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MG Midget and Sprite Technical - Mixture issues 1275

I suspect slightly lean mixture (even at 5,000 ft), and could use some help.

My car: stock 1967 1275 w/60K miles; pertronix distributor, new Lucas coil and wires; Moss (K&N) chrome filters on stock SU 1-1/4" carbs w/viton needle valves and new standard needles, dampers, and springs; stock oil breather setup (PCV valve working); Champion RN9YC plugs w/.025 gap; aftermarket electric fuel pump feeds filter/regulator from Moss (didn't touch the adjustment--bowl appears full when running); 91 octane premium from Shell has some ethanol in my market.

My symptoms: engine starts easily and generally runs well, but: (1) a little whiteness on #1 & #4; (2) mild oil residue on #2 & #3; and (3) hiccuping when cruising in top gear over 4,000 r.p.m. I yanked the choke a tad (i.e., dropped the jets), and the hiccuping stopped but she didn't feel eager to go faster--which she should.

I am thinking of trying: (1) readjusting the jets, and if unsuccessful (2) putting in rich needles; and, if anyone thinks this could be the culprit (3) putting new umbrella seals on the intakes. (I can apparently do this w/head in place using KD air fitting & special spring compressor.) I'd rather not resort to needle-polishing. Any suggestions?
JM Young


When you state Pertronix distributor, do you mean a new Pertronix distributor or a Pertronix conversion to your stock distributor?

If a Pertronix conversion to your stock distributor, there may still be a problem with the advance mechanism not allowing power above 4000 rpm (incorrect total advance, etc).

Regarding the fuel pressure regulator from Moss: If it's the standard one they sell, they have known reliability issues. I just bought a brand new Mr. Gasket fuel pressure regulator (which appears to be exactly the same thing as the Moss unit so probably made by the same company) which was defective right out of the box, allowing little to NO fuel passage. It's operation was erratic at best. Taking it out of the loop solved the problem.

If everything is fine up to 4000 rpm, then your needles are right for at least that part of the range. Buying "richer" needles (as provided by Moss, etc.) usually means richer throughout the whole range--not necessarily what you want. You might best be served by determining what your current profile is then looking for a needle that will be slimmer at the bottom of the needle--the last 1/4 inch or so. Of course, buying "richer" needles will be a quicker fix IF that solves the problem.

I had similar problems with mine (not wanting to rev much past 5000 rpm) and went to "richer" needles. Still had the problem. A friend finally suggested the following: set the rpm at 4500 (no load) then adjust the jets for highest rpm. It worked--I got another 1,000 rpm this way. I have plenty of power upwards of 4500 rpm and am slightly rich at idle.

JM Morris

Jack,

It's a new Pertronix distributor w/vacum advance. The one that came with the car was junk, and I wanted pointless ignition.

The filter/regulator I've got is Moss part #377-435. Perhaps I could take out the regulator guts and retain the filter function? I like the glass bowl and large replaceable filter. Anyway, I'll eliminate the possibility of restricted flow before moving on.

The carb needles. Just so I understand your method, were you doing this with the standard, or the richer needles?

Incidentally, Moss's 'lean' and 'rich' needles are shorter than the 'standard' needles. Are they supposed to be shorter? This never made sense to me.

I appreciate the tips. Here's a cyclist's contribution to a tidy engine bay: I used the curved aluminum tube from a Shimano 'V-brake' to direct the throttle cable 90 degrees toward the hole in the footwell with minimal resistance. Free or darned close in the odds-and-ends box at the local bike shop.

Joel.
JM Young


Joel: Moss no longer sells the pressure regulator I have. (VB still sells the culprit). Yours (the Moss unit) looks to be a little higher quality. Wish I had seen it first. So disregard my regulator statements.

Re the carb needles--I was using the standard needles.

Re carb needle lengths--I didn't know that. At the time, I was ordering carb needles from Joe Curto. I never saw any variation in the lengths. I, like you, would be surprised at any length variations.

Have you checked advance thruout the range? Total advance, etc? Is the Pertronic vacuum advance adjustable?

I doubt if umbrella seals on the intakes will make any detectable difference above 4,000 rpm or at any rpm. Maybe a slightly more even idle.

Keep us informed on what you find.
JM Morris

Joel
Sounds a tiddle strange to me
Have you checked valve clearances
Compression test - ? It could be the start of a blown headgasket between 2-3 Good luck Willy
WilliamRevit

Jack,

Sorry to be unclear - I only mentioned the umbrella seals because I suspect they're original (43 years old), hard as a rock, and letting oil past, contributing to some fouling in #2 and 3--and thus, intermittent missing. Didn't mean to suggest that they'd impact the mixture per se.

