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View Full Version : Tachometers for 6 volt positive ground systems



Tubman
09-23-2017, 12:08 PM
Although I am new here, I've been on several boards (mainly old Ford related) for a long time, and in my travels, I have seen more than a few requests looking for tachometers (http://rover.ebay.com/rover/13/0/19/DealFrame/DealFrame.cmp?bm=427&BEFID=96477&aon=%5E1&MerchantID=532444&crawler_id=532444&dealId=GjYYn6uyNq3BnvxAeL1CHg%3D%3D&url=https%3A%2F%2Fwww.moderngenauto.com%2FC3-Corvette-1978-1982-Tachometers_p_12753.html&linkin_id=8058742&Issdt=170923125843&searchID=p29.b92f62a44ba4757c0e75&DealName=C3+Corvette+1978-1982+Tachometers&dlprc=189.99&AR=1&NG=1&NDP=1&PN=1&ST=7&FPT=DSP&NDS=&NMS=&MRS=&PD=&brnId=14305&IsFtr=0&IsSmart=0&op=&CM=&RR=1&IsLps=0&code=&acode=442&category=&HasLink=&ND=&MN=&GR=&lnkId=&SKU=7371) to run on 6 volt positive ground cars. There seems to be one choice, and they are quite bland and expensive. Because of this, I've gotten together with a friend who is a long time electrical engineer and we have developed a "black box" that allows the use of most currently available 12 volt negative ground tachs on 6 volt positive ground cars. We made three prototypes about a year ago and have been field testing them since. The tests were successful, so we incorporated a few improvements we deemed desirable, and have just finished a run of 10 production units. Six have been spoken for, so I still have 4 available. I am posting this here to see if there is any interest. I've posted a couple of photos, The first shows a small SunPro unit in my '51 Ford at idle. The second shows the unit itself (the black box mounted (http://rover.ebay.com/rover/13/0/19/DealFrame/DealFrame.cmp?bm=65&BEFID=73188&aon=%5E1&MerchantID=300086&crawler_id=811181&dealId=o5v0FTy_Hu7On1EYEI2s-w%3D%3D&url=http%3A%2F%2Fclickserve.dartsearch.net%2Flink%2Fclick%3Flid%3D92700014999069 387%26ds_s_kwgid%3D58700001245061795%26ds_s_inventory_feed_id%3D9770000000100232 0%26ds_e_product_id%3D92564224%26ci_customer_id%3D1001227%26ci_cse_id%3D1004%26c i_feed_id%3D1004921%26ds_e_product_merchant_id%3D6382239%26ds_e_product_country% 3DUS%26ds_e_product_language%3Den%26ds_e_product_channel%3Donline%26ds_url_v%3D2 %26ds_dest_url%3Dhttps%3A%2F%2Fwww.kohls.com%2Fproduct%2Fprd-1016629%2Fbox-storage-ottoman.jsp%253Fci_mcc%253Dci%2526utm_campaign%253DEC%252520ACCENT%252520FURNITU RE%2526utm_medium%253DCSE%2526utm_source%253Dshopping%2526CID%253Dshopping17%26s dc_id%3D%7Bsdc_id%7D&linkin_id=8058742&Issdt=170923125843&searchID=p28.e1ce0844493ebb25e39c&DealName=Box+Storage+Ottoman%2C+Black&dlprc=101.99&AR=2&NG=4&NDP=5&PN=1&ST=7&FPT=DSP&NDS=&NMS=&MRS=&PD=&brnId=14305&IsFtr=0&IsSmart=0&op=&CM=&RR=2&IsLps=0&code=&acode=67&category=&HasLink=&ND=&MN=&GR=&lnkId=&SKU=92564224) on the firewall; please excuse the messy wiring; I'm still in test mode). Also, here is a link to a YouTube video of one of the prototype units running on a Mercury engine (http://rover.ebay.com/rover/13/0/19/DealFrame/DealFrame.cmp?bm=954&BEFID=96477&acode=939&code=939&aon=&crawler_id=455941&dealId=DKpVAb_5Ne8dCQiHMrrFnw%3D%3D&searchID=&url=http%3A%2F%2Fwww.partsgeek.com%2Frpdyvyt-lexus-es250-engine-coolant-temperature-switch.html%3Futm_source%3Dshoppingcom%26utm_medium%3Dpf%26utm_content%3Dttc%26u tm_campaign%3DPartsGeek%2BShoppingCom%26fp%3Dpp%26utm_term%3DLexus%2BEngine%2BCo olant%2BTemperature%2BSwitch&DealName=1990-1991%20Lexus%20ES250%20Engine%20Coolant%20Temperature%20Switch%20-%20Replacement&MerchantID=455941&HasLink=yes&category=0&AR=-1&NG=1&GR=1&ND=1&PN=1&RR=-1&ST=&MN=msnFeed&FPT=SDCF&NDS=1&NMS=1&NDP=1&MRS=&PD=0&brnId=2455&lnkId=8070676&Issdt=170922051323&IsFtr=0&IsSmart=0&dlprc=10.95&SKU=7514-02682144) on my test stand (http://rover.ebay.com/rover/13/0/19/DealFrame/DealFrame.cmp?bm=603&BEFID=96669&aon=%5E1&MerchantID=523588&crawler_id=523588&dealId=7teutQlXpMOtH-aHdNbyNw%3D%3D&url=https%3A%2F%2Fads.midwayusa.com%2Fproduct%2F798812%2Fhollands-third-hand-micrometer-stand%3Fcm_mmc%3Dpf_ci_ebay-_-Reloading%2B-%2BMetallic%2BReloading%2BEquipment%2B%2528Not%2BPresses%2529-_-Holland%2527s-_-798812%26sdc_id%3DeBay&linkin_id=8058742&Issdt=170923123601&searchID=p30.8b8febfdb1d1aff8e447&DealName=Holland%27s+Third+Hand+Micrometer+Stand&dlprc=39.99&AR=3&NG=4&NDP=5&PN=1&ST=7&FPT=DSP&NDS=&NMS=&MRS=&PD=&brnId=14305&IsFtr=0&IsSmart=0&op=&CM=&RR=3&IsLps=0&code=&acode=601&category=&HasLink=&ND=&MN=&GR=&lnkId=&SKU=798812). https://www.youtube.com/watch?v=TaxpuDkWAqc

If anybody has any interest in these, you can contact me by email at dennyodoms@gmail.com. The units are priced at $120 each plus $7.15 shipping.

StudeRich
09-23-2017, 12:58 PM
That is a very useful and needed item Denny thanks for posting. :!:

We know a Guy here that runs his '55 Stude. V8 at the Muscle Car Drags, that maybe could use that!

Tubman
09-23-2017, 01:21 PM
Rich, thanks for the kind words. I appreciate them. Yeah, for racing you can run one of the fancy new units with a shift light and rev limiter and all that jazz. We have tested this with everything from a $10 "swap meet special" to a $600 Autometer high end racing unit, and they all worked. We have found the more expensive the tach, the more accurate it will be.

Tubman
10-04-2017, 12:46 PM
Bringing this back to the top because I have only two of the original run left. If there is enough interest, I will try to get 10 more done before I leave for Florida (it it's open) for the winter next month.