furrybarry Posted June 19, 2010 Share Posted June 19, 2010 I have a laptop, die grinder and an N42 head sitting in front of me. Anyone got any first hand experience at not buggering up the porting on one of these? What are the areas to be careful of and where can I let rip without too much danger? Cheers, As an aside, what are the biggest valves you've successfully fitted into your head? Quote Link to comment Share on other sites More sharing options...
Scoota G Posted June 19, 2010 Share Posted June 19, 2010 I did a similar thing to my N42 head, spent a lot of time (12 hrs) on the extractors too which were a terrible fit. Also i have a fully ported head which is still at the shop. De-shrouding the valve stems is a good start as you can take off a lot of metal there without going anywhere near the water jackets (which is why the other head is still in the shop) if you can wait a week i can get some good pictures of the other head. Just bear in mind that if you hit a water jacket it will cost a bit to fix. Mine cost $150 to get fixed but i bought i like that. Good part was the repair comes with a warranty. Quote Link to comment Share on other sites More sharing options...
C.A.R. Posted June 19, 2010 Share Posted June 19, 2010 Quote Link to comment Share on other sites More sharing options...
Scoota G Posted June 19, 2010 Share Posted June 19, 2010 Hhahahahaaa Good one. I think best bet is to get a junk head and practice on that. It's an art though and unless you keen and know what your doing. I didn't know but i could tell the difference after, but still i can't wait to get the Proper head on. Quote Link to comment Share on other sites More sharing options...
furrybarry Posted June 19, 2010 Author Share Posted June 19, 2010 Excellent, thanks Scoota, I'll hold off on opening it right out. My chassis is actually in Avoca while the various engine bits are here Melbourne where I work. If you can get photos I'd appreciate it greatly, or even better drop in on my way through to Avoca if you have a spare 1/2 hour one weekend. Sacrifices to the gods of speed must be made Lurch. Quote Link to comment Share on other sites More sharing options...
Scoota G Posted June 19, 2010 Share Posted June 19, 2010 Yes he should, i was thinking of making a cast of the ports in the other head... maybe that would help if i could get stock port and do the same Like i'm thinking clay or something. Anyone got some idaes? Quote Link to comment Share on other sites More sharing options...
furrybarry Posted June 19, 2010 Author Share Posted June 19, 2010 I just happen to have some modelling clay in the shed. I'll go give it a try. Quote Link to comment Share on other sites More sharing options...
RB30X Posted June 19, 2010 Share Posted June 19, 2010 Don't use a steel bit in your grinder, use flap disc wheels with the 6mm shank. They take meat off smoothly and flow with the existing port wall. Spray crc on it as you do it to keep it lubed. Measure the ports on your inlet and exhaust manifold and mark that size on your head, and port to that diameter. Quote Link to comment Share on other sites More sharing options...
furrybarry Posted June 19, 2010 Author Share Posted June 19, 2010 Cheers RBx, the carbide bits are far too scary at 25000rpm on aluminium for sure. I tried to get a good impression of a stock port with the clay Scoota. Not really sucessful. I'll try it with glad wrap and some expanding foam tomorrow. Quote Link to comment Share on other sites More sharing options...
Scoota G Posted June 19, 2010 Share Posted June 19, 2010 Just if i could get a mould off the head that was ported properly i could send/ give it to you and you could use it like a template. . . . . Cue Lurch's post with the popcorn munching MJ. (i did go see him in concert when he was here in 1998. Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 19, 2010 Share Posted June 19, 2010 I actually had some cutaways of the intake and exaust ports made up... I've got some photos somewhere but cant get to them for at least a week and half 'cause im overseas atm , I found them to be extremly useful though... the greatest "danger point" is in raising the roof of the port near the intake face... annoyingly I feel this is also probably where some of the greatest gains could be made. Practice on junk, Use a new condition head for the "real thing" as a corroded water jacket will waste hours of work and port first then decide if your mistakes are worth fixing or starting again before getting refacing+/- welding paid for. I think anything over 40mm total port raised from the roof is getting so thin you are looking at probable welding money. (anything and everything i say is purely opinion, conjecture or rumor) Prost! -pete Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 19, 2010 Share Posted June 19, 2010 Also, I used a tungsten carbide cutting tool but you need a steady hand... smooth finish can be achieved with a flapper wheel after but the carbide wheel is pretty smooth anyway if used correctly.. plus you dont have to change it every 5 minutes. cheers +1 -poit Quote Link to comment Share on other sites More sharing options...
furrybarry Posted June 20, 2010 Author Share Posted June 20, 2010 That would be absolutely invaluable, thanks Kolonel. I had a bit of a practice with the double cut carbide bit today rather than the single cut bit. It's a lot more controllable and a smoother finish to boot. I talked to a girl last night at a rapidly deteriorating socceroos party and she suggested taking a cast of the ports using silicone with vaseline as a release agent. I didn't realise it might have been her pick up line until just now. Quote Link to comment Share on other sites More sharing options...
RB30X Posted June 20, 2010 Share Posted June 20, 2010 Classic, you missed out mate. Quote Link to comment Share on other sites More sharing options...
Scoota G Posted June 20, 2010 Share Posted June 20, 2010 Silicone, Vasaline? Sounds like she bats for the same side or makes those custom earpieces for people. Quote Link to comment Share on other sites More sharing options...
