Boring question?

[AzCoupe]

I've been looking into pistons and was wondering which sizes to stock. I'm sure most of us have our blocks bored during the rebuild process, but which size is the most common? For the time being, I will probably stock just one size, maybe two, but will offer the other sizes as a special order (two weeks out).

 

[Falcon62]

Are you wanting to know what we have or what we'd prefer? My 200 is .060 over but I'd prefer it to be .030 or less.

 

[wsa111]

mike i voted .040 over, my second choice would be .030 over. the cubic inches gained by a larger over bore are miniscule. just my past experience don't too large , just in case of a core shift. v/r william

 

[AzCoupe]

Are you wanting to know what we have or what we'd prefer?

Well......... Both I guess.

I've always heard that it is preferable to bore the cylinders the least amount possible, leaving meat for the next rebuild. The exception is a guy that doesn't care, as he is going for as much displacement as possible. I know a lot of guys would prefer the smaller, but with the age of our motors and the likelyhood of previous rebuilds, larger may be the norm. So both answers would be correct in this case.

I'm not real familiar with the poll option, can you vote twice?

 

[DaGr8Tim]

I'm not real familiar with the poll option, can you vote twice?

Nope, one shot and your done.

I voted for 20 over because if you stock flat top. I would be highly intrested if you offered some form of coated one.

 

[Anonymous]

I'd go with .030 or .040 over myself!

These engines are old enough that a lot of times they have allready been bored once or they have so much wear that they need more than the usual clean up overbore (.020) because they run so long without rebuilds

Later,

Doug

 

[CobraSix]

I agree...30 and 40 over will probably be a good idea. Gives people a margin. If I have a standard bore and doing a rebuild in a 200k mile block, probably would go 30 over, if I have a standard 20 over bore, maybe 30 or 40 over for the next set.

I think 30 is a good one to stock up on, and 40 to a lesser degree.

Slade

 

[Falcon62]

The exception is a guy that doesn't care, as he is going for as much displacement as possible. I know a lot of guys would prefer the smaller, but with the age of our motors and the likelyhood of previous rebuilds, larger may be the norm.

In that case, I'd say .030 & .060. For the guy who doesn't care, those 6 extra cubes won't amount to a hill of beans in performance, but will greatly increase the likelihood of cooling problems and possible core shift. :roll: However, I agree with you, and others, that most of our engines have already seen an overbore or two, so if we're to resurrect them we've got to go bigger, and in many cases that's .040 - .060.

I'm not real familiar with the poll option, can you vote twice?

Nope, only once just like the real thing.

 

[xctasy]

Your gonna hate me for this, because it indicates a sea change for me!

1.I've gone off big overbores since posts from other engine builders here. I have gone to 56 thou over, and I'm not certain that its a good long term move. Lets face it, a hot six cylinder engine is an asset. The thrust faces go down to 120 thou or so with a 60 thou overbore, and about 150 thou stock. The ideal for an 11:1 comp engine is 180 thou or so.

2.My recomendation is the least amount you need to get the bores true. If you can get away with 20 or 30 thou, then do it!

3. I'm looking at sleeving now. A set of Falcon XR6 Turbo size pistons are 3.632", 1.163" tall compression height, and with a 24 thou over bore, your 3.68" bore I6 could drop a 65 thou wall thickness liner like one of these * for small money, and I'd last the next 50 years of 20 thou over bores with each 15 years of balls out motoring!

This is an example of proprierty liners. Most Americans would never put six liners in an engine, but overseas, its done lots where good core units are harder to find.

* Shriram #2266, Dry liner, Semi finished. A 65 thou wall thickness liner which can be machined to take modern trim deck pistons!

http://www.shriramindia.com/prorange_ford.htm

eg. Pinto 2000
Capri 2000
Cortina 2000
Escorts Rs. 2000,
Taunus 2000,
Consul 2000 OHC

3.5748"
90.800mm
3.7045"
94.094mm

 

[Asa]

it is preferable to bore the cylinders the least amount possible, leaving meat for the next rebuild.

that's what i learned, that's what i'll be doing when i get around to rebuilding mine

 

[rbohm]

8) i have mixed feelings about this. .030" over is the industry standard when overboring, but .020 is better. though as stated, these engines get a lot of miles on them, but not as good maintenance as they should, thus .040 is also a good overbore size. since you plan on stocking one and maybe two, i would say stock .030 first, then .040. these i think are going to be your most common sellers.

 

[AzCoupe]

I guess I could stock three sizes, but in smaller quantities.
Judging from the poll, if I ordered thrity sets, it would look like this: 6 @ .020, 18 @ .030, and 6 @ .040.

And, if I get forged pistons manufactured, I'll go with .030 over, for now.

Thanks for the input guys.

 

[Anonymous]

I think 30 is a good one to stock up on, and 40 to a lesser degree.

Slade

I'm with you guys. My 200 is .040 over because that is just how much it took to clean it up but .030 would be a great size to stock. I am voting .040 though because I need some good pistons!

Dan