SNYDER’S 5.5 head vs 6.1

[Model A Ron]

Below is what Snyder's has on their sight. I see 54.6 HP for the 5.5 head and 57.5 for the 6.1 head. Does that make any real difference in what you will feel when driving?


The A-6010-HC 5.5:1 High Compression Head made 38.16 HP @ 1400 RPM and 143.15 ft lbs of torque and
54.6 HP @ 2500 RPM and 114.7 ft lbs. of torque with the A carburetor.

The A-6010-HC6 6:1 High Compression Head made a little flatter torque in the low range from 42 to 47 HP @
1500 to 1700 RPM and 146.4 ft Ibs of torque and 57.48 HP @ 2500 RPM and 120.75 ft lbs. of torque with
the A carburetor.

[alexiskai]

Most folks say the difference between the two is not noticeable for normal driving. The only caveat is that the higher the compression, the more critical your timing is, so if you're a set-it-and-forget-it guy on the advance lever, the 5.5 will be more forgiving.

[Model A Ron]

Originally Posted by alexiskai

Most folks say the difference between the two is not noticeable for normal driving. The only caveat is that the higher the compression, the more critical your timing is, so if you're a set-it-and-forget-it guy on the advance lever, the 5.5 will be more forgiving.

This is good advice. Do you have a 5.5 or a 6.1?

[alexiskai]

Originally Posted by Model A Ron

This is good advice. Do you have a 5.5 or a 6.1?

I actually have a Winfield 7, I was just reporting what I've observed on this forum over the last few years.

I haven't actually gotten the Winfield running yet, I started working on it in December and I've now replaced about half of the engine bay. Any day now!

[Model A Ron]

[QUOTE=alexiskai;2008598]I actually have a Winfield 7, I was just reporting what I've observed on this forum over the last few years.

I haven't actually gotten the Winfield running yet, I started working on it in December and I've now replaced about half of the engine bay. Any day now![/QUOTE


Do you run mechanical advance like Jack talks about? What he said makes perfect sense. I only ran the stock head and I do try to adjust the spark as I drive. You can hear and feel what engine needs but I am sure I am in no way as accurate as mechanical advance. I would however like to keep the spark advance if I can master the 6.1.

Ron

[alexiskai]

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Originally Posted by Model A Ron

Do you run mechanical advance like Jack talks about?

I do use mechanical advance. There are generally two ways to do mechanical advance: on the distributor shaft, using the Phillips/Nu-Rex toroid accessory, or in the distributor body itself using a B or Mallory distributor. I will say, I think the Nu-Rex one is a lot easier to source.

The reason I use mechanical advance isn't so much that I don't believe I couldn't learn to control the spark manually, but rather that I don't want to turn a car that "anyone can drive" into a car that only I can drive. I'm planning to sell this car in a few years, and I'd prefer it if the next owner didn't have to immediately take the cylinder head off in order to feel safe using it.

[ronn]

no question- I would go with the 6. still pretty mild.

[Colonial coupe]

I have the 5.5 and am very pleased. 28 Special Coupe. 3.70 rear, Mitchell OD. Older rebuilt motor in good shape. Happy cruising at 45/50 with plenty of power. It will go faster but why? 7:00-16 rear tires. Tillotson carb most of the time, Stromberg 97 on a burns intake
just for fun.

[Jack Shaft]

5.5 is a copy of the only performance combustion chamber design by Ford engineering for the model A.6.0 is a modified heart design combustion chamber.

The stock model a ford engine suffered from two issues, low compression and inadequate fuel.Building true performance is a sum of all parts,the head will wake it up,a single V8 down draft carburetor (Holley 94 or Stromberg 97) flows air (CFM) at the same rate the engine does,matching CFM flow rates insures adequate fuel at all rpms. A late model B camshaft increases actual valve lift by over .030 and by design builds torque to 2900 rpm,as opposed to the stock A's 2400.

The engine in stock form is pleasant to operate, low rpm torque is what makes it feel good,hop it up? the torque rises right along with it. with a mitchell gear splitter I can be in 'full pull' from ten to fifty miles an hour, you can actually school some folks in traffic

[Model A Ron]

Originally Posted by Jack Shaft

5.5 is a copy of the only performance combustion chamber design by Ford engineering for the model A.6.0 is a modified heart design combustion chamber.

The stock model a ford engine suffered from two issues, low compression and inadequate fuel.Building true performance is a sum of all parts,the head will wake it up,a single V8 down draft carburetor (Holley 94 or Stromberg 97) flows air (CFM) at the same rate the engine does,matching CFM flow rates insures adequate fuel at all rpms. A late model B camshaft increases actual valve lift by over .030 and by design builds torque to 2900 rpm,as opposed to the stock A's 2400.

The engine in stock form is pleasant to operate, low rpm torque is what makes it feel good,hop it up? the torque rises right along with it. with a mitchell gear splitter I can be in 'full pull' from ten to fifty miles an hour, you can actually school some folks in traffic

So if you could find 5.5 head for a bit less money would you go with that or is the 6.1 worth it? I really do not have the funds for a head right now but I would sure like to have one to go along with the Mitchell that I have on order.

[Jack Shaft]

5.5 especially if you are using the stock distributor

[CarlG]

I have the 5.5 head. That's all that was available 11 years ago when I needed one. It replaced a Police head that was on the engine when I bought the pickup.

[Model A Ron]

Do you need to shave /surface the 5.5 or 6.1 prior to installing?

[BRENT in 10-uh-C]

Originally Posted by Model A Ron

Do you need to shave /surface the 5.5 or 6.1 prior to installing?

No. It needs to be heat cycled first so the casting with move all it is going to move.

