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ZUKIWORLD Discussion Forum => Suzuki 4x4 Forum => Topic started by: cj on July 16, 2005, 12:32:34 AM
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Hi Zag,
All this talk of engine mods has got me thinking and wanting to learn a little more. You mentioned knife edging your crank and I was wondering if it is something that you have specific dimensions for or is it something you just give to a machinist and say "do it". Any pics?
Also, have you played around with windage trays and crank scrapers?
CJ
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Hi CJ
   This is an extreme modification that is really only apllicable to engines running at a
5000-6000rpm or more constantly.
   Basically you are eliminating the flat edges of the crankshaft counterweights to reduce rag as they pass throught the dense air/oil mixture hanging in the block.
   I don't have dimensions, I with the racing machine shop I use to come up with what I wanted and cut them loose to do it, the engines using these cranks (airboat/airplane) are already assembled and installed so I can't take pictures.
   There are a couple of good books that cover this type of extreme mod though
1) Power secrets by Smokey Yunik (I really/really like this book)
2) Unfair advantage by Mark Donahue (May be out of print)
   A guy by the name of Jack Brabham (F1 driver) had a company called REPCO down in your end of the world that also produced a great book on race preparation back in the 70's. If you can find it XLNT, I lent mine out and never got it back.
   I must stress this is an extreme mod and ugly expensive, I only used it on these engines because of the extreme prolonged high rpm use they are subjected to.
   The power gain is minimal 1-2hp, but it relieves the crank of a lot of shock loading and straight loading at these extended high rpms...for me it was a reliabiltiy, safety issue.
   The full prep on these cranks was around 1000.00 US each including all the mods done.
   The only other places I could see it making sense would be for Full Tilt Road Racing, Select Drag Racing classes, Select Jet Boat Racing classes where the engine fits the rules.
   The airboat and aircraft engines are built to withstand 11,000rpm (and I have tested one up there on the dyno several years ago), the reason is simple...to be sure they will be relaible at 5-6000rpm constantly. There ain't no place to pull over with the airplane, so everything on it is designed to a 100% safety factor.
Windage trays and crank scrapers are both good mods and cheap to do (DIY). The stock Kick pans I use have pretty darn good windage trays from the factory, I don't see a need to mess with them. Crank scrapers for the 1.6/8v I haven't done, but on a Nissan L-20B and the Small block Chevy they work great. The 1.6 IMHO has the crank up high enough that with the stock in pan windage tray there didn't seem much point in spending the time building one, it would be tough the way they sit in the block. But experiences on other engines show that in the right place they are a great inexpensive (DIY) mod that also helps oiling.
One of the reasons I selected the Suzuki for the airboat/aircraft projects was stuff like this, good internal oil control, relatively high mounted crank, stiff crank case....when the factory does it that good usually you don't need to go back and modifiy it.
Thanks for the questions CJ
Zag
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To everyone in General
After I replied I got to thnking....
   There are XTREME modifications out there that have very limited application ie:
- Race type port polishing (utlra smooth almost mirror like)
- Extreme valve bowl porting
- Shortening valve guides
- Beam polishing connecting rods
- Knife edging
- Shot peening
- Nitriding
- Massive multi carb induction systems
- BIG, BIG camshafts
- Big tube headers
and a bunch of other stuff that just doesn't work well in most DRIVING type applications.
   I do use many of them, but only in specific instances where there is a specific need to overcome a problem.
The best way to approach modifications is....
PLEASE, PLEASE think of the engine as a COMPLETE SYSTEM and define what you wan it to do and where you want your power....also think about what you are willing to give up in terms of fuel mileage and driveability.
   By figuring out what you want and where you will save TIME and MONEY with your modifications to the engine and DRIVELINE.
   I've been in the Automotive Game several decades and I'd hate to tell you how many times I've seen guys run such and such a cam cause his Buddy said so, and such and such an intake because it worked for another Buddy and wound up spending a pile of money with mis-matched parts that DID NOT WORK TOGETHER, usually made less power than stock.
   A little bit of research and planning will give you a much better combination for FAR less money every time.
Sorry for the rant....
Zag
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Thanks Zag, there's nothing like getting info from the guy who has done it. It's good to get both sides of the equation ie. where it's worthwhile and where it's not and the pros and cons. The knife edging is something I've had no experience with and it did look like something for a race engine trying to get every last bit. Hadn't thought about the load issues. Haven't looked inside my sump yet but I could see how a well designed windage tray and baffling/trap door would be a good thing for offroad use. The crank scraper looks like a simple and worthwhile mod to do. I even found a site where they have one available for the G16 engine.
http://www.crank-scrapers.com/prod01.html
OK, now next Q. Valves, 3 angle grinds I've heard about as quite common but I noticed you used a 5 angle grind, care to ellucidate?
