I am currently in the process of ordering parts to get my 1.7 heads rebuilt-
the 33mm exhaust valves need to be replace so I am going to replace with 34mm.
To go with the larger valves i need to get new valve seats and want to make sure i order the right size. Doing a search I can find 32mm, 35.5mm and 37.5mm and larger replacement seats - but it not clear if this is ID or OD of the -
Has anyone has done this on your heads? if so which is the correct size to order?
Thanks in advance for your input
You need a machinist with lots of air cooled experience
Dropped valve seats are a motor killer
And air cooled motors are good at dropping them
The expertise at this is significant
It’s also expensive
Sometimes cheaper to buy a better head
1.8/2.0 heads are out there
We have this done on race motors
The head work including flow porting is the most expensive part of a build
Other than exhaust valve size, are there any other differences between 1.7 and 1.8 heads? Port shapes or sizes? I'll be going down this path soon.
1.8 heads have a little more meat and much better for a 96 mm cylinders than 1.7 heads which are a bit thin
Plus the bigger valve sizes
You can buy new heads from AA Performance for what it will cost to rework your old heads.
Gents,
I greatly appreciate the input ! Looks like I will consider all options
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