PINK POWA update...

[David Coleman]

I decided to tear the rear head down in search of whatever the problem was over spring break. There was a click-clunking noise from the area around cylinder #1 and a fairly significant oil leak in the same area on the exhaust side of the head, dripping onto the intermediate shaft and spraying everywhere. So we got the rear head off after some socket confusion [see below notes]. None of the valves look damaged, though the K8 exhaust valves had a lot of brownish white buildup on them. The KF intake valves were nearly spotless, as were the lifters, cams, and rest of the head. I ran 0w30 Synthetic oil on this motor, about 5k between changes, frequently revving to 7000RPM+, not uncommon to bounce off fuel cut @ ~7800RPM. Despite my abuse, the rear head [K8 101] looks pretty stinkin good. The exhaust ports do have some carbon buildup on them, which I’m sure some carb cleaner will fix. I’m going to keep this motor around as kind of a long term project motor, probably for a turbo motor buildup. <P>Tips:<UL TYPE=SQUARE><LI>Remove the cam pulleys before you remove the cam bearing caps. Trust me, they won’t come out with the pulleys still on. <BR><LI>A 6” c-clamp, spark plug socket, and a grocery bag are a great combination for removing valve springs. You can go without the grocery bag, but only if you like crawling around your garage floor for a while looking for those tiny keepers.<BR><LI>Head bolts are definitely not a 13mm 6 point socket, though they WILL fit that nicely, and even pretend to break lose when you put a 60” cheater pipe on your breaker bar. 12mm 12 point works a whole lot better.<BR><LI>The pulley on the tensioner is held on by an allen head elevator bolt, around 10mm. And, if you, like me, do not have allen wrenches with nice 12” handles on them, you can get your handy dandy 10” socket extension and put a 10mm deep well socket on the end of it and make your own cheater pipe. <BR><LI>Drain all the fluids first, or you will make a heck of a mess<BR><LI>Tide and a push broom clean up big messes.<BR><LI>60” x 1” heavy gauge black iron pipe makes a great cheater pipe<BR><LI>60” cheater pipes will snap a ½” breaker bar in about 2 seconds if you’re not careful.</UL><P>Questions:<UL TYPE=SQUARE><LI>K8 exhaust valves are tiny. The KF intake valves are ~5mm bigger, but they seem to have interference problems with the edge of the combustion chamber when placed in the exhaust guides. Assuming you can just grind that back, what would be the disadvantages to running significantly larger exhaust valves? The KLDE exhaust valves are ~3mm larger, but what about the KJS?<BR><LI>How much bigger can you go on the intake side? Mine measure right @ ~1.125”, which is right inline with what the shop manual says @ 1.117-1.127”. The KL intake valves are 32mm. Now, I don’t see a whole lot of room between the two intake valves, but I’d think you could eat up a little of that space between them and go to 33mm valves. <BR><LI>The intake ports look pretty smooth and well blended to me, with no major bends or obstructions. Are there any areas that should be addressed here? I know on the exhaust side, we’d want to stay fairly small, and keep the divider angled towards centerline. I figure that grinding more of the top than the bottom would keep the gasses flowing more up than sideways, helping reduce the bends. <BR><LI>Does it really matter if the higher end of the progressive valve spring goes down ala stock? I can’t think of a reason why it would, but just wondering if anyone had a good reason why.</UL><P>Well, that’s all I can think of for now. Any comments or questions are welcome.

[ProtegeSTS]

Note Amendment #1= 60" cheater pipes will break that breaker bar, but will NOT break a Craftsman rachet with the same effort.<P>#2= Do NOT hammer upon the axle for the heck of it. It WILL mushroom the thing, and its a pain the butt. <P>#3= if you do decide to hammer upon the axle, make sure you actually hit the axle, and not the ring around it, as this WILL bend it, and you WILL snap hubcentric rings when mounting your wheels back on.<P>#4= If you strip the hole where you tighten down the speedometer gauge, it will not stay in with just finger tight application. A bent up paperclip works much better, and you WILL know your speed.<P> [img]shrug.gif"%20border="0[/img]

[pelado]

Jesse said it all with that reply!!<BR>Got any more questions Dave?

[pelado]

Dave, I only can apply generic knowledge since I haven't taken a K V-6 apart.<P>How big an exhaust valve? Don't know, exhaust valves are smaller for obvious reasons: less mass to flow so you don't make them any bigger than you have to. Must be some kind of rule of thumb for intake to exhaust ratio. Additional weight makes for more valvetrain mass, this theoretically makes an engine slower to rev and the added weight wears valve springs and other components out quicker. Use your head gasket as template, blue combustion chamber and grind to edge of blue to unshroud exhaust valves (larger cylinder bore aids in unshrouding too).<BR>Intake ports - the bottom is usually where most porters work unless the port is NOT a straight shot which for 4v heads it IS a straight shot. Work on the "short" radius, the bottom where the intake port turns down toward the valve seat. Look also at the area where the valve seat is inserted, grind off sharp edges there to get a smooth transition. Beware! Don't get carried away or you'll grind into the water jacket, it's easy to turn a head into junk. Make the metal too thin and the water pressure alone can cause a leak. Use the intake gasket as a guide and port match the head intake ports and the intake manifold also. Leave a little lip on the IM though as an anti-reverse flow deterrent.<P>Progressive valve springs and progressive suspension springs - Why is the bigger gap between coils up? Beats me, maybe it has something to do with spring lifespan or something.<P>You probably knew all this stuff anyway but I thought I'd give it my best shot. You don't want to grind too much material away in your ports, it's just as easy to screw flow up as to make it better. A flow bench helps.

[pelado]

Dave, I re-thought my porting advice after looking at a cutaway via a link in your signature. I thought the SAE paper on the K engines was unavailable since the link via MX-3.com no longer worked. <BR>Anyway, it appears there isn't a lot of porting work that can be done. The intake is pretty much a straight shot. There does appear to be two small rises in the floor and the roof right where the ports become independent (non-siamesed). The exhaust could use a little work on the short radius turn but not much.<BR>If you have a junk head and you know somebody with a band saw......cut it up!

[T Biller]

A couple of cautions yo umay or may not have thought of. Don't just make the ports bigger as this tends to slow the gas down and loose low end, shape is more important. The theory on valves I think is that because the exhast is under lot of pressure when it leaves, it will do so. More effective use of head square inches is to have bigger intakes to get more in to start with, also don't go too overboard with valve unshrouding to the extent that yu loose all flat head surface which provides turbulace in the chamber on compression to give a better burn.