Hi guys hope I'm posting in the correct place? I'm after some help from some of you Flathead gurus. I have a old 59ab in my 51 pickup ,it's not a fresh motor she's a little tired. I have just resealed her new gaskets & seals it's running a dual Fenton inlet manifold and twin 97s ,I put a kit through these a while back but I had not run them before this can't recall jet sizes. Distributor is a Mallory twin point and coil is new. New plugs gaped at .35" points at .16" there are No timing marks so I have tried to set it up with a Vac gauge. Problem is she runs fine a revs without pinging when stationary but after a short drive will bog down under load and has no power ,feels like she wants to die. I have pulled the plugs again and there fouled up again. Check comp all 8 cylinders are between 95 -100. Any hints or suggestions would be great. Thank you Posted using the Full Custom H.A.M.B. App!
You need to figure out if its spark or fuel related. It could be running out of fuel, put a gauge on it and make sure the fuel pressure stays consistent as a place to start with that issue.
I'd be callin' Bubba.... take a look at what he has to offer. Very often a tired old distributor will work fine at idle ONLY. He'll be able to tell you what you should be running to get the best out of that motor. I'd also find a way to locate TDC and get some proper marks on the crank...
What brand are the spark plugs? I had a new set of Champions a few years back that would not run over 3200. Changed over to NGK and it ran great up to 4900 and never missed a beat. A flathead with dual or tripple carbs can grow rather tempermental. I had to drive mine with one hand on the choke when cold and move the choke in and out several times durring warm up to make it run clean. If you foul the plugs when cold, they may never clean out. Also, cut the gap down to .028 to .030
Your coil could be breaking down under heat and load,hook up a timing light, tape it to the windshield and take a ride if the motor skips or misses and the light douse too.you know it's spark related Posted using the Full Custom H.A.M.B. App!
Slap the original distributor on there and see if problem clears up. Mallorys oft come with very strange choices of advance springs...you may have some that are too stiff and do not advance as engine revs. There are also assembly problems and wear problems...ones I have debugged have had primary electrical arcing to ground (look for burn marks on case near points), VERY rapid point wear, poor grounding of the also defective condenser...the ones I have worked on need replacement of tuneup parts with non-Mallory equivalents from NAPA and careful reassembly to eliminate shorts. As you can tell, I love and recommend these things... The running retarded will cause fouled plugs...this is a sorting problem, as over-rich and retarded can easily be confused...or combined. Put on a stocker here first, as it has good curve and decent points are available from NAPA. You need a part you can trust, as if ignition is dubious AND whole intake system is new and not known to be dialed in you have no way to decide where to chase problems!
I had the same trouble when I ran a Mallory, I switched to a msd ready to run model and she ran great.
If you got the Mallory used and didn't have it reconditioned or it wasn't gone though before you got it there is a pretty good chance that it needs to be rebuilt as they tend to wear enough to get out of kilter with a lot less miles than oem units. In the 70's I worked for the Central Texas guru of Mallory distributors and guys were always hauling in worn out Mallory distributors that some circle track racer had in his yard sale because it had been replaced with a new one. I'd say it would be well worth it to pull it out and take it to someone with a distributor machine who can set it up right and get the advance curve right for your application.
Any way of working out a timing mark Without removing the head? As the plug is not directly above the cylinder? Cheers Posted using the Full Custom H.A.M.B. App!
Thanks guys for the advice as for the plugs they are AC Delco and the distributor was running fine in another 59ab and the coil is new. I think I really need to work out how to time this old girl before I go any further. Please keep the suggestions coming. Fnjunk Posted using the Full Custom H.A.M.B. App!
Could someone please tell me what size main and power jets I should be running with a duel Fenton manifold carbs are 97s? Posted using the Full Custom H.A.M.B. App!
Lets get this corrected first. You say you have a 59a style engine in your 51 Pu but a 59 A style engine will have a front cam mount distributor. If your distributor is front right head positioned its an 8BA style engine which would be the engine of a 51. If your engine runs fine at idle but has a load stumble issue its a good guess that there is a vacuum advance issue in the distributor. Best suggestion you have gotten is to pull the distributor and send it to Bubbas hot rod shop for a rebuild.
Thanks Dick my engine is a 59ab with front cam driven crab style Mallory duel point distributor no vacuum advance. After a very short drive 3-4 miles the plugs a fouled up and the truck is near un drivable. I am pretty sure this is a fuel problem. Cheers Fnjunk Posted using the Full Custom H.A.M.B. App!
Sorry they are now at.035 . I had them at .025 earlier and was told to open them up with this distributor? Posted using the Full Custom H.A.M.B. App!
