<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">WOW - could it be that simple... ? I run modified 240Z finned aluminum drums - same as has been on the car for awhile. I have noticed while adjusting the rear brakes that they are not absolutely true - when adjusted a notch too tight, 180 deg. makes the difference from a bit tight to totally free. They have been that way for the couple years I've run them but never a problem. Curious though that you mention those 3 tracks - 2 that I've been on in the last two weeks and probably the fastest that I've ever seen and don't care to in the current condition. However, I would think that it would be a progressive problem - not one that would come on with such a difference [still not convinced that it is not 4th gear only - been racing, not testing and that is my fault]. I am packing spare cast drums, rear axle, hub and bearings and a diff cut off at the tubes [ not that I could DO anything with the diff. - only in hopes that I could find someone that could set it up should the need come up]. I guess that would be one change I could make for a chassis dyno. Otherwise I don't know that a dyno could help much. A really great stretch of road would be preferable but the 19 cops I've seen in the last couple hundred miles makes that seem unlikely. Wisconsin probably won't help either. There is lots to be said for New Mexico, and some of the "Last Open Roads" is near the top of the list.<div>Greg "Lunker" Hilyer</div><div>TR4 #314</div><div>Albuquerque NM<br><div><div>On Sep 15, 2008, at 7:20 PM, <a href="mailto:JHOUATHOME@aol.com">JHOUATHOME@aol.com</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"> <font id="role_document" face="Arial" color="#000000" size="2"> <div>Greg, </div> <div>My TR4 used to have a similar mystery vibration, which in the end, after much frustrating searching over many events, turned out to be an out of balance rear brake drum. Stupid, I know. I had also been through several attempts to balance wheels, replace wheels, and balance everything else, and simply never thought of those old iron drums. I swapped them out and never had the problem again. The strangest thing about it was that the problem seemed to be intermittent, and would crop-up with no pattern that I could figure out. In the end, that was it though. Upon more careful consideration I realized that it was only happening at Road America, the Glen, and BIR, all pretty fast places. I was delighted to figure it out. Hope this is your problem, and not something more expensive!</div> <div> </div> <div>Good Luck,</div> <div>John Houlton</div> <div> </div> <div> <div>In a message dated 9/15/2008 7:57:35 P.M. Central Daylight Time, <a href="mailto:lunkercars@earthlink.net">lunkercars@earthlink.net</a> writes:</div> <blockquote style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><font style="BACKGROUND-COLOR: transparent" face="Arial" color="#000000" size="2">Hello all,<br>Beaten by equipment...<br>My previous posting from Brainard quoted the common wisdom "you <br>gotta' finish to win". Well, I was reminded that you gotta' start to <br>finish. Sunday at Brainard shaped up to be what I would call "ideal <br>conditions"... cold, wet and basically miserable enough that only <br>fools/idiots/& the die-hards like me [3 in 1] would dare go out - <br>perfect. Not sure if excessive oil pressure from the 40ish temp on my <br>20W50 caused it [doubtful] or if it was just it's time, but upon <br>startup for the sunday race the oil cooler chose to rupture in the <br>pits and that was the end of that. Could have by-passed it for the <br>next race but it was canceled due to conditions too perfect for me to <br>even imagine. Oh well - finding out that the top 4 finishers behind <br>me on saturday are all ice racers boosted my ego enough and knowing <br>that they were all gunning for me might not have made sunday quite as <br>enjoyable as saturday.<br>Interesting to note that that although I do buy better that 50% of my <br>perts from Moss, 100% of my failures have been from parts they have <br>supplied. Once again, my cheepo nature has proven to be false <br>economy and bitten me in the butt.<br>Now on to good vibrations and bad vibrations. The Beach Boys told us <br>about the good ones but some aren't and never will be. First time I <br>ever felt the bad one was at Watkins Glen. It may well have existed <br>before but my car has never been on a track that fast. So far as my <br>butt and brain can tell, it doesn't come on until somewhere beyond <br>100mph. After getting the driveshaft straightened last week I thought <br>I had surely got to the problem. First couple sessions at Brainard <br>felt good but that proved to be a combination of wishful thinking and <br>not going fast enough. It's still there. For a time at The Glen and <br>again at Brainard I almost convinced myself that it was 4th gear only <br>but I am now pretty sure that it is only dependent on road speed - <br>i.e., it's felt near redline in 3rd and only gets worse as 4th <br>progresses. Scared the speed right out of me the first time I felt it <br>come on, but after many teeth grinding laps with nothing coming thru <br>the block [convinced it's not engine related], the trans. case, or <br>thru the floor, I've lived with it thru the last two races. Doesn't <br>mean I like it and that combined with a bum oil cooler, moody starter <br>[thanks again Moss Motors] and exorbitant entry fees, will likely <br>keep me from going to Road America.<br>Any Ideas? The drive-shaft straightening didn't seem to do anything. <br>I've run it on 3 different sets of tires and wheels, so that's not <br>it. U-joints are fine [by all appearances], can't find any slop in <br>the trans. output shaft or the diff, input [pinion] shaft nor any run- <br>out on the input shaft flange or axles. Defiantly not coming from <br>the front as it is not transmitted thru the steering wheel. Rear axle <br>bearings seem to be in fine shape.<br>The engine is fresh and in good balance. The trans. is new to me <br>[close ratio in a TR6 case] but no recognized problems from the <br>previous FoT owner. I have given the original, stock, open. 3.70 <br>differential a hard life since it's early retirement but I still <br>can't see how that would figure in. The only unknown is my frozen <br>axle shafts... As part of my recent "freshening", I sent the crank <br>shaft [more on that later], stub axles, front hubs, rear hubs and <br>half shafts to Controlled Thermal Processing [<a href="http://metal-wear.com">http://metal-wear.com</a>] <br>to be cryogenically frozen [-300f/+300f in a 68 hour process]. Being <br>unknown voodoo, I'm creating a scenario where the axle[s] have a bow <br>in it [them] causing a imbalance, causing the vibration but not <br>detectable from the flange end - not very likely but I'm grasping at <br>straws here [oh yea, I'm still in the mid-west so it must be corn].<br>Please believe me, at this point I am willing to consider any ideas <br>regardless how far fetched. And maybe one [some] of you know what I'm <br>feeling and have the spot-on answer.<br><br>Greg "Lunker" Hilyer<br>TR4 #314<br>Albuquerque NM <br> <br>_______________________________________________<br><a href="http://www.team.net/donate.html">http://www.team.net/donate.html</a><br><br>Fot mailing list<br>Fot@autox.team.net<br>http://autox.team.net/mailman/listinfo/fot<br><br></font></blockquote></div></font><br><br><br><div><font style="color: black; font: normal 10pt ARIAL, SAN-SERIF;"><hr style="MARGIN-TOP: 10px">Psssst...Have you heard the news? <a title="http://www.stylelist.com/trends?ncid=aolsty00050000000014" href="http://www.stylelist.com/trends?ncid=aolsty00050000000014" target="_blank">There's a new fashion blog, plus the latest fall trends and hair styles at StyleList.com</a>.</font></div></blockquote></div><br></div></body></html>