So i pulled my engine out so i could regasket it. Pulled off the oil pan and immediately saw a horrendous scar that is about an eighth inch wide and at least a couple thousandths deep. The scar looks almost perfectly symmetrical and it Tappers to a point at the bottom of the cylinder, almost looks machined in there. I will get some pics of it tomorrow at work oh and it is in cylinder 3. If it is machined, why would someone put it there? And how was my engine not smoking or running rough?

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73 Dart custom. Stock.

for now....

Get it to a machine shop. Cylinder taper and a bad ring at the gap probably is responsible for The damage. Time for a rebuild, with oversize pistons.

CJ

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Part of Tyrde-Browne Racing

Haha its already been rebuilt with oversize pistons. Will know exactly what size pistons are in it when i get them out tomorrow. How much can i over bore safely?

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73 Dart custom. Stock.

for now....

Safe overbore for most engines limit around 0.100" though there are some with enough core shift to make it unwise. There are options at .060" and .080", though ring availability can be a problem these days. Not insurmountable, but they don't keep them on the shelves many places.

All depends on what you are building. If your building a stocker for driving, then you may have to order parts through your machine shop.

Other options, K-1 rods and pistons. High compression, and the right way to go if your building street/strip or an all out racing engine. Available in .080 and .100 over-sizes from Wiseco. Not for regular pump gas builds.

There have been over-bores greater than 0.100", but you must check to make sure the cylinder bores can support anything beyond that point.
The cylinder walls are getting pretty thin, so core shift can result in failures.

CJ

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Part of Tyrde-Browne Racing

Basic plan for my engine was to build something reliable that had enough power to play when i wanted to. Will post up some measurements as i get time this week

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73 Dart custom. Stock.

for now....

So all 6 measure in at 3.432 give or take a thousandth in tolerances. So that would make my block already 30 over?

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73 Dart custom. Stock.

for now....

Yep. The next size up is .040, you may want to see if rings are available in that size as I had to wait 2-3 weeks to get a set as none were in stock from store's suppliers or rockauto (they had to be drop shipped from Fed Mog, oddly they could get .040 piston sets and singles the next day).

The next up from that is .060, unless you build a long rod motor then you will be between the .040 and .060 sizes.

-D.Idiot

What would be the downside of using the current 225 rods it has if i had to go bigger than .060? I'm not to worried bout a little wait time for parts as i still have a bunch of research and build matrixes to do

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73 Dart custom. Stock.

for now....