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Head Gasket Help
Hopefully someone can help me with this. I have a '97 Fiat Punto. A
couple of weeks back the end of one of the spark plugs dropped off into the cylinder. I removed the head, cleaned it all up, got rid of the bits of plug, checked for damage and refitted the head with a new gasket. A compression test showed that there was not very much compression in a couple of the cylinders and further testing showed that the compression in all cylinders was all over the place. I removed the head again and oil had made its way from the oil galleys and seeped out into the cylinder. I assume thats where the air was leaking out too - through the head gasket. So I got another gasket, a proper angle gauge (I guessed the angles before when I tightened the head bolts) I cleaned everything up a little more than before, oiled the head nuts more, and reassembled. Compression was even worse this time. If I try to start the car it turns over but misfires through the throttle body (sign of a blown head gasket?) I assume that the gasket has blown/not sealed properly. Can anyone give me an idea of what might be causing the gasket to not seal properly. Only things I can think of a I've not cleaned the mating surfaces properly I've not tightened to the correct torque for some reason The head is not perfectly straight. Are there ANY other factors at all that could cause a newly fitted head to not seal properly? I assume that if I can see where the oil has made its way through the gasket that means that the gasket isn't sealed correctly? Theres nothing else that would cause oil to make its way into the cylinder? I'm at my wits end with this damn thing. Cheers, Dave |
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#2
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If you aren't getting the timing correct you can have the symptoms you
are describing. If the valves aren't closing at the right times you will have little or no compression and it will backfire out the throttle body. The oil drip can happen when you are removing the head and doesn't always mean a blown gasket. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Dave Skirrow wrote: > > Hopefully someone can help me with this. I have a '97 Fiat Punto. A > couple of weeks back the end of one of the spark plugs dropped off into > the cylinder. > > I removed the head, cleaned it all up, got rid of the bits of plug, > checked for damage and refitted the head with a new gasket. > > A compression test showed that there was not very much compression in a > couple of the cylinders and further testing showed that the compression > in all cylinders was all over the place. I removed the head again and > oil had made its way from the oil galleys and seeped out into the > cylinder. I assume thats where the air was leaking out too - through the > head gasket. > > So I got another gasket, a proper angle gauge (I guessed the angles > before when I tightened the head bolts) I cleaned everything up a little > more than before, oiled the head nuts more, and reassembled. Compression > was even worse this time. If I try to start the car it turns over but > misfires through the throttle body (sign of a blown head gasket?) I > assume that the gasket has blown/not sealed properly. > > Can anyone give me an idea of what might be causing the gasket to not > seal properly. > > Only things I can think of a > > I've not cleaned the mating surfaces properly > I've not tightened to the correct torque for some reason > The head is not perfectly straight. > > Are there ANY other factors at all that could cause a newly fitted head > to not seal properly? > > I assume that if I can see where the oil has made its way through the > gasket that means that the gasket isn't sealed correctly? Theres nothing > else that would cause oil to make its way into the cylinder? > > I'm at my wits end with this damn thing. > > Cheers, > Dave |
#3
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On Sat, 15 Jan 2005 17:31:29 GMT, Dave Skirrow
> wrote: >Hopefully someone can help me with this. I have a '97 Fiat Punto. A >couple of weeks back the end of one of the spark plugs dropped off into >the cylinder. > >I removed the head, cleaned it all up, got rid of the bits of plug, >checked for damage and refitted the head with a new gasket. > >A compression test showed that there was not very much compression in a >couple of the cylinders and further testing showed that the compression >in all cylinders was all over the place. I removed the head again and >oil had made its way from the oil galleys and seeped out into the >cylinder. I assume thats where the air was leaking out too - through the >head gasket. > >So I got another gasket, a proper angle gauge (I guessed the angles >before when I tightened the head bolts) I cleaned everything up a little >more than before, oiled the head nuts more, and reassembled. Compression >was even worse this time. If I try to start the car it turns over but >misfires through the throttle body (sign of a blown head gasket?) I >assume that the gasket has blown/not sealed properly. > >Can anyone give me an idea of what might be causing the gasket to not >seal properly. > >Only things I can think of a > >I've not cleaned the mating surfaces properly >I've not tightened to the correct torque for some reason >The head is not perfectly straight. > > >Are there ANY other factors at all that could cause a newly fitted head >to not seal properly? > >I assume that if I can see where the oil has made its way through the >gasket that means that the gasket isn't sealed correctly? Theres nothing >else that would cause oil to make its way into the cylinder? > >I'm at my wits end with this damn thing. > >Cheers, >Dave Sounds to me like the head is warped. Have you put a good straight edge across it to measure it for flatness? And the same goes for the block itself. Put a good straight edge along it to see if it is flat. IOW, shine a hi-power light against one side of the straight edge and see if there is light shining through underneath where the straight edge is supposedly resting on the block and head. If you have light leaks, you're going to have oil leaks. One other thing that can happen is if you over tighten on an aluminum head, you can *pull* the metal to create high spots where the head bolts go into the threads, and these high spots need to be taken down to the height of the rest of the head. I think you have to make a decision. Bring it somewhere where they can machine the surfaces true, and pay through the nose, or start looking around for another car. Lg |
