Starwriter Posted March 2, 2013 Report Share Posted March 2, 2013 All I got out of that was blah, blah, blah, I'm an idiot. Soooo... It's a Billy Bob home brew port job with cast pistons. You're going to go broke trying to save money. Ya gotta wonder, is the exhaust port too wide? Did they raise it too much for stock transfers? Did they chamfer the ports? Is the ring gap too tight because the piston to wall clearance is too tight? After blow up number 2 are you going to be wiser? Should I have frosted flakes for breakfast? Quote Link to comment Share on other sites More sharing options...
KozyHeat Posted March 2, 2013 Author Report Share Posted March 2, 2013 Exhaust ports can be too wide, I can make a port map and measure the width based off a percentage of the bore of the cylinder port timing can be calculated for the different ports using a degree wheel The ports are chamfered really well I like this persons who handled that part was skilled. Yes I understand the p2w clearance could be tight but it would be an easy fix. No, I'm not going to blow this up. Frosted flakes are awesome but contain a little too much sugar, try a small bowl and finish breakfast with something else. You know I measured the ring end gap because I wanted to figure out all these things. Come on, they will be fine. Let me get everything else within spec and give it a good chance. Do you go to your builder for advice? Well I talked to MY builder and he said he likes cast pistons more than the Wiseco forged pistons in this particular application. Do you want a picture of the porting or something? Just ask, I kinda thought you were trying to help. Quote Link to comment Share on other sites More sharing options...
KozyHeat Posted March 3, 2013 Author Report Share Posted March 3, 2013 Exhaust port roughly 52mm wide ( Curling paper inside the cylinder ) it measures at 62mm if you lay the paper flat. 26.2mm to the top 30mm tall transfers next to exhaust are both 12.5mm high and have those eyebrows on the bottom. placed 43.5mm from the top of the cylinder I didn't measure up the intakes yet... Does that help out starwriter? Quote Link to comment Share on other sites More sharing options...
KozyHeat Posted March 3, 2013 Author Report Share Posted March 3, 2013 I'm not completely ruling out forged pistons still, I would just rather not drop the money and wait for the boring process. If this crank I am waiting for is sick I probably will just break down and get some. Quote Link to comment Share on other sites More sharing options...
Starwriter Posted March 4, 2013 Report Share Posted March 4, 2013 I'm not trying to help you. I'm trying to enlighten you. Everyone else has given up trying to help you since you have ignored their advice and did things your way anyway. And now you're about to do it again. I can assure you no one here has used a bent file to match cases. And making a template is not the correct way either. You put the cylinder on the upper case half and scribe it from the bottom with a hook shaped scribe. I don't claim to know a lot about porting. That's what I pay Cameron to do. But, from what I understand, 70% of bore diameter is the maximum allowable width for an exhaust port. You're at about 81%. Good luck with that. As far as port heights, it looks like they raised the exhaust 4mm without touching the transfers. Typical Billy Bob work. Pay a builder to do your port work, boring, and crank work. After that it's just assembly, leakdown, and tuning. Quote Link to comment Share on other sites More sharing options...
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