Snyder 5.5 Changes Things

[Brobrian]

I put a Snyder H/C head on my '28 coupe last week. The car runs quite differently now. This motor has been purring like a kitten for 20 years, but has seemed a little under powered. Especially with the higher ratio rear end I put in a few years back. (Sorry, can't remember which one. Might have been a 3.52)

With the new head it has a touch more power. Also, it cranks over more slowly when starting. It sounds a little more rumbly and runs slightly rougher as well. Today I noticed that when driving at less than full rpm and under a load the engine knocks (not a ping) a little when the spark is fully advanced. The knock goes away when I move the advance to about the middle. However, on the highway the car now cruises along at 50 -55 quite easily with the spark fully advanced.
Nothing scientific here, and I've heard a few of these comments from others hear at the Barn, but I thought I'd share my observations.

[Tom Wesenberg]

Don't use too much advance, or the engine can be damaged. The higher compression head will use LESS advance than the stock 4.2 head.

I have the stock head on mine and rarely use full advance. Full up to start, then half way down for idle and slow speed, and about 3/4 down for 40-45 MPH.

I'd like to have a 3.27 rear end.

[Mike V. Florida]

You will have to learn once again what your needs to operate now that you have the new head. Higher compression changes a few things; idle, advance, and exhaust sound are a few.

[Brian T]

Did you just purchase the head from Snyders? as they have been on backorder for some time, and was there a problem with stud length that as been discussed recently.

[Brobrian]

Never had to mess with the advance before. Full up to start and chug along, and full advance to run. That's were it worked best.
Now, things are different. I'm having to consider where to put the advance. Just got back from the hardware store and confirmed that I like town driving at about half advance. I still like the full advance at 50 - 55. Hell, I've never gone 55 in the car before unless it was coasting down hill.

[Brobrian]

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Originally Posted by Brian T

Did you just purchase the head from Snyders? as they have been on backorder for some time, and was there a problem with stud length that as been discussed recently.

I've had the head for a couple of months. I was waiting for the old man to come out so we could put it on together. He had a blast, by the way. Spent the whole four days messing with the "A''s. Brought down a motor he'd overhauled himself, and which he says he pulled from his father's (my grandfather's) combine harvester.

[Aerocraft]

You will find that the starter will labor if the ignition is not fully retarded.

Of course the higher power is terrific but I drive mine just as I did with the stock head unless I need more "zip" to get into traffic quickly. I do enjoy the much improved gas mileage. Gar Williams

[TerryH]

I've had my 5.5 HC head for about 5 years now on my 1930 TS and I have always been very happy with. I don't remember too much about it sounding and running that different at first, but maybe I have forgotten. I have also found that about 1/2 advance works best most of the time, and if I am on the freeway in overdrive at 60, then I usually give it 3/4 to full , but listen carefully to it. A great addition, especially on the heavier sedans. You will enjoy it!

[pat in Santa Cruz]

Rich Fallucca recommends no more than 28 degrees advance at any time, preferably only at high speed, with less when slow or laboring under a load. Les Andrews recommends around 25 degrees max with HC heads. If your timing is set at zero fully retarded, half mast is 20 degrees, full is 40. Count about 4 degrees per click. If you can feel the power level off as you advance that's where you want to stop. Too much will flatten your bearings pronto.

[Marco Tahtaras]

The increased compression speeds the burn of the fuel mixture in the cylinder which in essence advances your timing.

I set my timing so with the lever fully retarded I am essentially firing at TDC. Most folks set their timing a bit more retarded than that although they often don't realize it. When everything is setup as the cars were when new, the distributor had 40 degrees advance. If you have the timing set as I do that means full advance is 40 degrees BTDC which is way too much with 5.5-6.0 compression. In my experience 30 degrees is about the limit unless you are approaching 3000 RPM or more then you have a little more wiggle room. The result is NOT an audible spark knock but instead a pounding of the engine that resonates up through the controls. You can feel it but I doubt a passenger could.

