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Don, The 3.73 diff from a late rubber bumper Midget will drop a couple hundred revs at 70 mph, and larger tires a little too. Lots easier and cheaper than a different tranny. I don't remember what year your car is, but if it's a 1275, 4000 rpm all day long won't hurt it. Now that you're older (like me), you just worry more about that stuff. Just FYI, I have read that the factory test, when they were building new Spridget engines, was 100 hours on the dyno at max HP. That's about 10,000 miles pedal-to-the-metal. "Jeffrey Holmes"... MORE
My 'tu-pence' : I want to be able to drive the spridget..where ever and as often as possible. Spending nuff time in garage with sons Porsche. Agree with the hi-rev's/hi performance might equal more down time for maintenance. With that in mind, and funds being available, it would seem a blend of euro-asian makes sense. But then just how far should one push the blend? If the 210 box works great.. some other power plant as well work better than the std. 1275 (or whatever ones flavor of spridget came with)? Would like to think all spridget can be... MORE
May I disagree. For years I ran my mk2 Sprite with 1275 and 4.2 diff. It was a bit buzzy at 80mph on the motorways but easily bearable. Much of this was hood up to and it's much better with hood down which is I'm sure most of the year where you are. You then have the options of either a 3.9, 3.7 or even 3.5 (Moss now sell them again) to make things even better. 3.5s aren't cheap but they are cheaper than a datsun box and fitting kit. "Jeremy Cogman" 25208... MORE
Well said, Don May... You hit the nail on the head..exactly spot on. This is the position I found myself in, more or less. Prior to knowing about the Datsun 5 speed, I attacked "the problem" by moving the whole rpm range upscale to 7-7.5k rpm by "Vizarding" a 1275 and making 4-4.5k rpm a comfortable cruising rpm. Supertuning the motor to take higher rpm is not inexpensive... for it's operating range is just short of a track motor. Weber 45DCOE, bigger valves, prepared head, VP3 cam and 1.5 rollers, big bore LCB and large diameter free-flow exhaust system... MORE
"What's the sense of gearing these cars primarily for highway cruising?" Well.... 'Cause I didn't get a BE so I could leave it home in nice weather when I commuted down to NYC airports to fly the friendly skies in bascially 70mph limited access highway driving circumstances where having a 5 speed enables me to tune for low and mid-range instead of top end, as one might have to do with a 4 speed and 3.9. :):) All depends upon the driving circumstance, state of tune, spec., etc. Considering my engine spec in terms of torquey low and mid-range... MORE
Yes an excellent motor sport diff used it all last year however it is very busy on the road and a bit short on long straights and to get the best you need a free reving engine etc mine is safe to 7500 and revs freely to 7000. Some other competitors are using 5.3 very rare now only fitted to Morris Minor GPO vans I think "Peter Whittle" 25187... MORE
Well, Stewart... If the modded 1275 pulls smoothly from idle to the degree you state, I don't see the problem then in terms of low end and clutch wear...I'd go with the 3.7 and see how you like it? Cap'n. Bob '60 :{) PilotRob@... 25193... MORE
Don... "Sounds" (excuse the pun:) like you've got a glasspack (free flow) on there, maybe a Thrush or Cherry Bomb. These are "straight thru" designs (as opposed to the "baffled" stock (or Midas/Meineke/ Walker, etc.) system. It may also be the optional "GEX" straight-through type I've see advertised by MiniMania. "Straight thru" design with sound deadening packed around the "open" core allows for perfomance and/or gas economy along with allowing for a cooler running engine due to the easier trip the hot exhaust gases have outbound. allow the engine to run a little cooler as well as the exhaust... MORE
Jason... The engine should be running at the value of your thermostadt. Most shops (mechanics) have gauges to check the accuracy of your gauge in terms of comparison. Cap'n. Bob '60 :{) PilotRob@... 25190... MORE
The useless road engine was the cars original 948 motor.. that was a right screamer, and overheated in traffic all the time.. The Current one seems much happier, but as I said the result is it will not even notice going right round the rev counter and out the other side in 4th!. The modded 1275 does have a lumpy idle, but pulls cleanly from standstill, and can pull off from rest in 4th although this does require abuse of the clutch (but not as bad as you might think.) I believe my 1500 has a 3.9 diff so... MORE
Pretty sure the diff in it is the 4.55, whether its original or not! As for the engine.. its a bored out 1275.. to 1380. although not much more is know about it apart from the idle has always been lumpy and the car went like stink! The car itself was used for hilclimbing, but this was with the original 948 engine taken out to 998. this engine had been tweaked beyond all hope, and a useless road engine as a result (hence the later bigger engine). It has disk brakes on the front, riley 1.5 drums on the... MORE
Rob, Why? Mine is much better with all 4 wheels on the ground, in gear and with the engine running. It's much more fun that way. Have I lost the point of this thread? Guy "Guy Weller" 25160... MORE
You can anticipate the changes by working it out in terms of percentages. Changing a 4.22 diff with a 3.9 diff is about a16% change. Revs in any gear for a particular road speed will reduce by 16%. Or road speed will increase by 16% for the same revs. In theory (but not in practice) acceleration will be worse by 16% which sounds a lot but is barely noticable. That said, acceleration changes are not quite so straightforward as it depends on how well the gearing is matched to your particular engine torque and power characteristics. And these depend... MORE
