Timing = heating?

Fourdy

Fourdy

Well-known member
Okay, so I have been plagued with a heating problem with my blown 276 since I installed it in my 40. I have seen many posts relating retarded timing as one of the possibilities for the problem.

While I have the heads off and cleaning the block (a story for another post) I have been trying to learn about how the distributor really works. I read and read but it was time to get hands on and apply words to real life.

I am using a mallory non vacuum unit and the instructions that came with it said it was factory set for 24 degrees maximum advance. I find (by using mallory gauges) that the max. setting is actually 16 degrees. Joe Abbin has recommended 24 degrees at 3000 rpm. Seems to me that this IS a retarded state and could be a lot of my problem.

Appreciate any thoughts from you more knowledgable gents.

Thanks,

Fourdy
 
While you've got the heads off mark the front pulley for top dead center and then check timing with a timing light.
If the initial timing was set at 8 degrees plus 16 in the dist. would give you 24 total. Bill
 
Just getting ready to say, you need to add in initial timing. Even 4 deg, which is often suggested, would give you 20 (which is also often suggested). I agree with bbrocksr need to establish TDC and mark the crank pulley. Might even want to add some timing marks, or you could use a dial-back timing light. Everything I have heard says the timing curves in the Mallory distributers is similar to a SBC curve and not a good curve for a flathead. May need to be re-curved.
 
Next test...find out how quickly the timing advances. If it is slow, not coming in til high RPM, you are running retarded most of the time.
 
Fourdy,
The timing number Joe refers (24 degrees) is maximum or total advance. As above static (initial) timing say 8 + 16 in the dizzy = 24. Important BUT with a supercharger you need to retard the timing under boost, or you'll eat head gasket/pistons/heads! The 24 total should be retarded by 1-1.5 degrees per lb of boost. Thems the numbers in his book.
It does also state that blown flatheads normally want 16-20 degrees total, if no boost retard device is fitted, here is where your timing should be.
Do get the tdc marked up so you can use a light to double check what your really getting out of that red cap. Their very often nowhere near what a flathead needs.
You gota tell us why the heads are off, could be related.
Martin.
 
That is the part that confuses me. I have heard some refer to total timing (retard + advance) and then just referred to as advance. I want 4 degrees retard at idle and thought the 24 was after tdc. ????
Fourdy
 
Wow, you guys are fast.

I do have the btm and is set to 1.5 per J. Abbin. Joe is fantastic to deal and work with btw.

My pulley has been marked with tdc and tic marks for timing.

I have tried a dial-back light before and it was all over the place. I was told that they don’t work well with MSD electronic ign. I have a regular light and will try that.

When you say check for timing coming in too late are you just saying to check for max by 3000 rpm? Yes, I am learning about pink, brown, gray, purple springs. LOL

I will start at 4 after at idle and go for 24 total or on the 20 mark on the pulley.

I will put together a post about the heads off soon.

And, thank you so much for your advice and patience with us slow learners.

Fourdy
 
Fourdy said:
That is the part that confuses me. I have heard some refer to total timing (retard + advance) and then just referred to as advance. I would want 4 degrees retard at idle and thought the 24 was after tdc. ????
Fourdy
Click to expand...
Oh! Never heard on anyone wanting to run a flathead retarded. I would replace "retard + advance" (which is worded correct but a little confusing) with "initial + advance" which would be (-4) + (24) = 20. This is confusing because of the initial being retarded. Distributers actually are in cam degrees so would be half of the value you are stating, 12 vs 24. The 24 is crank degrees. But, the distributer should start at 0 and advance 12 degrees, so in crank degrees it would advance 24 degrees and it starts at the initial, so it would be a total advance of 20 degrees after TDC.

To figure out the rate of timing advance you need a distributer machine or check it with a degree wheel on the crank pulley and check the advance say every 500 rpm and plot it out. Flatheads want a faster advance rate than the stock Mallory typically has.

Does Abbin recommend the retarded initial timing, I don't remember that.
 
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Maybe you can tell me what gauge I use to set the max advance in the distributor. I believe I have 14,16,18,20,22,24,26,28.

Head spinning.

Fourdy
 
Really needs to be on a distributer machine. Are the numbers you listed springs for different maximum advances?
 
No, initial timing is not -4. It is 4 degrees before tdc (top dead center) all the rest of the timing is also before top dead centre. None of this happens after tdc.
It can be confusing, with all the terminology. Retarded or late timing is too late for the piston. It's less advanced than it should be.
Martin.
 
Those keys are to set the maximum advance of the distributor.
They plop in the gap in the advance plate.
if they are in distributor degrees. This is half crank degrees.
So if you want the distributor to advance 28 degrees, you use the 14 key.
That is if there distributor degrees, I bin'd my years ago, just time them on the engine, they wernt that accurate.
So if they are distributor degrees, you need keys smaller then them.
What is the cam?
If say 3/4 ish cam, you prolly want about 6-8 initial timing + 16 max in the dizzy. This would give you 22-24 total, might go a bit more. But to far costs money with a blower. Prolly all in by 2000rpm. And your boost retard module.
That explain it?
Martin.
 
There are posts here on locating TDC and then degreeing your crank pulley by using a compass and protrator to make a quick template to fit your crank.
Do this, then get someone to watch a tachometer while you note amount of advance from idle up to 3,000...I'd like advance in considerably befor 3,000 actually, with no supercharger to complicate life. If you reach 3,000 and timing has not maxed out, you need weaker springs in advance.
Flatheads also expect to have the advance curve start to go up immediately above idle. Slow is bad.
With you pulley degreed, a timing light, and a tach your engine is your distributor machine and you are seeing what is actually happening.
 
scooder,
I called Mallory and tech told me to add the initial to the key number for total advance then use springs for adjusting rate.

He specifically said that in a perfect world, if I use the 20 key and 4 initial then the timing light will mark the 24 on the pulley at max advance. I think I am beginning to understand thanks to all of you.

Fourdy
 
I worked on a Model A with a new Miller overhead valve head. It would not run right at all. It also had a Mallory distributer. I called the manufacture of the head who said the timing for that head required at least 60 degrees advance. Since the distributor had a maximum capability of 28 degrees, I had to set initial timing at 32 degrees in order to achieve 60 degrees at 2000 RPM. Malory sell a spring kit (variety of spring tensions) at a reasonable price. I had to end up using the stiffest set in order to get the right advance curve. I almost fainted when I was told I needed 60 degrees advance at 2000 RPM, but car ran great afterwards.
Don in SC
 
So Mallory tech said the keys are in crankshaft degrees, that takes some math out of it.
If that's the case, do as he said, and that would meen your timing was retarded, that would run hotter.
And yep, the springs change how fast that advance comes in.
Glad your getting your head around it.
Martin.
 
I also have a 3 bolt e-dist. from Mallory. Had some minor heating issues and Barners suggested checking the timing as set from the factory on the Mallory, but also wasn't happy with the way the engine ran. It was set from factory at 24 as indicated from Mallory. I was told by several Flatty builders the Mallory I have need to be reset using the #14 gauge. The springs which are color coded and have more or less tension are what makes the full advance come in faster or slower. I left the ones that were in there and it works fine for mine. With the blower you may want the springs that let it come to full advance faster. I believe in reading the looser tension lets it come in faster don't remember the colors that do that but if you have the timing kit it tells you. I did #14 gauge setting and reset my timing with the light between 4 and 6 degrees. I had resolved the heating issue with a Spal fan but the engine ran much better with the reset. The e-fan seldom comes on anymore so probably helped the cooling as well. I left the e-fan as it is hidden and unnoticeable between the radiator and grill.
 
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