Hello all what is the max I can bore out a 1725 block that will have 12:1 compression ? I have a block that is 030 over but needs to go to 050 to clean up ,did anyone ever sonic test the cylinders to see the thickness ? this will be strictly a race motor . Does any one have a std bore 1725 block in the MA area ?
-
Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.
If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.
Enjoy.
1725 over bore
- Thread starter Jake048
- Start date
My engine was bored 60 over without difficulty, although I don't drive it nearly as hard as a race engine. If you are building a race engine, you might find the article Jan Servaties wrote on the "Tedder" engine helpful. It can be found on our homepage. https://sunbeamalpine.org/wp-content/uploads/2017/10/issue_14.pdf
That is a new one on me. Can you tell us more about your engine?
spmdr
Diamond Level Sponsor
Jim, Here is a refresher:
DW
DW
alpine_64
Donation Time
As mentioned +.060 is no issue, the factory offered overbores up to this, Jahns pistons from Cali used to sell cast popup 12:1 +.060 pistons back in the day.
Once you go beyond +.060 you will start to look into custom head gaskets.
As dan mentioned 12:1 starts to cause issues with head gaskets . You really would want to have welded up the water crescents on the head and then a custom gasket with 2 holes rather than the cresent shape so the bridge area between chamber and water passage doesn't blow .
There were motors being done down under in the late 90s early 2000a that were +.110 over but they ran custom gaskets and the heads opened up to bring compression to manageable levels.
Once you go beyond +.060 you will start to look into custom head gaskets.
As dan mentioned 12:1 starts to cause issues with head gaskets . You really would want to have welded up the water crescents on the head and then a custom gasket with 2 holes rather than the cresent shape so the bridge area between chamber and water passage doesn't blow .
There were motors being done down under in the late 90s early 2000a that were +.110 over but they ran custom gaskets and the heads opened up to bring compression to manageable levels.
jdoclogan
Platinum Level Sponsor
alpine_64
Donation Time
While it's good to know the wall thickness... The other very relevant information. That the shop didnt put on the sheet is the current bore... Is it std, .010... .060...
alpine_64
Donation Time
Same bore and bore centres. So should be the same