I have just read the thread and there is some very good info. in it. I have never met John, but I have heard that he's a great guy. The information on the head is very interesting. For those who don't know, I'm with ERL and we have been doing alot of work on the K series oiling system. I've posted some pics. of an S2K pump on a K24 block. Like the others have said the S2K pump is very good as is from the factory. It is not a direct bolt up to the K blocks. Using our CMM (digitizing) the F20-22C and K blocks we have found small differences in the alignment and the hole patterns. We have made several components and brackets to make it work. The good news is that you are able to use your existing K24 chain, tensioner and guide (with the guide cut as in the picture). The bad news is that the S2K is a limited production car and the pump is $350 from the dealer before you make the brackets, custom dowels, modifications to the pump and misc. hardware to mount it. The supply will be limited by Honda since the # of cars being produced is small. This didn't seam to us as the solution for everyone, but I guess the question would be if people are willing to pay that much for an oil pump with the necessary components to run the S2K pump? This really isn't a fabricate at home project since the chain is traveling at nearly 7,000 Feet Per Minute (faster than most rifle shells)and the pump is turning over 16,000 RPM at 10K. Alignment is critical to say the least.
We have done a great deal of testing on the various pumps and have built an oil pump dyno that matches the crank w/the gear, tensioner, guide as they're mounted on the block. This gives us an actual assesment of the pumps in their actual mounted condition. We are able to spin the pumps to over 10,000 rpm crank speed and measure the flow and pressure in increments. We can also test various oil wts., oil temps, head heights (as NIKOS mentioned). This all takes a huge amount of time and progress is being made.
What we have found is that the S2K pump is good to approximately 9500 as is before cavitation starts. The lighter oils (5W30) helps to raise that point as expected. The modified RSX pump is what we offer to our customers.It is good to approx. 8800 momentarily (most racers)and is an easy bolt on to any K block after modification. The RSX pump is also more readily available with a lower initial cost. We offer these modified pumps with the proper chain, hardware and a new tensioner (highly recommend replacing it while doing the change). We have found an improvement that will raise the onset of cavitation in the RSX by 500 RPM, but is in developement for an economical way to implement it. Another design that we are developeing should raise the onset of cavitation in any Gerotor pump substantially.
As Sean has posted we are having custom main bearings made that have a full oil groove and will be a drop in for K series blocks. They will be available in both H and HX clearances to custom fit to your crank. They say we will have them here by Easter. This will give a constant supply of oil to both feed holes to the rod and eleminate the 1 hole 2hole pulsations that you get with std. bearings. It also works to lower the main bearing temps. by circulating oil (oil works as as coolant) through them rather than restricting the flow as std.(1/2 groove) or race (3/4 groove) style bearings. We have modified the customers blocks to achieve this in the past, but will have a drop in version soon. If you look the S2K uses full groove bearings. Without going into centrifugal effects and forces in the feed holes increasing by the square of the RPM and distance, high RPM and long stroke motors should use them. Our std. half groove Superback bearings are available for the K blocks which have a .010" oversize on the O.D. and a std. or .010 under on the I.D. for reground cranks. These are for repairing the split case K motors that have a spun bearing or need align bored to correct journal alignment without cutting the block and lowering the deck height.
We, like John have customers NA motors at 300+ HP with the std. width rod journals. They show no signs of fatigue from being overloaded and reduce friction in the NA motors. These are similar to the old F motors and you have to watch the bearing clearance to not create too large of a radial mis-match that lowers the support area for the oil wedge. IF YOU ARE BOOSTING or using nitrous, I HIGHLY RECOMMEND widening the journals.
I do not recommend enlarging the opening in the sheet metal at the pumps intake unless you can guarantee enough oil head in the sump to provide the necessary restriction designed by Honda. The restriction is there to force the "supercharged oil" from the by-pass into the rotors (not back out the inlet)once you have surpassed the SFM at the rotors pitch line that oil can be drawn in. The K pumps are spinning at 1.619 x the crank, so this comes very early and for that reason you shouldn't raise the initial opening pressure of the by-pass.
On the pictures; The restrictor (#6) must be removed and the hole plugged to run a RSX or S2K pump on a K motor that previously had the balance shaft pump. BOTH holes #9 and #10 must be plugged to run a dry sump system. The clay shows the sump pick-up clearance at 5/16" on the stock K24 pan and the mark left in the pan shows the location of the S2K pick-up. As you can see, this is the raised hump lower case and it clears the hump. We do not recommend cutting the hump with-out align honing, so our RSX pump's are clearanced for it.
A few pointers;
- Do not modify the ramps or slots around the rotors in the pumps, since these are carefully configured to lower the pulsations created by the pump.
- If the block is factory or one of our sleeved blocks that we've align honed, Mark each bolt for alignment prior to dis-assembly and keep it in that location (i.e. that bolt goes back in that hole ). When re-assembeling, put each bolt back in the same hole (lightly coated with 30wt. oil, not dripping) and torque in sequence to 22ft/lb. Each bolt should need approximately 60 degrees to make your marks align. Turn each bolt in sequence until the marks re-align.
- When dis-assembeling the split case blocks, loosen the main bolts 1/4 turn at a time in the opposite sequence that you torque them.
- If you lose the bolt location or position, USE THE TORQUE ANGLE METHOD! What you are trying to achieve is bolt stretch to pre-load the bolts. This is the most accurate method to achieve this where the length can not be measured. This is the method we use when the blocks come in dis-assembled. We stress relieve them (both heat and vibration) after initial torquing, then mark and re-torque prior to align hone to stabilize the block. We also stress relieve the block after removing the stock sleeves and again after the new sleeves are installed prior to cylinder hone.
- Do not pull more than 3# of vacuum in the crankcase if you are running a dry sump or a vac. pump. Oil will aereiate at 4 psi vacuum and it will draw the oil out of the bearings.
I hope this will help and update everyone on what we've found. As soon as more information is available, I'll try to post it.
yesCJM said:Very good thread. I have one question to anyone who can answer: Will the toda K20a chain tensioner work with the ERl S2K oil pump kit in a K24? I asked Sean in an email when I inquired about just getting this pump system and he said he was not sure. Can anyone help me out, does anyone know?:up:
Awesome! I do have one more question... Might not belong here since it's on the K20A2/K20Z1 oil pump though. But it still might be helpful from a compatibility standpoint.Yes, it works with the K20 Z3.