#4
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I did check the timing and I'm pretty sure its right, the marks on the
belt are lined up in the right place at least. Although I will look at it in a little more detail when I try again tomorrow. Could a blown gasket cause this backfiring through the throttle body in any way? Oh, forgot to say, there was also oil on the spark plug threads when I removed them after trying to start it. Cheers, Dave Mike Romain wrote: > If you aren't getting the timing correct you can have the symptoms you > are describing. If the valves aren't closing at the right times you > will have little or no compression and it will backfire out the throttle > body. > > The oil drip can happen when you are removing the head and doesn't > always mean a blown gasket. > > Mike > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's |
#5
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One tricky part of the timing is that the crank has 'two' top dead
centers or two different times the mark on the crank can be lined up right. You can tell pretty close by putting your finger into the spark plug hole for number one piston and hand turning the engine with a wrench on the crank bolt. If the valve timing is right, then as it comes up to the timing mark you can feel the compression under your finger with it maxing at the mark then dropping down and sucking on your finger. Mike Dave Skirrow wrote: > > I did check the timing and I'm pretty sure its right, the marks on the > belt are lined up in the right place at least. Although I will look at > it in a little more detail when I try again tomorrow. > > Could a blown gasket cause this backfiring through the throttle body in > any way? > > Oh, forgot to say, there was also oil on the spark plug threads when I > removed them after trying to start it. > > Cheers, > Dave > > Mike Romain wrote: > > If you aren't getting the timing correct you can have the symptoms you > > are describing. If the valves aren't closing at the right times you > > will have little or no compression and it will backfire out the throttle > > body. > > > > The oil drip can happen when you are removing the head and doesn't > > always mean a blown gasket. > > > > Mike > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > > 88 Cherokee 235 BFG AT's |
#6
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are you sure you put the timing belt on correctly?
it could be out of time and all those symptoms would be present. old john "Dave Skirrow" > wrote in message ... > Hopefully someone can help me with this. I have a '97 Fiat Punto. A > couple of weeks back the end of one of the spark plugs dropped off into > the cylinder. > > I removed the head, cleaned it all up, got rid of the bits of plug, > checked for damage and refitted the head with a new gasket. > > A compression test showed that there was not very much compression in a > couple of the cylinders and further testing showed that the compression > in all cylinders was all over the place. I removed the head again and > oil had made its way from the oil galleys and seeped out into the > cylinder. I assume thats where the air was leaking out too - through the > head gasket. > > So I got another gasket, a proper angle gauge (I guessed the angles > before when I tightened the head bolts) I cleaned everything up a little > more than before, oiled the head nuts more, and reassembled. Compression > was even worse this time. If I try to start the car it turns over but > misfires through the throttle body (sign of a blown head gasket?) I > assume that the gasket has blown/not sealed properly. > > Can anyone give me an idea of what might be causing the gasket to not > seal properly. > > Only things I can think of a > > I've not cleaned the mating surfaces properly > I've not tightened to the correct torque for some reason > The head is not perfectly straight. > > > Are there ANY other factors at all that could cause a newly fitted head > to not seal properly? > > I assume that if I can see where the oil has made its way through the > gasket that means that the gasket isn't sealed correctly? Theres nothing > else that would cause oil to make its way into the cylinder? > > I'm at my wits end with this damn thing. > > Cheers, > Dave |
#7
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Dave Skirrow > wrote in message ... > Hopefully someone can help me with this. I have a '97 Fiat Punto. A > couple of weeks back the end of one of the spark plugs dropped off into > the cylinder. > > I removed the head, cleaned it all up, got rid of the bits of plug, > checked for damage and refitted the head with a new gasket. > > A compression test showed that there was not very much compression in a > couple of the cylinders and further testing showed that the compression > in all cylinders was all over the place. I removed the head again and > oil had made its way from the oil galleys and seeped out into the > cylinder. I assume thats where the air was leaking out too - through the > head gasket. > > So I got another gasket, a proper angle gauge (I guessed the angles > before when I tightened the head bolts) I cleaned everything up a little > more than before, oiled the head nuts more, and reassembled. Compression > was even worse this time. If I try to start the car it turns over but > misfires through the throttle body (sign of a blown head gasket?) I > assume that the gasket has blown/not sealed properly. > > Can anyone give me an idea of what might be causing the gasket to not > seal properly. > > Only things I can think of a > > I've not cleaned the mating surfaces properly > I've not tightened to the correct torque for some reason > The head is not perfectly straight. > > > Are there ANY other factors at all that could cause a newly fitted head > to not seal properly? > > I assume that if I can see where the oil has made its way through the > gasket that means that the gasket isn't sealed