Careless Posted August 22, 2008 Share Posted August 22, 2008 56K warning. (and work warning for shots of nicely modified parts) Please accompany thread posts with as many high-quality server-hosted (so they don't go missing) photos in order to make your comments clear. If need be, I can host your photos. Just name the appropriately, or I guess I can do that for you. General info and pictures to discuss about ideas and solutions you have experienced or think people should know about. Quote Link to comment Share on other sites More sharing options...
Careless Posted August 22, 2008 Author Share Posted August 22, 2008 I'll start with detonation due to quench/swirl pads on the combustion chambers. I just took this picture with my new D300, and thought it would be good to show what cheftrd and Larry at Endyne have been educating us on. as you can see, both the intake and exhaust suffered on this engine head. Hopefully the rest of the head is still in good condition. From what I undertand, this engine ran down with heat due to the fact that the oil pump drive shattered, and the piston oil squirters could not keep up with low oil volume. From the front of the head, this is a picture of Chamber 2, I believe. Chamber 1 has a pin-hole or two on the exhaust side. Chamber 3 has a couple as well on both sides. I will be posting pictures of the head in detail, so that we can use them to dissect and draw upon. This would allow us to illustrate our thoughts better. As soon as I clean the work bench I'll get to it. I cleaned this head with some SuperClean (bad for aluminum if left on too long, just like SimpleGreen, be careful!), and then re-cleaned it with dish washing soap (mmmm... Dawn Ultra - Hint of Lime scent, aluminum safe!) to remove the remaining aluminum eating chemicals that could ruin the cam bores. I then sprayed it a bit here and there with WD40 to replenish lubricity between parts that I may move in my handling of the item. I cleaned the head with brass brush that was not too hard. It did not leave any scratches in the deck surface, which made me feel comfortable in using it to scrub the head really vigorously. Not bad for 2 bucks. I bought a small dremel brass brush attachment that I will be using to clean up the nooks further. Are there any picture requests for those inqusitive minds that need to know something or other? Let me know. Quote Link to comment Share on other sites More sharing options...
cheftrd Posted August 22, 2008 Share Posted August 22, 2008 Finished RB26 chamber. Remember that this mod is for high output engines. It's completely unnecessary about 99% of the time. It's what I call a give-and-take mod. You give something up to be able to push the engine further. If you're engine isn't at the "take" level, all this mod will do is take. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted August 22, 2008 Share Posted August 22, 2008 ^ wow! Cool thread idea, I am interested to see the information. Quote Link to comment Share on other sites More sharing options...
Careless Posted August 22, 2008 Author Share Posted August 22, 2008 Matt, aside from the obvious quench pad removal, and slight polishing of the combustion chamber and deck surface, what are the other mods here? do i see oversized intake valves and standard RB26 exhaust valves in your photo? are there any valve types you recommend with such a modified head? Titanium/Stainless? I know the exhaust ones are sodium filled already, but is it worth changing out the valve guides to the softer and less brittle aftermarket versions and spec'ing out titanium valves? And in the spark plug orifice, I see some chamfered cuts. Are these flame-front promoters of some sort? They differ from the shallow bumps on the original picture i posted. Have you any documentation surrounding the GT500 modifications you mentioned being publicly available in a thread from 2006? Most other website have threads "about" the RB26 head, but no pictures or little if any. lets make something worthwhile here. we're off to a good start. Quote Link to comment Share on other sites More sharing options...
stony Posted August 23, 2008 Share Posted August 23, 2008 I posted this in my thread but it probabaly could go here to. intake side of the squish removed Porting/knife edge of the splitter Here is what is done to the head to clear the 280 degree 10.3mm lift cam Quote Link to comment Share on other sites More sharing options...
Careless Posted August 23, 2008 Author Share Posted August 23, 2008 stony, thanks.. this exactly what I was hoping this would turn into. someone told me it was "obvious" what needed to be done to clear the additional valve actuation of the high lift cams. looks like something 10 minutes with a grinder can cure. Quote Link to comment Share on other sites More sharing options...
cheftrd Posted August 23, 2008 Share Posted August 23, 2008 Matt, aside from the obvious quench pad removal, and slight polishing of the combustion chamber and deck surface, what are the other mods here? do i see oversized intake valves and standard RB26 exhaust valves in your photo? are there any valve types you recommend with such a modified head? Titanium/Stainless? I know the exhaust ones are sodium filled already, but is it worth changing out the valve guides to the softer and less brittle aftermarket versions and spec'ing out titanium valves? And in the spark plug orifice, I see some chamfered cuts. Are these flame-front promoters of some sort? They differ from the shallow bumps on the original picture i posted. Have you any documentation surrounding the GT500 modifications you mentioned being publicly available in a thread from 2006? Most other website have threads "about" the RB26 head, but no pictures or little if any. lets make something worthwhile here. we're off to a good start. This head is going on a friends RB26 that's going into an S15 Silvia. The picture is deceiving: The chamber is not polished, but straight off the mill. The "chamfered cuts" are not cuts at all, but the original humps that have just been machined. They look like cuts, but are actually convex. The purpose is simply to protect the plug threads from carbon. Big intake valves and stock exhaust. Exhaust valves are the single largest contributor to detonation. The factory exhaust valves are sodium-filled inconel. There is nothing better for a turbo engine. Titanium in the intake is always a good choice, but expensive. Lighter weight means less bounce, less harmfull wave action in the intake tract, and more power. Bronze guides transfer heat out of the valve better, gaul less, and are good insurance in an expensive motor. The stuff on the GT500 motors was published in a book that I can't seem to find. The big standout was the chamber, where the intake squish pad was removed and the exhaust was chamfered. Everything else in the head looked stock except for minor porting. It doesn't take much to make 500hp... On a side note, the RB26 does not need larger valves. 1,000+hp motors do well with stock valves, and don't gain much with bigger ones. The major mods are cleaning up the bowl, knife edging the dividers, removing the hump in the exhaust port. High rpm motors will pick up a little by pushing back the intake divider 1cm. I'm not a big fan of flow #'s. Benches are OK (I have one) when used properly, but the #'s are deceiving. RB26's don't have steady-state flow, so I could care less what the steady-state flow #'s are... Larger #'s don't translate to more power. Even Superflow will tell you that the dyno is the ultimate tell-tale. Quote Link to comment Share on other sites More sharing options...
