Flathead frustration - "pinging"

I have a 59AB with a Mercury crank, mild cam, aluminum heads, electronic ignition, 2 - 97's. It's a higher compression flathead although I haven't calculated the ratio yet. In checking the cylinder compression on both sides, it's 120 psi in all cylinders. I'm experiencing engine ping. It was really scary loud and had me very worried. Here's what I've done to correct and reduce it so far:

1. had GMC Bubba fine tune my distributor, advanced the timing by rotating the distributor all the way - there is no more to go there.

2. re-jetted the Stromberg carbs to #43 jets with a #69 power valve per Uncle Max's recommendation. I've checked the plugs and the look great.

3. synchronized the carbs so no area of the motor is starved for fuel

4. running 93 octane ultra premium

There is still a little ping at the higher end of acceleration or when I'm cruising along at 45-50 mph. I know it's tough to diagnose without hearing it. Is this normal? Am I missing something? Will it hurt the motor to run it like this. It seems to be running very strong but I'm a flahead newbie. Thanks everyone for the previous help.

 

back off the timing or increase octane

 

hey JOHNNY...todays gas is pure CRAP! your mill is high compression. that's where the problem starts. only low compression engines don't ping. i would put the thickest head gaskets i could find on it. don't worry, you won't notice any power loss. call me POP...or the old FART!

 

Run 93 octane gas and octane boost; I also ran lead replacement in mine. If you run any lower octane, it will ping. My Merc flatty(mild hotrod build) did. If your running a stock distributor, tighten the internal springs (turn the posts to adjust) all the way out, and it will make a huge difference in the performance.

 

The old guys told me no more than six degrees on a flathead, ever. Some hold it down to 4. Make sure you have no more than 28 total.

 

With 120 psi cranking pressure, there is no way compression ratio is too high. That engine should run with 87 octane and should be able to take 6 to 8 deg initial. Why are you advancing the distributor if you are getting pinging? You should be retarding it. Do you have a timing pointer to check initial advance? If not, you need to get one so you know where you are at.

 

use an advance timing lite to be sure your getting 24-26 total when you bring the rpms up also recommend fattening the mixture run the stock #45's 43's are too lean.

 

One thing no one's mentioned is this. If it's just sitting at an idle, and you rev it up to the rpm that it seems to ping at while driving....does it ping then too? If it doesn't, then you need to check nuts, bolts, exhaust hangers, basically everything on the car to see what could be loose. If you've covered all of that, let us know, several other things to look at.... is the coil output high enough? Is your dizzy a points or electronic? Need some more info!

 

First off, thank you for all the good input. Here's some more info for everyone that asked.

I said advanced the timing all the way but I guess I had that wrong, it's retarded as much as I could go in an attempt to eliminate the pinging.

The distributor is electronic and was checked by GMC Bubba to be exactly 24 degrees. It has a brand new high power coil.

The #45 jets are smaller than the #43's. I guess the smaller the number the larger the opening on these. #43 size was recommended by Uncle Max. I purchase them and the rebuild kits from him. The carbs were rebuilt about 6 months ago.

There isn't a timing pointer on this 59AB. Is it supposed to have one? I thought I read in one of my flathead books that you had to do the timing basically by ear.

Regarding anything loose on the car, I've pretty much replaced or refurbished everything on the chassis. The interior is only the front seat and dash. The floorboards are new as is the transmission cover with new rubber gaskets, weatherstripping.

I haven't tried to get it to ping while standing still. I'll try that tomorrow. Thanks again.

 

incorrect on the jets for strombergs, the jet size is the # drill that fits.so 45 ARE larger.than 43. 48's stock jets for 48 carbs 35 or 37stock(not sure off top of my head) on 81's. pre 49's dont have a timing pointer. its easy to jury rig one on an assembled engine tho. snake a stiff peice of wire down the plug hole and CARFULLY SLOWLY bring it up on compression you can feel when the piston stops and starts back down. bend up a piece of wire and fasten under the lower rt timing cover bolt so it points at pulley and mark the pulley. walla instant pointer

 

another thing to consider...egge pistons +offy heads can = piston hitting head. did you check the piston to head clearance???

 

Good luck with it!

 

It's true that the 59AB does not have any pointer or timing mark. However it is essential when making any changes. Take a big tyewrap and shove the big end thru the plug hole till its over the piston. Rotate the crank until it contacts the tyewrap and stops. Don't reef on it. Make a mark on the crrank pulley. Now reverse rotation until it stops again. Make another mark and halfway between is TDC. Do it a again to double check.
Make a pointer to align with your TDC mark. Now using a setback timing light you can check your settings. Or measure the diameter of the pulley. Find the circumference and divide by 360 which will give you the spacing for each degree.

 

my thought exactly.....