The new distributor does appear to be advancing (watching the pulley with the timing light on the mark), and she pulls reasonably well through the rpm range. The hiccuping I've experienced is when cruising at a steady speed over 4K rpm. Unfortunately, the vacuum advance doesn't appear to be adjustable, but I'll double check.

I'll try to find some correct-length rich needles (I'll google Joe Curto), but first I'm going to try your method. It could be that the K&N filters leaned it up just a skosh, and the adjustment will do the trick.

Willy,

Yes - the valve clearances are correct. Compression was tested by the previous owner twice: once in 2003 (hot) 124; 123.5; 124; 124.5; once in 2006 (cold) 115; 117; 116; 116. I haven't checked it since I bought her in October of last year.

I am yanking the engine soon to put in a Rivergate 5-speed (Will Perry should be shipping the kit soon), and thought I'd simply replace the umbrella seals to see if it helped the fouling. But since it's easy with the engine out, perhaps I'll pull the head, lap the valves and of course install a fresh head gasket. There are only 60K miles on the engine, so I hadn't planned on having new guides installed... maybe it's worth doing a full valve job while the engine is out?

Joel.
JM Young

Id certianly do a compression check esp. after 4 years, Id suspect its more like 160,000 miles. If it where 60xxx that would barly be 100 miles a month...Im not saying it isnt 60,xxx but unless there is paper work proof, its most likly 160,xxx

my guess moss sent the wrong needles or the wrong ones where installed from previous owner, but yes I to find that disturbing. do they needles appear to be filed off the bottom or the back side, thats sorta an old school trick to richen them up.

on the vacume advance... some dissys you have to put an allen wrench into the hole where the vacume line slips onto... not sure what size

go to youtube and type in "setting distrubutor total advance" you will need to call pertronix and find out what the total advance degree is and at what RPM, for your car and if possiable how its adjusted

just to be clear... did you set the valve clearance to .12 while cold?


when you set the timing dont time to the round half drilled hole on the face of the crankshaft pulley, there is a fine notch thats hard to find on the edge of the pulley you time to

Prop

Prop


There must be more here than meets the eye. My thought is that Standard needles at 5,000 ft should run a little rich.

Prop:
1) He said he has new standard needles, so couldn't be from previous owner.
2) With 160,000 miles the engine would probably be slap worn out, smoking, etc. Most of our cars have sat for YEARS without accumulating miles. Maybe the engine was rebuilt at some point and the odometer reset to reflect the "new" engine. Maybe....Maybe....Maybe.....

You're grabbing at straws, bro. Stick to the post. :)
JM Morris

Hey JM,

The odometer only goes to 99,999 miles then rolls to 00,000 miles, most likely the engine was rebuilt at one time, doing a stock rebuild is rather simple on these little engines... Im not wanting to ruffle any feathers but I just want you to be aware of the possiabilitys so you have a better understanding of the wear on the car...in case it does have 160,000 miles. It really sickens me when a 4th owner sellers esp on ebay make that claim and say the car HAS Orginal 65,000 and yet the photo looks like it just spent the last 10 years in the amazon jungle... its fairly common practice esp. when the miles cant be documented

Sorry for the lack of clarity on the needle issue, I meant the person that used to own your car (PO) may have installed the wrong needles meaning they may have been to long... SU made alot of differant carbs similar to the HS2 that where used on alot of differant cars mainly the smaller engine sports cars like the datun 240-280 zx. so its plausable the a PO may have found some similar sized needle and installed them

If that where the case, it sure would account for why you cant get above the 5000 mark

and agian, Im just guessing on the needle issue, And I think this could be a big deal if they are the wrong needle id certianly try the new needles esp. being shorter so should be ALOT richer, esp. at idle.

Prop

Prop

JM,

Im not trying to be a headache to you, its just we have seen alot of screwed up stuff that has come thur the BBS that the (PO) blantly lied about inorder to sell and reap huge profits from, some stories are just sickening to read that cost into the 1000s to correct ... any time someone recently buys one of these cars and IT needs (""just a little work to drive as good as new""), it just sends a huge red flag up the pole in my eyes... So I always try and think what did the PO do to jimmy rig this thing to avoid spending no more then $3.79 to get this sold and pocket lots of cash

its one thing when the PO didnt know the problems existed, and I truly respect and have high regards for those that said well it has this small problem, but I dont know how to fix it and this is what I did, and I think it might need this...And I love the guy that says it has this issue, and I just jerry rigged it with some bailing wire to make it work caause I dont want to spend another dime on it.