If Mallory says .035...so be it. Here's some info on setting mechanical advance. Some of those new mallorys are a bit out of wack when you get them...might help. It's from this web site: http://www.btc-bci.com/~billben/flathead.htm _______________________________________________ "The following is what I do to set up a Mallory dual point dist on a 59AB engine. The Mallory distributors I've been seeing the last few years are coming from the factory with the centrifugal advance stops set for about 41-44 degrees centrifugal advance! Add in the typical 4-8 degrees initial advance and it gives anywhere from 45 to52 degrees total advance. Way to much in my opinion. The typical street FH will not tolerate total advance in excess of 21-22 degrees. I readjust these advance stops to limit the centrifugal advance to 17-18 degrees (note: the electonic dist uses the same centrifugal advance setup and can be set up the same way). Remove the breaker plate. See the two torx head screws holding a plate down? Notice there are two slots with tabs in them. These tabs are adjustable to limit the centrifugal advance. Mallory makes a set of "keys" to slip in these slots to adjust the tabs against. Good idea, but the keys are pretty expensive and aren't all that accurate in my opinion. Loosen the two torx headed screws slightly. Now use a 0.070-0.072"" feeler gauge (BillB uses an allen head wrench 0.068" wide across the flats since his feeler gauge is too wide to fit into the slot) and position it in the slot. Slide the tab up against the feeler gauge and tighten the torx screw. This will limit the centrifugal advance to 17-18 degrees. Since we want the total advance to be in the neighborhood of 21 degrees, this much centrifugal advance should not promote pinging (detonation) at 35mph and up. Do the same with the second tab and torx screw. Reassemble the dist plate and adjust the points. I set both sets of points at 0.021" using a feeler gauge. Reinstall on engine but only snug the two mounting bolts down since you want to be able to rotate the dist to adjust the timing. Start up the engine and warm it up. Hook up a vacuum gauge and advance the dist until the vacuum gauge shows the highest reading possible (I use a long screwdriver and hammer to tap the dist around.... be careful since there are fan belts and fans to reckon with). Now back the dist off until the vacuum gauge drops exactly 1" of vacuum. This is where your engine and mods are happiest. Tighten things up and you're through. I don't use a dwell meter unless the dist has a lot of wear on the shaft and/or bushing. I think feeler gauges are all that's needed for the majority of driving (exclude Bonneville, roundy-round, and all-out drag racing). I've checked a few of these on a dist. machine after I've set them up as I've described and found they were within a degree or two of the recommended dwell......." rumbleseat _____________________________________________________
When everyone is responding, I assume, as I am sure they do also, that the sparkplugs are GAS Fouled, WET. Find Number one cylinder for timing.Take a thick bent wire and place it in the spark plug hole so it is above the piston. Take all plugs out, turn the engine by hand clockwise till the piston hits the wire and stops. mark on the dampner and block a line that will match up. now turn the engine the other way till the piston again hits the wire and locks up the motor. make a mark like above. Depending on what you used for a wire you will have a distance of say a 1/2" or whatever between the two lines. Now place a mark between the two line and that will be your top dead center. Now put your distributor in so the rotor is pointing towards the number one cylinder, turn the switch on and rotate the distributor just to the point where the points snap, now give it just a little more turn and clamp down this should get you close till you fire it up and use a timing light. As for the carbs, I would block off one so" no air" or fuel till you get it running right, switch blockoffs to test both carbs. Once this is all done grab a plug and place it to a ground and spin the motor, look for color of fire in the plug, needs to be bright blue, if orange or any other color will indicate a weak fire. checks out the coil, hold coil wire away from ground spin the motor and check for GOOD fire. Do not rule out the condenser as it will do exactly what your problem is as it gets warm it steals all the firing power, All these procedures are back yard under the shade tree, but it is how we grew up fixing these old turds. Hope I explained it where anybody can understand. Make sure NO vacuum leaks. Good Luck, Deanno
Cosears, All excellent advice. One point. The engine may be 180 out. Put the number one plug in and turn by hand untill you feel compression. Then do as suggested.
Thank you Flthd31 cosears ,Andy and everyone else who has given advise. I have cleaned the plugs ready to set up the timing as advised in the next day or so. Then I will check the mechanical advance. I'm also thinking about just disconnecting one carb and taking her for a ride to see if the plugs foul up running only the one carburettor . I have done I little more reading on here and uncle max (Stromberg guru)has said run .043 main jets and 69 power valves with a dual set up,think I will switch to those also. Will keep you posted on the out come. Thanks heaps guys.
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