GAZ intake valve

[lsr490]

Question for the masses.
Has anyone had any experience putting a set of larger intake valves in a GAZ block?
Thanks

[Jim Brierley]

Not me, but if you look down into the water jacket you may be able to determine the thickness of the iron around the port. IMO, big valves help very little on a mild engine, and are not necessary unless building a hi-performance engine.

[lsr490]

Jim,
This is the situation I find myself in. Two weeks ago I sent my block off to Rich at Antique Engine Restoration for inserts. He informed me that the GAZ block weighed approximately 35 lbs more than a "B", but was uncertain where the water passages are and did not feel comfortable taking the intake to 1.7". Two weeks ago I was fine with that.
Yesterday I got my newly cast "B" head from Tod Buttermore and the compression ratio turns out to be 7:1, now i really would like to go to 1.7" intake.
Bill

[Synchro909]

Even with an ordinary A block, I thought 1.700" was too much so I put the valves in the lathe and took them down to 1.600". I thought that was a reasonable compromise and the motor goes well enough for me.

[Jim Brierley]

lsr490, Big valves may not be worth the trouble, I've run mostly stock size valves for many years, and done well with them on hill climbs, etc. Having said that, the heavier block indicates to me that you should have no problems with 1.7". Blocks are thick at the top surface, putting valves in using a 70 degree cutter means not so much is taken out of the port.

[katy]

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the GAZ block weighed approximately 35 lbs more than a "B"

I can believe that. When I worked in Siberia, (early 90's) I was told that the reason the diesel engines in the Kamaz trucks were fairly quiet was because the engine castings were much more robust (thicker/heavier) than North American engines.
M2M may know more about this.

[lsr490]

Originally Posted by Jim Brierley

lsr490, Big valves may not be worth the trouble

Fair enough, I was just double checking to make sure I didn't miss an opportunity that was right in front of me. Anyone who knows me knows that I say this all the time " I only have enough money to do this once, and I'm going to do right".
Thanks again


ps. Jim I just put your book down to respond to this, as I told you the other day I read and reread all the time, I really enjoy it. Thanks, Bill