CJ
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Hey CJ
  ÂÂ
   There are many different kinds of valve grinds, the most common are intereference and 3 angle.
   Interference is the typical cheap valve job, the seat is cut to 45 degrees and the valve is cut to 44.5 degrees, the interference point becomes the sealing point when lapped. does the job but the sharp break is poor for airflow and the narrow seat has a shorter life.
   A (3) angle grind is where 3 different angles are used to provide a gentler transition and a wider better sealing surface. This is the minimum acceptable valve job IMHO.
   A (5) angle is an expansion on the same theory.............I can claim no credit at all for it's creation, but I think the guy that owned the original shop that did my racing machine work in the 80's and 90's can.
  Unfortunatley this is another one of those extreme mods that for most applications is not worth the money.
   Back in the real early 90's when I started experimenting with the G13 sohc engines I had a bunch of flow bench work done to compare the G13 to the Subaru EA81, Honda 1300 and 1500 sohc and the Nissan E series as well as a couple others. that's part of the research that lead me to messing with the Suzuki's. By the By the flow benching at that time showed the G13 sohc cam head out flowed the others making it most likly to produce the target power levels.
   To make a long story short all this flow benching caught the shop owners interest and seeing as I had several heads in the shop getting cleaned up we teamed up to do some testing on the measurable flow bench effect of different valve grinds.
   Using the cores that I had we tried a different grind in each combustion chamber on each head and did back to back tests on the flow bench.
We tested
- Interference
- Factory specified
- Performance (3) angle
- and a series of 4-5-6 angle grinds
Each valve job was tested on the flow bench at actual valve lifts of
-.050"
-.100"
-.300"
This was a long time ago so my memory might be a little off but the basics are....
- Interferance flowed the worst
- Factory spec was about 20% better airflow than interferance
- Typical performance (3) angle was about 30-35% better airflow than interferance
- (5) angle was about 10-15% better airflow than the performance (3) angle
- The very best was a very complex (7) angle but it was extremely difficult to machine.
   The difference between the (3) angle performance and the (5) angle looks impressive...but in the real world only amount to 2-3hp on equally prepped engines (est)...which wouldn't be bad if it was only a little more expensive..problem is it took about 2-3 times as many hours to do as the (3) angle and wound up costing double or more........
      ***Not a cost effective low rpm/ low performance level modification***
   It's another case like knife edging..when you've run out of everything else to get power or if class rules restrict you to extreme measures to build power it has it's place.
  *** For 99% of the engines that get built it's not appropriate or worth the money.***
   I did it on my projects because I was looking to maximize breathing to get to the target hp with the absolute lowest stress possible on the engines, did it work, for me I'll never have conclusive proof as I have never back to back dyno'd equal engines with perf (3) angle and (5) angle.
   Interestingly the fellow that developed the valve grind went on to use it in a B/SA Mustang that he took several drag racing records with. The flow bench said it worked, the records proved it.
   Would I do it again with all the expense.....NO, my original target power levels for this project were 100hp |removethispart|@ 6000rpm and right now we are beating that all to pieces (est 113-114hp |removethispart|@5900rpm) for this application it was really wasted as I am already well over target.
   Would I recommend it....not for a regularly driven streetable vehicle, there's better places to put your money, and would only recommend it for extreme applications like I mentioned above.
   Could I do it again....that might be tough, the guy that developed the grind stopped doing automotive and performance machine work to concentrate on Oil Industry work, I'd have to go back through my stuff to see if I still have the angles and talk to him to see if he has the cutters he had made for the custom angles.
   The heads I used on the airboat and aircraft engines I think were the last his shop did with that combo and I'd been saving them for 6-7-8 years.
   Anyway it was a neat experiment and education...
     But from now on a good performance (3) angle is all I can see myself using
...live and learn.
Zag
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Mmmm... learning all the time ;D What angles have you found are worthwhile for the 3 angle grind? A basic 30/45/60 or are you going more something like 10-20/45/70? What about backcutting the valves? The improvement to flow at partial lift should be nice to have.
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Back to knife edging while I'm thinking about it. Are yours like a 45 degree cut on the leading edge or more like a wing shape with a radiused leading edge and knife edged trailing edge? I would think the latter would be a better design from the little knowledge I have but more costly to machine.
