My TM was running relatively well last week when I drove to work. When I was driving it later in the day it seemed a little rough,extremely rough at idle, almost like it was missing a cylinder.It came on all of a sudden and I just drove it home and there it ha stayed. Any ideas what I should be looking at? It isn't blowing smoke ( well a little at start up but it has done that for ages), hasn't lost any water, no bubbles in the radiator, no oil leaks visible. Any pointers would be greatly appreciated!

Tools

look at plugs and leads coil

fuel filter

what fuel you using ? leaded additive ?

Magna Buff to the rescue again ! I pulled the plugs out over the weekend and they were dry and seemed ok. I polished them up a bit with some sandpaper while they were out but it made no difference. I am using standard unleaded with an additive which is the same I have been using for a number of years. How can I test the coil? I don't think it has ever been changed in all the years I have had it. The leads are probably only about 18months old so I suspect that they are OK, but I haven't tested them.

Tools

I recall a thread from a while back that had the resistance to expect when testing leads but I can't find it again. Anyone know what is an acceptable/unacceptable reading?

Tools

coils are not cheap these days

a basic test
1 .try in the dark .... start the motor.... ,lift the bonnet and look for sparkles or arcing
around the cap and all the leads

2. you have some one crank over the motor
while you hold the dissy end of the coil wire near the motor
if good the coil should throw a nice bright arc to earth

3.volt meter across + and - of coil
I dont have a resistance figure for leads

this is going to sound stupid.

has it been rattling before the roughness started? has the rattling stopped/become less loud? *might* be that the chain has broken or has lost tension and skipped a tooth on the counter balance shafts. this really is very unlikely, but hey worse case scenario.

Do a compression test.

Lead resistance should be in a gregory or haynes manual. SHOULD be.

my moneys on head gasket between cylinders.

leads shorter than 635mm should read less than 30,000 Ohms and leads longer than 635mm should be under 35,000 Ohms according the the Gregory manual (its for a carby one if that makes a difference).
regards jay

forgot about a vaccume leak causing the fault:nuts:

Thanks for the suggestions guys. The leads,plugs,cap and rotor are all ok and there seems to be plenty of spark getting through. Looking down the barrel there seems to be plenty of petrol getting through.

If I do a compression test, will that tell me if the gasket has blown between cylinders? If I only do a standard test and not a leak down test, won't the cylinders all still have their normal compression?

I was not aware of any rattling before things started heading south.

Tools

Magnabuff, when you refer to vacuum, do you mean on the vacuum line for the distributor advance, or some other lines? I had a quick look at the hoses last weekend and they seemed to be ok. Maybe I should look more closely.

Tools

Magnabuff, I just noticed that you did refer to carby vacuum.

My dizzie has apparently not been looking good for a while. Is it possiblt that it has just worn out and thrown the timing out? I need to check the timing too I guess.

Tools

the vacume hoses to dashpots operating the choke butterfly
and the secondary stage of the carby
dissy vacumme lines
you need a timing light to make sure it is at 13 degrees
also that the dissy is advancing
antipollution pipes off the carby can be loose or perished at the joins

Well it looks like it is the head gasket. I did a compression test and 2 cylinders were around 11500, the other 2 barely registered. If I am going to so much trouble to replace the gasket, what else should I look at/ replace while it is in pieces? The tappets are a bit noisy,are they easy and cheap enough to replace? Anything else?

Tools

Well it looks like it is the head gasket. I did a compression test and 2 cylinders were around 11500, the other 2 barely registered. If I am going to so much trouble to replace the gasket, what else should I look at/ replace while it is in pieces? The tappets are a bit noisy,are they easy and cheap enough to replace? Anything else?

Tools
If you are keeping it for a while and have $$$, Get a Valve Regrind Gasket Set which should have all the gaskets and seals (including valve stem seals which can cause smoke on start up when they go hard) for the head. Resurface head, regrind/reseat valves, replace cam and crank seals, timing chain, tensioner and guides. Hopefully the waterways are not badly corroded.

Waterways can be welded up. Usually the head gasket is not sealing because of alloy corrosion. Check bore wear while the head is off, you might need a bore hone and new rings. Often a "blown headgasket" escalates to a full engine out and rebuild, depending on Km on the engine.

Draw yourself a picture of where the vacuum hoses go, as the manual isn't much help, before you pull them all off. You need 2 m of new hose to replace it all.

