Maniflow gasket...
Discussion
Hello,
After getting my car back from the garage today (to tweak the twin carbs *) the owner (nice bloke) said that it will be impossible to set the carbs up because the manifold gasket is blowing hence the problems I'm having. So the question is:
Is it hard to replace? I don't think it will be, looks fairly straight-forward to be honest. Any tips for taking the bolts of the exhaust section - apparently they will be tight to get off due to the heat they've been exposed to... (dad told me that one
)
It appears that the Marina 1800TC car has one gasket that covers both the Exhaust and the Carbs, does that make it harder (other than more things to take off)?
I'm asking this here so when I speak to my dad next, and eventually my bro-in-law (previous owner) I don't sound like a numpty and end up standing watching them fix my car again
Upsets me when they take over Well, bro-in-law anyway!
Cheers.
* I will learn to tweak them myself, along with the timing and everything, but due to just getting the car and wanting to drive it about still before the winter I figured it would be wise to get someone else to sort it out for me. At least this way it won't be off the road for x days.
>>> Edited by docevi1 on Tuesday 14th October 23:01
>>> Edited by docevi1 on Wednesday 15th October 18:26
After getting my car back from the garage today (to tweak the twin carbs *) the owner (nice bloke) said that it will be impossible to set the carbs up because the manifold gasket is blowing hence the problems I'm having. So the question is:
Is it hard to replace? I don't think it will be, looks fairly straight-forward to be honest. Any tips for taking the bolts of the exhaust section - apparently they will be tight to get off due to the heat they've been exposed to... (dad told me that one
) It appears that the Marina 1800TC car has one gasket that covers both the Exhaust and the Carbs, does that make it harder (other than more things to take off)?
I'm asking this here so when I speak to my dad next, and eventually my bro-in-law (previous owner) I don't sound like a numpty and end up standing watching them fix my car again
Upsets me when they take over Well, bro-in-law anyway! Cheers.
* I will learn to tweak them myself, along with the timing and everything, but due to just getting the car and wanting to drive it about still before the winter I figured it would be wise to get someone else to sort it out for me. At least this way it won't be off the road for x days.
>>> Edited by docevi1 on Tuesday 14th October 23:01
>>> Edited by docevi1 on Wednesday 15th October 18:26
The word you're looking for is 'manifold'....
Usually there's an inlet manifold and an exhaust manifold. The inlet can be (but not always) aluminium, whereas the exhaust tends to be cast iron. Some cars of that era had a combined manifold (cast iron).
Often you need hands like a paedophile to get into the manifold bolts or nuts: sometimes the nuts will rust to the studs and shear them off when you try to undo them. It's about a million years since I last looked under the bonnet of a Marina (my dad was a self-employed mechanic when I was a kid so I was always getting roped in) so I can't recall the setup. Usually you just remove whatever throttle/ choke cables are in the way, plus any coolant hoses that may go to heat the inlet manifold. Then whip the bolts/ nuts off and lift away the manifold(s). Ensure the mating surfaces are nice and clean and the manifolds are not warped, then install new gasket, refit nuts etc., torque to recommended settings and you'll be posing down Macdonalds before you know it.
Ian
Usually there's an inlet manifold and an exhaust manifold. The inlet can be (but not always) aluminium, whereas the exhaust tends to be cast iron. Some cars of that era had a combined manifold (cast iron).
Often you need hands like a paedophile to get into the manifold bolts or nuts: sometimes the nuts will rust to the studs and shear them off when you try to undo them. It's about a million years since I last looked under the bonnet of a Marina (my dad was a self-employed mechanic when I was a kid so I was always getting roped in) so I can't recall the setup. Usually you just remove whatever throttle/ choke cables are in the way, plus any coolant hoses that may go to heat the inlet manifold. Then whip the bolts/ nuts off and lift away the manifold(s). Ensure the mating surfaces are nice and clean and the manifolds are not warped, then install new gasket, refit nuts etc., torque to recommended settings and you'll be posing down Macdonalds before you know it.
Ian
By the sound of it, it's the inlet manifold gasket that needs replacing? I say this because I don't see how having a blowing exhaust gasket would prevent you from setting up the carbs*. 