Originally the spark lever quadrant had ten notches for the lever. Each notch advances the timing 4 degrees. The seventh notch is just slightly above parallel and provides very close to 28 degrees advance on my cars so that gives you an idea. From your description is sounds like you are running slightly more retarded than I am. That is actually too far advanced to just leave the lever in that position unless you keep the RPM way up through the gears like I often do but this is not common among "A" drivers.

As far as your engine running a bit rough, it shouldn't. In fact they often tend to run smoother when you increase the compression. My first thought is the added compression brought to light a minor weakness in your ignition system. While I've done ok running 3X plugs gapped at .035", Ford specified .025" gap with their high compression "Police head". my suggestion is to clean your plugs and try gapping them at .025". It may not pay off but it's worth a try.

[Geo. H]

Uh, Mister Ford Garage, maybe you're the only one in step, but I think you need to check your facts. Everyone I know thinks higher compression speeds the burn.

[dumb person]

Really?

[Marco Tahtaras]

Originally Posted by Geo. H

Uh, Mister Ford Garage, maybe you're the only one in step, but I think you need to check your facts. Everyone I know thinks higher compression speeds the burn.

That was just a VERY late night snafu (been there, done that). References have been deleted.

Thanks

[Aerocraft]

For what its worth, when installed in an airplane such as a Pietenpol, the generally recommended mag timing is 28 degrees BTC. Most of the mags that are used have an automatic retard termed an "impulse" that delays the spark roughly 25 degrees for starting. The impulse stops functioning when the RPM reaches 300 - 400 rpm.

There are a few of us that for years have tried to educate our local club members that the spark lever is not an "up to start, down to run" tool. Of course the "up to start" is correct, but "down to run" is not. We have tried to teach that "3/4 down to run" is much better for the engine. Of course, "tune it for conditions" would even be better.

As an aside, here is a picture of the drive for the magneto as recommended by Bernie Pietenpol.

Gar Williams

[Tom Wesenberg]

Gar, Is that a tach drive on the front of the camshaft?

Is that a special thrust bearing on the front of the timing cover? What is used to take the forward pull of the prop? Thanks

[gilitos]

Brobrian, Given your satisfaction with the HC head, maybe you should change your tag line to read "Fifty horses is plenty"!

[40 Deluxe]

Believe it or not, Tom, prop thrust was taken by the stock setup!

[TinCup]

Before I changed out heads I usually ran the advance about 3/4 down when running 40-45. After the head change I found that 2/3 was all that was needed to find that sweet spot. Other than the hi-comp head I have a stock motor. Didn't know about the gap for the plugs being .025". Will change that and see what we get.

[Brobrian]

Wow, I love all this info.!
It's cool to try something out and find your experience validated by the engineering as much as it is to discover that starting with the design translates to the experience. So I found the"sweet spots" in various situations. I was still a little uncomfortable with what I found. Thought maybe I'd made a mistake, until the rest of you guys shared the same observations and explained the reasons. Now I think I'll enjoy the new head with the different characteristics with more peace of mind.
Thanks, now I'm off for another drive.

[Aerocraft]

Originally Posted by Tom Wesenberg

Gar, Is that a tach drive on the front of the camshaft?

Is that a special thrust bearing on the front of the timing cover? What is used to take the forward pull of the prop? Thanks

Tom: Yes, the tach is driven by a cable that plugs into a drive very similar to the Model A speedometer drive. A fitting is screwed into the end of the camshaft.

What appears to be a thrust bearing is actually a holder for a Garloc seal which keeps oil from leaking out of the crankshaft. This engine has insert bearings done by Rich Falluca. The thrust loads are carried by a bronze split thrust washer on each side of the rear crankshaft bearing.

Due to the need of a tach drive, the two front castings which cover the timing gear are replaced by a split flat .062" steel plate. The front of the pan is cut off and half of that plate is welded in place. Originally, the rope front (rear in the airplane) seal was the oil seal. Pietenpol changed that by the addition of the two plates and he also installed a slinger to act as a "oil seal". The slinger works poorly at best and the Garlock seal works very well. My engine had the slinger and I recently machined the holder and added the Garloc seal.

