Valve Adjustment Question

[grey beard]

I am curious to learn if any of you gentlemen have ever successfully adjusted the valves on the engine of your Pilothouse truck with the right side inner front fender in place. Suffice to say that in my old age and present health, adjusting the carburetor idle mixture screw takes two hands. I cannot for the life of me imagine how anyone can adjust those valves with the nose intact.

I adjusted my own valves cold, with the nose off. It took about an hour to go over them all two times and then to double check so there would be no tight ones. Even in this advantagous position, it takes three hands to do the job, and you still gotta' hold your mouth just right. Yet my understanding of the shop manual instructions are to just adjust them. I know that MoPar automobiles have a removable inner fender panel made just for that purpose. Mebby I'll have to take my whiz wheel and make one for the next adjustment.

Now, that rescally fellow, Merle Coggins, tells me he can remove the inner fender apron with the nose in place. I am gonna' keep the salt shaker handy till I can be a fly on the wall and watch that operation. I had a struggle getting my inner fender apron in past the grille and over the shock mount with the right front fender OFF. Can't imagine putting that apron on with the fender in place.

But I'm here to learn. Please teach me . . . . . . someone . . .

[Tony WestOZ]

It can be done.

It usually involves hanging by your ankles and suffering a lot of pain.

Well maybe its not that bad but I find it extremely frustrating and time consuming.

If you can take the front wheel off, remove the inner guard, then go in through the side.

You guy`s over there are so lucky you don`t have a steering column getting in your way.

[wallytoo]

dave,

i was able to remove my inner fender without removing any other body parts. i did have to disconnect the heater hoses, and push the heater into the cab so the tube weren't in the way, but other than that, i could finagle the inner fender up and out of the engine bay to get at the valve cover to adjust the valves.

wally

[MBF]

GB-you can tell the guys that have successfully done the adjustment with the sheet metal intact-they have scars from 2nd and 3rd degree burns on their arms! Seriously-the innner panel on my 52, and on my 36 Plymouth were both missing bolts when I got them. I'm assuming that was done for easier access to the side covers.

I was at the board mtg in Boyertown yesterday-the ATCA Macungie show this June is shaping up nicely. Additional activities on Sat night, and we have the park until Sun morning. Mike

[Merle Coggins]

Dave, do you suspect that your valve settings are off? I adjusted mine cold too, when I rebuilt the engine. I've often wondered if I should go in and recheck/adjust them now that it's been running some. If that day comes this Rascal will try to remember to document the removal of the inner fender for you.

Merle

[grey beard]

Rascally Merle,

I set mine at .012 intake and .014 exhaust, and it runs and sounds well. But after driving it a while I now have an uneven idle that I am not able to adjust out. My feeling is that these engines should idle near perfection, but mine now blurbles out the exhaust just a little, and al lthe ususal adjustments don't seem to help. Idle sounds good under the hood, but the exhaust seems uneven.

Ever try to set the points on one of these with a dwell meter? Anyone know what the correct dwell should be for these six cylinder flatheads? I'm really scratching my nead.

[Young Ed]

Dave I don't remember the dwell spec off the top of my head but Dad tunes all the flatheads that way.

[Reg Evans]

A buddy and I took the inner fender off last year to adjust the valves in my 52. It was a little tricky but it came out and went back in after the adjustment.

[TodFitch]

Rascally Merle,

I set mine at .012 intake and .014 exhaust, and it runs and sounds well. But after driving it a while I now have an uneven idle that I am not able to adjust out. My feeling is that these engines should idle near perfection, but mine now blurbles out the exhaust just a little, and al lthe ususal adjustments don't seem to help. Idle sounds good under the hood, but the exhaust seems uneven.

Ever try to set the points on one of these with a dwell meter? Anyone know what the correct dwell should be for these six cylinder flatheads? I'm really scratching my nead.

