MG Page 3

Name: Wayne

Subject: 1980 MGB Backfire

Question: QUESTION: Hello Howard,

When going down a hill, with no foot on the gas pedal, if the engine is holding the car back, I hear a backfire in the engine.  At least that is what I call it.  The engine seems to run fine when accelerating or idling.  If I put the car in neutral while going down a hill, the backfire stops.  I do have an oil leak from the front breather cover (the vented one) which I am trying to fix.  Would that cause a backfire.  I remember the engine doing this before I had it rebuilt.  As is, I can't use the transmission to hold the car back on hills without having this noise.  It even does it 4th gear, though not as loud.  Any idea what is wrong?

ANSWER: Hi Wayne,
Backfires are usually out the tail pipe on deceleration and can be caused by several things. First is the most common and that is an exhaust leak close to the front of the exhaust system. Other causes are ignition timing off.
An oil leak at a breather pipe will not cause a backfire although an engine problem can cause a backfire inside the engine that can blow breather pipes off which then can be an oil leak. To be safe, you should have a compression test run on the engine to eliminate that one as a cause.
Let me know,
Howard

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QUESTION: Compression test results were:
#1 = 110 psi
#2 = 145 psi
#3 = 155 psi
#4 = 115 psi

This following an engine rebuild, including a new cylinder head (the old one was cracked - the guy who rebuilt the engine found a used head which he tested and said was good) and pistons.  Are these values acceptable? If not, what do you recommend I do?

Answer: Hi Wayne,
The #2 & #3 are ok but there is too much difference between #1,4 and the other two. Be careful that you don't condemn an engine unless the compression test was done with the throttle wide open and many revolutions were run on each cylinder. In a shop we would not condemn an engine on just these readings. It just means you need to do further tests to be sure. We would run the same test a second time and if the results were close to the same we would remove the valve cover and reset the valve clearance. If any clearance was found to be tight we would run the compression test a third time. This time we would do a "Dry" and a "Wet" test. (A wet test is done by putting about 4 or 5 squirts of engine oil in the plug hole just after you do the standard dry test and do another compression test right away) You will see an increase in the pressure but it should not be more than 10% to 15% higher. For example, if the "110" cyl. goes up to "165" on a Wet test it is MOST LIKELY a ring problem. If it only went up to 115 or 120 it is MOST LIKELY a valve problem.
After the wet and dry test and we would do another test and this one is only done when all the compression tests show there is a problem. You need compressed air to do this test but it is a final and very exact test. Meaning this test results no longer is MOST LIKELY but it is 100% SURE.
You also need a fitting (available from pro tool trucks and some auto parts stores) The fitting adapts an air hose to a spark plug threads.
The method of testing is to put #1 piston as close to TDC (on the compression stroke) as you can. (timing mark)Pull all the plugs and screw in the fitting into #1 hole. Put the car in 4th gear and pull the hand brake up hard. Then apply the air hose to the fitting. Now, open the throttle and listen in the air filter intake. If you hear even the slightest hiss, the intake valve is bad. Go to the tail pipe and listen up close and if you hear even the slightest hiss, the exhaust valve is bad. Open the radiator cap and watch for bubbles or a raise in fluid level. If anything is noted, you have a leaking head gasket or a crack in the head. This test will pick up even the slightest gasket leak even before it is noted as an overheating problem.
We would open the oil filler cap and listen but here you will hear hissing. ALL engines hiss here, we learned by doing this test on known good engines and known bad ring engines to be able to tell how much hiss is acceptable. This part is not necessary as the wet test is sufficient to test rings.
Keep in mind that a ring leakage after an engine rebuild where they used the same pistons and only put in new rings can be noted if the rebuilder did not deglaze the cylinders and the rings have not seated. (They will seat within about 500 mi of normal driving) However, the 110 and 115 reading would be considered too low to blame on normal ring leakage so if the readings are correct you have something wrong. Do all of the tests and don't skip any.
Let me know,
Howard

