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Oh yes, clean engine bay makes all the difference.
As for the knife-edged crankshaft, we weighted it, and here's what we got:
Stock crankshaft - 24.8 kg (54.7 lbs)
My crankshaft - 19.9 kg (43.9 lbs)
with my lightweight clutch, rods and pistons together with possible balance shaft delete this engine has a significant rotating mass reduction so I expect it to rev "a bit" quicker than stock..
by the way - the 18" 10j ET40 wheels fit early offset with no spacers:
Another thing - I am currently reading Ecumaster Emu standalone system manual, and it supports the stock 132 teeth trigger indeed. Here's the official list of supported triggers for those interested:
Toothed wheel with 3 missing teeth, Toothed wheel with 2 missing teeth, Toothed wheel with 1 missing tooth, Multitooth (no missing teeth, equal dist),
Nissan trigger, Toothed wheel with additional synchro tooth, Honda J35A8, Rover 18-1-18-1, Porsche 132 teeth, Rover 13-1-2-1-14-1-3-1 (Lotus Elise),
Subaru 36-2-2-2, Subaru 6 teeth, Dodge 18-2-18-2, Audi trigger 135 teeth, CAM toothed wheel with additional tooth, TFI (FORD TFI ignition system),
Renault Clio Williams 44-2-2, BMW E30 M3 116 teeth, Mitsubishi Colt 1.5CZ
To be honest I was hoping for feedback when i wrote "possible balance shafts delete".. Cause i did not know whether it's a wise idea or not. If you advise me against it, I will most likely leave the system intact.
However my original thinking and concern was:
1) if they are supposed to balance out rocking engine internals which are significantly heavier than in my case, then am I not obliged to reduce the mass of the balance shafts too?
2) if people are deleting the balancing system with heavy internals, isn't a well balanced lightweight set of internals gonna hold even better?
To be honest I was hoping for feedback when i wrote "possible balance shafts delete".. Cause i did not know whether it's a wise idea or not. If you advise me against it, I will most likely leave the system intact.
However my original thinking and concern was:
1) if they are supposed to balance out rocking engine internals which are significantly heavier than in my case, then am I not obliged to reduce the mass of the balance shafts too?
2) if people are deleting the balancing system with heavy internals, isn't a well balanced lightweight set of internals gonna hold even better?
For the record, I never ran balance shafts in my race engines to eliminate some complexity and pick up some power. They all had light cranks, light rods, and light pistons. As for harmonics, I did Loctite everything and avoided the factory (fragile) fuel rail. But these things should be done with any inline 4.
I'm not going to argue against balance shafts, but if you choose not to run them, you shouldn't worry about it.
If you plan using the car on streets (=significantly more mileage than with pure track car), I would advise against balance shaft delete. Both for vibration and engine life, fuel rail being the leats of the problems, worse will be oil pickup tube.
FWIW, I changed the regular crank pulley to S2 one with harmonic damper just for the peace of mind.
With turbocharged engine few lost hp from running balance shaft is nothing, with 500+ hp you won't feel it, I promise
I would always defer to someone like Michael who has many years of engine building behind him.
My concern is only based on our experience with a failed motor due to what we believe was the knife edged crank being weakened and seeing excessive crank whip. Removing the balance shafts might only exacerbate this. I'm sure there were mitigating circumstances involved in our motor's demise but my gut feeling is that even though you have now changed the weight of your internal components, having the balance shafts is still better than not. Clearly there have been people who have successfully run without b/shafts. There may have been a select conspiracy of circumstances that caused our issue that won't have any relevance to your build Chris. I certainly hope not.
Regarding the comment wrt lightened internals - I noticed the other day that Boadfoot Racing has a "Racing Balance Shaft modification" which includes cutting weights off each shaft, re-plugging oil galleys, and micro-polishing journals... interesting!
At the price he's charging for that service, I don't think he's in it for the money!
As for balance shafts - they're gonna stay since the car will not be daily driven, but it might have significant yearly milage. As for fuel rail - it's gonna be custom made. The oiling will have to be stock for a start A friend of mine who designs and manufactures a drysump system for me is very busy recently so the drysump project has to wait some time.
I've got some update on the head though. It was not in a perfect shape, there was some rust on valve seats because of which there was a bit of a leak on two cylinders, but it's fixed now, and everything's good to go.
On wednesday we were measuring the "new" stock 16v head and the results are significantly lower than those of the previous, "mis-modified" head.. So it seems that at least improving flow of the first head was not f-d up by the other machine shop after all. Actually I'm looking forward to them sending me back that head after they mend all the stuff they did wrong..
Back to the current stock head:
Seems that there is either a huge difference from not using plasteline nor bellmouths; or there's something different in the very setup of this superflow sf1020 machine (to the ones used by other rennlisters as both of my heads ended up with much lower numbers to adequate heads). Either way I am satisfied of the results because even though the numbers are much lower than any other 16v head measured by rennlisters, it's still far higher than the best measured 8v head, and that means it has to work as intended (more power @ lower boost). I think I'll throw them my old 8v head for comparison some time.
I'd be concerned with knife edge and balance shaft delete but happy to be proven wrong.
Originally Posted by Refpotsirk
However my original thinking and concern was:
1) if they are supposed to balance out rocking engine internals which are significantly heavier than in my case, then am I not obliged to reduce the mass of the balance shafts too?
2) if people are deleting the balancing system with heavy internals, isn't a well balanced lightweight set of internals gonna hold even better?
Originally Posted by 333pg333
My concern is only based on our experience with a failed motor due to what we believe was the knife edged crank being weakened and seeing excessive crank whip. Removing the balance shafts might only exacerbate this.
b-shafts and harmonic balancers are fixes to 2 different problems.
it's possible that removing the b-shafts would help reduce crank whip since there's one less thing pulling on the crank nose. the balancer is there to dampen the whip motion from a long, flexible crank.
as i understand it, b-shafts counteract the vibrations caused by the piston/rod assembly, not the crank...the crank weights are self-balancing, as in #1/#4 weights are to balance against #2/#3, and the mass is for smooth running...not to account for the rod/piston weight.
so you could have a lighter piston/rod combo with a stock crank and it may be prudent (but not necessary) to lighten the b-shafts accordingly.
or you could lighten the crank and use the balancer to keep it from whipping around.
Thanks I didn't know that. Thought the mass of crankshaft also plays a role in the balancing shafts system. I will leave the balancing shafts in place as they are. The mass reduction on the pistons and rods is about one kilogram total, not a drastic one at least for now. I've got some further plans for the future, but for the time being i want the car to run.
I do wonder why did the machineshop need my rods if they play no role in the balancing of the crankshaft. I know they balanced them and paired them with pistons so that mass differences between cylinders are negligible, but after they did, they gave back my pistons, but left rods in the shop since they were needed to properly balance the crank..
07-16-2015, 03:56 AM
A friend of mine who designs and manufactures a drysump system for me is very busy recently so the drysump project has to wait some time. 
