Hi compression head and stock ignition
 

Just thinking here..
Bad idea on keeping stock ignition with a new 6:1 head?

I have the head already.

I’d like to get a B distributor eventually and elimate the manual adjustment, but finding one and having it rebuilt may take a while.

Any suggestions/thoughts on the topic?

Re: Hi compression head and stock ignition
 

I run the 6.1 head with stock ignition and it runs great. Lighten flywheel and stock zenith also.

Re: Hi compression head and stock ignition
 

Agreed. I have the 5.5 head but I can't see the 6:1 being any different. Just remember you won't have to pull the spark lever down as much. I only go to about 10 o'clock, maybe 9:30.

Re: Hi compression head and stock ignition
 

I have the 6.1 and a Pertronix ignition and love it.

As said above I too run at about 9:30.

And yes, if the car is in a position to lighten the flywheel and install a v8 clutch then do it.

You will then have a great combo and it looks stock to the prying eyes.

Re: Hi compression head and stock ignition
 

The tolerance for timing deviation decreases with higher compression,the effects of spark knock increases as well.When buying a B distributor its important to check the lower advance plate and shaft for wear.

Re: Hi compression head and stock ignition
 

I run a 7 to 1 with stock ignition. Gave up on electronic when it left me on the side of the road. Runs great.

Re: Hi compression head and stock ignition
 

Dave Renner at Renner's Corner, (734) 428-8424, is the "go to" person on B distributers, either to buy one outright, have yours rebuilt or just buy parts. I use a high quality Model A condenser from Bratton's in mine by attaching a pig tail at the end and elongating the slot for the screw.

Charlie Stephens

Re: Hi compression head and stock ignition
 

Same here with h.c.head, very sensitive to spark adjustments; also the stock ignition gives more ability to retard on steep hills to prevent knocking which may happen with the Zippers, etc.
Does anyone move their condenser up to the firewall which hopefully would be cooler there ?

Re: Hi compression head and stock ignition
 

I'm running an "A" distributor with the "B" point cam now with my new 6.1 compression head. It runs so nice, I for the first time since finishing the truck, really feel like I can take it anywhere.

Re: Hi compression head and stock ignition
 

I realize this is probably redundant to even mention but do understand that the function of the distributor itself as it relates to a cylinder head (-high compression or not) is nothing more than providing a spark in relation to the piston and camshaft. It is the Coil that creates the spark, ...and more specifically the windings that determine the intensity of that spark. While the distributor is vital, it is my opinion that the intensity of the spark under higher cylinder pressures is more crucial.

Re: Hi compression head and stock ignition
 

I drove with an HC head and stock ignition for quite awhile, and got to like it. The head is more sensitive so you can more readily find the "sweet spot" and adjust as it changes with different driving conditions. Full retard going down hill helps with engine braking; reduced advance going up hill, just shy of detonation; you can easier feel power changes on level, etc. I thought it made me a better driver as I got used to it.

Re: Hi compression head and stock ignition
 

Have a 6-1 head with stock ignition, had to many issues when I was using the FSI, so I went back to stock.

Re: Hi compression head and stock ignition
 

If I have an automatic spark advance (Nu-Rex centrifugal), do I need to worry about it if I switch to HC in the future? I can still make adjustments the standard way, but the Nu-Rex has its pre-set advance per unit rpm curve that I can't change.

Re: Hi compression head and stock ignition
 

What sort of issues did you have? Asking because I have a FSI ignition and am planning to purchase a rebuilt motor with a high compression head. I didn't expect to have issues with the higher compression because in the scheme of things a 5.5:1 CR or 6.1:1 CR is fairly low.
Thanks,
Eric

Re: Hi compression head and stock ignition
 

The FS Distributor has a very poor curve and too much total advance.


These distributors are designed to be timed at TDC which is the way a stock model A Distributor is timed. This results in very slow timing at idle and thru most of the RPM range below about 1600.


The "B" Distributor has a MUCH better curve and are designed to be timed at 17 deg before TDC. The "B" engine uses a front cover with the timing pin location in a different position than the "A" front cover. This allows for timing the "B" Distributor at 17 deg BTDC.


You can rework an FS to give you less total advance and a better slope to the curve but you have to be able to set the timing with a timing light.


If you are using a 6.0 CR head, do not set the full advance much more than 26-28 deg at 2000 RPM.


My experience and my opinion,


Chris W.
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Re: Hi compression head and stock ignition
 

I also have a 5.5 HC head, been running it for almost 14 years now with everything else stock, except lightened flywheel and v-8 clutch. I adjust the spark lever all the time as I’m driving...it’s like second nature now...and mine runs just great at 9:00 when I’m driving normally.

Re: Hi compression head and stock ignition
 

I'm running a 5.5 head with the stock distributor with the addition of a Phillips Automatic Spark Control. It limits auto advance to 30°. I also have a Pertronix Flame Thrower Coil. The combo works pretty good, no detonation. I can still retard/advance manually if needed. The lever is usually at ~10 o'clock. No need to move the lever for starting either.

http://www.fordgarage.com/pages/phillipsspark.htm

Re: Hi compression head and stock ignition
 

I've been confronted with a similar situation and my solution was to set the timing a bit retarded so that it was right when advanced. It was trial and error. I'd set it and then take it out and try to make it ping. If it did so too easily, I'd come back, retard it a bit more and try again. Once I was happy with it, I left it alone for years. The motor spend by far most of its time running with the timing advanced. Idle was tyical of a retarded engine but it wasn't hard to live with.

Re: Hi compression head and stock ignition
 

Improper timing leads to detonation,high compression is not as tolerant of manual spark control as stock is. Detonation or spark knock is one of the leading causes of bearing failure,that knock is like a sledgehammer to the top of the piston.

If you install a high performance head for better performance wouldn't you want automatic,accurate timing at any rpm to make the most of it?.1 degree of advance for each 100 rpm up,and down,is impossible to achieve by 'feel'..so you set it at 9 o'clock for instance..at one part of the engine acceleration its too far advanced,the other its retarded. But if your running a stock Zenith carb it really doesn't matter,you're not getting the fuel the engine can handle to begin with.Performance lies with balanced air flow,air in,through and out of the engine,You are providing more efficient combustion with higher compression but not utilizing its full benefit by fixed timing and using a carb that flows half the CFM of the engines capacity.

Re: Hi compression head and stock ignition
 

Thanks for the pointer to fordgarage.com. Here is a relevant chart from the site:

http://www.fordgarage.com/images/nurexvsb.jpg
Note that, because the camshaft rotates 1:2 with the crankshaft, all these values are 1/2 the crankshaft values, e.g., at 2000 engine RPM the Nu-Rex is advancing the timing to 29° at the crankshaft.

So it looks like the B distributor and the Phillips/Nu-Rex aftermarket product have pretty similar advance curves, with the B curve starting from a more advanced position. This may reflect the 4.6:1 standard B engine compression. If that's true, then the Nu-Rex timing at idle with a HC is more retarded than optimal, but as Synchro said, not a big deal.

As Vince states on fordgarage.com, "The Model B is a higher compression (cylinder pressure) engine which uses more initial spark advance, and lower maximum advance compared to a Model A. This is consistent with the operation of the B engine and the need to protect it from the effects of running too far retarded or over-advanced."

I wonder whether, given that the B curve continues to advance above 2000 rpm while the Nu-Rex curve does not, it would still be advisable to add some manual advance if one were running at 50 mph+ for long periods (assuming no overdrive).

Per these instructions, the Phillips auto-advance originally came with a "spark lever lock" attachment that you used to clamp the spark lever in place once you had driven around and performed your fine-tuning.