I am putting together this No Nonsense FAQ for the "Hey, I just bought a Midget, now what?" folks. Aimed mostly at new Midget owners who have at least a little experience with cars in general, and want to get their cars up and running quickly. If I had had all of this information in one spot when I started my project it would have saved me quite a bit of time.
I am centering on 1275 based cars (MG Midget Mk III & Austin-Healey Sprite Mark IV) as that is what I have, I would imagine most of this info is good for all of the rear wheel drive A-Series based cars. I am going to try and keep the answers short rather then go into long explanations. If people need more information or want to go deeper into a particular subject, searching the forums is your best bet. I am also hoping that others will contribute with model specific information where it is lacking.
Disclaimer – While I am fairly confident the content provided here is accurate is this is not meant to be a replacement for proper research. Also some of this information is based upon consensus opinion I've found on this forum and other sources. Opinions can vary and it is not my intention to discredit these varying opinions with this information.
This FAQ is based on the following topic in the MG Experience Midget Forum: http://www.mgexp.com/phorum/read.php?3,2306820
If you would like to contribute to this document, scroll to the comments section at the bottom of this article, or follow the link to the Forum topic above and post a reply.
1. Where can I find parts?
There are many active forum members that also sell parts, I encourage you to visit the MGExp Vendor Forum as they can often save you money and are more likely to assist you with tech questions. The two most common "big box" parts stores in North America are Moss Motors and Victoria British.
2. What kind gasoline/petrol should I put in my car?
If you can find non-ethanol gasoline, use it. Using E10 doesn't seem to cause immediate problems, but there are long term issues with dissolving rubber gas lines and premature valve and valve seat wear. There is little reason to use premium gasoline in a stock engine.
3. What spark plugs should I use?
NGK BP6ES are the most common replacements for the Champion N9Y
4. What is the firing order?
The firing order is 1,3,4,2. #1 cylinder is at the front of the engine.
5. What direction does the distributor rotor turn?
Counter- (anti-) clockwise
6. What should I gap the points at?
.015" or a dwell of 60 degrees
7. What should the spark plug gap be set to?
8. What should the valve gap/clearance be set to?
9. What oil should I use for the engine?
There are many different answers to this question but probably the simplest answer is Valvoline VV211 VR1 Racing Formula SAE 20W-50 oil. It contains the ZDDP content needed for our flat tappet engines and can be found at some of the "big box" automotive stores. Oil capacity is 7.8 pints or 4 quarts.
10. What oil filter should I use?
Mobil 1 M1-102
11. What is ZDDP?
Zinc dialkyldithiophosphates/ In simple terms it's an additive that was used commonly in motor oils before catalytic converters. It's important to have ZDDP in older MG and BMC engines to reduce tappet wear.
12. What should the oil pressure be?
At Idle around 40psi. At high revs 70psi
13. What oil should I use for the transmission?
Any quality 20w-50 motor oil should be fine. Capacity is 2.7 pints or 1.35 quarts
14. Where do I check and fill the transmission oil?
The port to fill the transmission is under the carpet to the left of the gear shift lever. 21mm
15. What oil should I use in the rear diff?
90 Weight Gear oil. You will find some topics addressing issues with the use of GL5 type gear oil and while there were some issues in the past it seems that GL5 is now safe to use.
16. What brake fluid should I use for the brakes and clutch?
17. What type of coolant should I use?
With out getting brand specific any 50/50 mix of propylene glycol based coolant should be fine. Water Wetter is a common additive used by folks on the forums. 12 Pints (6 quarts)
18. What are the black caps on the two carburetors for?
Stock HS carburetors have dashpots that require oil. These are the oil fill caps for the dashpots.
19. What oil should I use in the carburetor dashpots?
While there are specialty oils available standard 20w-50 motor oil works fine. Filling can be messy and you may not realize that you've overfilled until its too late, so have a rag ready. Using a syringe make it easier.
