puff out the rear of cylinder head

I have a pan chopper. 48 front head, 50 rear head Flooded it bad a couple of times then changed the oil twice. Ran O.k. for a while (this is a new rebuild on a 69 STD) Then after warm up rear head exhaust starting
puffing (light gray/white smoke) as well as a puff out the rear of cylinder head (at gasket) when throttle was snapped open quickly. Had a slight gas leak at the rear also. Pulled the head. Gasket seems O.K. noticed some
oil on the exhaust valve stem when looking inside port.
exhaust port deposits were dry and wiped off with a finger. Both valve faces have have black deposits and grit around edges as well as plug threads. Before all of this was noticed, bike flooded often but idled great. loss of power and real bad gas mileage. I know this is a lot of info but wanted a direction to go in to solve problem.
Intake manifold O.K. timing etc. When head was pulled there was oil and maybe gas on the bottom of gasket as well as on one head bolt only. rockers, pusrods, tappets and adjustment all fine.

Ron L. (bonham3)

[Cotten]

How did you determine that the manifold was "OK"?
What do you mean by "Had a slight gas leak at the rear also."
An airleak past the headgasket, or anywhere else, runs your combustion temperature up, and makes you over-enrichen the mixture to accommodate it. That would most likely explain the raw carbon.
Considering that one head wasn't secure after a rebuild it would be prudent to cover all bases with a thorough inspection beyond visual appearances. Lapping your headgasket surface upon a flat plate will soon show any warpage or protruding inserts.

[bonham3]

Thank's for the reply, appreciate it. Checked intake manifold body and o-rings. S&S manifold. Orings were like new (they are) tightened and soapy water. the gas was a slight drip coming out the back of the head gasket area. i had carb problems ie: sticky float, flooding while bike was just sitting, etc. rear plug was always wet (gas) actually i had to lean mixture for proper rpm and idle. It's a zenith carb.
i was told to lower float level on carb. have not done that yet. i had hoped to find the head gasket all shot but it looked fine. did not want to just put a new gasket on and still not solve the cause. will ck. head trueness with feeler gauge on a flat plane first. I'm a pan newbie but experienced mechanic (auto and industrial) was concerned about the valves and carb. one rocker (exhaust spins around freely but intake has a chrome piece on
it (bracket with a short tube) what is that for? the intake rocker has a slight drag on it and it hits that tube. Sounds like a novel now Smile Oh well !!!
what did you mean by inserts? the head gasket is just a flat gasket (nothing arond the bolt holes).

Ron L. (bonham3)

[Plain]

Bonham3

Clean the head mating surface. Look closely at the threaded bolt holes in the head. You will see a star shaped pattern around the outside of the bolthole. This is the insert. That is, the threads are created in an insert which is affixed in the aluminum head. These inserts can dislodge, turn loose, and begin to come out of the head. Once you recognize the star shaped pattern of the insert, check to see that all are level with the head. If one is moving then you will have to have that repaired. If all are good, check for head flatness. You may have gotten out very easy and just had an undertorqued headbolt. Stopped and pulled the head before any real damage was done.

Adios-----Plain

[Plain]

Well I fat fingered that one and posted when I did not mean too.
The tube that you mention is the intake valve oiler. Inside the tube is a ball bearing that sometimes sticks and causes a lack of oil to the intake valve. It should not be hitting the rocker. You can bend it somewhat, but remember that the puropse of it is to deliver oil to the intake valve so watch the final postion.
Slight drag on rocker is hard to diagnose, but there should not be a "drag" Check your rocker arm end play (easy). Limit is .004 to .012". Fit in bushing (.001 - .002")is harder to check and you probably will have to disassemble the rocker arm, depending on how you decide to approach this. Word to the wise if you disassemble them. Those small flex nuts on the rocker studs are a stone bitch to get off. Don't reuse them. Colony sells new flex nuts and rocker arm studs. Other than that about the only place that you can get nuts or studs is V-Twin.
Check the books section for recommended reading. At the very least pick up a readily available copy of the Clymer Harley Davidson Panheads - 1949 - 1965 Service, Repair, and Maintenance manual.

Adios Again-----Plain

[bonham3]

Thank's everyone for your help. I have gotten it down to just one problem now. How did oil get down that one head bolt? When i pulled the head i noted four bolts were dry (except for never seize on them) and the bolt
that was in the same area as the head (gasket) leak was covered with oil (threads) It is near the exhaust valve. Oh well !!! and why would the ex valve stem look wet and sooty? (looking through the ex port) Hope just
a new head gasket and torque will do it. I had so many diff opinions from locals around here from valve spring failure to who knows what and you guys seem to make more sense. By the way, a pic. is posted of my ride at this site. (50 pan chopper) once again thank's for any info.