correctly? Theres nothing > else that would cause oil to make its way into the cylinder? > > I'm at my wits end with this damn thing. > > Cheers, > Dave Well you didn't take the advice of people who recommended overhauling the head while it was off and having it skimmed or at least checked for truth so I suspect they won't have much sympathy now you're having to do it all again. The simplest explanation (Occam's Razor) based on the fact you didn't listen previously is that you're so far out of your depth you haven't got a clue how to do the job properly or how to spot any faults that need correcting. There might be bent valves, warped head, damaged head or block faces, you've messed up the cam or ignition timing while putting it back together or a combination of the above and/or something else. It would be a damn sight easier for someone who knows what they are doing to take a look at it for 5 minutes than people on here speculate about the multiple possibilities ad infinitum because they can't examine the actual engine. -- Dave Baker - Puma Race Engines (www.pumaracing.co.uk) |
#8
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>
> Well you didn't take the advice of people who recommended overhauling the > head while it was off and having it skimmed or at least checked for truth so > I suspect they won't have much sympathy now you're having to do it all > again. The simplest explanation (Occam's Razor) based on the fact you didn't > listen previously is that you're so far out of your depth you haven't got a > clue how to do the job properly or how to spot any faults that need > correcting. There might be bent valves, warped head, damaged head or block > faces, you've messed up the cam or ignition timing while putting it back > together or a combination of the above and/or something else. It would be a > damn sight easier for someone who knows what they are doing to take a look > at it for 5 minutes than people on here speculate about the multiple > possibilities ad infinitum because they can't examine the actual engine. > -- > Dave Baker - Puma Race Engines (www.pumaracing.co.uk) > > erm, ok. I'm not after sympathy, Im after advice really. I got a lot of conflicting information and decided on the best course of action for me based on what other people had told me. I listened to everyone. Some people said just put it back and test the compression and some said overhaul the lot. I didn't overhaul the head because of the cost of it. I can't afford to have someone else look at it and I want to learn to do it anyway. My plan was to refit and test the compression in the cylinder that had the initial fault. I figured that if there was any problem on that cylinder I could then take it apart again and look at it. The only problem is that there is no compression on the other cylinders. Based on what I know, I didn't expect this as I assumed that after losing the head of a spark plug in a cylinder, it wouldn't effect the other cylinder. The timing is fine. The marks are aligned on the belt and the No.1 cylinder is at TDC of its compression stoke while the cam marks are lined up. The ignition timing can't be adjusted. I assume that a bent valve would only effect the cylinder that had the problem in the first place. If I can't fix this myself the car will have to be scrapped. I can't afford to pay someone to fix it so I'm going to have to have a go myself. If I have to overhaul the head I will do but I don't want to start doing that if I don't have to. If someone could tell me whether a blown/leaking head gasket could cause misfiring through the throttle body that would be a start. If it does then I think I can assume that no compression, misfiring and oil on the plugs means a leaking head gasket and Ill take it apart again. If the misfiring can't be put down to this then I will try and figure out what that fault is before taking it all apart again. Also if someone could tell me if there is anything else that could cause the head gasket not to seal or to blow right away, other than: Surfaces not clean Surfaces not true Wrong torque Thanks to everyone for their help. Dave Baker, I'm sorry if it bothers you that I have ago myself, but as I say it's really the only option open to me at the moment. Aside from that I want to learn to do this stuff myself and the only way for me to learn it is to have a go. Cheers, Dave |
#9
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On Sat, 15 Jan 2005 18:14:49 GMT, Dave Skirrow
> wrote: >I did check the timing and I'm pretty sure its right, the marks on the >belt are lined up in the right place at least. Although I will look at >it in a little more detail when I try again tomorrow. > >Could a blown gasket cause this backfiring through the throttle body in >any way? > >Oh, forgot to say, there was also oil on the spark plug threads when I >removed them after trying to start it. > >Cheers, >Dave > > I agree with Mike on this one.. Your timing is not correct. A blown head gasket will not cause a backfire through the throttle body but incorrect timing will. You would be hard pressed to blow a head gasket before the engine even started. Steve B. |
#10
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Steve B. wrote:
> On Sat, 15 Jan 2005 18:14:49 GMT, Dave Skirrow > > wrote: > > >>I did check the timing and I'm pretty sure its right, the marks on the >>belt are lined up in the right place at least. Although I will look at >>it in a little more detail when I try again tomorrow. >> >>Could a blown gasket cause this backfiring through the throttle body in >>any way? >> >>Oh, forgot to say, there was also oil on the spark plug threads when I >>removed them after trying to start it. >> >>Cheers, >>Dave >> >> > > I agree with Mike on this one.. Your timing is not correct. A blown > head gasket will not cause a backfire through the throttle body but > incorrect timing will. > > You would be hard pressed to blow a head gasket before the engine even > started. > > Steve B. Ok cheers, I'll take another look at the timing. If it's the timing i will be a very happy man! Any idea on how how oil could have made it on to the plug threads? That's one of the things that has been bothering me. It's on all the plugs. Cheers, Dave |
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