For my Delco-Remy equipped 1933 PD the dwell angle is specified as 36 degrees. For the AutoLite equipped 1937 P-4 the dwell angle is specified as 38 degrees. Both are specified as 0.020" point gap. The dwell numbers came from the August 2002 issue of Skinned Knuckles which I can pull out when I get home to see if it has the P15 numbers in it. Actually, they ought to be in the service manual too.

By the way, on my car the idle sounds good under the hood but the exhaust also sounds uneven. Pretty much the same as yours. I haven't ever spent the time to get to the root cause but I have wondered from time to time if it weren't because of a worn distributor bearings.

[Don Coatney]

If you hold a dollar bill or a piece of paper at the end of the tail pipe does it suck the paper into the pipe occasionally? My engine does this until it comes up to operating temperature. Once it is fully warmed up the sucking stops. I believe this is due to a sluggish valve not closing as quickly as it should. My engine also sounds good under the hood when this is happening. I dont think this is a valve adjustment issue but simply a temperature related issue. Last time I adjusted my valve lash was when I assembled my engine on the bench 5 years and 25,000 miles ago.

[grey beard]

Don,

Interesting information you have there. Can you remember what you set your valves to cold? I think this is the logical way to handle this adjustment, yet I have head little from anyone who has done this until your post on this thread. Then again, I remember seeing your pics of your motor hooked up on a test stand. Mebby you did set 'em hot. Do tell . . . . . .

It would be interesting to set the valves on one of our engines cold, and then run it to operating temperatures and see how the gap compares to the hot setting. Now THAT would be good information to have. The problem is that valve adjustment hot in the vehicle, is much more difficult in a truck application than in an auto, because of the removable inner skirt issue that is not shared with trucks.

I wish they made a P & G valve gapper tool to fit flathead engine valves.

[Young Ed]

Dave both my flatheads were set cold by the machine shop that rebuilt them and neither have been touched since. I don't have as many miles as Don but I've got 3K on one and 8K on the other.

[grey beard]

Younger,

Good to know. D'ja know what clearance they set them to?

Thanks

[Young Ed]

Sadly I do not.

[Jerry Roberts]

Dave both my flatheads were set cold by the machine shop that rebuilt them and neither have been touched since. I don't have as many miles as Don but I've got 3K on one and 8K on the other.

Dave , My valve settings were also set cold by a very experienced flat head machinist . This was a couple of years ago and he told me that I would never have to reset them , and I haven't . I don't remember the settings , but he said that there were a number of opinions on the subject .

[grey beard]

Looking at the electrical specs in the 1953 Dodge Truck Shop Manual, I see dwell specs of 38 to 40 degrees. While doping out a high speed miss, I had my distributor apart several times - shaft out and all, and found a loose centrifugal weight pin. Fortunately I have a spare distributor of a different number that has some pieces missing. I pulled the spare apart and cabbaged the shaft and advance assembly.

Now I know that we're not supposed to mix and match parts from different number distribuors. In a perfect world this would never happen, bur rhis shaft fit just fine, and had much less wear than my original part. What was different was the indexing of the shaft. I pulled the original distriburtor out with the rotor pointing to 5 o'clock. Without turning the engine over, but with the other shaft installed, the rotor now pointed to seven o'clock. Had to reposition the plug wires on the cap to keep things honest. Works fine now.

Also, along these same lines, I've been playing with my 12-volt digital timing light/dwell/tach tool a little. Here's what I have learned. Both tach and dwell work okay on six or twelve volts, but the readout jumps around a little more on six than on twelve volts power supply - I use a battery charger to supply twelve volts, cause the light is too dim to read on six volt power. This means I can hook the meter up and go down the highway to learn my true crankshaft speed at sixty, etc. My points are set at .020, but my eyesight is abonimable, and dwell shows around 28 degrees, so I need to revisit that adjustment again and get it closer to the ball park.

Sure wish I had a distributor machine. They worked so well, back in the day. I don't believe there is a better way to set points or check bushings or distributor cams and advance curves than these machines. In point of fact, if I can find a shop that still has one, I may pay him to dust it off and check my distributor out.

