My wife's 26 Tudor needs a bit of engine work since the wrist pin in # 1 decided to gouge two vertical GT stripes up the bore, so l am in between, flats with Z or flats with 8:1.
I'm after some feedback as to the performance.
I have used a Z head previously and wasn't all that happy with it.. I don't have it anymore.
Thanks in advance for comments.
Two friends have run the Sherman heads (one after previously using a Z head). Both were impressed with the performance when running premium gas. The 87 octane stuff caused excessive pinging with the Sherman but had been OK with a Z head. One friend has a large journal Scat crank and is very happy with the combination. The other friend broke a T crank after just a couple hundred miles. Of course that crank may have broken with a Z or stock head too but I suspect the Sherman head helped it fail sooner rather than later. The car ran great until it broke. If I were planning on running a Sherman head, I'd want the stronger crankshaft. Your mileage may vary.
David, I am not sure why you were unhappy with the Z head on your car??? Myself and many others here will testify as to the all round improvement of the car after the addition of the head. Perhaps deficiencies in other areas such as the coils, valves, camshaft etc masked any improvement the Z head would have made? Now with a new rebuild the Z head should be all you will require. I could not recommend one highly enough.
Perhaps you could go a different route and try the new PRUS 8:1 high comp alloy head. They are also getting great reviews. Frank still has a spare Z if you need one!
Yeah thanks Warwick.
My thoughts on the Z are as they are, 8.1 with some care might just be the way to travel in a heavier T.
I have run both an early Sherman head (from before the current production) and a Z-head on the same engine in my '16 T. I ran each one for over 3 years. I currently have the Z-head installed.
Both combustion chambers are nearly identical. The performance difference is imperceptible to me. Both are an improvement – neither stood out.
I have used 97 octane since I owned my T (1988).
At the current prices, the Z head is a better value in my opinion.
Question for Bob or anyone else running a Z head.
What is your average compression?
Should I use high octane gas?
My use of 97 octane fuel is a preference not a necessity. My '16 is a hand cranker so have never checked my compression. Occasionally I have run 87 octane without any pinging or other symptoms.
I am using an Anderson timer - once started, I run fully advanced (lever all of the way down).
I haven't checked the compression either on my Z head motor. 87 octane with up to 10% corn which is typical here works just fine. Like Bob, Anderson timer, almost always fully advanced after start up. Runs best on Mag.
What is the difference between a PRUS and the Sherman style head ??
I think l just found the answer - THEY ARE THE SAME THING. PRUS and SHERMAN STYLE alumin heads.
A bit more reading shows the potentially best plug to run in this head is a modern Champion 120 N5C plug.