Originally Posted by yamahaSHO

The oil level was not low enough for the pickup tube to become uncovered in addition to lack of G forces don't allow oil to pool anywhere. If being roughly half a quart low on oil caused oil starvation, anyone who tracks would spin bearings regularly with the oil level right up to the top.

I have a friend that intentionally ran his oil level low to prevent it from being sucked up into the intake. He also got low enough to lose VTEC operation once. He came off track, topped it off and went back out. When he came to my local track, he was a tenth or so of the class lap record on his first session out on the track, ever, with 225 R-comps that were heat cycled out. That car saw so much abuse between all the codriving at autoX and track events, it was unreal. He sold it last year to someone else who tracks it still.

Originally Posted by DavidNJ

He seemed to have a fundamental misunderstanding of 4 cylinder balance. As long as the bobweights are the same (none are needed) a 4-cylinder is in perfect primary balance (the secondary balance isn't that good, which is my most over 2L have balance shafts). Urge pointed that out showing a 4-cylinder crank with counterweights only at the end.

The counterweights are used to minimize stresses and bending within the crank by offsetting each throw individually. It won't show in a balance as the counterweights will offset each other and the rod journal throws will offset each other. Note that an underlying problem with the high RPM and the larger displacement Honda engines is the low or zero overlap of the main and rod journals. It makes the crank weaker and is discussed in some of the 2.4L engine discussions here.


Balance is specified in oz-in or gm-mm left and right. The measurement is just taken at the ends of the crank. "318gm @ 27 degrees" is the correction for a specific (and in this case unspecified) radius where the adjustment is made. Most of the shop balancers will translate that to where hand how deep a whole to drill (bit diameter is specified by the machinist for the width of the counterweights or how much mallory to add. They also have the option of multiple holes. Lots of racing engine builders take the weight off the side of the counterweight rather than drill on the end because of windage concerns; power spent throwing oil around inside the engine is power not going to the rear wheels.

Endyn showed the balance info from a CWT balancer. It showed very, very tight balance, far more than is necessary. CWT has an hour long set of 6 videos on their balancer; this is the link to the first: https://www.youtube....h?v=d9DZzrpjc5Y. Given that they turned it in a lathe rather than drill holes which can be done on the balancing machine, the engine builder (Endyn) must have had a very good sense of how to balance this crank. If you don't agree, try a little static balancing experiment where you add weight by eye.

I wouldn't be surprised if your shop left a weight off one of his bobweights and didn't recheck because he was scrapping the crank.

Dropping reciprocating weight is very important on a high rpm 4 cylinder. The reason is secondary balance. The only ways to affect it are balance shafts, reciprocating weight, and rod and stroke length. Constraints are rules and cost, both initial and ongoing maintenance (really light stuff doesn't last forever). Where the rules involved in the original order requiring a stock crank and rods? I like billet cranks and rods, which really aren't that much more expensive. But even at $10k+, the extra $1000-$1500 for a billet crank and maybe $300-$500 for lightweight rods (over the cost for standard billet rods) maybe out of budget.

The block looked like it had Darton sleeves. Does this engine have a big 90mm bore? I don't think you ever provided bore/stroke, compression, and cam timing info.

Which brings up the next issue: running a 9500rpm engine at 8500rpm loses a lot of power on the track. It can make sense as a tradeoff when the engine has a large displacement (2.4+L) where the trade off also provides a wider powerband and allows less expensive components. However, if the dyno run on the first page is this engine, it seems the head, cam, intake, and exhaust are setup for 9500rpm on that displacement. It held its power peak for 500 rpm through 9000 and at 9500 it still had as much power as it did at 7100. Unless you have very, very close gearing or are running on the high banks of Daytona loosing those rpm will put you into a much lower part of the powerband with a lot less HP.

Originally Posted by MB

Just goes to show you don't need to shave an OEM crank then

Tuner didn't let his foot off - that's the limiter set. The RPM can always be slightly off on a dyno depending where you take the rpm.

Yep the torque is nice