fentin_fury Posted January 15, 2008 Share Posted January 15, 2008 Well i have started the rebuild of my BNR34. Not that it was necessary - just felt that I have been pushing the limit of the stock internals (430 rwhp). The stock long block has about 5-6000kms on it - so I don't expect any suprises. As part of this rebuild I am going to port the head. I have searched and been looking for pictures/comments/others' approach to this. I find little available - ie. sharpening the ridge between the intake ports, etc. I was wondering if anyone here has some detailed pictures of what they have done? Any info appreciated and as I move along I will post pictures here. Fyi the cams I am going to use are: TOM1421270102 Tomei Camshaft: Procam In 270-10.25Mm TOM1426270102 Tomei Camshaft: Procam EX 270-10.25MM Q Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted January 15, 2008 Share Posted January 15, 2008 I have no specific input on the head situation, but many will agree that you were not pushing the stock internals at 430rwhp That said, I know for a fact that there is a member or two here who have had RB heads ported. I would love to have a head done, but with my "modest" power goals I can spend money elsewhere. Evan Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 15, 2008 Share Posted January 15, 2008 http://forums.hybridz.org/showthread.php?t=119140&highlight=head+porting http://forums.hybridz.org/showthread.php?t=99737&highlight=head+porting http://forums.hybridz.org/showthread.php?t=100762&highlight=head+porting Spoon feeding has been completed. Quote Link to comment Share on other sites More sharing options...
fentin_fury Posted January 15, 2008 Author Share Posted January 15, 2008 http://forums.hybridz.org/showthread.php?t=119140&highlight=head+porting http://forums.hybridz.org/showthread.php?t=99737&highlight=head+porting http://forums.hybridz.org/showthread.php?t=100762&highlight=head+porting Spoon feeding has been completed. I new that existed here somewhere - thanks!!! my search was obviously wrong. q Quote Link to comment Share on other sites More sharing options...
Makenski Posted January 15, 2008 Share Posted January 15, 2008 A comment from matt: The intake is good, but the bowl needs to be smoothed out. The “lump” in the exhaust port has to go and the bowl needs to be smoothed. For a road race engine, half of the quench pad on the intake side of the chamber needs to be removed. For a drag engine, the whole pad needs to go. If not, you will get pocket detonation above 600hp. YOU WILLL NOT HEAR IT! But the pistons will burn on the intake side if this mod is not done. The only way around this is to use a 1mm gasket and custom low-dome pistons to lower the compression to make up for the thin gasket. You will also need extreme rods on the order of Pauter billets or titanium to keep the piston off the head at 9000 rpm. The RB is relatively inexpensive up to 600hp. This is a very high power level in a S30 or S31. The price increases exponentially above this line. Reliable 1000+hp RB’s can have $20,000 tied up in the head alone.[/font'] And another: Smooth the bowl and short-side radius' date=' knife edge the splitter, push the splitter back about 1 cm into a "V" in higher rpm engines. Exhaust side gets the "lump" removed and the bowl and short-side radius cleaned up. Knife edging the splitter in the exhaust port will give very small returns. Both ports can be manifold matched and the valve guide boss' gets smoothed into a "V". Remove the intake squish pad and chamfer the exhaust. These are the basic head mods that every tuner in Japan does. The pads in the combustion chamber are not quench pads designed for inert effects, like an OHV American V8. They are squish areas to promote chamber turbulance and a faster burn at lower engine speeds. Mid level engines have the intake side removed and the exhaust side chamfered. Full race engines have both pads removed (the Pulsar GTI-R SR20 chamber is like this from the factory). Removing the pad on the intake side has two effects, besides lowering compression, it unshrouds the intake valves for a substantial power increase and eliminates pocket detonation. Without this mod, you will burn the pistons on the intake side when getting near 600hp. You will not hear the detonation, but it's there. A knock meter won't pick it up in a 700 hp engine because mechanical noise is substantial.[/quote'] Quote Link to comment Share on other sites More sharing options...
fentin_fury Posted January 16, 2008 Author Share Posted January 16, 2008 I was wondering why the "quench pads" were removed. Matt has always offered very relavent information. q Quote Link to comment Share on other sites More sharing options...
1 fast z Posted January 16, 2008 Share Posted January 16, 2008 THis is all my opinion from years of head building, take it as you wish. You would never ever ever want to remove quench pads. The increased flow you would gain, you would loose that much more effieciency on the loss of the quench and swirl effect. Your engine will detonate more with pump gas also without those quench pads. The trick is to get your head to flow great numbers but dont increase those numbers while removing the pads. I left the pads on my ported head just for that reason. Quote Link to comment Share on other sites More sharing options...