Ron (bonham3)

[Cotten]

The most common way for oil to get into the combustion chamber, and therefore into the exhaust port, and even to seep into the headbolt inserts, is past the headgasket at the drainhole from above.
Your feelergauge may not find it, but when grinding to flat, many heads display a 'low spot' in the narrow area directly between the hole and the edge of the chamber.
Commonly the broader areas of the gasket surface directly over the ports (as you look at the head upside down) also are lower than the rest of the deck. The casting thinner in these regions, and distort over decades of heat-cycles. Aluminum is actually quite mushy, and this is why proper use of a torquewrench is important.
Note that the headbolt inserts are also subject to the pounding of thousands of motorstrokes, and slight protrusion can be expected without fear of their distruction. Only vicious over-torquing would loosen or destroy them, as they are cast-in. Most folks merely grind them flat again, although some actually counterbore them slightly.
And a note on the intakevalve oilers: They were intended to work in cooperation with the felts. The Genuine manual warns against re-use, stating that they will over-oil(!) Modern repops are occasionally quite questionable, so boiling out the originals is usually the best option.

[bonham3]

Well, it sounds to me like you guys know what you are talking about. Makes sense also. Cotten, thank's for the info especially. Glad to know there are some good techs out there. Will go with a new head gasket and
proper torque and fire it up!
I had one local custom bike shop here in Mass. that wanted me to pull the motor and bring it down to him to look at because he thought the oil was from the rings. @$60.00 per hour. Also stated to me that the intake oiler was in the wrong place, it should be on the exhaust side. Oh well, i hope the balance between the two diff. heads will be O.K. seeing as the 50 rear head has a bigger intake port (as i was told anyway) and now by the same bike shop that the 50 had a bigger bore than the 48. It keeps getting stranger. Interesting piece of machinery the panhead motor!!!
Guess we all have much to learn.
By now you are probalby tired of hearing this 48 y.o guy asking so many questions ;D Might as well write a list now then.
1. V power spark plugs or something else? type/p/n
2. proper gap for a basically stock engine? (plug)
3. E or F ? my bore size (tape measure) Smile 3 and 5 16ths.
4. push rod drag, smooth or slight drag? (many opinions
on this one)
5. O.k the most important, how many licks does it take to get to the center of a tootsie pop? Once again, thank You all......................
Oh and that friggin flooder of mine, the chrome plated Zenith. bike sits-rear plug is wet....................... lower the float level or sink the ship? Smile

[Plain]

Bonham3

Well, you have me thoroughly confused. I will leave this to much sharper minds after cleaning up a few items in my last post. I am one of the ones that Cotten indicated likes to slightly counterbore the inserts. After milling a head, or serious lapping to get it flat my opinion is that if you do not slightly counterbore the insert the bottom thread will have a tendency to roll down when the headbolt is torqued causing a slight high spot. Then you are torquing against high spots.
Surely you misunderstood the man and some yahoo did not actually tell you to install the intake valve oiler on the exhaust valve. You should know that the front head intake oiler and the rear head intake oiler are different. Care needs to be exercised when disassembling so that they go back on the correct head. Perhaps the reason that you have the rocker arm hitting the oiler is that you have a rear head intake oiler on a front head, or the other way around.
50 has a bigger bore than the 48. Huh, ello, whot? If you are measuring correctly, then the bore that you are measuring is for a 61 cubic inch engine. I assumed that we were talking about a 74 cubic inch engine. 61 cubic inch engine had a 3-5/16" bore. 74 cubic inch engine had a 3-7/16" bore.
I will leave the other questions to better minds than mine. Final caution, as Cotten stressed, make sure that head is perfectly flat before going back on the engine.

Adios-----Plain Not Going To Install An Intake Oiler On An Exhaust Valve

[PanPal]

I too would advise flattening out the head. Below the exhaust ports, heads have a tendency to warp and inserts pull. I had problems in this area as well.
Cotton has a table that he uses to do this, but I found a piece of mirror and adhesive backed emery paper worked well. Use plenty of WD-40 and clean often. Move head in a figure eight pattern to clean up the surface evenly. This must be done with short strokes as the exhaust port will not allow you to center the head on you work area. It will hang over the edge of your piece of glass or mirror. The inserts will probably protrude so much that counter boring, or my preference counter sinking them first will save a lot of bench time. If you do not feel comfortable with your handy work on these vintage parts, take it to someone that can flatten the heads out for you. The steel from the inserts can gouge the aluminum very easily and you do not want to damage the surface. CLEAN CLEAN CLEAN
Plain, I was not aware there was a ball inside the intake oiler. I'm not tearing mine down just to free it up now, but I know there was no rattle in my tube when I installed the intake oilers. I learn something new here every day Wink Thanks Man ;D

[Plain]

Bonham3:

With regard to your question 4 - push rod drag. What setup is in your engine? '48 - '52 engines came with solid lifters and hydraulic pushrods. Your engine may have been converted to either solid lifters and solid adjustable pushrods or hydraulic lifters and solid adjustable pushrods. Different procedures for solids and hydraulic lifters. You do not find the hydraulic pushrods often as they were a PITA and usually got replaced. My general rule on solid lifters. Dead cold engine. With lifter on heel of cam a dry finger drug across the pushrod should spin the pushrod. Hydraulic lifters get somewhat more complicated with a number of methods to adjust, up to and including measuring valve lift and comparing that to cam lift. Again, general rule for adjusting. Dead cold engine. After preload is established and with lifter on heel of cam, AND lifter has bled down, you should be able to spin pushrod between your thumb and index finger. Because of the preload this pushrod will feel different than one spun in a solid lifter.

