10-17-2017, 10:13 AM | #1 |
Senior Member
Join Date: Jul 2014
Location: Danbury Ct
Posts: 1,254
|
Head Questions
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? |
10-17-2017, 10:24 AM | #2 |
Senior Member
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,089
|
Re: Head Questions
I see no downside to the 6:1 head. They are a direct bolt-on and use the stock spark plugs.
|
Sponsored Links (Register now to hide all advertisements) |
|
10-17-2017, 10:27 AM | #3 |
Senior Member
Join Date: Jun 2014
Location: Rocklin, CA
Posts: 779
|
Re: Head Questions
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.
|
10-17-2017, 10:28 AM | #4 | |
Senior Member
Join Date: May 2010
Location: Eastern Tennessee
Posts: 11,516
|
Re: Head Questions
Quote:
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. . |
|
10-17-2017, 10:51 AM | #5 |
Senior Member
Join Date: Jul 2011
Location: Redondo Beach, CA
Posts: 5,849
|
Re: Head Questions
|
10-17-2017, 11:48 AM | #6 |
Senior Member
Join Date: May 2010
Location: NC
Posts: 2,975
|
Re: Head Questions
Sponsored Links (Register now to hide all advertisements)
|
10-17-2017, 12:12 PM | #7 |
Senior Member
Join Date: Aug 2016
Location: Alberta
Posts: 930
|
Re: Head Questions
Could you elaborate?. Having trouble wrapping my head around the concept of it being EASIER on the mains.
|
10-17-2017, 04:51 PM | #8 |
Senior Member
Join Date: May 2010
Location: NC
Posts: 2,975
|
Re: Head Questions
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.
|
10-18-2017, 10:57 AM | #9 |
Senior Member
Join Date: Jul 2014
Location: Danbury Ct
Posts: 1,254
|
Re: Head Questions
|
10-18-2017, 11:06 AM | #10 |
Senior Member
Join Date: Jul 2014
Location: Danbury Ct
Posts: 1,254
|
Re: Head Questions
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!
|
10-18-2017, 11:07 AM | #11 | |
Senior Member
Join Date: May 2010
Location: Central, IL
Posts: 3,968
|
Re: Head Questions
Quote:
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....
__________________
1929 Model AA - Need long splash aprons! |
|
10-18-2017, 12:31 PM | #12 | |
Senior Member
Join Date: May 2010
Location: now Kuna, Idaho
Posts: 3,779
|
Re: Head Questions
Quote:
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. |
|
10-18-2017, 01:43 PM | #13 | |
Senior Member
Join Date: May 2010
Location: Central, IL
Posts: 3,968
|
Re: Head Questions
Quote:
__________________
1929 Model AA - Need long splash aprons! |
|
10-18-2017, 01:47 PM | #14 |
Senior Member
Join Date: May 2010
Location: NC
Posts: 2,975
|
Re: Head Questions
The crank angle is better with a high compression head, because you can fire it latter also. Which helps along with what you said.
|
10-18-2017, 01:56 PM | #15 |
Senior Member
Join Date: May 2010
Location: Central, IL
Posts: 3,968
|
Re: Head Questions
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....
__________________
1929 Model AA - Need long splash aprons! |
10-18-2017, 02:25 PM | #16 |
Senior Member
Join Date: May 2010
Location: NC
Posts: 2,975
|
Re: Head Questions
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.
|
10-18-2017, 02:49 PM | #17 | |
Senior Member
Join Date: Mar 2017
Location: southern California
Posts: 725
|
Re: Head Questions
Quote:
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. |
|
10-18-2017, 04:40 PM | #18 |
Senior Member
Join Date: Apr 2011
Location: New Zealand
Posts: 444
|
Re: Head Questions
|
10-18-2017, 04:51 PM | #19 | |
Senior Member
Join Date: Apr 2011
Location: New Zealand
Posts: 444
|
Re: Head Questions
Quote:
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 |
|
10-18-2017, 05:58 PM | #20 |
Senior Member
Join Date: Dec 2014
Location: Santa Maria, CA
Posts: 985
|
Re: Head Questions
Curious:
With a 5.5 head, what would the compression reading be? With a 6.0 head, what would the compression reading be?
__________________
Alan 1929 Special Coupe 1941 Pick-Up 1955 Victoria |
|
|
Sponsored Links (Register now to hide all advertisements) |
|