Z head,advantages?

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Model T Ford Forum: Forum 2017: Z head,advantages?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, October 23, 2017 - 09:15 pm:

I was going to ask about a aluminum head as I have a chance to get a Z head for 200 dollars but have no idea if there is any real advantages to it.Seems it would cool better.That is to much money to pay for something if it is of improvement.
I used google and read thru some stuff posted here and such and really can't decide.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevada Bob Middleton on Monday, October 23, 2017 - 09:52 pm:

I buy it myself
Get more water and couple more horses
With no extra strain on the bottom end
I gonna dig out my 3 low heads and try sell to get one or prus


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, October 23, 2017 - 10:10 pm:

Cleaner combustion, more power.... and what Nevada Bob said .


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Monday, October 23, 2017 - 10:14 pm:

Thanks,I will give it some thought as i have to be careful with funds. it appears to be in great shape,run very little,don't know why it was removed.
Fellow bought it for a early car and it won't fit,not enough clearance he said.Should fit the 26 engine that will be in my speedster if I live long enough to finish it! :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, October 23, 2017 - 10:22 pm:

Measure the depth where the valves would rise. Could be head was shaved ??

My "Z" head is ok with the Stipe 280 cam ( higher lift valves ), otherwise may be ok with standard lift valves ( lobes ).


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Townsend ; ^ ) Gresham, Orygun on Monday, October 23, 2017 - 10:33 pm:

Mack-
Fantastic deal! Buy it. Do you have a running car? It will make a noticeable difference.
-Keith


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Monday, October 23, 2017 - 10:52 pm:

Mack,
That would be right, not enough clearance, as in they hit the wood fire wall on some early T's.
Another issue with them is the pistons can hit the Z head, so some grinding could be called for in the combustion chamber.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Monday, October 23, 2017 - 10:52 pm:

I'm with Keith. $200 is a good deal. It will give you about 7 more h.p., which is noticeable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Noel D. Chicoine, MD, Pierre, SD on Monday, October 23, 2017 - 11:34 pm:

A high compression head like the Z or Prus is the best thing, in my opinion, you can do to a stock T to make it easier to drive in traffic and go up hills. I have aluminum ones on 2 of my T's, and am debating getting another or a Prus head for my roadster. The Prus seems to have a little more power. Both Z'ed engines have .280 cams also but the head made the most difference. Good luck, Mack


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Kelsey on Tuesday, October 24, 2017 - 02:46 am:

It makes a huge difference, in my opinion.
When I bought my sedan 11 years ago, it came with a Z-head. When I had the Z-head milled several years ago, I decided to pop on the stock had that came with the car just to see if there was a difference - there was. The car did not accelerate as fast and did not have very much power. I was glad to have the Z head back on.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Whelihan Danbury, WI on Tuesday, October 24, 2017 - 07:40 am:

For $200 I don't think you can go wrong. If you buy it and don't like it, you can for sure get your money back selling it. A Z head or Prus head is probably the single best thing you can do to improve performance on a mechanically solid engine. I've had both; the Z head and Prus head on the same engine. The Prus variety definitely gives you a little more power, but for $200 I'd sure find a way to be happy with a Z head.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Killecut on Tuesday, October 24, 2017 - 08:56 am:

Mack, I have a Z and a Prus. I am not a fan of the Z,as they are very crude. I had to send the fist one back as it was unusable. Both had to be surfaced before they could be used and a lot of die grinding from the piston hitting the head and on the one I kept a lot of grinding at the back coolant passage. There was also issues with the area between the cylinders. I got it to work but don't trust it and carry a head gasket with me. The Prus head is a work of art compared with it. There is a good chance the one that's available has had head gasket problems because it wasn't initially surfaced. If so you could add that to the cost.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mack Cole ---- Earth on Tuesday, October 24, 2017 - 04:56 pm:

Ok,thanks for the tip about surfacing.I can get that done reasonable as I have a couple friends that run machine shops.If things work out I will check with the fellow when the extra funds come thru in a couple weeks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Tuesday, October 24, 2017 - 05:27 pm:

The problem with drawing extra power out of a Model T Ford is the weakness in the bottom end; the crankshaft. -That's the car's Achilles Heel. -Before it went through about a century of metal fatigue, the crankshaft was designed to absorb 20-22 horsepowerówith maybe a little extra safety margin on top of that, but not a whole more, because Hank didn't believe in needless weight, anywhere.

I didn't know that when I bought my Flivver and the first thing I did was have the seller (who was a Model T mechanic) equip the engine with a high-compression head and a high-flow intake manifold, even before I even took delivery of the car. -It just seemed to make sense that more power was better (Thank you, Tim the Tool Man).

Shortly thereafter, I took my Model T Mentor (a long-time, multiple brass car owner with thoroughly proven expertise) for a ride in my Flivver and he, in a tactful way, made me understand how the driving habits I was developing would eventually cause an increase the membership of the 2-piece crankshaft club by a factor of one. -Apparently, swinging the throttle wide open to make the car behave more like its modern brethren was not optimum technique. -My friend taught me to baby the engine and treat the throttle like a loaded bazooka.

So now that I know about the crankshafts propensity for breakage (and according to popular legend, there are two types of Model T drivers; those who have broken a crankshaft and those who will), I'm very careful to gently nudge the car into motion, shift smoothly and not lug the engine in high-gear. -And as I've become unwilling to open the throttle wide, the extra power provided by the speed equipment is never used. -I might as well have left the engine alone. -On top of that, it was recently pointed out to me how a high-compression head increases the stress on the crankshaft all the time the engine is running (which, intuitively, makes sense).



I've driven other Tin Lizzies and yes, they do require a bit more throttle to move out the way my car does, but so what? -Either way, the same modest amount of power is applied to the rear wheels. -Yeah, I might as well have just left the engine the way it was.


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