PanPal:

You are welcome. Before leaving heads to better heads I would like to pose another question. Cotten indicated that the intake valve oiler was to work in cooperation with the felts. Harley service manual calls them cover pads. You sometimes see them refered to as "sound deadeners." I have never seen anything in the literature that actually discusses the felts at length. Back in the day, when the earth was young, I was taught that the felts were an important and essential part of the Panhead oiling system, and that they should be correctly placed and firmly fixed to the panhead cover.
That begs a couple of questions. My recent experience indicates that current felts vary widely in quality. I have a pair of felts purchased a couple of years ago. They are relatively thick, stiff, and the fibers in the pad are well bonded to each other. Recently got a pair out of a Cometic gasket set. Looks like someone cut the tops off a pair of argyle socks. Soft, mushy, and the fibers are NOT well bonded. Glued into the pan I think that they would fall out almost immediately leaving a bunch of fuzz stuck on the pan. How many pans have you pulled to find the felt laying on top of the rocker, or cheerfully being munched by the rocker? This brings up one of life's torments. Afixing the felt to the pan cover. Over the years I have experimented with a number of adhesives. I find hot sixty weight to be one of the better adhesive removers of all time. Considering that a decent felt can be found, the best that I have come up with is to rough the inside of the pan with eighty grit sandpaper and slather the felt with aviation Form A Gasket. Weight the felt down and let that cure for a couple of days before installing. Has anyone found a better, or more bullet proof method of gluing the felts to the cover?
Last question concerning panhead heads. Last couple of years I have been using the teflon coated head gasket, with what I think is superior results, but jury is still out. Anyone out there used the teflon coated head gaskets and had a good or bad experience?

Adios-----Plain

[PanPal]

I had problems before resurfacing my heads using OEM head gaskets. These are thicker and seem like they would fill more voids in the mating surfaces. perhaps even work better if the heads had some warpage. I now have the Teflon coated gaskets on and have not had near the problems I was having before. I did notice That each time I retorqued with the OE gaskets I was getting more out of the head bolts, like I was never done. With the Teflon, one retorque seemed to do the trick. On another thread some time ago A fire ring gasket was mentioned. This gasket would have compressible ring inserted in each hole in the gasket. Like old Felpro gaskets I have used in the past. I liked these on the old small block Chevy's.
Plain,
I am using aluminum rocker covers on my pan. I do not think there is a lot of clearance between the studs and the cover. I have my felts sitting on top of the rockers in position. They are not glued in at all. I do not think they will go anywhere. They are sandwiched in place. I feel the movement of the rocker arm squeezes a little oil out like a sponge each time the rocker moves. Back in the day they may have used varnish to attach the felts. Just a guess, but it was commonly used to attach one side of gaskets back in the day.

[Plain]

PanPal:

Exactly what I found. OEM gaskets, the retorquing never seemed to end. The James Teflon - JGI-16770-48 has a starting thickness of .046" and a final crush of 0.040". Like you, I find that after the first retorque there is no more movement of the headbolts in subsequent torque checks. I am unfamiliar with the Fire Ring gasket that you describe. The James Firering - JGI-16770-48-X has a single compressible ring around the cylinder. None around the bolt holes. It does have a thin line of a red silicon type beads on the fiber portion in a similar configuration to the raised portion on the OEM gasket. Starting thickness of .046" and final crush of .042". I like it better than the OEM but not as well as the teflon. Carefully flattened heads and teflon gaskets seem to me to be the combination to avoid aggravations I've had in the past.
Aluminum pans. Wow! Haven't seen a set in years. Last set that I owned cracked with a vengence, probably due to some negligence on my part. And yes, back in the day it was varnish, or IndianHead Gasket Shellac (with an evil little dauber in the small bottle that was absolutely impossible to coax out without getting the stuff all over the place). Aviation Form A Gasket seems to work better for me than either of those.

Adios-----Plain

[57stroker]

I used aviation on my felts, same method as you describe. After a year, they were still there. Do a search in past posts for EML or evil manifold leak. Make a dummy carb plate to check. This alone will save most of your sanity. The only other thing I can think of is read about valve seats. Try to preserve your original brass seats. (Don't let any of your automotive buddies try talk you into putting in hardened ones.)

[VintageTwin]

Yellow, 3M waterproof weatherstripping adhesive for glueing the Pan felts to the top of the rocker cover.