Name: Ron

Subject: steering rack

Question: QUESTION: hello: the ball joints on the rack that I bought from Vit Brt is so tight tha  it takes great preasure to move them when off the car and on the car the wheel will not come back to center after a right or left hand turn. Are there shims in these new ones to removed? Thanks

ANSWER: Hi Ron,
The ball joint on each end of the rack should be a little tight and I can't see how they could be so tight as to stop the car from returning the wheel to center. If they are so tight that you can't move one (disconnected from the tie rod end) with one finger, then you need to return it to Victory British. If you take it apart and try to adjust it yourself you will probably void any warranty you might have. If they messed up that bad, I shore would not want to put my life in the hands of that rack as they may have messed up the rest of the rack too. Does the rack rotate right and left with ease?
Disconnect the tie rod end and grab the threaded end of the tie rod between your thumb and index finger and see if you can move the tie rod forward /back and up/down. It should not be easy but you should be able to move it full travel. If not, return it and DON'T put it on your car.
Howard

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QUESTION: howard: Thank so much for getting back to me. This problem is on my 59 bugeye sprite and no, the rack will not move left and right very easy. You have to pull hard.. i put the old one back and it steered much better. Before putting the old one back on I moved it left and right by hand and it was much easyer but not able to do it with index and thumb. I am trying to find another rack and if not I see that Moss sell parts to rebuild it . Thanks again  Ron Lasita  Sarasota Fl. P.S I have had 2 rack from BV and the second one is even harder at the ball joint.You have to hold it down on a bench to move the ball joints

Answer: If the rack is not under a warranty of any kind you can easily do the repair yourself.
With the boot off look closely at the ball end and you will see that the large outer shell of the socket is a nut. Some were punched or peened at one point to lock it. Some of the older racks had a lock tab bent to lock it. You will also note that there is a second inner part that screws into the rack itself and it usually has a lock tab also. You want to unscrew the outer nut (shell) only meaning you have to hold the inner nut so it does not unscrew from the rack. With the outer shell off you will find a little plunger and spring. The plunger and spring are to keep the ball snug and not allow the little bit of free play to cause wheel shake from road conditions. Some I have done had thin shims between the outer shell and the inner nut to adjust the tension on the ball. Some had a large plunger and had shims under it to control the tension on the ball and the spring only kept additional tension on the ball. I always did my adjusting with the spring out and when I was satisfied, I put the spring back in. Be sure to grease it well as no oil comes from the rack to lube it.
I am sure I did rebuild Mk I racks in the dealerships but that was 40%+ years ago and I don't remember any of the racks I did being much different.
Let me know,
Howard

Name: YT

Subject: 79 MG

Question: Hello Mr.Howard,

My father owns 1979's MG which has Spitfire engine.
And it is a California version so that there is EGR component inside.
I have been looking for a L-shaped EGR pressure hose.
but, I am not sure if this is the right name to be called.
I ordered some catalog for MGB and Spitfire but it seems like there is no EGR stuff in Spitfire's catalog.
How could I look for the part?
If I could upload picture, I want to show the pictures because I have pictures of the broken part and the engine room.
Please tell me any suggestions.
Sorry for lack of informations.


Answer: Hi YT,
Yes, all MG midgets from 75 on had 1500 Spitfire engines. As for a name of a hose all you need is to describe the hose to who ever you are trying to purchase it from, Moss Motors, Victoria British, Roadster Factory or Engel Imports. Just tell them where it goes from/to and if it is metal or rubber. Some had a metal pipe with a banjo fitting on one end others were rubber and in a "U" shape. All the suppliers have toll free numbers so you can call them and ask if they have such a hose. Most parts are still available for that car. Look on the net for each phone number to call.
Howard

Name: Jonathan Smith

Subject: 1967 mg b gt Special edition

Question: QUESTION: I have recently started restoring my car, to find out the pistons are seized, I've taken the eng out and have started the tear down. it will not come un stuck, what it the direction of rotation, so I down mess this up