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When I was building bike engines back in the mid 80s we used to do a 3 angle grind and then very carefully radius off the outer angles to improve the flow. I guess a 7 angle cut would have been more accurate but it was all done on a very tight budget. I would have thought that it would have more effect on a more stock setup as with the wilder cams the valves were already a fair way open before the piston swung past btdc/tdc. We also used to cut the seat widths back, open up the throat a little and reprofile the valve head. That way you could effectively get a bigger valve without needing bigger valves (that really needs a sketch - I think thats what CJ meant). Drawback is shorter service intervals, not that important in racing. Zaggy, when you refer to shortening valve guides, you mean the bit that protudes into the port to improve airflow? we used to reshape them a bit to improve airflow but as we had to shorten the other end to give clearance for higher lift we used to keep them the stock length to avoid too much vlave rock..
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Hi Guys
A typical (if I remember right) 3 angle is a 30/45/60 series of angles. A performance grind
(every racing shop seems to have a different favorite) is typically a little more gentle like the 15/45/75 you describe.....
Back cutting both valves and seats as you both describe is also a good mod when going after that little extra power. Depending on the shop it is usually not that expensive, and when combined with valve bowl porting very effective.
Cam grind does not seem to have a detremental effect, as it has been explained to me, the hi flow valve grinds work well reguardless of cam type and give a greater advantage at all levels of lift.
Service life does not seem to be detrementilally affected, remember the Suzuki's use hardened valve seats so they hold a grind well from my experience.
But remember these are really small power gain mods, if yo have a shop that can do them at a reasonable cost great, if it's going to be expensive....is there a better place to spend the money.
Rhinoman.....
When I talk about shortening the guide, back when I raced H Production sportscars (undr 850cc, talk about needing more power) we went nuts looking for airflow and would actually eliminate the part of the guide that protruded into the port, then polish the whole thing like a mirror. We also tried tapering them, shaping them aerodynamically, custom making really wild tulip shaped valves, even tried narrowing the valve stems (bad plan blew up real good parts everywhere)....went to unreal extremes to find 1-2 hp......learned more about engines and making bad choices in those days than I have since........but.
Back then production class racing was really restrictive and you had to be looking for every advantage...weird valve grinds, any airflow mod, crank knife edging, polishing the inside of the block to try and decrease the amount of oil in the atmoshpere inside the block I could go on. But boy was it a learning curve.........
CJ.....
Knife edging produces a shape on the counter weights that is a more aerodynamic shape, like the horizontal stabilizer on an airplane....the theory is it allows the counterweight to pass throught the dense air/oil atmosphere of the crankcase with less resistance and it the oil bounces out of the pan (on a bump) to cut throught it with less shock loading.
Straight angles, I am told, would not give anywhere near the same advantage and being a pilot with a decent understanding of aerodynamics I have to agree.
Thanks for the questions and comments guys
Zag
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Did I miss anything............????????
Zag
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This has been great. Makes a refreshing change from talking suspension and lockers even if most will probably never use it. Been toying with the idea of getting a project to tinker with when space and time allows and it's nice to know what to and not to consider doing while an engine is stripped down. There's plenty more to discuss like porting, big bore mods, stroking, compression ratios, forced induction and engine management etc. Be nice to get a few more involved in the Q & A as I'm sure there are others out there with experiences in modding all sorts of engines. There hasn't been a lot of tech about modding the G16 series (both 8v & 16v) engines around and it would be nice to get some facts accumulated.
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MMMMMMMMMMmmmmmmmmmmmm
Forced Induction
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Wild you are a baaaaad influence....
Besides......
I'd rather be blown than injected
(Automotively that is)
Zag
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Blown and injected :o
;)
I like them both
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Got my hands on a couple of FSM's and was interested to see Suzuki says for the 8v and 16v engines to cut the valves at 45deg. but the 8v seat gets a 15/45/60 while the 16v seat just gets a 15/45 cut
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Thats unusual
   When we went throught the flow bench drill years ago we measured the used valves and seats and found that they were all just an interferance...could they all have been done? or did they make a running change we didn't catch?
   The FSM 8v grind sounds almost optimal with the valves done to match.
Zag
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Hey CJ
Went back over my old note books and your FSM info is bang on....all our flow bench work was done with G13B heads, we assumed the 1.6/8v would be the same. Oh well you know what that say about assume.
Thanks for the info.
Zag
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One customer sent us a G13B crank that Suzuki Racing Development had knife-edged and polished. He wanted us to make a Teflon crank scraper to fit which we did. You can also see the Pauter rods he used -- very nice pieces.
Kevin
(http://www.crank-scrapers.com/suzuki%20rd%20pic.jpg)
(http://www.crank-scrapers.com/suzuki%20rd%20pic%20b.jpg)
(http://www.crank-scrapers.com/suzuki%20rd%20pic%20c.jpg)
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Man.....
That looks like real nice stuff...I like the idea of the teflon crankscraper for the big rpm engines.