So unless you really know the PO, just be skeptical untill everyhting is sorted out, till its running with reliability... its still the PO car, your just the car docter putting up the cash to fix the problems from before.
Prop

Joel: If I were in your situation in regards to the valve seats, etc. I would definitely pull the head and take a real close look at the valve seats. If that's the original mileage the head may never have been off. And it was built at a time when there was leaded gasoline, and has been run since (?) on unleaded. Now would be a great time to go to hardened valve seats, if it doesn't already have them. Not a big expense at all at the machine shop, and of course new valve guides.

(Not that any of this has anything to do with your original problem--just additional comment since you mentioned it.)
JM Morris

The other JM (Morris) makes a good point, if the engine really is 60,000 orginal miles, and your going to be pulling the engine anyway to install a 5 speed box,

I think you might be way ahead of the curve to do a basic freshen up of the engine. esp with the last compression test being 4 years ago and all readings at the 110-118 psi range down over 10 psi from just 3 years befor that (2003).

Hone the cly, with new rings, new bearing shells, complete gasket set and seals, head rebuilt with new guilds, no lead head kit, fresh 3 angle valve grind, new springs, water pump and oil pump

It would certianly eliminate future problems do to the engine sitting for such extended periods of time.

Prop
Prop

Im TOTALLY CONFUSED!!

If My above postings make no scence ... Its because I screwed up and got my "JMs"and "Youngs" mixed up as to who was saying what to whom.

So pay no mind to me, its not the 1st time ive screwed up... okay maybe its the 5th, but whos counting..LOL

Prop... proud to be the crazy uncle in my family
Prop


Prop: I like Joel's approach better. IE, approach the problem with logic and eliminate potential sources of problems one by one. From what I've read of Joel's other posts, he maintains his car to a high standard and approaches problems methodically. Much better than just throwing money at it willy-nilly. Unless, of course, you've got mountains of money to go crazy with. But where's the fun/challenge in that? You've not learned anything about why/how the problem was solved.

Really, Prop, your posts above seem to be a case of "preaching to the choir". All the things you are suggesting are things that Joel (I'm sure) already knows, and for that matter, 90% of the posters on this board. Joel is not a "newbie". I think you like to "hear yourself talk", bro. :) But I love your enthusiasm.

Years ago, I had an old Harley ('73 FXE). I used to farm the serious work out to various local shops. All they knew how to do was remove and replace. They didn't know how to solve a problem. (It seems that every biker over the age of 40 with a beard and a tattoo thinks he's a Harley mechanic). Not until I started to solve the problems myself was I able to stop throwing money at it and do things they said couldn't be done.

Frankly, the "fix" I performed on my 1275 (adjusting the jets at a high no load rpm) is a temporary bandaid that still doesn't solve the problem--finding the correct needle profile. That's an issue we'll all continue to face with anything other than bone stock specs and parts. I do not look forward to polishing needles but there's a methodical way to approach that, and once the right profile is found, I suspect that something very close to what I need is already available among the hundreds of profiles out there.

I'm afraid my .02 worth turned into a diatribe. Guess I'm guilty of hearing myself talk, too! Please accept my apologies!! :) I look forward to Joel's solution.
JM Morris

Sorry Morris,


Im not sure I understand what your saying...And who is Joel?

But yes, a metodical logical approach is always best if possiable

In the above thread, Ive never advised JM to purchase any extra parts beyound what he already has.

All Ive advised JM to do in the above thread was use the shorter needles he already recieved from Moss plus gave my opinion on why they maybe shorter then the ones in his carb, I advised him to check his compression do to the length of time scense its last been done, check his valve clearance as willy later noted he should retest as well, advised a possiable way to adjust his vac advace on his new dissy as he was unclear if it was possiable, and advieced him of youtube has many MANY videos for recurving and resetting his dissy total advance for his aftermart dissy, which he was in question about... as well as other minor issues

As To JMs ability, Ive never meet him or talked to him until this past week that Im aware of, So I have no Idea what JMs abilitys and skills are, for all I know he may design F1 engines or cant figure out how to change the oil, But he is here and asking for help, that said its a free advice forum, the advice is worth what you pay, he can take it or leave it...ultimately it is his call to do what he feels he is comfortably doing with the avialable resources.