ANSWER: Hi Jonathan,
The engine turns clockwise as you face the front of the engine. We run into this all the time and you should remove the plugs and put something like WD-40 in each plug hole and let it soak for a day or so. If the engine is out already you can bolt the starter back up and connect a good battery to the starter to try to brake it loose after the soak. If it will not brake loose by the starter you will need to take the engine apart and remove the crank and head and find a large piece of thick wall steel pipe that closely fits the cylinder bore. Then strike the steel pipe with a lead mallet. One mechanic used a wooden block he had turned on a lathe to just fit the bore and he would use a large hammer to beat on that. If you are trying to save the pistons you need the load to be distributed over the whole piston so as not to put a strain in one small part of the top of the piston. The problem is that the rings rust to the cylinder walls and need to be broke loose. NEVER try to beat on the top of a piston with the crankshaft in place. We usually save most but some are rusted so badly they will brake the ring lands on the piston before they brake loose. Once you brake one down a little you then need to sand or hone the upper cylinder to clean off the rust and you can then remove the piston out the top.
Good luck,
Howard

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QUESTION: Howard,
thank you for the info, I have the eng out if the car on a stand, with the head
off and clutch off, also the oil pan and sump filter, along with starter, oil
filter, ie.....everything.. I've put some oil/ WD-40 in the top off the pistons to
soak them. it's been four days now and it still won't budge. when I Pulled the
car out a ladys yard 6 months ago and I first looked inside the eng it was
wet.. so I did'nt think it would of been this siezed, any ideas..thanks again.

Answer: The only thing I can tell you is to try what I said, Put the starter back on, and connect up a good battery. The starter can produce more torque than you will be able to do. If that don't brake it loose, remove the crankshaft. You will probably find that all the pistons are not stuck. AFTER the crank is out get either a block of wood that fits well on top of the piston or a thick  wall steel pipe that just fits in the cylinder and hit it with a large hammer to try to brake the pistons loose that are stuck, then sand or hone the upper cylinder walls clean of rust, then oil them and bump the pistons up out. There is no magic trick I know of to get them loose. I seen some stuck so solid that the mechanic destroyed the piston braking it loose. Most will usually brake loose with the methods I told you.

Name: MIKE

Subject: 1979 MGB LIMTED

Question: WAS THE CARPET BLACK IN THE FRONT & TAN IN THE BACK? THE OWNER WANTS TO PUT DUEL SU CARBS ON THIS ENGINE WITH THE CROSS-FLOW HEAD. CAN YOU TELL ME WHAT PROBLEMS THAT I WILL HAVE

Answer: Hi Mike,
I never seen an MG with two color carpets (front/back). Moss Motors is pretty much the Guru on paint and carpet colors so you might ask them also.
Other than what ever your local emission laws are and the cost of that change over, I can't think of any draw-backs to that conversion. I always wanted to do it, except cost stopped me. With a cam, raised compression and a free flow exhaust, it should wake that 1800 up. (Be sure to route cold air to the carbs)
Howard

Name: ryan

Subject: '74 midgit clutch

Question: QUESTION: You said to refill the clutch with DOT4 brake fluid but the manual said 3. How come?

ANSWER: Ryan, I don't know what manual you have, but DOT 3 brake  fluid will eat natural rubber and the British own most of the natural rubber in the world and they used a lot of this natural rubber in their seals and that was true in 1974 also. So If you want to use DOT 3 fluid that is your choice. If all your seals are doing well in the next few months, let us all know.
Howard

---------- FOLLOW-UP ----------

QUESTION: Howard it was the Haynes service manual for MG midgits that said to use DOT3.  I am off to pep boys for DOT4.

