Kevin Shasteen Posted November 16, 2001 Share Posted November 16, 2001 Ok, Davy opened this can of worms on the "Short Stroke SBC" post whereby he made mention of a 327 crank in a 400 block. Surely this has been done before; yes/no? Anyone have any info on this combo? The curiosity bit me bigtime; so I plugged the #'s into my slider/crank format, these #'s are as follows: 1) Bore = .030 400SBC = 4.156 2) Stroke = 327SBC = 3.250 3) Piston Comp.Height = 1.560 4) Rod Length = 5.703 As a reminder; the slider crank mechanism (thanks again Pete for making me aware of this) is that once a graph is plotted, 180 degrees=1 degree for each crankshaft rotation, you can tell the speed at which the piston moves the most; if you want different data then simply alter you parameters. Anyway, I immediatedly noticed the piston deck to block deck height tolerance was a wopping .137 thousanths of an inch; so you'ld have to do a lot of decking of the block to get near 0.0" or .005" tolerance. This wasnt the surprising part-just thought I'ld pass it along as food for thought. The surprising data was that the piston seemed to hang around TDC, even more so than the 327 SBC in its stock configuration. The piston's actually .020" slower in all measurements, at the top of the cylinder than the 327. Its not till the piston reaches 90* (the * icon = Degrees). This is the interesting part. At 90* the piston is dead center .500" in the middle of the cylinder, and from here on to BDC the piston travel is an exact duplicate to the 327sbc. The pistons on all other SBC configurations, from TDC to the 90*' mark of crankshaft travel, is about .020" further down the cylinder. Can someone aid me in translating this phenomenon(?). Would this not be a good thing for Dwell Time? Has someone put a 327 crank in a 400 block before? I'ld bet this engine would a revving mama-jama...unless again I'm completely off my rocker, which is quite possible. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 16, 2001 Share Posted November 16, 2001 Kevin, I see no reason why the 353 and the 327 would have different graphs considering they both have the same stroke/rod length, which is all you need to produce such a graph. Could you post a link to a site with the crank slider applet? Too lazy to look for it myself Now hot-rodders (especially oval racers) have been sticking 327 cranks in 400 blocks for a while. Hot Rod magazine recently did a write up on this combo outfitted with longer rods for more efficiency.. Check it out, here is the link: http://www.airflowresearch.com/Articles/A3-P1.htm Yes, it does indeed rev to the moon, and 11:1 compression on 87 octane and a 215* @0.050 cam is VERY impressive... Goes to show the benefits of a good rod/stroke ratio that I outlined in a previous post, and that is why I am trying to find a combination of rod and pistons to increase the l/s ratio for cheap. $600 for a set of custom pistons is a bit too rich for my blood... Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted November 16, 2001 Author Share Posted November 16, 2001 Omar, I couldnt post anything if my life depended on it; computer illit myself Thanks for reminding me of that site; I remember it being posted a couple times last year but didnt remember what components were used. I still dont like the short piston comp.height they used as the pin is well into the ring lands..not too sure about durability(?). I remember reading that site before but that was prior to my understanding the crank/slider mechanism & formatting it on excel. FWIW: when using the crank/slider mechanism as a tool for piston location, you have to use a Block Deck Height to Piston Deck Height Tolerance of "0"...which means a theoretical "0" block to piston tolerance. Otherwise the piston is still down in the cylinder, for the purpose of the graph, & the results indicate neagative numbers. This would skew your attempts. That's why I mentioned the excessive decking. Anyways, I'll to get my brother (IT Tech) or my mom to instruct me on how to "post" pic's here at Hybridz so everyone can see; he's suppose to be visiting for T-giving. I'll try to post something then. Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 16, 2001 Share Posted November 16, 2001 Kevin, I don't see why the deck height has anything to do with it. The graph should always go to TDC height, not the deck height of the setup. So for the same stroke and rod length, the graphs are identical. In otherwords, use the TDC point as the datum, not the highest deck height - that's too variable and has nothing to do with the slider crank issue. BTW, they used a Ford 300 6 Cylinder rod to get the deck height to a reasonable level. That will change your slider crank results appreciably though. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted November 16, 2001 Author Share Posted November 16, 2001 Okay guys...figured out the mystery. On my form for my slider crank I can input the parameters which alters the #'s but in order to know which engine combo is being plugged into the format I have to 'change the heading' from one engine to another; which appears on a few of my print outs the header was changed but not the parameters. Translation: Junk In=Junk Out Now I have to go thru each one of my print outs just to confirm which are correct & which are not correct. I knew that Block Deck Height has no bearing on piston speed...as that is a function of stroke, rod length; which is why I was so surprised when I got the 'new numbers' I thought I had. Oh Well; guess that Nobel Piece Prize will have to wait afterall. I momentarily got off track from throwing myself a curve...but I'm back to the normal abnormal self. Kevin, (Yea,Still an Inliner) Kevin, (Yea,Still an Inliner)...now I'm repeating myself-is that normal? Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 16, 2001 Share Posted November 16, 2001 quote: Originally posted by Kevin Shasteen: I momentarily got off track from throwing myself a curve...but I'm back to the normal abnormal self. Thank goodness for that - we need your normal abnormalness to keep the atmosphere here correct Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted November 17, 2001 Share Posted November 17, 2001 just for the record....if you deck height is taller on one block than another it will significantly change the compression height. That's why people deck a block to boost comp. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted November 18, 2001 Author Share Posted November 18, 2001 It appears the saga continues w/my Dynamic Compression Slider Thingy. Prior to having a new computer my brother copied from the old hard drive to the new hard drive; anyway's it did something to my slider crank formula & caused the numbers to be skewed so my previous #'s on my printout's were correct. Luckily I had the old format copied to disk; but, to say the least...this has been a pain! I still will go thru each printout of each eng.configuration just to make sure which is correct & which is not. I've been slimed by my own computer that hurts! Blasted Computers! Kevin, (Yea,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
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