If your needing any help or advice, with your ride, By all means let me know, Id be more then happy to share what ever opinins thoughts ideas and experiances I have to help you fix your ride.

Prop...Im the answer everyone is seeking
Prop


Prop--JM Young has been signing his posts as "Joel". Thanks for the advice and help offer! I certainly need it.

Sincerely,

JM (Jack) Morris
JM Morris

Prop, Google is your friend and will tell you faster than getting a reply here, but you need to spell it right :-)
"A popular unit because of its ability to regulate and filter fuel without restriction for carburetor fuel systems"
David Smith

My 1971 also gets testy at 4,000 RPM at 5,000 FT. above sea level. There is a miss and sometimes a strong fuel smell. I haven't figured that one out yet. I believe it may be related to oxygenated fuels mandated in the region.

At altitude, the engines run richer, not leaner. I run about 2 flats lean at ABQ but when I drive to sea level, must richen the mixture for proper performance and in order to lower the idle.
Glenn Mallory

Sorry for the interim silence. Life and work have intervened, and unfortunately, it'll be a few weeks until things settle down a bit, and I can get back to turning wrenches.

Prop and Jack, here's my two cents on this forum and 'the meaning of midgets.' I first picked up a wrench ~ 38 years ago, have four college degrees (which I'm thinking of laminating for a lovely set of place mats), and with sufficient time can figure out most things without books or the internet. But to my mind, these little cars were designed for the sheer joy of driving, tinkering, and perhaps most important, for sharing.

Sadly, we don't live in the same town, and can't bring our cars to the club garage on Saturday mornings, slurp coffee, peruse the pastries, and ponder the latest 'two-pipe problem' facing one of our friends. This forum is the next best thing. I'm grateful for it, and for all of you.

I'll keep you posted on my little red hiccuping 'Jenny' as soon as life evens out a bit for me.

Joel.
JM Young


The Zen of Midget Maintenance!

Glad you're back, Joel. I was afraid that mine and Prop's conversation had run you off.

I see that Glenn is in your neck of the woods and deals with the same altitude problems. That doesn't mean you guys can go off somewhere and solve the problem in secret :) , although it appears that Glenn has his dialed in--found the correct profile. The problem is always that no 2 engines are ever alike.

I deal with a mini-version of your problem. My workshop (where I do maintenance and tuneup on the Midget) is 2,000 feet higher than where I live, work, and do most of my running around. I'm up and down these altitudes every outing, so it's impossible to be right for both, although your difficulties are much more exaggerated than mine (our "mountains" are just hills in your area). But that's partially why I'm so interested in how you solve your problem.

Glenn-what are your engine specs?

--Jack
JM Morris

Happy Memorial Day weekend, gents.

As I hinted above, health, work, and other exigencies have pushed 'Jenny' to the back of the list for a few weeks--maybe even (gasp) a couple of months. That said, here's how I intend to proceed when I'm able:

1) While engine & trans are out for the Rivergate conversion, pull the head and have a valve job done with hardened seats and guides installed. I think you guys are right: the valve job and new head gasket will eliminate some variables. (Prop, she doesn't smoke or knock and the oil pressure's great, so I'm going to leave the bottom end alone for now. I generally like a physcian's approach of trying the least intrusive fix first.)

2) Run her down the highway in 4th and 5th gears between 4~5K rpm and see what's what. She'll track straight and steady with the new Frontline conversion and Tom Colby's tapered bearing setup, and the brakes are working properly (albeit strictly a stock setup), so I'm not afraid to get her wailing a bit.

Glenn - I understand how air density affects mixture, but as you'll note above, we're facing a counter-intuitive conundrum in this case. I assumed she'd be a tad rich because of altitude, somewhat balanced by the leaner-running K&Ns. However, adjusting a few flats hasn't helped the hiccuping and Moss's shorter, 'lean' needles run so badly there's no point in leaving the driveway.

So, I'll try the shorter 'rich' needles from Moss, and if they don't fix the problem and/or foul my plugs, I'll hunt around for custom profile (and possibly correct length) needles, or even polish my own if need be. I've found a good article on-line with a solid methodology, and stock diameter 'blanks' are not expensive, so developing 'high desert profile' needles could be an interesting exercise. Here's the article: http://terryhunt.co.uk/mini/pics/tech/picsb/pics.htm. Terry is spinning needles for a turbo Midget, and he refers to Des Hammill's book for normally aspirated enginges. I'm going to order the Hammill book if it's still available.

T.T.F.N.,

Joel
JM Young

I have also tried lean needles with little success. Fuel economy always seems to take a hit.