 

Number drills get smaller in diameter as the number gets larger, so a #45 would *not* be larger than a #43. #43 = .089, #45 = .082

Bob

 

Well, I'm confused as hell on the jets for my Strombergs but the plugs did look good, Uncle Max. And yes, I only bought the rebuild kits from Uncle Max so if there was any inference that Uncle Max rebuilt the carbs, it was unintended and I apologize for any confusion there.

I did have a problem with a piston hitting a head. I'm using older Weiand aluminum heads but we corrected that and checked all the other pistons to make sure.

Thanks for the help and suggestions on the timing mark. That will help a lot.

 

Back to school.... You are correct about "number drills". BUT, Stromberg jets are measured in inches. Powervalves are measured in number drill size.

 

Duly noted. I was simply commenting on the sizing of number drills, not the sizing system of the jets and power valves which I know little about. I'm paying attention, however, because I'll soon be tuning a freshly built '42 Merc flattie.

 

The guys have mentioned all great things. One thing I might try -- just for diagnostics -- is racing gasoline. Sure, it's expensive, but so are new parts. If you can get either racing gas or aviation gasoline, then you can make sure it's a combustion knock-related issue.

Also, when you mention that your distributor retard is maxed out, couldn't you just switch the plug-wires to the next position?

Anyway, good luck and please post what you learn.

 

NO WAY is 120 psi too high a CR !!

Simply slapping on thicker head gaskets is a band aid fix to a "problem" that shoud'nt exist.

If he has .040"-.050" piston to head clearance, by adding a thicker head gasket you will reduce usable quench to the point where the engines octane requirements will be WORSE and knock resisitance will diminish.

Piston to head quench is vital - the closer/tighter it is (some guys run .025" with a steel rod !) the better the engine will run and the less sensitive it will be to ping/knock due to the improved turbulence/flame travel in the chamber/cylinder.

I have 155 psi in the cylinder and run a blown FH engine and get no rattling,....so something is WRONG in that engine.

Check EVERYTHING, assume NOTHING. Bubba does great work with distributors/ignitions but im betting TDC is way off and initial timing is too high therefore making total timing 30 deg plus.

Just a guess....let us know how you make out !

Rat

 

my bad. its not the drill size but the hole size...,043 045 etc...

 

How could you check timing at all if you don't have a TDC mark or similar???????

Before you do anything else you have to get atleast a TDC mark and then make
a mark 4° BTC .
You will find info on th HAMB and in the rest of the ww how to do it.
Michael

 

Yeah, do not mess with timing with no reference point! This thing should not ping, so sort out actual timing and curve first. Modern gas is way better than what these engines ate new!
Look at the disc brake adjustment for timing RATE after you get static to about 4 and whole curve in by 2000. The brake needs light tension to stabilize the brake disc (it can wander if there is zero drag). Back off the 1/2 headed bolt all the way gently BY HAND so you do not pop bolt and spring seat apart, then turn it in maybe 2 turns. Turning it in farther will put increasing drag on rate of advance, Ford/Mallory's cure for pinging on extreme low octane. You should NOT need this, but it is a useful testing device...

 

Thanks again for all the help. I will be determining a TDC mark and a mark for 4° BTC so I can set the timing correctly. Everyone has been very kind in offering their knowledge and suggestions. I have learned a lot. I will update this thread when I get it done. Thank you.

 

Use the interference method (outlined above) to mark proper TDC. Measure your pulley OD. Steal a protractor and compass from someone in 8th grade plane geometry and draw a bigger circle than that, and mark off about 30 degrees across it. Draw another circle same size as pulley, cut it out. Use your creation to mark off about 30 degrees advance on your pulley...5 degree increments are plenty. You can guesstimate pretty accurately within the 5.

 

I did a search and came up with this thread.

I am puting a flathead back together that was originally built in 1952 (52 pennies in heat risers is my evidence). 283 inch 59 AB. Offy 400 heads came with the engine so that works out to about 10 to 1. Should I worry that that is too high for driving arround.

Did jonnyzepp ever get it figured out. He is leaving us hanging.

Tim

 

what flatjack said! that's a quick and dirty way to find true tdc, but I use a piston stop with the head off. Without knowing where true tdc is it doesn't matter how much mechanical or vacum advance you have. Flatjack you must be an old racer most "hot rodders" don't even think about piston overlap at tdc they just run the piston all the way up

 

i'm runnin more than 10-1 with my high dome navarro's you should be fine

 

We fell into a similar trap hearing a pinging noise , so we continued with a new motor for 2000 miles playing with timming etc. it was a 260 merc motor with a SCOT blower on top. Constantly playing with timming etc. running a little fluffy one side. So eventually got tired of the "ping" and pulled the blower off to find a horseshoe clip not holding a guide in properly. Though that wasn't the end of the issues as by my guess playing with timming had caused an overheat , but it sure near showed. So warped heads and a badly cracked block were the result. Don't ignore the ping !!!!

 

In my experience it is pretty hard to get a motor to ping from idle when there's no load on th emotor, like when in neutral.

It can be done but you have to be quick with you ears as it may only ping two or three times.