Whereas a leaking inlet gasket would upset the mixture going in, as extra air could be being sucked in after the mixture has been mixed.
Thankfully the inlet manifold is a lot eaiser to get off, as the nuts generally don't tend to rust to b*ggery in the way that exhaust ones do!
*Correct me if I'm wrong about this
Whereas a leaking inlet gasket would upset the mixture going in, as extra air could be being sucked in after the mixture has been mixed.
Thankfully the inlet manifold is a lot eaiser to get off, as the nuts generally don't tend to rust to b*ggery in the way that exhaust ones do!
*Correct me if I'm wrong about this
This is a combined cast iron block/head, apparently.
As for the word, well I knew what I typed (in my head) The computer typed it wrong
Thanks for the tips, and yes it is just a Marina unit but for a complete novice like me talking and finding out things not to do before trying it is more appealing than doing it and finding out the hard way you don't do xxxx.
And yes, I am aware it has no air-filters and no, I'm not putting any on. Doesn't need em!
>> Edited by docevi1 on Wednesday 15th October 16:54
[quote=docevi1
And yes, I am aware it has no air-filters and no, I'm not putting any on. Doesn't need em!
[/quote]
Wrong, all engines need air filters. If you run with no filters you will end up with a knackered engine. The dust and other road crap will be sucked straight in to the cylinders, causing excessive wear, and larger lumps may well ruin the valves or other parts as well. The only engines to run without filters are generally race engines that are rebuilt several times a year.
And yes, I am aware it has no air-filters and no, I'm not putting any on. Doesn't need em!
[/quote]
Wrong, all engines need air filters. If you run with no filters you will end up with a knackered engine. The dust and other road crap will be sucked straight in to the cylinders, causing excessive wear, and larger lumps may well ruin the valves or other parts as well. The only engines to run without filters are generally race engines that are rebuilt several times a year.
docevi1 said:
And yes, I am aware it has no air-filters and no, I'm not putting any on. Doesn't need em!
Just to agree with the other sensible replies that you do need air filters if you care at all for your engine. I bet you also didn't realise that by running the carbs as they are now, you are actually losing airflow?
If you really don't care about excessive and premature valve seat and bore wear, then at least fit a set of trumpets to attempt justify not fitting filters.
Because of the carb heat sheild, you won't be able to see much until you get the carbs off
As for the gasket leak, I assumed it was the exhuast as any leak in the inlet will have it running extremely badly or not at all
I asked for a photo because I though the side of the bonnet might open (in an old car engine cover type of way) after seeing it I reckon it's deep breath and get in there time
And fit some air filters, K&N do some that bolt straight onto SUs even with little trumpets
As for the gasket leak, I assumed it was the exhuast as any leak in the inlet will have it running extremely badly or not at all
I asked for a photo because I though the side of the bonnet might open (in an old car engine cover type of way) after seeing it I reckon it's deep breath and get in there time
And fit some air filters, K&N do some that bolt straight onto SUs even with little trumpets
Ah, I didn't mean it "didn't need them", I meant I couldn't fit them!
Yes, I do care about my engine, and yes I am very concerned that it has no air-filters what so ever (bar a little grille) but this car/engine has been rebuilt and travelled 5k since, with no air-filters, so damage will have already been done. Secondly, the re-builders (reasonably knowable), the garage.. all say not to worry. I'm trying very hard not to worry about it!
My problem is that I can't mod the body-work for 2 reasons (1) my insurance will sky-rocket and (2) I don't want to spoil the lines of the car with air-filters (i.e. make it more sporty).
As for the sock filters, well I honestly don't have a clue but there is very, very little room to put anything on them, anything at all. CB Dave was having a look at it at NE PH2 and he couldn't spot a solution easily either. There is really very limited room under the engine, very limited room.
Would it work if I were to put something like a long pipe off the carbs and attach the air-filters lower down (where there is room)? I remember CB Dave mentioning that I could frabricate a plastic "ram" to move air and filter it there?
Cheers, as for the gasket, well that'll be done anyway, I was just asking simple questions.
Yes, I do care about my engine, and yes I am very concerned that it has no air-filters what so ever (bar a little grille) but this car/engine has been rebuilt and travelled 5k since, with no air-filters, so damage will have already been done. Secondly, the re-builders (reasonably knowable), the garage.. all say not to worry. I'm trying very hard not to worry about it!