This site is a good source of information for comparing needles: http://www.teglerizer.com/cgi-bin/needle090db.cgi

I just got the head back on my car after having it down for a couple of months. The fuel in the tank is "winter" fuel so vapor locking in the fuel pump and carbs has been noticeable. The miss at 4,000 RPM is especially accentuated. It is my impression that the miss is fuel related at 5,000 Ft.

If you decide to pull the head, be sure to check my recent threads in the archives. It took three times to get it to seal properly and the information that came back from my postings on this site turned out to be of vital importance. ARP studs, should you use them, must be treated differently when torquing. Running the engine without coolant for a minute and retorquing the next day seems to have been a good idea. A fine spray of the copper seal gasket sealant hasn't done any harm.
Glenn Mallory

Joel- If you can, do a leakdown test. It will tell you exaclty what is wrong or right with your engine as far as the valves, rings, etc. You might not need a head gasket at all! The testers are about $100 or so, but worth their weight in gold. Especially if it saves you having to pull the head. You can find excatly where or if there is any leakage. We do this on our race car after every race weekend and I also check my street car each year. Since you are going to have the engine out anyways, I probably would check the valves.

Glen - ARP studs do not have to be treated differently than stock. If you use the ARP lube, it reduces the friction between the nut and the stud. This allows the same clamping force (which is why we measure the torque) to be reached with a lower torque setting. I know many racers who always torque the head to 50 ft-lbf and never have problems. Also, fill your engine with water before starting up, run it to temp then let it cool overnight. The re-torque. If you use water, you can just dump it out on the ground and not have to worry about the nasty stuff from anit-freeze. You could also find any leaks with the water and fix them before putting in the anti-freeze.
Tim Michnay

Glenn - yes, the corn-fed fuel may be a problem at our altitude and ambient temp. I'm determined to find an engineered solution. Maybe these cars need a full-on recirulating fuel-feed system, like most modern fuel-injected cars use.

I had her out yesterday for a few final errands before yanking the engine/trans for the Rivergate conversion (I'll have a free weekend in mid-July). (Solid ribcase selling for cheap soon.) Over ninety with sun beating down mercilessly on the bonnet, and while the engine temp was stable even at longer stop lights (aluminum radiator w/overflow tank and thermo-controlled electric fan), I did get some vapor lock.

I kept the plastic fan mounted to keep air moving over the manifolds/behind the head shield. So, I'm now focused on the cheapo electric fuel pump, as the level in the glass filter bowl wavers at 1/2 full and is inconsistent. I'm putting in a new Faucet pump & in-line filter (aft), then will patch in my fuel pressure gauge between the main filter/regulator (under bonnet) and carbs. We'll see how the pressure is, and eliminate that variable. If pressure's good, I'll do a volume test, too.

Tim - thank you for the suggestion. I have a compression tester somewhere (gathering dust in my tool box for years). I should get off my duff and do a leak-down test. However, the compression has evidently been going down steadily--and unevenly across the cylinders--for some time prior to when I bought her. Also, with the engine out it's easy to pull the head, and there's an excellent local machinist who will do a valve job with hardened seats and new guides for ~$100. It's almost crazy *not* to do it while the engine's out. Re-seal the timing cover and oil pan (only leaks on the car), and drive her for another 60K.

Wasn't going to swap out the studs, as I'm fairly confident the engine's never been cracked open. Is this a mistake? Are they only good for one use? It's been a while since I mounted a cylinder head, but I do seem to recall spraying the gasket with something... maybe it was the copper stuff.

Joel - jmyoung@swcp.com
JM Young

I recently used an exhaust gas analyzer to adjust the mixture on my 1275. I ended up leaning the mixture from about 10 down to around 6 flats. I also retarded to timing slightly. With the CO at the indicated .02, the miss at 4,000 RPM is gone, there is no rough idle, the engine has more power and that puff of smoke at acceleration is gone.

I would avoid removing the head of compression is even. I had difficulties getting the gasket to seal properly following a recent rebuild. Mine ran about 60,000 on unleaded fuel before the head was rebuilt with hardened valves and seats. There was no significant wear even then. Removing the head is easy with the engine in the car as long as the hood is removed.

Glenn Mallory

when it comes to changing carb needles, Joe Curto is the man in my book. When I was considering a needle change he actually spoke with me on the phone about what engine set up I had, what carbs and what needles I was currently using, symptoms, etc. He could have easily sold me anything, but he took the time to make sure it was the right needle for me. he might be able to help. I just switched from ABC to AAC, which seems to be doing ok for me. (slightly richer at high revs, about the same at lower rpms.)