Careless Posted August 24, 2008 Author Share Posted August 24, 2008 so what about a choice for NA engines, although definitely not as popular, when talkin valve choices. will the titanium help toss the heat to the surrounding head material faster through bronzanium guides? and as for valve springs, I hear that the Cosworth ones are new and are relatively good for a wider range than the double spring rate kind, seeing as the seat pressure is very high on the double spring versions from what I read on another thread (this is the only place where I can get my info anyway... not too many people doing a LOT of RB26 head mods around here to make it a viable option for seeking info). There are about 3 N/A projects going on around here, and I'm sure an RB25DE or two... would piston coats like jet-hot help in reducing exhaust valve heat? I'm thinking the best way to get rid of the heat are the beryllium valve seats, seeing as they put a better conducting metal closer to the water jackets that run close to the valve seat. Quote Link to comment Share on other sites More sharing options...
Careless Posted August 25, 2008 Author Share Posted August 25, 2008 any requests for pictures while my head is out in the open? I'll go in the garage tomorrow and snap some 12.3 Megapixel photos Quote Link to comment Share on other sites More sharing options...
Careless Posted October 22, 2008 Author Share Posted October 22, 2008 bout to put my VG30ET heads back on the Z31, so now I'm looking at the RB26 head again. Anyone have some good experience with various valve train parts? I talked to a machinist yesterday who works on Elephants (Mopar), and he was advising me against titanium valves, stating that there is so much I can do before that which will net me more power. Then he went on topic of taking junk parts from a bunch of mismatched mopar tear downs and could lay down more than 400 hp, yet people are spending 5000 + on a 1.8 Litre Honda that makes 220 or so. I don't think he realizes that a Mopar Big Block doesn't fit in a Honda Civic engine bay. Heck, it COULD fit, but then you turn a go-cart into a shopping-cart. I mean, I've gotten just about everything I need for the bottom end, save for a dry sump system which I will not be getting. I'm going with the Tomei pump, and a common accusump safety kit to make sure there's constant oil flow. The bearings I got are coated and made to retain Oil so that I could do 2 or 3 half mile laps on a road course at low-speed if I wanted to, and they'd be ok to drop into the next motor. I know someone who went through that experience with the same coating/bearings on an SBC. What the heck else could I use to maximize horsepower other than a super-lightweight valve train, some top-notch heat transferring alloys, and some quality head porting and combustion chamber re-shaping? 24 bronze valve guides, 24 berryllium seats, 24 valve angle jobs, 24 titanium retainers, harder springs, hardened locks, 24 lightweight lifter cups (all though the standard ones are said to be light as hell) and 24 x whatever else is involved. So what am I looking at here? 2000 - 3000 in machine work for the head alone?? That's fine by me. But should I be looking elsewhere for power instead of a lightweight valve train? I got a very powerful EMS. I got all the stock injectors, which are good for 400+ hp on a GTR I'll be getting a better fuel rail. I got the rods. I got the pistons (which I may or may not use) I got the bearings. I got the entire fastener set for RB26, ARP wherever possible/most common. I got a good idea of what's to be done to the ports and the combustion chamber. I can't think of anything other than the ITB setup that I'll be using, since I won't be going turbo. But that's all once the head is said and done. Am I really missing something here? Not looking for more than 350 N/A hp. I know it's all in the head, but perhaps I need to lighten the bottom end too? Quote Link to comment Share on other sites More sharing options...
NCchris Posted October 31, 2008 Share Posted October 31, 2008 Found this and thought I'd share. http://www.theoldone.com/components/cylinderheads/skyline/ Sorry if it's a repost........ Quote Link to comment Share on other sites More sharing options...
Careless Posted November 1, 2008 Author Share Posted November 1, 2008 Yep, a number of us have been in contact with Larry Wildmer. He is very helpful and also a very busy guy. In my opinion, reading his technical articles has led me to believe he is one of the top in the industry. I may or may not send another head to him in the future. But I had good results porting my VG-E heads so i'm going to do it myself with the RB one too awesome stuff though, eh? Quote Link to comment Share on other sites More sharing options...
Careless Posted November 4, 2009 Author Share Posted November 4, 2009 Small update: Weighed an RB26 head today, upright/vertically. No cams. All cam caps installed. All valves, springs and retainers installed. No lifter cups or shims. No covers. 45.2 lbs. so for shipping purposes, 48lbs sounds about right without the cams or valve covers. Quote Link to comment Share on other sites More sharing options...
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