Port and Polish

dipapadakis

dipapadakis

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Joined
Jan 20, 2011
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I spoke with a very old machinist at a diesel specific engine building/machine shop and asked him about porting and polishing my 12v head. he said no. he said they can port and polish it down to the dime but, on a turboed engine it wont make a difference. he said either way you have no flow, just pressure if you get a "flow meter" in there it wont make a difference. he completely despised the idea of p&p it and told me i wouldnt notice any difference yet i hear of a few people p&ping theyre heads any one deal with this? anyone notice any differences after p&p? is it worth it? thanks
 
You can build all the psi you want but the small port will only let so much through into the cylinder in the time the valve is opened and a ported head will flow more volume with less psi faster.
 
The port job to me is only as good as the size of valves you have and the valve job to go with it. I agree on these being turbod and when you have pressure in excess the the valve is the limiting factor. Now cam choice can make the valve stay open longer so there are variables but the valve is still the bottle neck.

That being said I don't deal with that stuff so mine is ported and polished
 
ya thats basically what i said he said it wont make but a **** hairs difference... i didnt really believe him but with that said im not sure if he has delt with trucks hot enough to ever effect it so in his eyes it probably didnt... did you guys notice a difference when porting and polishing?
 
Yes there is a difference. A good valve job is a huge difference. P&P is too. Whats the point of having a big charger if you can't use the air its capable of pushing. My ported head over stock on the same charger was night and day difference. It got a 5 angle comp valve job, its been ported as much as possible without cutting off the intake, some bigger valves, upgraded springs, locks, retainers. So far the head work done was the best bang for my buck when it comes to performance. I can see in the near future going a little farther and doing away with the intake. Put a stock head and a ported head on a bench and let the numbers speak for themselves.
 
Don't have him do any of your work lol, and the dual feed is on its way.
 
awesome! thanks guys this will definitely be my next step again and about how much does a 5 angle valve grind, bigger valves and a p&p cost so i know about how much im looking at here in the near future, thanks again comp-d
 
The way I see it, pressure is created by resistance to flow. So if you reduce resistance and run the same pressure you'll have more flow, which means more air. But I may be over simplifying it.
 
I can agree on polishing. Why bother? But more volume and less resistance does tend to shrink a charger.
 
Snedge said:
I can agree on polishing. Why bother? But more volume and less resistance does tend to shrink a charger.
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This. Nearly every dyno in the summer, guys would be crying about their chargers not lighting. My 66/480 would get up on them pretty quick still, never once had them not light.
 
dipapadakis said:
awesome! thanks guys this will definitely be my next step again and about how much does a 5 angle valve grind, bigger valves and a p&p cost so i know about how much im looking at here in the near future, thanks again comp-d
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I can't remember exact prices off the top of my head but I think I payed somewhere around $600 dollars for valves, springs, retainers, locks. And for the P&P, 5 angle valve job, it got cut for fire rings too, Exhaust was gasket matched and everuthing assembled I wanna say it was around $900. They even sprayed some paint on it.
 
whoever told you that porting doesn't make a difference? i definitely wouldn't let him touch any part of my motor because he is wrong. next time you see him ask him "if porting doesn't make a difference....then why can't you just shrink the port". see what he says then. id be very curious to hear his answer:hehe:
 
lenahan05 said:
whoever told you that porting doesn't make a difference? i definitely wouldn't let him touch any part of my motor because he is wrong. next time you see him ask him "if porting doesn't make a difference....then why can't you just shrink the port". see what he says then. id be very curious to hear his answer:hehe:
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Mo powa yo! Air velocity is faster!

Posted via Velocity LG ALLY
 
oldestof11 said:
Mo powa yo! Air velocity is faster!

Posted via Velocity LG ALLY[/QUOTE

is air velocity that important to you? then why couldnt you just run a port with a quarter inch hole with an 1.870'' intake valve? how well do you think that motor would run? :bang:hehe:
Click to expand...
 
I think your sarcasm detector has malfunctioned. LOL

Posted via Velocity LG ALLY
 
I think lenahan may be a little low on sleep:kick:
Why not do away with valves and a charger and just run on onboard compressor. Call it air injection...
 
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