Head Questions

[pgerhardt]

No not mine. I already know how that is functioning!! (Actually I really do. After my stroke, I was tested "up the kazoo".)

Snyder's offers two cast iron HC heads; the A-6010HC (5.5:1) and the A-6010HC6(6:1)

Question1:
The 6:1 head is only $10 more than the 5.5to1. My question is why would you not want the 6:1 head, which makes more consistent power over the model A's RPM range? Put another way, what is the down side to the 6:1 head?

Question2:
Are these cast iron HC heads a direct bolt on (without any mods other than using a model B gasket) replacements for the stock head?

Question3:
Are they machined to use the larger model A spark plugs, and can I use my Champion 3X plugs?

[Jim Brierley]

I see no downside to the 6:1 head. They are a direct bolt-on and use the stock spark plugs.

[JohnLaVoy]

I've used the 5.5 on a couple of cars and have the Brumfield 5.9 on one car I really like the 5.5 and don't notice a significant improvement in the 5.9 but haven't used the 6.0.

[BRENT in 10-uh-C]

Originally Posted by pgerhardt

No not mine. I already know how that is functioning!! (Actually I really do. After my stroke, I was tested "up the kazoo".)

Snyder's offers two cast iron HC heads; the A-6010HC (5.5:1) and the A-6010HC6(6:1)

Question1:
The 6:1 head is only $10 more than the 5.5to1. My question is why would you not want the 6:1 head, which makes more consistent power over the model A's RPM range? Put another way, what is the down side to the 6:1 head?

Question2:
Are these cast iron HC heads a direct bolt on (without any mods other than using a model B gasket) replacements for the stock head?

Question3:
Are they machined to use the larger model A spark plugs, and can I use my Champion 3X plugs?

This is often a very controversial topic, but IMHO the one to purchase is the 6:1 compression head. Now you are going to hear some folks swear that this will be difficult on the babbitt bearings, ...and while there is truth to that in certain circumstances (such as having an engine that has poor babbitt) the honest answer is there were many diesel engines that had babbitt bearings with double the compression ratio, and they were fine. Therefore the 6:1 CR head is not the issue. Even the Brumfield head was 5.9 and many, MANY engines lasted for a long time with that head.

These heads are indeed a 'bolt-on' if the valves are stock diameter. It might be worth asking you, how do you know your cylinder case (block) surface is level?

Yes, you can use your 3X plugs. If you like, contact me thru a PM and I will walk you thru the steps to camouflage your new head to mimic the looks of an original head even passing Fine-point Judging criteria.


.

[Y-Blockhead]

Originally Posted by pgerhardt

Question3:
Are they machined to use the larger model A spark plugs, and can I use my Champion 3X plugs?

Is there a larger plug than the 3X? The 3X fits in the standard hole...

[George Miller]

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In my opinion the 6-1 head is easier on the mains if you use the spark lever properly. The engine does the job easier with the 6-1 head. So in the end it is less strain on the mains.

[Licensed to kill]

Originally Posted by George Miller

In my opinion the 6-1 head is easier on the mains if you use the spark lever properly. The engine does the job easier with the 6-1 head. So in the end it is less strain on the mains.

Could you elaborate?. Having trouble wrapping my head around the concept of it being EASIER on the mains.

[George Miller]

Originally Posted by Licensed to kill

Could you elaborate?. Having trouble wrapping my head around the concept of it being EASIER on the mains.

Say you are running 40 miles per hour. With a high compression head you can do it with less throttle and less spark advance. The engine will be running smoother with less strain on the mains.

[pgerhardt]

Originally Posted by Y-Blockhead

Is there a larger plug than the 3X? The 3X fits in the standard hole...

No, but some of the HC heads come machined to use modern plugs that are SMALLER than the large model A plugs.

[pgerhardt]

Originally Posted by BRENT in 10-uh-C

These heads are indeed a 'bolt-on' if the valves are stock diameter. It might be worth asking you, how do you know your cylinder case (block) surface is level?


.

Of course I don't know yet. Once the head is off and the top of the block cleaned, I'll do my best to check it with a steel straight edge and look for any signs of cracks. More than that will require taking the engine out. Which will need to be done if I find anything wrong with the block. Let's hope not!

[SeaSlugs]

Originally Posted by George Miller

Say you are running 40 miles per hour. With a high compression head you can do it with less throttle and less spark advance. The engine will be running smoother with less strain on the mains.

But the compression is higher that requires more force to push the piston up to compress and thus harder on the mains (and crank)... Least that's how I'm thinking it...

Kinda like a tire with 10 psi vs 30 psi - 10 psi you can press it a certian distance with your foot with ease - try pressing it the same distance at 30 psi and see how much force it takes.

I may be thinking of it all wrong so please explain my thought if it is....

