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Rocker clearencing for Toda high profile cams into f20/f22
Stumbled across a set of Toda spec b cams for a great price so this was really a case of find the parts first then worry about how to get them working on the engine later.
The only info I could find online suggested clearance between cam and rocker needed to be done with a Dremel, I really did not like the sound of this at all, roller could be damages if you slipped, swarf could get in and mess with roller bearing, plus it would be a mission to measure if you had taken enough material out which would mean constant fitting to check for clearance.
Decided to take the Rockers that needed machining apart, the 8 exhaust side rockers (4 LH and 4 RH) which was pretty simple just had to knock out the retaining pin that holds the roller assembly on the rocker.
It took a bit of force to do it and it's a 2mm pin so taper punch was really the only way, giving it a few solid hits on the top end I found was the best way it broke the swage and gave you more room to pull it out with a set of plyers from the bottom end.
Ones the shaft and roller bearing was out just needed to work out a way to mount them in a milling machine and work out the radius and which cutting bit to use.
There was a bit of educated guessing involved as I didn't have the engine with me and we could not work out the movement ratios from the drawings but managed to get it pretty much spot on.
With the required 1mm plus a little more just in case, each rocker was quite different to the next.
Managed to avoid cutting into any of the strengthening ribs or anything critical so really didn't effect the integrity of the Rockers at all.
Ones they were all machined I polished them up with a range of flapper wheels as well as very fine grit sand paper and a lapping stone to make sure there were no sharp edges or burs.
Have a look at the attacked pictures and feel free to ask any questions.
Probably over done but hey if it's worth doing it's worth overdoing I guess.
I guess I could do this for anyone if they needed it done, this process would be the same for any larger profile than OEM cams only other one that comes to mind right now would be brain Crower???
The only real way to make power from cams on these engines IMHO is with a larger than OEM profile and matching this with a head that flows better than OEM not necessarily to much more than OEM, but that's just my opinion I could be wrong and am willing to retract that statement if someone has better info.
Came up with a mounting solution to fit the rollers one at a time to the Malling machine. Milled the cut out shape through the mount, this also gives you an idea of how it was bolted down. Here is the first one done and after polishing, hard to tell from the picture but it is polished. Because I had to take the rollers out to do the job had to fit the rollers back in one at a time one some grease to hold them in for re assembly All the roller bearings back in. Roller back into the rocker This is the pin that was knocked out of the ones that needed to be machined. It's the pressed retaining pin that holds the roller assembly in place. Here is the machined assembly back together with temporary roll pins holding them together, I did this for test fitting and to make sure all the math (guess work) was correct and there is no contact with the cams. Side profile. Because roll pins would not hold with engine vibrations I had to get some 2mm OD silver steel / ground finished rod to replace what was there as per OEM. This was a bit of a pain in the butt to do, this would have been easy in the assembly plant as I'm sure they would have just had a simple hydraulic setup squeezing the pin from not ends. Had to drill a bit of steel to match the shape of one end of the pin get it into place in the rocker then form the other end with a hammer and punch. Picture after forming the end with hammer and punch it's not coming out of there any time soon.
The only real way to make power from cams on these engines IMHO is with a larger than OEM profile and matching this with a head that flows better than OEM not necessarily to much more than OEM, but that's just my opinion I could be wrong and am willing to retract that statement if someone has better info.
That looks like fantastic work! I'm eager to see what these do for you.
Can you elaborate the on the bolded part of this a little bit more? I don't feel like I'm following what you are saying.
A stock S2000 head flows roughly 330 CFM (28”of H2O) and OEM valve lifts which out flows every other 4 valve production head. The problem with the S2000 is that it has relatively large ports as Honda tuned it for high RPM. This is why the F20C (MY00-03) has a noticeable lag below 5000 RPMs. The engine simply does not have enough stroke, compression or displacement for such large ports. This is also why F22C (MY 04-09), with an extra 8% of stroke/displacement, responds as low as 3000 RPM and makes 10+ more HP at 500 less RPM. The larger stroke/displacement increases the air velocity moving through the large ports.
Larger ports explain why headwork has not been a popular S2000 modification to date. Most head porters simply make the ports even larger which will increase flow but reduce air velocity making the engine less responsive. Although the top end may pick up some HP with larger ports, the midrange and low end will bog down significantly reducing overall performance.
Hi guys thanks for the messages, yes I believe Patrick has the right idea with his head work, most NA Hondas work on that principle but even more so on the F series engines, you gain more if the gasses move faster rather than a slower larger volume, which isnt just a simple port and polish job it means in most cases reshaping the ports without opening them up.
But Like I said I could be wrong and this is just how I believe you will gain the most from High profile cams on a F series engine, I doubt you would see more than a few HP gain if you were just to install Higher profile cams onto a factory head.
When do you think you will have the cams installed and dyno'd? Do you happen to have a comparison before dyno so we can get an idea of what they do?
Cams are in and I am running the car in at the moment (run in tune was limited at 6000 rpm with no vtec and it made around 150 rear wheel kw), I do have the dyno sheet for the old build and I will overlay the new one once the run in and full tune is done.
Only issues is with the cams I also put together a brand new engine, new F22c bottom end, Urge head, toda cams, and the urge unicorn header. The old engine had all the same I/H/E bolt ons other than a toda header but had around 80 000 kms on it.
A friend of mine blew his engine and desperately wanted a new one so I took the opportunity to sell mine and build a new one.
I got the tuner to overlay the curves for the old and the new engine.
Please excuse the hard to read green lines, only realized after I got home.
Green line is old engine red line is new, nice gains between 3000 - 4000 ish, it really opened up up top. Torque curve also more linear up top which is nice.
Green line is old engine red line is new, nice gains between 3000 - 4000 ish, it really opened up up top. Torque curve also more linear up top which is nice.
Rocker clearencing for Toda high profile cams into f20/f22