Gar Williams

[crminal]

Interesting reading here. So here comes the question....
I am using a FS electronic ignition which is self advancing up to 28 degrees (right way to put it?)
When I set up my ignition, I made a pointer which lined up with my pulley and marked it a TDC. Would you ever rotate the dizzy to advance or retard timing? What would be gained if anything?

[Art Bjornestad]

I think an impulse mag has a spring that lets the mag spin very fast after is is wound in the first few seconds of the engine start procedure. This allows the mag to get enough revs to produce a stronger spark. Art

[BRENT in 10-uh-C]

Originally Posted by crminal

Interesting reading here. So here comes the question....
I am using a FS electronic ignition which is self advancing up to 28 degrees (right way to put it?)
When I set up my ignition, I made a pointer which lined up with my pulley and marked it a TDC. Would you ever rotate the dizzy to advance or retard timing? What would be gained if anything?

Lets start by asking you how do you know that 28° is the optimum timing for your engine?

If you were to say your engine makes peak horsepower at 27°, then theoretically you could retard the initial timing of the distributor by 1° to accomplish 27° of full advance.

[columbiA]

I am running Champion C16C,s gapped at .035" in my "B" with a 5.9 head for 14,000 miles with no problems.

[Patrick L.]

I'm kinda of the opinion that less is more, at times.. And this is one of those times.. Regardless of which cylinder head these little engines have,, why would they ever need 40º of advance.. I don't think they do.. I don't think any 2000 rpm engine needs 40º of ignition advance.. i doubt there are very many of us that even run our engines that fast.. My left lever is usually at 9:00-9:30 and thats its 'sweet spot'..

[Brobrian]

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Originally Posted by Patrick L.

I'm kinda of the opinion that less is more, at times.. And this is one of those times.. Regardless of which cylinder head these little engines have,, why would they ever need 40º of advance.. I don't think they do.. I don't think any 2000 rpm engine needs 40º of ignition advance.. i doubt there are very many of us that even run our engines that fast.. My left lever is usually at 9:00-9:30 and thats its 'sweet spot'..

I suppose we can only compare spark advance from car to car if we agree to set the points to just open at TDC (using the pin) and as long as all the linkage on the advance lever is straight.

With those things in mind, my cars both ran best in the full advance position. Now, since installing the HC head, the coupe runs best at 9 o'clock or so.

BTW I still don't prefer the new running characteristics. Just doesn't feel right, and I can't relax for listening for engine knock.

[Keith True]

I have one truck with a Brumfield head that I can only run very little advance on.Start it up,pull the lever down 2 or 3 clicks,and that is it.Any more and it actually pounds and bucks.I'm just not used to that.All my cars have always been sensitive to the spark and GAV settings.Start at full retard,a couple clicks down for idle,about halfway down around town,and all the way down for flat out.Each one has a little variation,but that was always in the ballpark.The truck with the Brumfield head has a B cam,and is either .060 or .125 overbored.I did a couple of engines over years ago and I can't remember which car got the big drilling.The main thing is,it doesn't bother in the least.Three clicks down and it runs like a bear all day long.Another thing with it,is if I do advance it too much,I never hear a ping,it just goes right to detonation,or hammering.It is combustion,not bearing noise.

[BRENT in 10-uh-C]

Originally Posted by Brobrian

BTW I still don't prefer the new running characteristics. Just doesn't feel right, and I can't relax for listening for engine knock.

You can if you 'up' the octane rating of the fuel you are using. A higher octane rating will compensate for detonation (within reason!!).

.

[crminal]

Originally Posted by BRENT in 10-uh-C

Lets start by asking you how do you know that 28° is the optimum timing for your engine?

If you were to say your engine makes peak horsepower at 27°, then theoretically you could retard the initial timing of the distributor by 1° to accomplish 27° of full advance.

Thanks for the response. I think I know where you are going here.

So, if I wanted to do some "trial and error" timing by rotating the dizzy a degree or two, it would be okay. Then I could optimize my timing.

[Duffy1]

So how can you tell if you are running it too retarded are to advanced . Too retarded causes carbon build up.Too advanced causes rattling and is hard on the engine.