[40 Deluxe]

Originally Posted by SeaSlugs

But the compression is higher that requires more force to push the piston up to compress and thus harder on the mains (and crank)... Least that's how I'm thinking it...

Kinda like a tire with 10 psi vs 30 psi - 10 psi you can press it a certian distance with your foot with ease - try pressing it the same distance at 30 psi and see how much force it takes.

I may be thinking of it all wrong so please explain my thought if it is....

The extra force needed to push the piston up on compression stroke is minor and will not harm the bearings in any way. What needs to be considered is the extra force generated on the power stroke (the downward push). This firing pressure is much greater than compression pressure. I searched for some definite numbers for this but only found estimates, as the number varies greatly. But consider: At 60# cranking compression, the force on the rod bearing is 365# (60# X 6.8" piston top area). If we say peak combustion pressure on the power stroke is 4 times greater (a very rough estimate but in the range of my research), we have a force on the rod bearing of 1632#. This peak force occurs about 15 deg. after top dead center, and if you mike a well worn crank (on any old engine) this is where you find the most wear. Newer engines don't seem to wear like this: they last until they get run out of oil, overheated or get abused.
That much pressure on a Babbitt bearing won't hurt it. But detonation will spike that pressure much, much higher and will cause damage. We need to pay attention to timing with a HC head! Timing, by the way, is controlled with the spark lever, not by obsessing with the distributor points cam. That is only an initial setting.

[SeaSlugs]

Originally Posted by 40 Deluxe

The extra force needed to push the piston up on compression stroke is minor and will not harm the bearings in any way. What needs to be considered is the extra force generated on the power stroke (the downward push). This firing pressure is much greater than compression pressure. I searched for some definite numbers for this but only found estimates, as the number varies greatly. But consider: At 60# cranking compression, the force on the rod bearing is 365# (60# X 6.8" piston top area). If we say peak combustion pressure on the power stroke is 4 times greater (a very rough estimate but in the range of my research), we have a force on the rod bearing of 1632#. This peak force occurs about 15 deg. after top dead center, and if you mike a well worn crank (on any old engine) this is where you find the most wear. Newer engines don't seem to wear like this: they last until they get run out of oil, overheated or get abused.
That much pressure on a Babbitt bearing won't hurt it. But detonation will spike that pressure much, much higher and will cause damage. We need to pay attention to timing with a HC head! Timing, by the way, is controlled with the spark lever, not by obsessing with the distributor points cam. That is only an initial setting.

ohhh I see thanks!

[George Miller]

The crank angle is better with a high compression head, because you can fire it latter also. Which helps along with what you said.

[SeaSlugs]

Makes sense and I can see how adjusting the spark lever is that much more crucial on HC heads. Makes you wonder if ol Henry purposely didnt increase the compression to create a longer lasting engine where the general public wouldn't be paying attention to timing and proper lever use....

[George Miller]

Yes it does take more force to push the piston up. Also under a given load to reach a certain speed.The combustion with higher compression is pushing down on the bearings with more force as well so it is naturally harder on them. But once that speed has been reached and the load is reduced, or in other words, kinetic energy is in force, the higher compression engine will apply less force on the bearings to maintain the speed. the more efficient the engine, the less throttle it takes to do a given amount of work.

[1930-Pickup]

Originally Posted by SeaSlugs

Makes sense and I can see how adjusting the spark lever is that much more crucial on HC heads. Makes you wonder if ol Henry purposely didnt increase the compression to create a longer lasting engine where the general public wouldn't be paying attention to timing and proper lever use....

Most cars used low compression engines due to the limitations of the fuel at that time. Many gasolines detonated easily and could cause knocking and damage.

[wensum]

Originally Posted by pgerhardt

No, but some of the HC heads come machined to use modern plugs that are SMALLER than the large model A plugs.

The advantage of the smaller plug is the greater range available.

[wensum]

Originally Posted by SeaSlugs

Makes sense and I can see how adjusting the spark lever is that much more crucial on HC heads. Makes you wonder if ol Henry purposely didnt increase the compression to create a longer lasting engine where the general public wouldn't be paying attention to timing and proper lever use....

Running a 7:1 head and shell bearings (and all accurately balanced) our original crankshaft with welded on counterweights, cracked behind the No. 1 main bearing
In replacing that with a new Burlington shaft plus all new shell bearings, it was discovered that two of the big end shell bearings were distorted around the hole and appeared to be starting to break up.
Discussion with Snyders did not come to any real conclusion as to the cause, but we did experience some pinking or pre-ignition if too much throttle was given whilst in the 41% overdrive and have since learnt how to avoid that by more judicious use of the throttle and careful use of the advance & retard lever

[Anteek29]

Curious:

With a 5.5 head, what would the compression reading be?
With a 6.0 head, what would the compression reading be?