arnout Posted October 21, 2004 Share Posted October 21, 2004 Hi Guys, A few months ago I posted in this thread on Supraforums about a company here who can make any crank in any dimension. So I asked them to make a stroker crank with the exact same specifications as the HKS 3.4L kit. This company makes one crank at a time, and usually it takes about 6 weeks before it's finished, but they were quite busy and I didn't have the time to pick it up, so it turned out to be 3 months.. BUT.. it arrived, yesterday. And here are the pictures: http://www.supras.nl/iB_html/uploads/post-2-87662-stroker_013.jpg This is the crank. Using this crank makes the stroke 94mm (+8mm). To compensate for the bigger stroke we have to install custom rods and custom pistons. I don't have these yet, but I will check to have pauter make the rods and JE pistons make the pistons. The pistons will be +1mm oversize (2nd oversize), same specifications as the HKS stroker kit. Obviously the pistons will get a deeper dish, lowering the compression because of the added stroke. We could choose to have a crank made in any specification, but as a 'fully counterweight balanced' crank is these days the 'best' option to go with, we had this one made. The counterweights are kind-off 'knife edged' so they 'cut' through the oil like a knife. http://www.supras.nl/iB_html/uploads/post-2-87878-stroker_002.jpg The part of the crank that connects the rod journals with the main journals represents the strength of the crank. As you can see in the following picture, we made the crank as thick as possible to get the best strength. Yes, we're aiming over 1000 HP with this crank. http://www.supras.nl/iB_html/uploads/post-2-88000-stroker_006.jpg I don't have the pauter rods yet, so I test fitted with a set of Eagle rods we had in stock: http://www.supras.nl/iB_html/uploads/post-2-88137-stroker_001.jpg The journals are all the same size as the stock crank. This allows us to make use of stock size bearings. On the next picture you see a standard size bearing (clevite 77) on the rod journal. As you can see the bearing could have been choosen to be a little bit wider, like the twinsturbo guys suggest in their videos. The bearing will have more 'area' but in return the thermic stress on the bearing will be higher. In practise is already shown the stock size bearings are sufficient for high horsepower, but obviously we can experiment with this. http://www.supras.nl/iB_html/uploads/post-2-88355-stroker_009.jpg Now we gotta wait for the matching rods and pistons and I can build a block during winter and do some dyno-ing with it! Wish me luck :-) Quote Link to comment Share on other sites More sharing options...
michael Posted October 21, 2004 Share Posted October 21, 2004 Great to see more and more bespoke parts appearing - looking forward to following your progress Quote Link to comment Share on other sites More sharing options...
Miguel Posted October 21, 2004 Share Posted October 21, 2004 Top man! that looks fantastic. I will be keeping a close eye on this project me thinks as it has weted my tastebuds.....keep it up you talented man :thumbs: Quote Link to comment Share on other sites More sharing options...
dandan Posted October 21, 2004 Share Posted October 21, 2004 You must have some serious ££ floating around Arnout. Some very good projects coming from your direction, keep it up and best of luck. What material is the crank? EN40B, forged? Quote Link to comment Share on other sites More sharing options...
Digsy Posted October 21, 2004 Share Posted October 21, 2004 Hopefully EN40B. It looks like a billet crank though. Nice job Arnout! Any case hardening or other surface treatments? Nitriding, peening, etc? Crank arm number 2 in the top pic looks thin. Is that just an optical illusion or is the crank really like that? Did they work from a pattern crank or a drawing or what? Again, nice one! Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 22, 2004 Share Posted October 22, 2004 Not much pin overlap, but at least it's fully counterbalanced. That's one hell of a long stroke Arnout. It will be a brave man who tries big revs on that baby! Good work, you are getting into this custom stuff big style! Quote Link to comment Share on other sites More sharing options...
Gaz Walker Posted October 23, 2004 Share Posted October 23, 2004 All I have to say is Gaz. Quote Link to comment Share on other sites More sharing options...
veilsideTT Posted October 23, 2004 Share Posted October 23, 2004 Arnout, Is that my old block????????? Scott. Quote Link to comment Share on other sites More sharing options...
arnout Posted October 23, 2004 Author Share Posted October 23, 2004 Originally posted by veilsideTT Is that my old block????????? Yes indeed! And we used your worn out crank as a sample for the stroked crank! Quote Link to comment Share on other sites More sharing options...
Guest Usmann A Posted October 23, 2004 Share Posted October 23, 2004 Very nice indeed! Will you be using billet main caps? or stock? I know they are not as stressed as rod bolts/caps ... But another re assurement none the less. By you increacing stroke, like you say will lower compression by deeper pistons bowels .. what compression ratio you aiming for? even with deeper cut bowels, due to added stroke itll be near stock 8.5:1? I understand if you do not want to share . Great stuff. Quote Link to comment Share on other sites More sharing options...