DatPilot Posted June 21, 2010 Share Posted June 21, 2010 Why would you be speaking to a girl about DIY head work in your garage?.... oh i see! Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 22, 2010 Share Posted June 22, 2010 I remember I had one of them on photobucket from a while ago... I'd probably be happy to lend these to anyone who wants to pick them up from my place in sydney with some kind of assurance of return. I have all the intake and exausts on an e88 mould but this is the only photos I have untill i get home to oz. Cheers, -pete Quote Link to comment Share on other sites More sharing options...
. Posted June 22, 2010 Share Posted June 22, 2010 I love that photo. Kinda reminds me of those people that slice dead things into 100 slices....remind me to keep my dog away from you Seriously though it really illustrates the safe areas for working. Quote Link to comment Share on other sites More sharing options...
1600dave Posted June 22, 2010 Share Posted June 22, 2010 I love that photo. Kinda reminds me of those people that slice dead things into 100 slices.... Like the one below ? When porting mine (a 4 cylinder one), I used carbide cutters initially then finished it off with a flapper wheel. With the carbide cutters, I found that cutters with an "open" patern on the cutting blades didn't clog up as much as another cutter that had a "cross-hatch" finer pattern. I tried to take a little out of one port then replicate that on the rest of the ports, rather than finishing one port completely before tackling the next. Made it easier to keep the ports uniform. Once I got closer to finishing, I used a pair of inside calipers to compare port sizes at regular intervals down the port to finish them off. I was reconditioning the head so I knocked all the guides out before doing the porting. I removed the guide bosses in the ports completely, and shortened the guides themselves by 5-10mm. Its a race car, I don't know if I'd go to this extent on a road car due to worries about it not lasting as well - would probably be OK though. I have no idea on what performance gains I achieved with the porting as the engine was completely rebuild with different pistons and cam as well as increased porting. Here's my "practice" head, all done with a hacksaw Quote Link to comment Share on other sites More sharing options...
Zeddophile Posted June 22, 2010 Share Posted June 22, 2010 When porting mine (a 4 cylinder one), I used carbide cutters initially then finished it off with a flapper wheel. With the carbide cutters, I found that cutters with an "open" patern on the cutting blades didn't clog up as much as another cutter that had a "cross-hatch" finer pattern. ..... Here's my "practice" head, all done with a hacksaw Thats exactly what those carbide burrs with big scary looking teeth are for - aluminium! And for exactly the reason you mention - the smaller teeth burrs (which also have many more teeth) clog up badly, they're really designed for steel. If you're vigilant, when the burrs with smaller teeth start to clog, have a quick buzz on a piece of scrap steel, and you'll often find it'll unclog somewhat. The other trick, when doing almost ANYTHING with aluminium, is candles. Yes, candles - cut into the candle with whatever you're using (hacksaw, 1mm cut off wheel on the grinder, carbide burr) enough to get a bit of wax on the surfaces, then go at the aluminium. Repeat as necessary. Sounds silly, but just give it a go sometime - try without first, then with, and see the difference. And speaking of hacksaws - how's your arm after cutting that head up!!! I would have probably gotten about 1/4 of the way through the first cut, and gone bugger this, must be something more interesting to do. That, or found someone suitably stupid to finish the job for me... Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 22, 2010 Share Posted June 22, 2010 I love that photo. Kinda reminds me of those people that slice dead things into 100 slices....remind me to keep my dog away from you Seriously though it really illustrates the safe areas for working. Bodyworks? I went to that exibition when it was in sydney a few years ago. Awesome preparations... we have many similar at uni... but no dogs hmmm... Springs to mind- The guy behind body works made a really freaky preparation with a human cadaver riding a cadaver horse. On a more mechanical note. Last time we were in japan we took some photo at the nissan museum where they made cutaways of a older DOHC formats. *rummage around* ahh here we go Quote Link to comment Share on other sites More sharing options...
DatPilot Posted June 23, 2010 Share Posted June 23, 2010 My uncle was proting some little toyta thing, to get uniform DIA throughout the runners, he found a coles / kmart bouncy rubber ball that was the perfect size. just push down the hole and where it catches on the wall, buzz that bit then try again. eventually the ball would roll straight through Quote Link to comment Share on other sites More sharing options...
. Posted June 23, 2010 Share Posted June 23, 2010 Excellent idea. I will be happy when a basketball flows straight through Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 23, 2010 Share Posted June 23, 2010 alternatively; go to a Head machine shop and pick up some of thier smashed(bent) valves - they will be happy to give them to you in all sorts of diametres if you ask nicely or throw them a beer-sized amount of money. if you hold the stem of the valve and push it to where the head of it can clear no longer, then twist it... you leave a nice clearly visible scratch where you need to removed material... also consider a tapered port using a succession of valve diameters at different depths. (this is probably much more useful when taking a "reshaping" approach to porting rather than a "hogging out" approach) Since the valve steal is much harder than the aluminium of the head it will leave a visible mark without much effort and will not wear down after repeat use. Remember to try to make your approach to each port exactly the same... I've found it helps to work in stages on all ports simultaneously so that you dont forget how much to work each area or have some kind of methodological drift cheers! -poit Quote Link to comment Share on other sites More sharing options...
kolonelklink Posted June 23, 2010 Share Posted June 23, 2010 oh and im sure you've head this already but: DONT TOUCH THE BASE OF THE PORT OTHER THAN TO POLISH IT!! or you will kill all flow (I hear) Quote Link to comment Share on other sites More sharing options...
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