I am not here to dispute what John is saying regarding using a stock distributor, -however the 6:1 head is very, very similar to the 5.9 head that Larry Brumfield produced for years and years. These heads were used by folks with stock Model-A distributors for years. No one ever complained about having detonation issues. IMHO, most of this stuff is 'he said/she said' where someone said you need to have a centrifugal distributer with your 6.0 head or you will blow up your engine. Nothing could be further from the truth.

I have sent a bunch of engines out the door, an every one of them use a Snyders 6:1 that we re-machine the surface (-generally about 0.005") and install. Back when Larry first introduced those heads, 98% of all engines they were installed on were cast bearings. The only bearing failures that were talked about on the forums (Ahooga and the original Fordbarn) back then were generally attributed to poor quality babbitt work. Today, using a 6:1 head does not need anything different than a 5.5 head.

[alexiskai]

Originally Posted by BRENT in 10-uh-C

Back when Larry first introduced those heads, 98% of all engines they were installed on were cast bearings. The only bearing failures that were talked about on the forums (Ahooga and the original Fordbarn) back then were generally attributed to poor quality babbitt work. Today, using a 6:1 head does not need anything different than a 5.5 head.

I mentioned in another thread, back in the '30s 6:1 on poured bearings was the way cars came from the factory, there's nothing weird about it. I agree that the conventional wisdom that HC is bad for bearings assumes that the engine has bad or worn-out bearings to start with.

[Model A Ron]

Originally Posted by BRENT in 10-uh-C

No. It needs to be heat cycled first so the casting with move all it is going to move.

I am not here to dispute what John is saying regarding using a stock distributor, -however the 6:1 head is very, very similar to the 5.9 head that Larry Brumfield produced for years and years. These heads were used by folks with stock Model-A distributors for years. No one ever complained about having detonation issues. IMHO, most of this stuff is 'he said/she said' where someone said you need to have a centrifugal distributer with your 6.0 head or you will blow up your engine. Nothing could be further from the truth.

I have sent a bunch of engines out the door, an every one of them use a Snyders 6:1 that we re-machine the surface (-generally about 0.005") and install. Back when Larry first introduced those heads, 98% of all engines they were installed on were cast bearings. The only bearing failures that were talked about on the forums (Ahooga and the original Fordbarn) back then were generally attributed to poor quality babbitt work. Today, using a 6:1 head does not need anything different than a 5.5 head.

This is good advice as well. Will I see a difference in the amount of attention I will need to give the spark advance between the 5.5 and the 6.1?

[Bruce of MN]

See the little device I made and the whole thread: https://www.fordbarn.com/forum/showt...ce#post1872892

I have only driven my Coupe with a stock head and a 6:1. In OD, on level ground at 50 mph, it sounds and feels better at less than 28 deg advance. If I come to a slope more than a gentle one, less advance is needed. You need to play with it under various conditions and listen and feel how the engine is straining or clattering and advance and retard as needed. Too much advance for a couple of revs won’t hurt the motor, ditto for too retarded. After a while, it becomes habitual.

[Model A Ron]

Originally Posted by Bruce of MN

See the little device I made and the whole thread: https://www.fordbarn.com/forum/showt...ce#post1872892

I have only driven my Coupe with a stock head and a 6:1. In OD, on level ground at 50 mph, it sounds and feels better at less than 28 deg advance. If I come to a slope more than a gentle one, less advance is needed. You need to play with it under various conditions and listen and feel how the engine is straining or clattering and advance and retard as needed. Too much advance for a couple of revs won’t hurt the motor, ditto for too retarded. After a while, it becomes habitual.

Bruce
I do appreciate your feedback. When it comes to compression the stock 4.2 is very low so going up to 6.1 should not be an issue unless the engine is ready for a rebuild anyway. My engine is strong and I have no problem playing with the spark advance when needed so the 6.1 sounds like the way to go for me. Thank you and thanks to all for the feedback.

Ron

[BRENT in 10-uh-C]

Originally Posted by Model A Ron

This is good advice as well. Will I see a difference in the amount of attention I will need to give the spark advance between the 5.5 and the 6.1?

Most Model-A drivers tend to over-advance, ...meaning they set the initial timing too far advanced which allows too much total advance when the spark lever is pulled all the way down. This really is not complicated other than some people try to overthink this. If someone is concerned/worried about the possibilities of detonation, then they should add an octane booster or just fill the gas tank with a mid-grade or premium grade of fuel. If the price difference between low and mid-grade is a dome, then we are speaking about a dollar more on a fill-up. FWIW, adding oil into the gasoline can lower the octane. If someone is actually using enough oil additive to be effective, (-not just a tablespoon or whatever) then it can increase the possibility of detonation.

[Model A Ron]

Originally Posted by BRENT in 10-uh-C

Most Model-A drivers tend to over-advance, ...meaning they set the initial timing too far advanced which allows too much total advance when the spark lever is pulled all the way down. This really is not complicated other than some people try to overthink this. If someone is concerned/worried about the possibilities of detonation, then they should add an octane booster or just fill the gas tank with a mid-grade or premium grade of fuel. If the price difference between low and mid-grade is a dome, then we are speaking about a dollar more on a fill-up. FWIW, adding oil into the gasoline can lower the octane. If someone is actually using enough oil additive to be effective, (-not just a tablespoon or whatever) then it can increase the possibility of detonation.

Brent
I try to adjust the spark to what my car likes. When I start the car the spark is retarded and after I get it running I drop it a click or two until the engine sounds good to me but it's above 1/2. When I am driving along at 45 to 50 the stock head seams to like it about 1/2 way down. When I am going over 55 I drop it a click or two but my car never seems to like it all the way down even when I am running full out. Is this normal? How different will a 6.1 be from the method I use with my stock head? Forgive the simple questions as I have only had my car a few months.

Thanks
Ron