20. What steps should I take before starting an engine that has been sitting a long time?
This topic should be well researched to prevent any damage you could do to the engine after it's been sitting for a long time. The important points are to make sure you pre-lube the cylinders and to turn the engine by hand before attempting to start it up.
21. Are there any "miracle-in-a-bottle" remedies that are worth it?
While a majority of the bottles of "stuff" found on the auto parts store shelves are full of empty promises there are a few items people swear by: Seafoam, Marvel Mystery Oil, Water Wetter, and PB Blaster are the products with good reputations not only here but in other automotive circles too.
22. What size tires?
Original stock tires 145 R 13, but 155 R 13 most available replacement
23. What should the tire pressure be?
For radial tires 22 psi in front and 24 psi in rear
24. What is that faucet knob on the top back part of the engine?
This valve allows or restricts coolant flow to the heater core thereby controlling the temperature of the air in the passenger cabin. Open it up when it's chilly to warm the air coming in to the cabin and close it off when it's warm outside. In most cases your feet will be well done while the rest of you will freeze.
25. What do all the buttons and lights do on the dash?
For 1968 and newer style dash, from left to right. Dial controls the airflow into the cabin, two position switch turns on the fan to boost air flow to the cabin, Red "button" is the brake check light (should light up when pressed and if there is a pressure loss detected), Pull knob is for the choke, 3 position switch exterior lights off / parking / on, orange jewel light indicates charging (on when charging is low), blue jewel light is high-beam head light indicator, two position switch on left side of radio consol is the Hazard lights. There is a third jewel light on some models that I am not sure of.
26. How do I reset the trip meter on the odometer?
There is a knob to turn on the underside of the dash on the odometer it self.
27. What do I set the ignition timing to?
This is a topic that should be well researched before attempting but a safe starting point for a 1275 engine is 10 degrees BTDC.
28. Where is the timing mark?
For some reason it's at the bottom of the engine. There are kits available to move to a top side timing mark.
29. What tune-up steps should I take when my engine is not running well?
Assuming there is no other major issues, adjust the valves, clean or replace and gap the points, check the spark plugs, set the timing, and adjust the carburetors.
30. What numbers should I be getting with a compression test?
This is a topic that you should research thoroughly before attempting a test and interpret the results. But you want to see anything from 130-160psi with not more then a 10psi difference between high and low. In general, seeing similar numbers between cylinders is more important that absolute numbers.
31. How do I adjust the carburetors?
This is a topic that should be well researched before attempting and always address ignition system issue first. Also once set you should not need to adjust very often. But the overall concept is to balance the air intake on both carburetors and then adjust the mixture on each. Rinse lather and repeat that process a few times.
32. What MPG should I be getting?
A well running 1275 Midget gets around 34 average MPG but it varies widely with condition, mods, and driving styles.
33. How should I fold the top down?
There are a number of how-to articles on this topic. But the main point is DO NOT LET THE SOFT TOP FOLD INTO THE FRAME. Pull the soft top away from the frame as you lower it. The top should be folded in half lying on the back of the car |___| allowing the frame to fold into the inside of the car. Then fold the outer corners to the middle front should look like \__/ if looking from the back of the car. Then pull the back up and over the frame tucked into the car behind the seats.
See also this topic on folding the soft top in the MGExp Midget Forum:
34. Where do I start when I have electrical problems?
This is a huge can of worms and probably one of the more overwhelming facets of trying to fix these cars yourself. It goes well beyond the scope of this FAQ, but some general guidelines are: Clean and check connections at the fuse box. Check grounding connections. Very rarely will issues ever be inside the wiring loom. Get a test light. Make several copies of your car's wiring diagram and color code specific sections on separate copies., it helps to brake it down into small chunks.
35. What are the most common things that will make me pull my hair out?
Rust, rust and more rust. Bleeding the clutch system. The odd mix of fastener sizes you have to deal with. Lucas Electrics, they don't call it the "Prince of Darkness" for nothing. Other drivers in big trucks who are inconsiderate to the fact you might as well be on a motorcycle.