David said: Don't forget though, that BMC could get away with making 1275 Spridgets I think we forget just how much roads in the UK have changed over the last 30 - 40 years! There were few roads of anything like the current standards. Most, even "A" roads, were really quite twisty (Ok, some exceptions) and with poor surfaces. Dual carriageways were still very much the exception. Most other traffic, (except e-types !), were a good deal slower with common saloon car open road cruising speeds of 40mph or less. Even so, contemporary test reports from ' 68 complained... MORE
Stewart..... If your engine is tuned for the high end (and it certainly sounds this way.."useless road engine"...."lumpy idle"), then going to a 3.7 will make it more a useless road engine in terms of the low end. So...it you are using the car mostly at highway speeds (say, 3k or higher) than no problem. Town driving will become more of a hassle as you'll be at lower rpm more of the time at lower speeds, unless you retain lower gears more of the time then you are currently used to. The more available 3.9 might make for a... MORE
I want to put a coin box on it, and mount it on a pedestal in front of the local supermarket as an amusement ride? When you are retired on a fixed income one must come up with ingenious ways to support the spridget habit. :-) I was working out in the driveway yesterday and a fellow saw a couple of my spridgets and commented that he once had a collection of 13 Nash Metropolitans. Men and their one-up-man-ship. All I really want to do is mount my spare the engine and transmission back in my 69 parts car... MORE
Seems the PO's of my purple 73 wanted that race car sound, well its not modified to be a race car and the sound level is annoying especially out on the freeway, like riding on top of a WW2 buzz bomb. It's a fairly new muffler and pipes so its not loud because of age. The question is, what are the considerations I should keep in mind when choosing a new muffler? Don't care if it is stock as long as it fits and is correct for the engine which I suspect is bored out a bit but otherwise... MORE
You've successfully made every argument on the situation. Pick your poison...'-) The OD unit is probably the easiest and most practical. Your other option is to install a 1275 with a Datsun 5 speed. That's the best choice in my opinion. Easily done too. You could opt for all Datsun drive train too. Gerard "gerardchateau" 25154... MORE
Dear Listers, After tinkering with my '75 Midget all summer I finally have the beast to some standard of reliability having (knock on wood) cured the lean running problem. My next endeavor is to swap the Stromberg for a pair of SU's and to replace the clutch due to weak springs, I hope. I will probably lighten the flywheel while I'm at it. Since I will be pulling the engine anyway why not address the unsatisfactory gearbox as well. Running 4000 rpm at 65 mph doesn't sound good to me. Unfortunately the 1500 engine doesn't have a nice swap... MORE
Stewart, is the 1275 in standard tune? If so, the acceleration won't be sparkling but it's perfectly usable and much more relaxed than your original (which would have been 4.22:1 not 4.55) The top gear mph/1000rpm will go up from around 15 to 18, so 70mph will see the revs drop from 4700 to 3900 (roughly) Don't forget though, that BMC could get away with making 1275 Spridgets with 4.22 diffs as standard, so they must've thought it was reasonable at the time! Regards David "David Jacobs" 25148... MORE
IIRC the fraction you refer to is in fact the number of teeth on the pinion/crown. Actually I was gong to ask about diffs any way. I have two for the frogeye (which has a later 1275 motor) the original one which IIRC is 4.55:1 and a riley 1.5 one which is a 3.7:1 diff. What would the effect of fitting the 3.7 diff to the frogeye have, as it stands its will rev straight through the red line and out the other side in top gear, even up hills speed at the red line is 80 ish with... MORE
Don, Depending on the severity or gentleness of the curve, use a longer or shorter board for sanding. (Steep curves= shorter board.) For inside (concave curves) use a cardboard roll or a very short nap paint roller woth sandpaper rolled around it. Also, remember I told you to sand "crosshatch" so you avoid low/high spots. This is especially true for curved areas. It does take some artistry , a sensitive touch and a good eye though. Did you buy the guide coat like I suggested? This helps a lot too as vents you from sanding too much. You should... MORE
Wake me up please. Our '73 RWA 1275 cc has a neg. ground where as the '59 Bugeye has a pos. ground? Correct?? Looking for battery cables in Brit. Vic and they have corn-fused me. (8-3051, 8-4300 and 10-337) Thank you, Bill French frenchww@... 25134... MORE
From: gerardchateau To: midgetsprite@yahoogroups.com Sent: Wednesday, September 10, 2003 1:15 PM Subject: [midgetsprite] Re: Compound curves Don, Depending on the severity or gentleness of the curve, use a longer or shorter board for sanding. (Steep curves= shorter board.) For inside (concave curves) use a cardboard roll or a very short nap paint roller woth sandpaper rolled around it. Also, remember I told you to sand "crosshatch" so you avoid low/high spots. This is especially true for curved areas. It does take some artistry , a sensitive touch and a good eye though. Did you buy the guide coat like... MORE
When I converted the 65 Midget to negative earth, the only thing that neede d attention was the tach. I just unhooked it. Wiper motor, fan motor, fuel pump, etc. not affected by the swap. Brad "Brad Fornal" 25130... MORE
