March Month Coupon 5% off
   Forum Width:     Forum Type: 

 Posted: Jan 5, 2019 06:07AM
Total posts: 8066
Last post: Mar 20, 2019
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
A previous owner of my Mini dropped a MG Metro 1275 lump into it... poorly - unknown but worn dizzy, tired HS4 carb and Siamese cast iron manifold, probably all from the original 998. I can only assume it was dropped in with the final drive and speedo drive gears unchanged. I still don't know how fast I am really going in it - no tickets YET! It seems to show lower speed than actual speed. When I got the car, the speedometer would show kph until the engine warmed the outer sheath of the speedo cable, and its expansion would pull the core out of the drive gear. The needle would immediately drop to zero... WARP Speed! A new cable solved that problem. I got a speed app that will work on my phone but have to wait until spring to try it out on the Mini.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jan 4, 2019 09:37PM
 Edited:  Jan 4, 2019 09:40PM
Total posts: 
Last post: Jan 4, 2019
Member since:Jun 7, 2000
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
Dan, your comments about speedo drive gear and final drive ratio concerns are spot on.  Except sometimes there is an unexpected easter egg.  When I changed the final drive in my Innocenti to 3.1 but left the speedo drive gear alone, the two errors (speedometer internal error and drive gear error) neatly canceled each other - my speedometer is "dead on, balls accurate" ("it's an industry term") https://www.youtube.com/watch?v=y8hcfTFVJ9k

 Posted: Jan 4, 2019 01:29PM
Total posts: 3842
Last post: Mar 22, 2019
Member since:Oct 8, 2011
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
Thanks for the mention, yes I love to do tranny work. My driver is an 85 1000E. We started with a 998 with a 2.95 CWP. It would run 69 /70 but was a bit weak starting out. About 6 years back I replaced the 998 with a 1360 Cooper S engine with a rod change DAM5626 built with an Ultra-wide ratio gear set pulling a 2.76 CWP and an overdrive primary and first motion input gear. End result overall ratio of 2.56. Third gear gives the same speed vs RPM as a 3.44. 3000RPM with this setup results in 70 mph in fourth. I have mine and two others set up this way. I also have several with std gears sets pulling 2.76 CWP with a single O/D drop gear. I can put you in contact with either set up if you want feedback. I'd suggest you consider an SW5 or another cam with good low-end torque. And maybe a mildly ported cyl head. Steve (CTR)
  

 Posted: Jan 4, 2019 04:25AM
Total posts: 8066
Last post: Mar 20, 2019
Member since:Aug 14, 2002
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
CA
Another thing to verify is the speed you are actually going. The speedometer is governed by both the final drive ratio and the speedometer drive gear. You will have to match both for the size of wheels and tires you have. And then there's the speedometer accuracy itself. Start with a cellphone speedometer app to check yor actual speed.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jan 2, 2019 05:11PM
Total posts: 3383
Last post: Mar 5, 2019
Member since:Feb 26, 1999
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
First you need to decide what you want - it's a speed vs acceleration thing, you sacrifice one for the other.  First I would get a tachometer, whether it is one you put in the car or a test meter with cables long enough to have in the car while you drive.  You will need to verify how fast you are going at what RPM.  It would also help you to give some idea of the final drive you currently have.  For example running 165/70-10's with a 3.44:1 final drive you are going right at 65 MPH, and with a 2.95:1  it is just above 75.  There are also 4 other ratios in between 3.44 and 2.95.  To change the final drive ratio is an engine out job.

 Posted: Jan 2, 2019 09:49AM
Total posts: 8866
Last post: Mar 20, 2019
Member since:Jun 5, 2000
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
US
I agree with Bill that if you want to turn lower revs on the highway you will want different final drive gearing in the differential.  Steve (CTR) for years drove a Mini with something like a 2.95 final drive and from memory he said it worked well on the highway.  Steve could probably make this swap for you (if the gearing is available) but your profile says you are in CT.  Steve's shop is in coastal VA.

For reference, a Mini on 10" tires with a 3.44 final drive will be turning about 4000 RPM at 65 MPH.

As for the tachometer, almost anything you find in a parts store will work with your '89.  Look at the space available in/on your dashboard and select something you like that is of an acceptable size.  There is a pretty much generic wire color code used with modern tachs.  You will find at least red, black, green, and white wires.  Black is for ground and gets connected to a metal point somewhere on the dash.  Red is switched +12V.  Look for any (solid color) dark green wire behind the dash and splice the red wire into an existing green wire.  The tach's green wire is pulled through the firewall and run to the ignition coil.  Connect it to the coil (-) terminal.  Finally, the white wire is for gauge illumination.  Red and red/white wires behind the dash will be for gauge lighting. Splice the tach's white wire into one of those wires.    

Doug L.
 Posted: Jan 2, 2019 07:28AM
Total posts: 3295
Last post: Mar 22, 2019
Member since:Oct 4, 2013
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
scuba..  well..  best to talk to steve gibbs/ cooper tune racing..  65 MPH max seems strange in 1275.. I had one in my blues wagons.. and drove it every day for 10 years.. plus .. might change  to 2.9 final drive.??. later bc

 Posted: Jan 2, 2019 06:51AM
Total posts: 1
Last post: Feb 28, 2018
Member since:Jun 1, 2016
Cars in Garage: 0
Photos: 0
WorkBench Posts: 0
1989 Rover w/1275.

I want to make this car a daily driver, or atleast a few days a week, instead of the Sunday driver.  The biggest issue I have is that I drive on the highway most of the way to work, and the car seems like it is near its redline at about 60-65 MPH.  I do not have a tach (if you know how to add one, and which one to add please comment).  I would like to keep the 1275 engine, i dont have the cash to do the VTEC upgrade....is there a cheaper option which would make this little guy get better on the highway...maybe upgrade the gearbox? Any suggestions would be greatly appreciated.  I love driving this car and want to drive it more, but highway cruising is tediuos at best for this little guy.  HELP!!!