ANSWER: I looked in several Haynes manuals and you are correct that they say DOT 3. I seen too many incidents where DOT 3 destroyed the seals in older MGs. I will confront Haynes about it and post their answer.
Howard
---------- FOLLOW-UP ----------

QUESTION: I got the new master and slave from victoia british and the fill cap on the master syas DOT3 only so I guess this one is safe to use DOT3.  However I have been unable to remove the master from the pedal box. I can get the top bolt out but no wrench or socket that I have wil get me access to that bolt or nut.  How do I do this?
ryan

Answer: Hi Ryan,
The bottom bolt is difficult but can usually be removed with a 90 degree opened end wrench. A tool truck that services repair shops or Sears would have one.
I got a response form Haynes.
 
 "Dear Sir,
I don't have an answer for you.
All I can say is that use the fluid recommended by the manufacturer."

I guess the answer is liability issue. I guess as it stands I say DOT 4 and if the lid says DOT 3 it dumps it in your lap to use either one. Let me know how it works out.
Howard

Name: Dana

Subject: 79 Midget Clutch

Question: I've been told by former Midget owners that it is possible to replace the clutch without completely pulling the engine and gearbox. As the manuals only go over the complete removal method, I need some help figuring out what to do

Answer: Hi Dana,
I have put a lot of clutches in Midgets and have tried it leaving the trans in and removing the engine and trans and in a dealership we look for the easier way on all jobs and I found it to be no advantage trying to leave the trans in. As for changing a clutch without completely removing either, That will never happen. Unless you mean by not completely removing the engine by leaving just the throttle cable attached.
If this is your first be sure to replace the clutch release bearing too and do the whole job by the book. There are some clutch jobs that you can bypass the book on but the Midget is not one of them.
Howard

Name: Ern Harris

Subject: 79 mg midget electrics

Question: I've been experiencing problems with the windscreen wipers working very slowly and indicators not working intermittently. I undid the wiper motor plug and connected directly to the battery and they worked fine. I cleaned up the fuse box connections and contacts on the wipers switch - still no good. when looking at the ignition switch, I noticed a connector casing on the back of the ignition / starter switch had melted. So am going to replace the starter switch to see if this solves the problem - Do you have any other thoughts what this could be and also, how do I get the starter switch out of the steering lock housing to replace it ..... any help appreciated.

Answer: Hi Ern,
The first thing you need is a wiring diagram of your car. I would not plug a new electrical switch into a harness that had melted a wire. If there is a short somewhere you will just melt the new switch.
The MINIMUM tools you should start with is the wiring diagram, a volt/ohm meter, a test light and a couple of test wire leads.
To remove the electrical switch from the lock assembly look on the bottom of the lock to see a small set screw a short distance from the electrical switch. After removing the screw you should be able to remove the switch from the lock assembly. Look on your diagram for the color code of the wire that is melted and see what it goes to. Then disconnect that item. Now take your test light and connect the clip end to a power supply and touch a ground with the probe to confirm you get a light, then touch the end of the melted wire. You should not get a light. If you get a light, you have a short in the harness, if not then it is possible that the item that was powered is shorted internally and it needs testing. If you need a diagram send me your e-mail address.
You can get a test light form any auto parts stores, or better still, get a "Logic Probe" from a place like Radio Shack. Make sure it is in the 12 volt DC range. They are not expensive and you will rarely use a test light when you start using a Logic Probe.
Howard

Name: Thomas

Subject: Antifreeze Leakage into Engine

Question: On a 1969 Engine and 1972 Body Can Antifreeze leak into the engine Through the Radiator or Oil Cooler and if so what would cause this? Im experiencing this anti freeze problem. Thanks for your help. Tom

Answer: Hi Thomas,
MG didn't have any oil coolers in the radiator so that is out. I did once see a oil cooler mounted at the oil filter, that had antifreeze to and from it. I think it was an aftermarket item. I never seen one from MG. If you don't have one of these coolers on the side of your engine then you need to look at a possible cracked head or block or head gasket problem. The head gasket is the most likely. Cracked head second and cracked block third most likely.
Howard