Paul -C- Posted October 24, 2004 Share Posted October 24, 2004 Looking good arnout! Quote Link to comment Share on other sites More sharing options...
arnout Posted October 24, 2004 Author Share Posted October 24, 2004 To answer a few of your questions: Yes the crank is of the same material strength as EN40B / Billet. Obviously you can nitrate the crank, but I think it will not be needed for this unit. Shotpeening is normally done to rods, not really to cranks. The crankcase is a different story. I've never done any material strengthening operations on crankcases. Chris: I know about the pin overlap, that's why we made the crank way thicker on the connection pieces from the rod pins to the main pins. This way we can guarantee the strength of the crank. About revving: The crank itself should be able to rev up to 9000 RPM. The problem relies in the whole stroker kit design. Having the stroke increased means we need shorter rods. This gets the rod / stroke length currently at 1.51 which is pretty low. A safe rev limit for this would be 7500 RPM (maximum). But obviously with this increased stroke you don't need to rev the engine that high because it's building more torque (and boost) due to the increased volume (so it doesn't need to get it's power from increased rev limit). I might be able to make a spacer plate to be placed (and welded) on top of the shortblock, to increase the cylinderheight which allows us to put longer rods in the block. But I will investigate that when the first versions (with the shorter rods) are produced. We will not use billet maincaps. Instead we will use longer ARP studs on the stock caps. The longer ARP's allows us to place a cradle plate (stud plate) on top of the main caps. This gives the whole engine more strength. The compression ratio must be determined by the engine shop who assembles the whole engine. Our kit will be using something between 8.5 and 8.2 most likely, but final compression ratio can be compensated (and must be compensated) by the engine builder. You never know how much a head or block is resurfaced, and you can buy headgaskets in various thicknesses. Quote Link to comment Share on other sites More sharing options...
veilsideTT Posted October 24, 2004 Share Posted October 24, 2004 Yes indeed! And we used your worn out crank as a sample for the stroked crank! I want it back!!!! With all the goodies attached!!!!!! :D Jus kiddin! Nice to think that my old block will be used on a monster supra!! Good work arnout! Quote Link to comment Share on other sites More sharing options...
Digsy Posted October 24, 2004 Share Posted October 24, 2004 Originally posted by arnout To answer a few of your questions: Yes the crank is of the same material strength as EN40B / Billet. Obviously you can nitrate the crank, but I think it will not be needed for this unit. Shotpeening is normally done to rods, not really to cranks. The crankcase is a different story. I've never done any material strengthening operations on crankcases. Chris: I know about the pin overlap, that's why we made the crank way thicker on the connection pieces from the rod pins to the main pins. This way we can guarantee the strength of the crank. About revving: The crank itself should be able to rev up to 9000 RPM. The problem relies in the whole stroker kit design. Having the stroke increased means we need shorter rods. This gets the rod / stroke length currently at 1.51 which is pretty low. A safe rev limit for this would be 7500 RPM (maximum). For a one-off or limited run billet EN40B is the only real choice. I have some figures at work somewhere for increases in strength for nitriding. No idea how much it costs but I would have thought it was worth it. Cranks can be shot peened around the crankpin and main journal fillets, where the highest fatigue loading is (the same area that you have reinforced by adding material to the crank arms). Its an alternative to fillet rolling without the need to undercut the fillets or set up costly tooling. But you are right, it is more usually done as an all over operation on rods. Speaking of the extra material on the crankarms, have you made it thicker in the "along the crank" direction, or wider "across the engine"? Along the crank would be better from a section strength point of view but any extra material will help. Along the crank you are obviously limited by the distance between the main journal and the crankpin. There was another thread a while ago that touched on the pros and cons of boring and stroking where the inertia problems of decreasing the L/R ratio were dicsussed. A block spacer plate is a novel solution. Not something I have experiance with. I guess you would have to have the block re-honed with it in place? I agree that there is no point in strenghtening the caps themselves just because of the increased HP. You would run a main bearing long before you broke a cap. The extra stiffness from a bottom end ladder frame is something well worth considering though. I'm sure you would be the first to do that to a 2JZ! Keep us all informed Quote Link to comment Share on other sites More sharing options...
arnout Posted November 15, 2004 Author Share Posted November 15, 2004 Originally posted by Digsy The extra stiffness from a bottom end ladder frame is something well worth considering though. I'm sure you would be the first to do that to a 2JZ! We're also the first one (most likely) who did this to a 7M. Here is the engine cradle (stud plate / bottom end ladder) for the 7M engine I'm building for Christian in Germany. http://www.supras.nl/iB_html/uploads/post-2-34919-mini_DSCF0011.JPG No news on the stroker kit as of now. We're waiting for the rods and pistons to arrive. Quote Link to comment Share on other sites More sharing options...
arnout Posted February 4, 2006 Author Share Posted February 4, 2006 Finished an engine with this kit the other day. Here are some pictures. Ken, check my 2jz-gte girdle, you'll like it! Here is the crank in the engine: http://www.supras.nl/phpBB2/attachments/kappengemonteerd_663.jpg I flattened out the main caps and used spacer rings and longer main studs: http://www.supras.nl/phpBB2/attachments/dscf0003_101.jpg Here is the girdle mounted in the engine: http://www.supras.nl/phpBB2/attachments/dscf0001_313.jpg Perfect fit: http://www.supras.nl/phpBB2/attachments/dscf0006_162.jpg Quote Link to comment Share on other sites More sharing options...
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