[Purdy Swoft]

I feel that driveing to slowly in an attempt to be easy on the engine causes most of the problems. When some speed and momentum is not maintained when approaching hills you will end up lugging the engine. Timing knocks occur when the engine is lugged and that is when the spark needs to be retarded to cushion the knock. A lot of people read the owners manual and try and use the spark as was necessary over eighty years ago. In the day that the manual was printed, the roads were mostly trails, fuel octane was very low. driving speed was slow and more use of the spark was necessary because of the conditions of the time. Its not safe to drive at the creepy speeds that they were driven eighty years ago on todays highways. To be perfectly honest, most just don't understand or know how to drive a model A. A lot of people are either lugging the engine to the point of timing knock or running so retarded that the manifold runs red hot, neither is good for the engine.

If you are driving on trails like I like to do or driving slow on back roads. more spark retard is needed. If you hear knocks, retard until they go away. If speed and momentum is maintained , run full advance, or you will lose power and run hot. On the highways or main roads, I put it up on 50 mph and let er go. With my 5.9 head and other mods, mine runs about like modern cars. I can accelerate up the hills if I need and I never lug the engine. I run 3.78 gears and believe that is the best all arround ratio. With any manual transmission vehicle, you will do more damage to the whole driveline by lugging in high gear!!!

[Tom Wesenberg]

Originally Posted by Duffy1

So how can you tell if you are running it too retarded are to advanced . Too retarded causes carbon build up.Too advanced causes rattling and is hard on the engine.

Too retarded causes loss of power and overheating. Too advanced causes hammered out babbit and knocking.

[spdway1]

I NEVER move my spark lever, not even to start it, am I doing something wrong? Its starts fine, runs fine up and down hills, back roads and highway.

[steve s]

Originally Posted by spdway1

I NEVER move my spark lever, not even to start it, am I doing something wrong? Its starts fine, runs fine up and down hills, back roads and highway.

Depending on exactly where your universal setting is, it could run even better and with less risk of busting or jamming your starter mechanism.

Steve

[modelAtony]

I have 5.9 brum , 3.27 gears in my inserted engine . don't know about sniders 5.5 but basically same as brum. DONT run your spark more than 1/2 . REALLY more like 1/4 at 50 mph. DONT CARE WHAT PEOPLE TELL YOU . 1/2 IS TO MUCH. HAVE FUN MODELaTONY LAFAYETTE,LA

[marc hildebrant]

spdway,

Why would you NOT adjust your spark ? Surely the fact that the spark has an adjustment for the driver means that it was normally moved during operation ?

Marc

[spdway1]

Originally Posted by spdway1

Its starts fine, runs fine up and down hills, back roads and highway.

I don't see/feel/hear a difference. So why would I?

[duke36]

just to confirm, what should be the spark plug gap be for a Brumfield 5.8:1 hi compression head?

[ronn]

I don't see/feel/hear a difference. So why would I?

are you sure it isnt disconnected......................?

[colin1928]

Originally Posted by rip94611

just to confirm, what should be the spark plug gap be for a Brumfield 5.8:1 hi compression head?

That would depend on the strength of the ignition system (voltage out of the coil) and spark plug design
Generally go with what the spark plug manufacture recommended
Maybe start at around 0.032" and adjust as needed

[Dick M]

I have the 5.5 head on my coupe. One way to find optimum advance setting is to continue retard the spark until the knock goes away. I find with mine that the knock is gone and optimum power is achieved with the spark advance about 1/3 down. I believe Les Andrews advises against too much advance with the higher compression heads.

[Mike V. Florida]

Originally Posted by Dick M

I have the 5.5 head on my coupe. One way to find optimum advance setting is to continue retard the spark until the knock goes away. I find with mine that the knock is gone and optimum power is achieved with the spark advance about 1/3 down. I believe Les Andrews advises against too much advance with the higher compression heads.

"With increased flame speed, if the timing is not sufficiently retarded, too much of the burning process will occur early when the piston is in its top dead center position. At that position, the piston is static for an instant and resisting downward motion. While the piston is temporarily static, the heat of the flame is increasing the chamber temperature which will promote detonation. Any great rise in heat also necessitates the need to further retard the timing because the heat increase makes the mixture burn even faster."