|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
01-07-2020, 10:08 PM | #1 |
Senior Member
Join Date: Feb 2011
Location: Lincoln, Nebraska
Posts: 1,914
|
High compression head choice.
I will be installing a Warford overdrive in my 29 AA. I plan to change over to a high compression head. Thoughts on going with the 5.5 to 1 or the 6.0 to 1?
Also are the high compression heads sold by Snyder's and Bert's the same? Price is markedly different between them.
__________________
Dave / Lincoln Nebraska |
01-08-2020, 12:56 AM | #2 |
Senior Member
Join Date: May 2010
Location: Santee, California
Posts: 3,505
|
Re: High compression head choice.
Definitely go for the 6.0 to 1. Spectacular improvement in my light 29RPU. Also you will get the best price from Snyder, same head.
|
Sponsored Links (Register now to hide all advertisements) |
|
01-08-2020, 06:40 AM | #3 |
Senior Member
Join Date: May 2010
Location: Gwynn's Island Va
Posts: 1,406
|
Re: High compression head choice.
6.0 is a great head.
|
01-08-2020, 07:04 AM | #4 |
Senior Member
Join Date: Aug 2016
Location: West Virginia
Posts: 430
|
Re: High compression head choice.
What are the advantages to having the high compression heads? What kind of improvements do you achieve in performance? I am currently going through my AA engine. Are there any drawbacks from deviation from stock head?
|
01-08-2020, 07:49 AM | #5 |
Senior Member
Join Date: Jun 2013
Location: Marana Arizona
Posts: 1,777
|
Re: High compression head choice.
I went with the 6.0 head and immediately noticed an increase in power, I guess at least 25%. After asking and researching I opted for the 6:0 just because it wasn't that much more money. Very scientific approach I know. But was extremely pleased with the decision.
Remember with the new head you need less advance with the spark level. My 30 liked it at about the 9:30 position, a notch or two above horizonal for regular cruising. The engine temp will let you know where your "sweet spot" is. "Enjoy the adventure"... Chap |
01-08-2020, 08:27 AM | #6 |
Senior Member
Join Date: Jan 2016
Posts: 2,114
|
Re: High compression head choice.
Sponsored Links (Register now to hide all advertisements)
David R, You will notice that hills are much easier to climb. There is less shifting involved because you are not always looking for that sweet spot where the engine runs best. Your take off speed will be faster. You should always take the head to a machine shop and check it for being straight. Both heads had to be straightened a little. My spark is best at 9-9:30. Last edited by old31; 03-13-2020 at 05:28 PM. |
01-08-2020, 09:29 AM | #7 |
Senior Member
Join Date: Oct 2015
Location: Bay City Michigan
Posts: 1,050
|
Re: High compression head choice.
putting more pressure in the cylinder may put more stress on the bottom end.
|
01-08-2020, 09:32 AM | #8 |
Senior Member
Join Date: Apr 2018
Location: Mebane NC
Posts: 2,376
|
Re: High compression head choice.
Considered against the range of compression ratios used in the auto industry in the '30s, it would be more accurate to describe the "high compression" 6:1 heads as "normal compression" and the stock head as "low compression." I've never heard anyone report operational issues with the 5.5 or 6.0 heads.
|
01-08-2020, 10:37 AM | #9 |
Senior Member
Join Date: Jan 2015
Location: New York
Posts: 943
|
Re: High compression head choice.
Have the 6.1 running great.
|
01-08-2020, 10:42 AM | #10 |
Senior Member
Join Date: May 2010
Location: N. GA
Posts: 533
|
Re: High compression head choice.
I have an NOS Brumfield head. Anyone have good/bad experience with these?
TOB |
01-08-2020, 12:02 PM | #11 | |
Senior Member
Join Date: May 2010
Location: Santee, California
Posts: 3,505
|
Re: High compression head choice.
Quote:
With the 6.0 head I just fly up the grades and not having to shift down any more. With the 6.0 head just be mindful of not advancing spark to the same level as the 4.5 |
|
01-08-2020, 12:05 PM | #12 |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 8,099
|
Re: High compression head choice.
