I need clarification on bore size...
Thread Starter
|
Advanced
Joined: Oct 2016
Posts: 64
Likes: 1
From: Reno
I need clarification on bore size...
I'm rebuilding a '83 FXWG. The Cylinders are Zodiac Enterprise "big bore."
I just dropped them off at a local (very reputable) machine shop for honing. I asked them to call me with the bore size when they had a chance to mic. He just called me back with 3.657". We had a short discussion on bore sizes. He assured me that "thirty over" means additional diameter, not cutting thickness. I always thought that it was the other way.
So... it sounds like I have 3-5/8" bored 0.030 over which is 3.625" plus 0.030" for a total diameter of 3.655". (allowing a couple thousandths for hone.
Is that correct? I was always under the impression that "thirty over" meant adding 0.060" to the bore.
I need to order my rings and I would like to have a little higher confidence level.
I just dropped them off at a local (very reputable) machine shop for honing. I asked them to call me with the bore size when they had a chance to mic. He just called me back with 3.657". We had a short discussion on bore sizes. He assured me that "thirty over" means additional diameter, not cutting thickness. I always thought that it was the other way.
So... it sounds like I have 3-5/8" bored 0.030 over which is 3.625" plus 0.030" for a total diameter of 3.655". (allowing a couple thousandths for hone.
Is that correct? I was always under the impression that "thirty over" meant adding 0.060" to the bore.
I need to order my rings and I would like to have a little higher confidence level.
Sponsor
Joined: Dec 2007
Posts: 12,084
Likes: 829
I'm rebuilding a '83 FXWG. The Cylinders are Zodiac Enterprise "big bore."
I just dropped them off at a local (very reputable) machine shop for honing. I asked them to call me with the bore size when they had a chance to mic. He just called me back with 3.657". We had a short discussion on bore sizes. He assured me that "thirty over" means additional diameter, not cutting thickness. I always thought that it was the other way.
So... it sounds like I have 3-5/8" bored 0.030 over which is 3.625" plus 0.030" for a total diameter of 3.655". (allowing a couple thousandths for hone.
Is that correct? I was always under the impression that "thirty over" meant adding 0.060" to the bore.
I need to order my rings and I would like to have a little higher confidence level.
I just dropped them off at a local (very reputable) machine shop for honing. I asked them to call me with the bore size when they had a chance to mic. He just called me back with 3.657". We had a short discussion on bore sizes. He assured me that "thirty over" means additional diameter, not cutting thickness. I always thought that it was the other way.
So... it sounds like I have 3-5/8" bored 0.030 over which is 3.625" plus 0.030" for a total diameter of 3.655". (allowing a couple thousandths for hone.
Is that correct? I was always under the impression that "thirty over" meant adding 0.060" to the bore.
I need to order my rings and I would like to have a little higher confidence level.
.030" oversize is what you have.
If .060" o/s, that would have you at 3.685".
Scott
Thread Starter
|
Advanced
Joined: Oct 2016
Posts: 64
Likes: 1
From: Reno
Thanks for the confirmation, guys. I've had several engines bored from a KZ-400 to big block V8's and everything between. I guess this is the first time that I've actually determined an existing bore to match rings for. I've had the same misconception the whole time.
Thread
Thread Starter
Forum
Replies
Last Post
GfromAlberta
VRSC Models
5
Jan 7, 2012 08:55 AM
