8BA timing help

2

27lizzie

Member
the only timming marks that I have is a slot cut into the crank pulley and the pointer on the cam gear case cover. Question are those marks t.d.c. and what is base timing set at. I am having a heating problem under driving conditions and I was told that it might be my timing. Thanks Marlon
 
The mark on the crank is NOT the TDC indicator, it is the timing mark. The timing should be set to the mark on the crank.
 
There is a V grove in the out rim of the crank belt pulley and the pointer on the front cover these are the only marks, I was told that when lined up i am set up at 2 BTD ? or are these marks TD Marlon
 
27lizzie said:
the only timming marks that I have is a slot cut into the crank pulley and the pointer on the cam gear case cover. Question are those marks t.d.c. and what is base timing set at. I am having a heating problem under driving conditions and I was told that it might be my timing. Thanks Marlon
Click to expand...


It very well could be your timing. Does the distributor vacuum unit even work?
The loadamatic must have a proper vacuum signal and is the only advance the unit has. A no working diaphrahm would retard timing causing heat problems.
Is the carb orginal ????
 
Sorry about the lack of details This motor has an HEI Dist that was recurved to work in the flathead and the carb is a holley 94 had the upper vacuum port hole in the ventury pluged so that the vacuum advance was only picking up from the to port holes on either side of the throttle plates. The dist was set up to have max vacuum advance of 8 degrees at crank. and max 20 degrees cent.adv. at crank. Vacuum advance is being picked up from the carb not at manifold. So to be real honest about this I am not to sure how to fix my problem Marlon
 
Ford didn't put a TDC mark on either of the 8BA family crank pulleys. Some folk mark them for TDC when they do an overhaul. It is difficult to do with the engine together but not impossible. A person can put a tie strap head first into the cylinder through the spark plug hole on #1. The tie strap has to be pushed in to where it will stop the piston. Mark the pulley where the piston stops then rotate the other way till it stops again & mark the pulley again. TDC will be centered between the two marks.
 
27lizzie said:
Sorry about the lack of details This motor has an HEI Dist that was recurved to work in the flathead and the carb is a holley 94 had the upper vacuum port hole in the ventury pluged so that the vacuum advance was only picking up from the to port holes on either side of the throttle plates. The dist was set up to have max vacuum advance of 8 degrees at crank. and max 20 degrees cent.adv. at crank. Vacuum advance is being picked up from the carb not at manifold. So to be real honest about this I am not to sure how to fix my problem Marlon
Click to expand...

since you have centrifugal advance and a timing light you can at least verify any advance. Each 10 degrees advance is about 5/8" on your crank pulley. You can mark about 1 1/4" from the notch, rev your engine to about 2000 and verify the advance. That will get you close enough to rule out timing as a factor to your overheating.
 
Vacuum should be manifold vacuum. The lower holes near the throttle plates on an 8BA type carb arnt manifold vacuum, they are sorta "timed" or "ported" vacuum, sorta. Before trying other stuff get the vacuum plumbed in to manifold vacuum source.
How much timing is the vacuum can supposed to be adding? With an otherwise stock 8BA mechanical advance can be upped a bit to 23-25 and vacuum adding up to 28ish.
Have a play with the vacuum disconnected to set a comfy mechanical advance number, test driving each adjustment. When that's where the engine wants it, try adding vacuum advance so it cruises nice an has good response. You may end up after this taking a bit of mechanical out and adding a bit of vacuum in.
When all this is done, go back and have a look at what the idle timing is. Should be with the timing marks lined up. If this is to far from the marks, adjust the mechanical advance mechanism stop in the dizzy so you keep all the max timing where the engine wants it, where you just road tested to be the best, but extend or shorten the amount of advance to now reach the idle timing.
Idle timing is done with vacuum disconnected.
hope you have adjustable vacuum can and ignition parts, if not there easy to find for that Chevy hei.
Good luck,
Keep us posted,
Have fun.
Martin.
 
You have enough information her to get the job done, but you might want to know why?? TDC is the most importing starting point and is a bump on the crank pulley. A pointer , pointing at the bump tells you you have 2degs of ignition advance. ( on the compression stroke). Now having 20 degs mechanical in the distributor is alittle much, but we'll get to that later. Advance should be all in by 2000 RPM. The vacuum canister should have 8 degs. With all this said this is how all the stuff should work in an ideal situation.
starting the engine with 2 degs of advance should work pretty good ( I use 4 degs). The minute the engine starts, it gets 8 degs of vacuum advance, so you now have a totle of 10 degs and Flatheads just love that. Accelorating in low, kills the vacuum so th most the engine will see is 20 degs, however when you get into cruise the total will be 28. now if the AF is in the 14.5/15.5 your gas mileage will be great. climbing a hill will bring the timing back to 20, all is good.
Now you know why. You might have to putz with the numbers, but a good running stock flathead will run just fine with these numbers. nao as for the carburetor??
 
Update After locating t.d.c. and setting the timing, it is working just the way you guys said it should work, so that's not the problem. So back to the cooling system. had the rad cleaned new drake water pumps new 180 states. I did notice that after the states open up there does not seam to be alot of water flow. What kind of water flow would you see in the upper tank. I thought I would try it without the states in it just to see what the flow would look like. This thing wants to heat up when under throttle on the highway
 
If you take out the thermostats, it should run lower than normal temperatures unless your ambient temperature is high and the vehicle is under a good load. We may need to know more about the type of vehicle, type of radiator, and state of build on the motor. Flatheads love to get little leaks in the cooling system and sometimes they are not evident as to source.
 
going to pull the states out today and see what it does, this is a 50 coupe rebuilt motor stock heads, 4 core rad, stock 4 blade fan. Was a stock rad a 2 or a 3 core. I was wondering if maybe the core is to thick and it wont let enough air to pass through it when under load to cool properly. Marlon
 
BUBBAS IGNITION said:
It very well could be your timing. Does the distributor vacuum unit even work?
The loadamatic must have a proper vacuum signal and is the only advance the unit has. A no working diaphrahm would retard timing causing heat problems.
Is the carb orginal ????
Click to expand...


I never did hear what unit you have , a non working load a matic distributor will be retarded under load and over heat..........................:eek:
 
I'm running a very similar EAB in my '52, with a 4-row truck radiator and a (car) 3-blade fan. I drive it in 90+ deg temps a fair amount, on the highway and stuck in traffic. The temp gauge barely moves. I am running 160 thermostats and actual normal running temps are around 185 - 190. IMO I'd run 160 Stant thermostats.

Although the other question is whether your temp gauge is accurate, and what you consider "hot"?
 
Just ran it with no stats,took some time to bring it up to 175 temp sitting in the shop and if I took it up to 1000rpm you could see the fan pull the temp down so I know I have good air flow through the rad, and rad is doing its job. So I will try 160 stats next, good water flow with the stats out. closer to solving this. Marlon
 
You must log in or register to reply here.
Back
Top