Allow $1K for the head work, but it can spiral up to $3K.

Allow $1K for the head work, but it can spiral up to $3K.

1k?! are you talking diy or a mechanic to do it?
cos if diy you can pritty much do a mild top to bottom rebuild for around that, 3k would be mad hetic complete rebuild

I have decided to just do the gasket as the car isn't worth spending too much on. I took the head off this morning and it was a blown gasket between cylinders. I don't know where the missing piece of gasket went... out through the exhaust maybe? I have most of it back together now, but am having trouble getting the timing chain sprocket back on. I think the tensioner has taken hold and I need to pull the sprocket up another 10mm but can't move it. How do I get the tension off the chain to get it back together?


Tools

I have decided to just do the gasket as the car isn't worth spending too much on. I took the head off this morning and it was a blown gasket between cylinders. I don't know where the missing piece of gasket went... out through the exhaust maybe? I have most of it back together now, but am having trouble getting the timing chain sprocket back on. I think the tensioner has taken hold and I need to pull the sprocket up another 10mm but can't move it. How do I get the tension off the chain to get it back together?


Tools

Most cars have an automatic tensioner. If there's no access point in the tensioner you might have to remove the timing cover to get access to it and compress it so the chain will reach. Have you changed a head gasket before on an engine?

The 2.6 has a spring loaded tensioner. If you took the head off and kept the chain on the top sprocket, then rested that on the support, then all you need to do is pull up on the chain to retract the tensioner. If you took the chain off the sprocket or the support is missing, then the tensioner has popped right out and the front cover has to come off. Lots of extra work, if that is the case. Use a torch and look down the timing case cover to see what has happened. Even if you sat the sprocket and chain on the support, a stretched chain will still allow the tensioner to pop out. Most mechanics who know this problem wedge a piece of wood between the chain runs before removing the camshaft pulley bolt so the tensioner can't move.

Most cars have an automatic tensioner. If there's no access point in the tensioner you might have to remove the timing cover to get access to it and compress it so the chain will reach. Have you changed a head gasket before on an engine?

Yes, but it didn't have an OHC.

The 2.6 has a spring loaded tensioner. If you took the head off and kept the chain on the top sprocket, then rested that on the support, then all you need to do is pull up on the chain to retract the tensioner. If you took the chain off the sprocket or the support is missing, then the tensioner has popped right out and the front cover has to come off. Lots of extra work, if that is the case. Use a torch and look down the timing case cover to see what has happened. Even if you sat the sprocket and chain on the support, a stretched chain will still allow the tensioner to pop out. Most mechanics who know this problem wedge a piece of wood between the chain runs before removing the camshaft pulley bolt so the tensioner can't move.I did keep the chain on the sprocket and I have tried pulling the chain up but with no luck.Is it possible to lever the tensioner back in from the top without removing the timing cover? I looked down the timing case and all I coulod see was the two side of the chain pushed together which is why I summised that the tensioner was doing its job.Can I cut a timber wedge and lever them apart?

Tools

red arrow is the tensioner

http://i253.photobucket.com/albums/hh59/magnabuff/chain_marks_189.jpg

Looking at that pic Magnabuff I don't think mine has the sprocket support, and the sprocket was probably just sitting on the chain guides. When the cover is removed, will the tensioner push in by hand?


Tools

yes the tensioner can be pushed in by hand
there is no ratchet.... just a compression spring
behind the tensioner guide into the pump


you may be in luck if the chain hasnt moved off the tensioner

take care with the tensioner if forced you may crack
the oil pump housing at that point (I did crack one )

hope you dont have to take off the timing cover
because the sump has to come off as well

Without the support the tensioner drops out of the oil pump, removing the front cover is the only option. You will need to drop the sump a bit and lift the head slightly so you don't damage the sump gasket or head gasket when you take the front cover off. You will need to get another support to hold the sprocket up when you reassemble it all. Try the wreckers. Feel free to swear at the person who left the support off.

A good study of the manual before you started would have saved you a lot of grief at this stage.