I have never had a problem of any kind with my 5.9 Brumfield heads . The 5.9 heads give a good increase in power and hill climbing ability , they will allow the engine to have an increase in top speed . The engine will run a bit cooler and I have NEVER needed to down shift on any hill as long as momentum is maintained . If I wanted to increase the power on an original type model A , I would use the 6.0 Snyder head because it appears to be original . If I was building a hot rod or speedster I would prefer the Lion head that doesn't appear original and has higher compression ratio .
|
01-08-2020, 12:19 PM | #13 |
Senior Member
Join Date: Jun 2010
Location: Temecula, CA
Posts: 4,097
|
Re: High compression head choice.
The two quickest and easiest ways to more power in a Model A are compression and a bigger carb. Compression won't hurt the babbitt as long as you don't let it detonate, so less advance will be needed. When I bought my tudor years ago, I ran it on a F.A.S.T. hill climb in Auburn, CA. A few months later I had changed to a 6:1 Winfield head, it picked up a full second on that same course. On that same day I changed to a Stromberg 81 and picked up nearly another full second! Later I switched to a 97 carb and picked up about 3/10 of a second. That's on a 1/10 mile course of about 6% grade.
|
01-08-2020, 01:08 PM | #14 |
Senior Member
Join Date: May 2010
Location: Alabama
Posts: 8,099
|
Re: High compression head choice.
I agree that a bigger carburetor will help a bit . I prefer to run dual model B carburetors than the later Ford or Stromberg two barrel carburetors . Updraft carburetors don't flood like downdraft carburetors can . I like the look of dual updraft carburetors . I run dual model B carbs on cast iron manifolds on two of my model A's . I'm thinking about instaling dual Marvel carbs with an aluminum Charley Yapp intake manifold on my September 29 . It will already run faster than I would want to drive it . I really don't much care if the Marvel carbs don't give a big increase in power . I'm more after the look but more carb will increase top speed a bit .
|
01-08-2020, 01:41 PM | #15 |
Senior Member
Join Date: May 2010
Location: Eastern CT
Posts: 2,732
|
Re: High compression head choice.
Higher compression, oversize intake valves, and a B carb make a world of difference.
|
01-08-2020, 02:54 PM | #16 |
Senior Member
Join Date: Apr 2011
Location: New Zealand
Posts: 444
|
Re: High compression head choice.
One needs to realise the improvement in the quality of petrol since the Model A was new.
I run a 7:1 head, still low by todays standards and I am running it on 91 octane petrol without problems. Early pre-ignition problems were solved by fitting a Mallory distributor, which together with the harmonic balancer pulley were the two greatest improvements to the smooth running of the engine |
01-08-2020, 03:03 PM | #17 |
BANNED
Join Date: Dec 2019
Posts: 1,196
|
Re: High compression head choice.
The stock model a engine is detuned by 50 % ,low compression and low carburetor air flow are two areas with the greatest 'return on investment'.Model AA's were the first market for engine performance,truck owners wanted more power.
|
01-08-2020, 03:06 PM | #18 | |
Senior Member
Join Date: May 2010
Location: Durango CO
Posts: 1,312
|
Re: High compression head choice.
Quote:
Started with the original B-F head and went to the B-F Super Head and never looked back. Hard to find a B-F head as Larry quit making them years ago.
__________________
No restorable Model A's were harmed in the building of this truck! |
|
01-08-2020, 09:38 PM | #19 |
Senior Member
Join Date: Sep 2016
Location: Long Island
Posts: 172
|
Re: High compression head choice.
What are the thoughts on the even higher compression heads? I happened to have a Winfield red head 7.1. I recently purchased an engine fully decked out in Winfield. (Almost certain its all repop). I've had it running but it's not in the car yet. It is a recently rebuilt babbet engine. Electronic 6v igniton as well. It should make my roadster a pretty fun machine. I'm pretty light on the pedal so I don't have much concern for the babbet.
|
01-08-2020, 09:47 PM | #20 |
Senior Member
Join Date: Feb 2011
Location: Lincoln, Nebraska
Posts: 1,914
|
Re: High compression head choice.
Thanks for all of the input. Very interesting. I'll be going with the 6.0-1 head.
__________________
Dave / Lincoln Nebraska |
|
|
Sponsored Links (Register now to hide all advertisements) |
|