My problem is that I can't mod the body-work for 2 reasons (1) my insurance will sky-rocket and (2) I don't want to spoil the lines of the car with air-filters (i.e. make it more sporty).
As for the sock filters, well I honestly don't have a clue but there is very, very little room to put anything on them, anything at all. CB Dave was having a look at it at NE PH2 and he couldn't spot a solution easily either. There is really very limited room under the engine, very limited room.
Would it work if I were to put something like a long pipe off the carbs and attach the air-filters lower down (where there is room)? I remember CB Dave mentioning that I could frabricate a plastic "ram" to move air and filter it there?
Cheers, as for the gasket, well that'll be done anyway, I was just asking simple questions.
I've found out why it doesn't have air-filters (handy that).
With the engine been off-set to the left, it is very close to the bodywork (the problem), so the previous owner had shaved (something) down to make the carbs sit closer to the engine. This had the effect of frying the fuel when they changed the head to run on unleaded. So with the introduction of the heat-sheild (makes the car run) there isn't enough space for filters.
Under recommendation of a MGB driver (with similar problem) Howard simply removed the air-filters and put the gauses on. The MGB driver did say he had Rams of some kind on (can't remember what now) but they aren't needed. He'd ran his car every day for 10years and had no trouble.
Maybe the Marina Engines (friggin old) are different to others, I don't know but I'm trying hard not to worry!
With the engine been off-set to the left, it is very close to the bodywork (the problem), so the previous owner had shaved (something) down to make the carbs sit closer to the engine. This had the effect of frying the fuel when they changed the head to run on unleaded. So with the introduction of the heat-sheild (makes the car run) there isn't enough space for filters.
Under recommendation of a MGB driver (with similar problem) Howard simply removed the air-filters and put the gauses on. The MGB driver did say he had Rams of some kind on (can't remember what now) but they aren't needed. He'd ran his car every day for 10years and had no trouble.
Maybe the Marina Engines (friggin old) are different to others, I don't know but I'm trying hard not to worry!
BMC A and B series manifold gaskets are dead easy to replace. The inlet and exhaust manifolds share a single gasket. Undo the nuts on the studs holding the manifolds to the head, and you'll probably have enough movement in the exhaust to pull them far enough away from the head to get the old gasket off and the new one on, without having to take anything else apart. (Though you might be a bit short of space in your setup...)
The nuts do seize to the studs sometimes but generally all that happens is the stud then comes out of the head, so you can still get it apart. Put the studs back in the same holes though. Make sure you use a well fitting socket. 1/2" is not the same as 13mm. Replace any missing washers. Sometimes you may encounter brass nuts: take care not to strip them.
And get some air filters on it!
The nuts do seize to the studs sometimes but generally all that happens is the stud then comes out of the head, so you can still get it apart. Put the studs back in the same holes though. Make sure you use a well fitting socket. 1/2" is not the same as 13mm. Replace any missing washers. Sometimes you may encounter brass nuts: take care not to strip them.
And get some air filters on it!
Pigeon said:
BMC A and B series manifold gaskets are dead easy to replace. The inlet and exhaust manifolds share a single gasket. Undo the nuts on the studs holding the manifolds to the head, and you'll probably have enough movement in the exhaust to pull them far enough away from the head to get the old gasket off and the new one on, without having to take anything else apart. (Though you might be a bit short of space in your setup...)
I second that take the inlet manifold off first complete with carbs and you will have all the room you need
The nuts do seize to the studs sometimes but generally all that happens is the stud then comes out of the head, so you can still get it apart. Put the studs back in the same holes though. Make sure you use a well fitting socket. 1/2" is not the same as 13mm. Replace any missing washers. Sometimes you may encounter brass nuts: take care not to strip them.
And get some air filters on it!
danhay said:
Stephan,
you mention gauses (gauzes?) so I take it there are some wire mesh thingies providing a basic form of air filtration...namely keeping out the larger insects/smaller birds?
yes, the wire mesh sits on the front of the Carbs (you can just see them in the pic).
I'm going to ask about this in the MGB owners forum and see what they come up with...
Thanks for the tips Pigeon, we plan to do it next weekend when I have the time.
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