A good study of the manual before you started would have saved you a lot of grief at this stage.
No grief at all really. I cut a timber wedge out of a 500 long piece of 42 x 12 KD. Within 15 seconds of slipping it in between the chains the tensioner had pushed back and the sprocket was back on. It is all back together again but the fading light beat me. No parts left over which is a good thing, and it started first time. I didn't get to check the timing yet, but did notice that the engine is racing, and not sure why. I checked the compression on all cylinders and they are all exactly the same at just above 11000, which is slightl less than the 2 good cylinders were before the strip down. So I am nearly there, just keep running out of time!

Tools

it is getting dark quick now and if its not dark its belting down with rain so no one can win. good to hear people still bother with the good old magnas, as they are a dieing breed around my parts probably because of all the snobs that are to proud to drive something sensible (my mother included).

you fixed that car quickly Tools

good to hear of DIYS turning out successfully

especially on the first gen engines

Thanks Magnabuff, I certainly appreciated your help. I still have to sort out why the engine is racing though. My first guess was that the throttle cable might have snagged on something but I just looked at it in the dark and that doesn't seem to be the case. I don't know if it is a choke thing as it is really revving hard. Any suggestions what to look at?

Tools

Check that the hot water still flows through the hoses to the auto choke. Hoses should get hot quite quivkly. Dows the choke flap actually open? Take the air cleaner off and start the engine, then manually open the choke flap and see if the revs come down.

just a guess

now you have better combustion you may need adjust the air fuel mixture

make sure the line up point and markings are ok

http://i253.photobucket.com/albums/hh59/magnabuff/choke1_117.jpg

like he said time to do some carb adjustments

I had a play with the idle speed screw and it didn't make any difference. I will check the choke and then play with the mixture.

Tools

Well in the 5 minutes I had between getting home and it getting too dark to see I manually opened the choke and it didn't make any difference. it still idles at around 3000.Magnabuff when you say make sure the line up point and markings are ok, what am I looking for with them? The manual says that the mixture screw should only be adjusted by someone with an exhaust gas analyser. Am I going to be able to successfully make adjustments without having one, or am I just going to make things worse for myself?

I had unbolted the carby when I did the head gasket and just pushed it to the back to let me get at some of the manifold nuts. Could I have dislodged something that might have now stuck when the carby was turned on it's side?

Tools
"

the choke isnt staying on thats the main thing

dont think choke is your problem because
the car was running before you took the head off

tipping the carby a bit wont cause a fault as the
float and needle stay put.... if the top stays on

http://i253.photobucket.com/albums/hh59/magnabuff/carby_side_2_153-1.jpg

if you adjust the throttle cable screw what happens
the carby should wind down to 1000 -950 rpm

the factory set air mixture jet (at the back of the carby under the plug)
should be around 3 1/2 turns from needle seat base

My first thought had been that maybe the throttle cable had snagged on something and that was why it was revving,so I undid the adjustment nuts and pulled the cable ou of it's holder so there was no tension at all on the cable, and that didn't make any difference either. If the air mix is factory set I am concerned about playing with it when I really haven't done anything except change a gasket and put it all back together. It really has me stumped.

Tools

Maybe I should give the mix adjustment half a turn and see what happens. If I do it in a controlled fashion I can return it to where it was if it doesn't sort things out.

Tools

by tipping the carby you may have disturbed
sediment at the bottom of the bowl
you have the car running so dont think it is a clogged jet
its as if the second stage is stuck open

recheck the dashpots see if they hold vaccume

the previous carby picture gives you a
few adjustment screws to play with

just move them one at a time 1/2 a turn then back to
its original place

the revs should drop

Well it has got me stumped. I thought I would take it for a drive to warm it up this morning, and eventually the revs did drop, but now the bloody thing won't idle! I had played with the idle adjustment screw earlier on to try to bring the revs down, and I suspect that it is not back in it's original position. Which way should I be turning it to increase the idle speed, and how do I determine what it's position should be in relation to being fully in or out? Because I don't know where this point is, I don't know if it is this adjustment that is the problem and to persist with it or of it is something else.

tools

turn the big knob in (clockwise )to increase speed
no number of turns info (trial and error)
just use the taco

http://i253.photobucket.com/albums/hh59/magnabuff/carby_side_2_153-1.jpg

if its auto then in neutral it should be between 750 and 850 and for a manual it should be between 700 and 800. i wind it in until the engine smooths out and runs even, as long as thats not too far over the limit, especially in an auto. the ear seems to be the best tool for this one. i had much the same problem on a 202 holden with the secondary sticking a little but it didn't go away even when warm. it sounds as if it could be something to do with the auto choke because when the car heats up it seem to go? i dont know allot about the the system in the magna because mine is good old flawless EFI but in my friends mazda b2000 it opens the throttle plate a little too when the choke is applied, so if it sticks as it use to the revs would stick a little high. could this be your problem? although i doubt it would open it up enough to get 3000 rpm.
hope this helps, its just a few ideas
regards jay