Careless Posted January 16, 2008 Share Posted January 16, 2008 You would never ever ever want to remove quench pads. The increased flow you would gain, you would loose that much more effieciency on the loss of the quench and swirl effect. Your engine will detonate more with pump gas also without those quench pads. The trick is to get your head to flow great numbers but dont increase those numbers while removing the pads. I left the pads on my ported head just for that reason. In the case of the RB the reason why the quench pads are a hindrance is probably due to the sharp edge creating a heat pocket that could potentially start to form an ember and pre-ignite the mixture, and apparently it does little for swirl and shrouds the valves so much that it not only creates a flow issue, but i think the sharp angle that the air comes into the chamber at can also negate the effects of a high velocity port design when in boost, due to pressurized air being forced against a wall right near the intake valve. If you look at the Roller Wave pistons for RB's that endyn has made, you will see that they look like a baseball was welded to the top of the piston. You could probably get a compression ratio that is similar to theirs, but the sharp angles used to create the much higher dome on the pistons manufactured by other piston producers still does not interfere with the valves but would require higher octane gas because they also become a heated thin and sharp edge of aluminum, thereby creating a heat pocket that can also expand at a higher rate than the rest of the piston causing not only detonation, but material breakdown over time. expansion in the middle of the piston would probably cause the pin to warp or gall, or it would expand the crown to the point where the ring lands get very weak. I'm trying my best to figure out how I'm going to avoid this in my setup without losing 11.25:1 compression ratio. Quote Link to comment Share on other sites More sharing options...
Cal Poly Zmanaustin Posted January 16, 2008 Share Posted January 16, 2008 http://forums.hybridz.org/showthread.php?t=119140&highlight=head+porting http://forums.hybridz.org/showthread.php?t=99737&highlight=head+porting http://forums.hybridz.org/showthread.php?t=100762&highlight=head+porting Spoon feeding has been completed. Anybody got a towel? I think I just creamed myself. Wow that is gorgeous! Quote Link to comment Share on other sites More sharing options...
Careless Posted January 16, 2008 Share Posted January 16, 2008 Anybody got a towel? I think I just creamed myself. Wow that is gorgeous! yea i would post the piston too but it's not on their site, so i don't feel good about doin it Quote Link to comment Share on other sites More sharing options...
fentin_fury Posted February 21, 2008 Author Share Posted February 21, 2008 Porting begins... some pics more to go!!!!! Q Quote Link to comment Share on other sites More sharing options...
Careless Posted February 21, 2008 Share Posted February 21, 2008 Glad to see this, Q. Do you know someone who flow benches in Ontario for a good price? I'd like to document the flow numbers when my head arrives, as I'll be attempting my own head work. Is this Mike's work? Raff Quote Link to comment Share on other sites More sharing options...
Careless Posted February 21, 2008 Share Posted February 21, 2008 and don't forget to tell mike about the quench pad problem. you'll be making well over 600hp this time, so it will be a requirement if you want those pistons to stay in one piece maybe direct him to this thread or some of the ones on the board.... pdf and print them too? Looking forward to the finished product. Quote Link to comment Share on other sites More sharing options...
fentin_fury Posted February 22, 2008 Author Share Posted February 22, 2008 and don't forget to tell mike about the quench pad problem. you'll be making well over 600hp this time, so it will be a requirement if you want those pistons to stay in one piece maybe direct him to this thread or some of the ones on the board.... pdf and print them too? Looking forward to the finished product. Not Mike doing the head work - Tony. I don't believe we will remove the quench pads - but they will get radiused - no more sharp edges. Q Quote Link to comment Share on other sites More sharing options...
Careless Posted February 22, 2008 Share Posted February 22, 2008 Not Mike doing the head work - Tony. I don't believe we will remove the quench pads - but they will get radiused - no more sharp edges. Q i think we discussed this before as well. Larry @ Endyne said that might be a viable approach, and it should work. It would make sense to just radius them now. If it starts to detonate at high output, you would have to change the pistons you bought. step by step When she gettin all back together? And Paul @ Neetronics said your car gave him nightmares. Raff Quote Link to comment Share on other sites More sharing options...
stony Posted February 22, 2008 Share Posted February 22, 2008 http://www.theoldone.com/components/cylinderheads/skyline/ Quote Link to comment Share on other sites More sharing options...
fentin_fury Posted February 22, 2008 Author Share Posted February 22, 2008 Stony that is nice stuff. I think I will be ok with mine once it is done. Will post some more pics later on. Q Quote Link to comment Share on other sites More sharing options...
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