BRENT in 10-uh-C
Well-known member
Re: SnyderÂ’s 6:1 head
I also get the part where you are "over it" but as an engine machinist speaking here, I will tell you that if the gasket is blowing in different spots, it is my opinion that the issue is NOT with the head. If the head has an issue where it is unlevel in a certain area, it will repeatedly fail in the same location. The same can be said with cylinder block's deck. Based on your responses above, it is my opinion that the issue is with the head gasket installation. If I could inspect the gasket, the fasteners, and the block, I could likely pinpoint it even further as to the culprit.
Now the next issue you have is really not the manufacturers fault however they will likely get the blame. As soon as the installed cylinder head came up to operating temperature a couple of times, the cast iron will move by nature as it "seasons". If you check it after that heat cycle time you will almost always find it will be unlevel. Ford's O.E. heads did/do the same thing until they have seasoned and new engine components also do the same.
Adding to the above, most modern machine shops do not have a good way to support a Model-A cylinder head to resurface it. I have shown this to people in my own shop where if a Model-A cylinder head is supported on a surfacer with 3 stands and checked with an indicator, it will show one measurement however to anchor the head to keep it stationary on the resurfacer, the head is generally anchored to the table with a bolt down thru a couple of spark plug holes. When the head is tightened enough to anchor it securely, it generally deflects the head anywhere from 0.005"-0.010 in the center. That is why you typically hear of heads being distorted right out of the box.
A Model-A head is that flimsy by its design which is why the tightening process is to be performed radially and in graduated fastener tightening increments. This is another reason why clean and lubed fastener threads are important, and another area where hobbyist mechanics tend to miss the mark. At minimum you need to have your present cylinder head checked by someone who has experience and knowledge on how to correctly resurface a Model-A head. I would expect that it will be 'warped' simply because it has been heat cycled.
And finally, about the ONLY way you can accurately check a cylinder block for a level deck is with a Machinist's Straight Edge or a long Machinist's Level. The minimum length is 18" and the edge must be precision ground. Most hobbyists do not have that level of equipment to check or verify the deck surface and so their readings are false.
I also get the part where you are "over it" but as an engine machinist speaking here, I will tell you that if the gasket is blowing in different spots, it is my opinion that the issue is NOT with the head. If the head has an issue where it is unlevel in a certain area, it will repeatedly fail in the same location. The same can be said with cylinder block's deck. Based on your responses above, it is my opinion that the issue is with the head gasket installation. If I could inspect the gasket, the fasteners, and the block, I could likely pinpoint it even further as to the culprit.
Now the next issue you have is really not the manufacturers fault however they will likely get the blame. As soon as the installed cylinder head came up to operating temperature a couple of times, the cast iron will move by nature as it "seasons". If you check it after that heat cycle time you will almost always find it will be unlevel. Ford's O.E. heads did/do the same thing until they have seasoned and new engine components also do the same.
Adding to the above, most modern machine shops do not have a good way to support a Model-A cylinder head to resurface it. I have shown this to people in my own shop where if a Model-A cylinder head is supported on a surfacer with 3 stands and checked with an indicator, it will show one measurement however to anchor the head to keep it stationary on the resurfacer, the head is generally anchored to the table with a bolt down thru a couple of spark plug holes. When the head is tightened enough to anchor it securely, it generally deflects the head anywhere from 0.005"-0.010 in the center. That is why you typically hear of heads being distorted right out of the box.
A Model-A head is that flimsy by its design which is why the tightening process is to be performed radially and in graduated fastener tightening increments. This is another reason why clean and lubed fastener threads are important, and another area where hobbyist mechanics tend to miss the mark. At minimum you need to have your present cylinder head checked by someone who has experience and knowledge on how to correctly resurface a Model-A head. I would expect that it will be 'warped' simply because it has been heat cycled.
And finally, about the ONLY way you can accurately check a cylinder block for a level deck is with a Machinist's Straight Edge or a long Machinist's Level. The minimum length is 18" and the edge must be precision ground. Most hobbyists do not have that level of equipment to check or verify the deck surface and so their readings are false.