Well I took it to my fuel specialist who is pretty cluey with all things fuel related, and he thinks it is an inlet manifold leak, but he doesn't do that sort of work so I will have to do it myself. Does that sound like a possibility that this could be the problem? I used a new gasket when I put it back together so don'tt know why it would have such a severe leak.

Tools

thats whats wrong with mine after i put it all back together the car wouldnt idle at all, ive just got to replace the gasket again and re-tighten all the bolts

the old mechainics use to use a squirt of oil
around the joints and bolts of an inlet manifold
to see if oil was drawn into the combustion chamber

if you used the sealants for water and oil in the
right places on the inlet gasket it should be all good

http://i253.photobucket.com/albums/hh59/magnabuff/inlet_gasket_168.jpg

I only used sealant on the two water chambers. Should I use it on the whole gasket? It was only a paper gasket, is there a better type to use?
Mu fuel guy sprayed ether I think (something like "start ya bastard")on the manifold and things calmed down whcih is why he thinks it is an inlet manifold leak. I am just miffed as to why it is leaking at all. It was probably the easiest part of the operation and I buggered it up!

Tools

there might be a small warp in the
inlet manifold itself

anyway looks like you will have to use the water sealant
and cover both sides of the rest of the gasket with permatex blue or black

you can buy the gasket seperate from supercheap
might come with a spare exhaust gasket

I would highly recommend against coating the complete gasket, this can cause the gasket to become soft over time and allow it to suck in

Tale your inlet manifold off, use a big FLAT block of wood with some 320 wet and dry paper and reface it. These are well known on the Carb models for flaring around the mounting points and then they do not seal properly post refit.

Again, you can use a vac guage to determine if there is a vac leak, low reading will indicate this.

I took the manifold off again today and the gasket was ok but I had bought a new one anyway. I cleaned up the faces ready to take the new gasket, or so I thought. It turns out there were a couple of bits of the old gasket still stuck to the faces. The original gasket that I removed a few weeks ago had been there for 25 years and had stuck fast to the metal. I had scraped it with a blade and thought I was getting a metal on metal scrape, but the gasket had gone hard and looked and felt like metal. Anyway so I cleaned it off and put the new gasket on and when I started it it was idling a bit below 3000 this time, and when it warmed up it was idling quite well at around 1200. I can't get it to go lower than that though, don't know why. It drives well and I will see how it goes over the next few days. I don't know if when I start it from cold it will idle at 3000 again.

I gave myself better access to the manifold this time and I notice dthat there is a hole about 20mm diameter in the middle, towards the bottom. Does anyone know what this is? It was clogged solid with a black substance, and the corresponding hole was the same in the head when I had it off.

Tools

Things had been going pretty well all week but today when I was about 50km from home I had steam coming out from under the lid. it is coming from somewhere under the inlet manifold on the right hand side so I don't know if for some reason the inlet gasket has let go or if it is something else. Is there anything else under there that it could be?

Tools

just a guess
the hole is probably where the manual
fuel pump goes from sigma days

for the steam ?
welsh plugs or heater hoses

Turned out to be a welsh plug, and not the one just below the manifold but the one a bit lower.It could have happened when I have the manifold etc out to make it easier to get to! The air con pump and mounting bracket had to come off to get to it. So she is up and running again, but not running all that well anymore......I don't know if the steam bath has buggered something else or if I just need to adjust the timing.

Tools

you really have worked hard to keep
this first gen on the road

well done :facejump:

you really have worked hard to keep
this first gen on the road

well done :facejump:

I have had this car since 1989 (21 years !) and have never had to spend anything on it, which is why I have held on to it for so long. It is old and crappy and I would love a new car but can't justify the expense when she keeps going with just a little TLC.Maybe it is on a downhill slide now though. Over the years I have done the usual brakes and tyres and I think an alternator, but really nothing else and now it is all catching up with me!