Piston and Crank Questions

[HolySheet]

Ok so after all my spark issues and putting my turd back together, I had 100psi in each cylinder. So I went to work pulling it apart and was wondering if these numbers mean anything to you gurus'. Pistons are #9439 67.92mm. Rods say WSM 45-520. Are there any bore size issues or is this a weird rod number? In advance, thanks guys.

[Pastrykiller]

Sounds like a stock length rod and Vito's pistons

[HolySheet]

Is that the biggest I can go without sleeving?

[Pastrykiller]

From my understanding 68 is the max. You are at the end of the line with these cylinders. If they are ported, they will have to be redone when you re sleeve due to port durations.

[HolySheet]

http://m.facebook.com/photo.php?fbid=10200543499698415&set=a.2247751481717.136688.1486090903&type=1&relevant_count=1&ref=nf&refsrc=http%3A%2F%2Fupload.facebook.com%2Fhome.php&_rdr

[HolySheet]

Is this cylinder ported?...

[Pastrykiller]

 

http://m.facebook.com/photo.php?fbid=10200543499698415&set=a.2247751481717.136688.1486090903&type=1&relevant_count=1&ref=nf&refsrc=http%3A%2F%2Fupload.facebook.com%2Fhome.php&_rdr

Link doesn't work. Use photobucket

[HolySheet]

http://m1188.photobucket.com/albumview/albums/BUstedZJ/D2DE847A-C14F-4B0C-83F2-59C90B2AA003-71224-000046924B04C474.jpg.html?o=0

 

http://m1188.photobucket.com/albumview/albums/BUstedZJ/5CCC7316-D845-4B7D-B5C9-8CE85D067DBA-71224-000046923BE25C28.jpg.html?o=1

[Pastrykiller]

Those have been ported but can't tell u how much because you have to measure the durations. There is a knife edge present but that all we can see.

[HolySheet]

How do I measure the duration, the bottom ports are worked over as well. Just trying to figure out what the person was going for when they did it.

[Pastrykiller]

Those are called transfers. The port duration is established by raising and lowering the intake and exhaust ports. Search the forum and I'm 100% positive that you will find exactly how to measure. Best thing to do in my opinion is to ship it to a sponsor who can look it over to make sure you can actually use them with your setup.

[HolySheet]

I ran it all last year, ran good. I would have expected more out of it though. Must be a shitty port job, or I'm just crazy.

[Pastrykiller]

Not gonna critique the work because I've seen work that looks like shit run like a champ. Call a site sponsor and see if they will help you with determining the best setup for what u got. You could be giving up a lot of power with the wrong setup.

[HolySheet]

Good idea. Thanks a lot.

[HolySheet]

Made a couple calls, took some measurements, and found that it is aggressive trail ported. The first site sponsor I called was assloads more helpful then the second one. I gave the first guy just the numbers and he told me how it should run, and he was spot on. Was very happy finding out its not a mathematical disaster.