Burtz high compressinon head 6.5:1

Johan Ottosen

Johan Ottosen

Junior Member
Hi everyone. I have just recieved the Burtz 6.5:1 High Compression Head, as you can see in the pictures.
And I have two questions:
- is the imperfections in the texture over the pistons there by design?
- Is an uneaven surface better than a complete level one?
 

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It looks to me like the surface in the combustion chambers is the same as the outside of the head. That is what you get from a sand casting. It would be impractical to machine the inside of the combustion chamber so it is left as it came out of the mould. IMO, it makes no difference tot he performance of the head. Others may have a different opinion though
 
An as cast finish in a Model A head is not issue relative impacting performance.
Explain what you mean by uneven surface. If you are referring to the lines in the machined surfaces these are usually the result of the machining parameters used which can impact surface finish. If you were to measure the depths of the lines they are probably less than .0002" . The appearance of the machined surface finish is also affected by the direction and intensity of light projected on the surface. The most important head machined surface condition is flatness.
 
Gene F said:
So I guess they sourced it from Snyders...
Click to expand...
No it's a new design and made by Terry Burtz - sold by Snyders (and others).


https://burtzblock.com/products/cylinder-head


This newly manufactured Model A cylinder head is identical in appearance to the original heads manufactured by Ford for the Model A engine. It has a 6.5:1 compression ratio and improved coolant circulation openings to maximize even cooling from front to back. It is manufactured with modern grade cast iron and is dimensionally accurate.
 
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Hi CT Jack. I am referring to the cast iron finish inside the cylindertop as you can see on this picture …
On each surface there is a round protrution …
 

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That little bump will not mean a thing on the scope of things. You certainly could file it flat if you wanted, or if it made you feel better.
 
Johan have you installed this head yet? I am curious what you think of it and if it is working well for you.
 
I just installed the Burtz 6.5 head, replacing a Snyders 5.5 head. There is an improvement in performance, maybe 10%. My test hill passed at 35 mph in third whereas before it was 32 mph.
 
smjacob said:
Johan have you installed this head yet? I am curious what you think of it and if it is working well for you.
Click to expand...

Yes. It runs fantastic. I had to make adjustments for my enlarged intake valves, though. I dremmeled off a portion of the chamber over the valve.
 
The purpose of that area is to provide a puff of air into the combustion chamber when the piston is at the top to increase turbulence and improve burning. Theoretically a smooth finish would allow the puff of air to blow out easier but in a practical sense it probably doesn't matter. It is more important to assure a clearance of 1/16 inch. You can measure that with some modeling clay. Account for the gasket compression when the nuts are torqued. To check for clearance, set the head on the block without a gasket and without nuts and turn the engine over. If the head moves you may need a thicker or two gaskets. Or machine the pockets. You only need two studs, one in back and one in front, when you set the head on the block to check for clearance.
 
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nkaminar said:
The purpose of that area is to provide a puff of air into the combustion chamber when the piston is at the top to increase turbulence and improve burning. Theoretically a smooth finish would allow the puff of air to blow out easier but in a practical sense it probably doesn't matter. It is more important to assure a clearance of 1/16 inch. You can measure that with some modeling clay. Account for the gasket compression when the nuts are torqued. To check for clearance, set the head on the block without a gasket and without nuts and turn the engine over. If the head moves you may need a thicker or two gaskets. Or machine the pockets. You only need two studs, one in back and one in front, when you set the head on the block to check for clearance.
Click to expand...

Thank you, nkaminar. It is on and running. I had to take something off the head to accommodate my 1.73" intake valves and IB330 cam. The dents where kept.
 
Hi everyone. I forund that the clearance for the "bump" was enough.
BUT I had to take some of the cast iron off the head to accommodate the lift of the IB330 cam and the large, 1.73# intake valve. I measured every valve clearance in the head by applying play-puddy in the head sand lower it onto the block with the studs in place - each intake valve at a time. It took a whole week. It has now been running for 6.000 kilometers and it is such a pleasure to drive.
One thing I noticed, though: It is running much cooler, even the exhaust is cooler.
Thank you for the inputs!
 

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This appears to have water holes like an early 28 or 29 style head. Ford later added an oval hole to the center area of head. So if this runs cooler they had it right the first time?
Any thoughts? :)
 
Flathead said:
This appears to have water holes like an early 28 or 29 style head. Ford later added an oval hole to the center area of head. So if this runs cooler they had it right the first time?
Any thoughts? :)
Click to expand...

It is deliberately designed to suck more water from the back of the engine. In my opinion it works.
 
A higher compression head will naturally run cooler because more of the energy in the fuel is converted to torque and less is left over for heating the engine. This in addition to any changes in the coolant flow.

Nice job in reworking the head for the valves. Your engine looks beautiful.
 
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