K8 tuning [stroker motor]

[David Coleman]

Hey all,<P>I've just been milling around in my head ideas for K8 tuning, and I figured <BR>I'd bounce my latest one off of you. I'd like to put a KL crank and rods in <BR>a K8. Doing the calculations shows that the K8 stock combustion chamber is <BR>about 33.42cc's, with the swept volume being 307.48cc and the CR being <BR>9.2:1. Swapping to the 74.2mm stroke over the stock K8 stroke of 69.6mm <BR>will bring the swept volume to 327.81cc and the CR 9.8:1. The motor's <BR>displacement with the KL stroke/K8 bore would be 1967cc's. With a 9.8:1 <BR>compression ratio and almost 2 litres of displacement, I'd think that would <BR>be a very torquey motor for street driving with hopefully 120 ft/lbs of <BR>torque at around 5000RPM or so.<P>I don't believe this would be too expensive, as I can get KL bottom end <BR>parts from some probers for dirt cheap after they part out their KL03's when <BR>they swap to ZE's. They can usually get rid of the top end of the motor, <BR>but 90% of them get stuck with the bottom end sitting in their garage. So <BR>demand is low, supply is high. I would wager that the most I would spend <BR>for a KL crank and 6 rods would be $200USD. I'm picking up some old K8 <BR>heads to do a little port and polish work to; mostly line of sight, cleaning <BR>up port work. However, if I were to build up a KL/K8 hybrid, I suspect that <BR>larger ports to offset the small valves would be good for the increased <BR>swept volume. So for under $300USD for the main parts, I could have a nice <BR>torque boost for less than my clutch cost. Of course, I don't know what <BR>bearings and gaskets I'll have to replace.<P>A long time ago I posted about a KL crank/rods in a K8, in my early, <BR>ignorant days of MX-3 tuning . If I recall correctly, Vaughn mentioned <BR>that it would be alot of work. Something about grinding the block for <BR>clearance or something. I'm not sure if I want to do that. I just crunched <BR>the numbers this morning; I'll be looking at my shop manual this week and <BR>looking at what parts specifically will need to be replaced, as I've never <BR>even seen a crank in a car. Yet. Currently a KL swap is out of the <BR>question for economic reasons; I'm not going to buy a cheap KL03 for $800 <BR>now when I can wait till I graduate and pick up a ZE or build up an 03. I <BR>suppose in my 20 years I've developed a wee bit of practicality. But not <BR>enough to prevent me from tweaking my K8 powered EC into a strong street <BR>car!<P>So do you guys have any comments or suggestions?<BR><P>------------------<BR>David Coleman- <B><I>Moderator</B></I><BR><A HREF="http://www.PinkMX-3.com" TARGET=_blank>1993 Mazda MX-3 GS Special Edition</A><BR><A HREF="http://www.wuname.com/cgi-bin/wuname/wuname.pl" TARGET=_blank><B><I>Wu Name</I></B></A>

[Bri94GS]

Sounds like it could work...let me know how it goes....<P>Would it be easier to bore out the engine?? Or is there no room to do this??<P>------------------<BR>~'94 GS

[mendel00985]

Dave, have you considered extrude honing the heads, intake manifold, and the exhaust manifold? If you should look into it, please let me know what the cost is...Manny

[David Coleman]

I think extrued honing would be a waste of time, but that's just my opinion. I know a buddy of mine got his lower GT40 done for like $300 a few years back.......not worth it on our cars.<P>------------------<BR>David Coleman- <B><I>Moderator</B></I><BR><A HREF="http://www.PinkMX-3.com" TARGET=_blank>1993 Mazda MX-3 GS Special Edition</A><BR><A HREF="http://www.wuname.com/cgi-bin/wuname/wuname.pl" TARGET=_blank><B><I>Wu Name</I></B></A>

[DiGiTaL]

Especially not worth it for the exhaust manifold. It would be almost useless.

[mendel00985]

The reason that I mentioned the exhaust was that the extrude honing would "clean up" the alignment of ports on the cylinder head thus assuring a straight flow thru from intake thru heads thru exhaust: It was only an idea -thrown about as a 'What If..."---Later...Manny

[David Coleman]

If you want to discuss Extrude honing, post a topic about it. This topic is about K8/KL stroker possibilities.<P>And back on topic: does anyone know the pin diameter for the KL or K8?<P>------------------<BR>David Coleman- <B><I>Moderator</B></I><BR><A HREF="http://www.PinkMX-3.com" TARGET=_blank>1993 Mazda MX-3 GS Special Edition</A><BR><A HREF="http://www.wuname.com/cgi-bin/wuname/wuname.pl" TARGET=_blank><B><I>Wu Name</I></B></A>

[Stevekowalchuk]

Hey.....found this old string and im interested........... anyone got more info on this?

[David Coleman]

The K8 valves are too small to make any real power with a KL bottom end. Especially the intake side, which is key. It would probably be cheaper and much easier to pick up a junkyard KLDE from a PGT or MX-6 and drop it in the car, and you'd have more power and torque. [img]shrug.gif"%20border="0[/img]

[maldo]

Just a note on costs for your project. My rebuild for the B6T is costing me a fair bit. Any time you remove the pistons you should replace the rings, the cost for a set of 4 here is $200CDN. You also will have to replace the head gaskets since you will most likely be pushing the pistons/rods out the top, again this cost me $260CDN for the kit. You may as well get a valve job with the heads off, mine is around $160CDN for 3-angle and back cut valves. The costs add up rather quickly. If you need to replace any internal parts, the majority can only be purchased as a set of 6 for your motor. That being said, if it can be done, go for it.

[David Coleman]

I entirely agree Chris. I've since changes my plans to just getting a KLZE. Cheaper, easier, and more powerful

[chance]

What is a KLDE?<BR>What years were they used in the MX-6 and the PGT?

[codyhoover]

the main bearing size on the crank is different also. the kl has a larger diameter crank so youd have to grind out the bearing mounts.