Joel, I also just completed the datsun conversion about a month ago... totally worth it! Just be prepared to put the engien back in a tiny bit at a time. If you have questons about the conversion, it's still fairly fresh in the memory. :)
Chris Edwards

Glenn,

I think that it is pretty cool that you run your carb two flats lean at sea level to make it possible to use the mixture cable to lean or enrichen the mixture.

I have an an airplane with a carburetor and I can tell you that if you fly from sea level to 5000 it will be necessary to lean the mixture. Given the design of these SU carbs it makes sense that your trick is a good idea.

Rebecca
R Harvey

Glenn - I may take your advice and hunt down an exhaust gas analyzer. I will post the results to this thread, though it may be several weeks til I work out some other bugs and wedge in the Datsun 5-speed.

Chris - I heard Joe Curto's name before. Do you have his contact info? Also, if you'd email me your contact info, I am eager to talk about your experience with the Rivergate conversion.

Becca - If I'm not mistaken, Glenn lives in my neck of the woods, at around 5,000 ft. (I could be wrong.)

Joel - jmyoung@swcp.com
JM Young

here you go JM

http://www.joecurto.com/
Prop

Joel--will an exhaust gas analyzer help when you have 2 carbs? I can't see a tail pipe unit being of much use. And the weld-in sensor types would have to have one in each outboard exhaust runner. Possible with headers I guess, depending on the header design.

???

--Jack
JM Morris

Cool, Prop - thank you!

Jack, I have never used an analyzer. I've always tuned carbs by ear, checking the plug color, and, with the Midget, using an 'ashtray' balancer (which works surprisingly well).

However, Glenn seems to have used one to good effect. I guess the assumption is you adjust the carbs in unison and hope that your CO measurement--though an aggregate--more or less reflects equal contributions from each SU.

I should report that I recently discovered a new wrinkle, which should've occurred to me early on, given the pinion shells with teensy nibble marks I found in every nook and cranny (including *inside* the original air cleaners). That is, I'm starting to suspect that a contributing factor may be meeses pieces floating around in my tank and intermittently stopping up the feed pipe. The guy I bought the car from was... well, lazy, and I'd bet a dollar he never flushed the tank. Wouldn't it be ironic if my pain-in-the-neck was a tiny cervical vertebra, popping in and out of the feed pipe at odd intervals?

Ah, well. Not a big job to yank the tank on these cars, and I'll have the drivetrain out for the Rivergate conversion anyway, so what the heck! The local radiator shop will hot-dip the gas tank for a coupla dollars, and it'll be good as new. Might as well replace the diff front seal while I'm at it...

Joel
JM Young

LOL! That's why I always have a sense of foreboding when something major needs to be done. Tackling the job usually uncovers 3 other "needed" fixes.

I've fought the mouse problem too. Recently found 3 different nests in my shop: One in the tailpipe of one car (discovered upon startup, when it blew out the rear), one in a storage box, and one in the trunk of a car, up under the spare (plus 4 small babies!) The big black snake that has lived around here for the last 3 or 4 years has apparently moved on, because his job is not getting done! Had to revert to rat poison which has cleaned the place out.

Actually, I was playing the devil's advocate a little bit in regards to the analyser, just to get your thoughts. A buddy of mine and I are both about fed up with trying to reach a high state of tune with just the typical SU tuning equipment. We're considering going in together on a decent analyzer. But we can't agree on whether to take the tail pipe route or the weld in route. The Innovate units are really nice, but lots of bucks.

GLENN--where are you? What analyser are you using?

--Jack
JM Morris

Jack,

I am using a gunson's analyser. It has definitely helped achieve a proper mixture. I am located in Albuquerque.

Joel, feel free to contact me if you run into any Rivergate issues as I have installed a couple of Datsun transmissions by now. Also, will be happy to share results of tuning exercise and to share the analyser if you wish to give it a try.
Glenn Mallory

Joel,

Glen wrote; "I also retarded to timing slightly." That was exactly what stopped the hickup in my sprite after trying a lot of other possibilities. Modern fuels (BP utimate RON 98 is the best here on the continent.....) need at least 4 degrees less total(vacuum+rpm) advance. So try 28 degrees instead of 32. I t will cost you 5 minutes. And is the hickup also there when cold?

Flip
Flip Brühl 948 frog 59

This thread was discussed between 08/05/2010 and 05/07/2010

MG Midget and Sprite Technical index

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