Yesssss more 4 valve content please!!

@servediocylinderheads

24 күн бұрын

@@alejandro52612 It is the worst!

Cool. Interesting project. Want to check back for feedback from customer.

Thank you Charles love seeing this stuff i got a 5mge head to do up sometime its 2 vale off 1985 supra 2.8l inline six

Very interested in this. I have a scooter i built, and 4valve heads sre available. I got about 35cc from a big bore. And a high compression piston, ported two valve , (with oversize valves). head, with a cam and carb. With exhaust. But its still not enough, it needs more compression . And more cam its seen 10200 rpm but was useless spinning that fast. I think it actually lost power up there. Around 9300-9500 is peak id love to get a cam ground change the timing around a bit. And get a small lift gain. And some duration peak power is 7500-8500 stock, move that up to 9250-10k should get some gains, but double the displacement will gain more! Have a awesome day!

@servediocylinderheads

24 күн бұрын

@@jamest.5001 Cool!

Leave springs out. Use your TDC bridge with a magnet between valve and bolt. Tymco...Chinese terrain vehicles. Remember how the clutches work with these. They pin them at high rpm and wait for the rest to catch up. It's all about the high speed side. Have fun with this one Charles. Very small changes makes a big difference.

@servediocylinderheads

24 күн бұрын

@@approachingtarget.4503 Cool, thanks

thanks

@servediocylinderheads

24 күн бұрын

@@RussellCompton-fh3gr You are welcome.

That head needs welding and cutting to fix that exhaust outlet. It would help alot with it straight and a cnc head pipe adapter. With long sweeping turn!

@servediocylinderheads

24 күн бұрын

@@jamest.5001 No doubt!

That sharp corner @4:00 in the exhaust port makes me wonder about its affect on reversion. Air speeds across the port might tell alot. Just me thinking. I am definitely not an expert. Very interesting.

You think that is tiny try porting quad transfers in a 25cc two stroke. I have a dental tool attachment for a foredom

@servediocylinderheads

24 күн бұрын

@@Super-Dave-Outdoors No thanks!!!!

Cool little project. Id definitely need my readers to work on that! When you say high rpm don't like back cuts, how high should you not?

@servediocylinderheads

23 күн бұрын

Depends on application. My rule of thumb was 7000 +

You can go to Ace hardware and find springs for checking. Have you seen Bryce Star videos? He is the motorcycle race man. What engine is that?

@servediocylinderheads

24 күн бұрын

@@dondotterer24 I talk about the engine in the second video. Thanks

@mandapalque

23 күн бұрын

It is a yamaha zuma 125 bored to 67mm piston and a +10.2mm cranckshaft = 240cc

4 valves create tumble. you'd do well to increase air speed to the back of the valve. How much can you do when you can't get your pinky finger in there? :)

@servediocylinderheads

24 күн бұрын

@@chrisstavro4698 Stay tuned...

Tiny valves but what is the comparison of valve curtain areas between a typical SBC valve and these?

@servediocylinderheads

24 күн бұрын

@@Mr34blazer Lots to the cc displacement.

Swirl doesn't work too well on a 4 valve pent roof, or rather doesn't bring any substantial benefits. 4 valve pent roof likes tumble more than swirl. To make swirl and poly-quad work on a pent roof, the valve angle needs to be very narrow, nearly vertical, like a diesel. You also need a special spark plug that looks like a non-fouler. Instead of having a hole in the center, it's a cap with holes drilled around it. The swirling action creates a low pressure core that pulls fuel and air to the center, and the holes on the cap over the spark plug shoot out like a jet and ignite the fuel very quickly. The ignition is so fast that you can run much tighter timing advance.

@servediocylinderheads

24 күн бұрын

@@rolandotillit2867 I disagree and so does D.V. his poly quad design introduces swirl to a tumble design and makes better power.

@rolandotillit2867

24 күн бұрын

@@servediocylinderheads I didn't say it doesn't work, I said to get the best out of it requires a different approach to the whole combustion process. The chamber, ports, spark plug, and fuel injection have to change to accommodate it.

@oldblueaccord2629

24 күн бұрын

Sounds like you need to stick to sim rolando....

@rolandotillit2867

24 күн бұрын

@@oldblueaccord2629 How does introducing swirl to tumble create more power? How do you get more power if you're not increasing the amount of fuel or air? The only thing you can do is increase the combustion speed, which means the only benefit comes from less timing advance at higher rpm, and running higher compression ratio.

@oldblueaccord2629

24 күн бұрын

@@rolandotillit2867 Thats not what Endyne found on Honda heads....you do much Pro stock work like they used to do?

What is the bore size Charlie?

@servediocylinderheads

24 күн бұрын

@@theshed8802 Tiny, he told me but it was forgotten. Sorry

@mandapalque

23 күн бұрын

67mm

What is a "quick lab"?

@servediocylinderheads

24 күн бұрын

@@mandapalque Lap

@mandapalque

24 күн бұрын

@servediocylinderheads and what is a LAP? I am going to Google it in the cylinder head world. I have 0%knowledge on cylinder head porting. I have watched some of the DAVID VIZARD videos, but it's hard to me ton understand.

@servediocylinderheads

24 күн бұрын

@@mandapalque lap is to seat the valve on the seat using lapping compound to see the interface.