By the bye, shop manual specs for our advance curves says centrifugal advance should be 18 to 22 degrees @ 2850 rpm, and vacuum advance should be 18 degrees with full vacuum. I know that the centrifugal springs I installed on the second shaft were much stouter than the original springs, so I may be way down the garden path away from correct advance curve specs. I know the advance curve can be checked with an advance timing light in the engine, but those distributor test benches were just the ticket.This is truck specs. Sorry but I do not have car specs, and don't know how they would compare with this. Mebby Don can tell us. Maybe they're all the same.

Also interesting to me is the fact that only truck models B and C - half and three quarter ton sizes - have vacuum advance specs. Trucks of larger size than this did not use this feature at all.

[wallytoo]

Also interesting to me is the fact that only truck models B and C - half and three quarter ton sizes - have vacuum advance specs. Trucks of larger size than this did not use this feature at all.

that's correct, dave.

and the reason the larger trucks don't have vacuum specs is because they lack a vacuum advance mechanism.

[Don Coatney]

Don,

Interesting information you have there. Can you remember what you set your

valves to cold? I think this is the logical way to handle this adjustment, yet I

have head little from anyone who has done this until your post on this

thread. Then again, I remember seeing your pics of your motor hooked up on

a test stand. Mebby you did set 'em hot. Do tell . . . . . .

Dave;

Factory valve lash recommendations for my 1953 Desoto engine are

intake .008" Hot, and exhaust .010" Hot.

I have a re-configured cam in my engine. It is now 260 degrees duration

@ .410" lift. The cam grinder recommended a lash setting of .014" cold for

both intake and exhaust. This is what I set my valves to cold on the bench.

I did not set them hot on the engine test stand.

On the distributor issue the factory settings for my 1953 Desoto engine are

centrifugal advance starts 1 degree @ 400 RPM's. Full in 10 degrees @ 1425

RPM's. Vacuum advance starts 1 degree @ 6" of mercury. Full in 9 degrees @

15" of mercury. Cam dwell degrees 35-38. Breaker point gap .020". Breaker

arm spring tension 17-20 ounces.

I am running a dual point distributor in my engine. With this setup the first set

of points opens, then the second set of points opens, then the first set of points

closes, then the second set of points closes. This increases the dewll

time (coil saturation time) from the factory setting of 35-38 degrees to 43-

46 degrees. I also reduced the point gap from .020" to .017" with this dual

point setup. In theory this will increase point life due to less arcing.

I used an electric drill to set my dwell on the bench. This worked almost as

well as a distributor machine. I also used a hand held vacuum generator to

set my vacuum advance curve. I was able to get it very close to factory

settings.

Thanks to James Douglas I now have a second dual point distributor ready to

install that James setup on his distributor machine.

[grey beard]

Don,

Now that's what I call clever thinking - using a drill to simulate a test bench and set the dwell on the bench. Now if we could just invent those six little strobe lights - mebby six timing lights - and shine 'em on a degree wheel, we could verify each cam lobe's accuracy, just like a Sun Distributor test bench.

If you don't mind, I'll steal that idea from you and use it to see how my own dwell looks with the distibutor in my bench vise. Too bad we can't set that advance curve in the vise, as well. Mebby if I take my fan off and use a degree wheel on my vibration damper, I can get that too. My timing light has the advance feature, so I should be able to figure it all out. I know that both the centrifugal and vacuum advance units can be adjusted to get the proper curve.

Good thinking there, man. We'll need to keep a closer eye on your shop, to see what other secrets come out of it.

Thanks for sharing this.

[Don Coatney]

It helps to have a bench top 6/12 volt power supply. But I believe a battery

charger will work. To work correctly an ignition coil must be used on the

bench. Make sure you dont get your body parts near the high tension open

end of the coil when setting the dwell on the bench as the coil is seeking

a return path to the ground on the distributor.

[grey beard]

You've got some neat old tools and test equipment there, Don. I still use my battery charger for a power supply. Burned out one doing that so far . . .