Zag
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That was the nice thing re the dyno testing on the Suzuki G10 engine it showed power increases from 2750 rpm all the way to redline (or max for the econo cam) at 5300 rpm. Not really a high rpm engine. Easy 3% hp boost. Lots of people think the full windage trays on the G series engines stops windage loss completely -- no, they don't come close.
Man.....
That looks like real nice stuff...I like the idea of the teflon crankscraper for the big rpm engines.
Zag
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Thats alot from straight windage control....
I say that because we never saw that kind of percentage on the Chevy Sprint Car (355cid) engines when we dyno'd them.
I still think the Suzuki has got pretty darn good oil control, but if you are getting that kind of percentage on the dyno I'll have to re investigate on the next build.
Zag
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On the Formula 1 tech lists I have seen remarks from designers that 8% can be regained but that involves a lot of money. Also straight percentages can be misleading but that is why I try to stick with dyno info from NA engines. That is just the way the data comes out.
Church's dyno in LA did testing for a Honda team on the D16 patterns and saw 3% gains and that is interesting considering the massive girdle structure in that engine. The Honda B-series engines with full windage trays showed 2.5% increases after a scraper was added. The reason is that a windage tray serves a different basic technical function: it is a shield for sloshing or splashing sump oil. Numerous OEM and aftermarket windage trays do have scraper louvers built in -- the iterative extension of that idea is the diamond stripper expanded metal screening sold by many suppliers. However, the trays present in the Suzuki G engines (that I have seen) do not fill a dual purpose.
For a very long time (post WWII designs) positive lubrication automobile engines have had rotating assemblies that spin well clear of the sump fill line in a static engine. Windage losses occur nonetheless because they are fed by large amounts of oil ejected from the rods, mains, oil relief valves and draining oil from the head. Good places to look at the design consequences are the late model BMW engines. They have dedicated passageways that isolate draining oil from the head that flows into the sump. This is a sea change from earlier designs. [The same design evolution can be seen going from the Toyota M series straight sixes to the JZ straight sixes.]
Here is a pic of a windage tray from a BMW m52tu that virtually seals off the sump: if you look at the bottom edge there is a series of large oil drain holes that link to tubes running to the head. Also note that the tray itself has many internal facing louvers -- those are actually another form of crank scraper.
(http://www.crank-scrapers.com/bmw_m52tu.jpg)
You might not have seen those percentages on the SBC because the skirts on the block are already very tightly confined around the rotating assembly (at the pan rail) and the scrapers for those engines tend to be quite narrow. Nevertheless, crank scrapers (versus windage trays) are considered to be such an unfair advantage at many circle tracks that they are banned (and often windage trays are allowed). Interesting, no?
Kind regards,
Kevin
Thats alot from straight windage control....
I say that because we never saw that kind of percentage on the Chevy Sprint Car (355cid) engines when we dyno'd them.
I still think the Suzuki has got pretty darn good oil control, but if you are getting that kind of percentage on the dyno I'll have to re investigate on the next build.
Zag
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Kevin,
Thank you for contributing to this thread. This is very interesting. Can you you tell me how much greater are the benefits of the Teflon scrapers over the clearance style.
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Neat stuff Kevin
Thanks for adding to the information pool...
Zag
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Kevin,
Thank you for contributing to this thread. This is very interesting. Can you you tell me how much greater are the benefits of the Teflon scrapers over the clearance style.
I do not have back to back dyno figures but my guess is that closing up the recommended .040" running gap on the steel scrapers is worth .5%, as in moving from 2.5% to 3%. Many professional engine builders will take clearances on the steel scrapers down to .015" and even .005". At .005", however, there is no room for error as the sum of the bearing clearances (mains added to rods) will approach this amount. That is also very close to the thrust clearance on some engines -- definitely something you should only do on an engine that is regularly torn down and inspected. The Teflon, however, allows you to safely accommodate these issues and run closer still.
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Checked out your website....
Neat stuff...what's the life expectancy of the scrapers?
Zag
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They should last the life of the engine like other mechanical components.
Checked out your website....
Neat stuff...what's the life expectancy of the scrapers?
Zag
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Kevin,
Thank you for contributing to this thread. This is very interesting. Can you you tell me how much greater are the benefits of the Teflon scrapers over the clearance style.
I do not have back to back dyno figures but my guess is that closing up the recommended .040" running gap on the steel scrapers is worth .5%, as in moving from 2.5% to 3%.  Many professional engine builders will take clearances on the steel scrapers down to .015" and even .005". At .005", however, there is no room for error as the sum of the bearing clearances (mains added to rods) will approach this amount. That is also very close to the thrust clearance on some engines -- definitely something you should only do on an engine that is regularly torn down and inspected. The Teflon, however, allows you to safely accommodate these issues and run closer still.
Thanks Kevin