Weird noise , opinions please

[Mad4slalom]

Hi all, scary one this eve . Just neen recovered home by the AA , took my friend for a little ride , we were going about 25 mph when something metallic let go and sounded like it was rattling around under the car, we stopped half expecting a bit of wire or road debris had flicked up underneath. Anyway couldnt see any thing but now aware of a chuffing or blowing sound, nothing apparent under the hood but we thought a spark plug may have come loose and was leaking. Couldnt determine which as sounded one side then the other side then the front. Called the AA, guy didnt think it was a plug , he was thinking bottom end but not knocking more scraping type noise. Two other people I knowheard it and one very familiar with the 350 although in boats says he has never heard one sound like this. AA man suggested removing belts to eliminate water pump alternator and power steering , I will do this tomorrow. Dont know if it could be valvey or inlet or exhaust manifold blow or if could still be a plug, bearing in mind I did change the plugs and was struggling from the top to get spanner access to the drivers side ones so could have been a bit loose. Any thoughts or previous experiences, fingers crossed it not serious. Only 4 K on motor over 6 years since it was rebuilt in the states, baffledto say the least.

 

[Roscobbc]

Had this with my '68 a few years back en-route for its MOT. An odd scrapeing noise like something metallic was touching the ground. I turned out to be a fractured trailing arm pivot bolt, the scrapeing sound being the inner wheel rim rubbing the trailing arm I think. Is it speed related or rpm related? - water pump pulley is very close to water pump and can rub if spacers not used. Not unknow if a manual car for the 'tin' bellhousing cover to rub against the flywheel.

 

[Forrest Gump]

Not unknow if a manual car for the 'tin' bellhousing cover to rub against the flywheel.

That was exactly my first thought. The cover does sit very close to the flange on the back of the crankshaft so if a bit of road debris got flicked up and caught the cover in the wrong spot.....

 

[Chuffer]

As soon as I read Mad4`s woes , I thought of bell housing cover too ! Doubt it is plug related as the sounds described don`t add up for me . If it only happens when car is moving it could be a small stone caught up between a brake disc and the inner cover plate . Hope you get sorted easily Mad4 as you seem to be suffering one thing after the other recently

 

[Chuffer]

Apologies ! scratch my comment about not plug related as just re read the bit about a " chuffing or blowing sound" .

 

[Oneball]

Also look at the fan and viscous coupling

 

[Corvetteville]

Could be something simple. My Jeeps brake backplate watershield somehow got bent due to been thin & corroded, made a horrible noise, touching the disc. Initially I was dreading the cost thinking gearbox, 2 diffs, trans box, loads of drive shafts? Anyway Didn't cost much in the end, but the disc has to come off.

 

[Mad4slalom]

Had this with my '68 a few years back en-route for its MOT. An odd scrapeing noise like something metallic was touching the ground. I turned out to be a fractured trailing arm pivot bolt, the scrapeing sound being the inner wheel rim rubbing the trailing arm I think. Is it speed related or rpm related? - water pump pulley is very close to water pump and can rub if spacers not used. Not unknow if a manual car for the 'tin' bellhousing cover to rub against the flywheel.

Thanks rosco, a few things there to check tomorrow

As soon as I read Mad4`s woes , I thought of bell housing cover too ! Doubt it is plug related as the sounds described don`t add up for me . If it only happens when car is moving it could be a small stone caught up between a brake disc and the inner cover plate . Hope you get sorted easily Mad4 as you seem to be suffering one thing after the other recently

thanks all, it is something to do with this plate on the bellhousing as you can feel it touching and make the noise worse if you press it in. On bolt by the oilfilter was missing , the other 3 were loose or finger tight.we tightened them , no diference, we removed them and flexed the plate out but noise still there . It is held by the starter motor so need to pull that as it must be scraping toward the top of the plate. Any thoughts or experiences. Checked all plugs and none loose. Guessthe chuffy noise could have been scrapey noise. And the rattly and tinging noise we heard first could have been the bolt dropping out and rattling around underneath. Also the power steering pump brackets were loose , one out past the belt so that could have been some of the initial noise. A bit peeved that we thought we had found the problem with the tin bellhousing plate but still there, so got to remove that next.

 

[Mad4slalom]

Could be something simple. My Jeeps brake backplate watershield somehow got bent due to been thin & corroded, made a horrible noise, touching the disc. Initially I was dreading the cost thinking gearbox, 2 diffs, trans box, loads of drive shafts? Anyway Didn't cost much in the end, but the disc has to come off.

Thanks , had the old bit of gravel behind the disc shield on various cars /vans. This is in time with engine when stationary now and related to flywheel / ring gear touching this plate at bottom of bell housing.

 

[Mad4slalom]

Apologies ! scratch my comment about not plug related as just re read the bit about a " chuffing or blowing sound" .

Hi chuffs, plugs were tight I just suspected that as I had recently changed them , I ghink the chuffing is actually scraping as in interference, dont know what could have changed tho so suddenly, .

 

[Oneball]

Mine has some tabs that hold it in place by clipping over the pressed edge of the sump. The bit that’s probably touching is where my thumb is in 2nd pic as that’s by the crank flange that the flywheel bolts to

 

[Mad4slalom]

Mine has some tabs that hold it in place by clipping over the pressed edge of the sump. The bit that’s probably touching is where my thumb is in 2nd pic as that’s by the crank flange that the flywheel bolts toView attachment 10086View attachment 10087

Thanks rosco, great pics, we tried pulling the bottom edge out but still touching I guess highr up where your thumb is. So starter out next and look further. thank you

 

[Mad4slalom]

Thanks rosco, great pics, we tried pulling the bottom edge out but still touching I guess highr up where your thumb is. So starter out next and look further. thank you

Sorry oneball, my mistake , thanks to all you guys

 

[Corvetteville]

Thanks , had the old bit of gravel behind the disc shield on various cars /vans. This is in time with engine when stationary now and related to flywheel / ring gear touching this plate at bottom of bell housing.

Starter motor gear not returned down shaft?

 

[Corvetteville]

Whoops didn't read the thread properly

 

[Forrest Gump]

Mine has some tabs that hold it in place by clipping over the pressed edge of the sump. The bit that’s probably touching is where my thumb is in 2nd pic as that’s by the crank flange that the flywheel bolts toView attachment 10086

View attachment 10087

Thats it exactly. It should all fit in theory but I couldn’t get mine to stop rubbing in that area so took the tin snips and trimmed that top edge away.

 

[Chuffer]

Hi Mad4 , a chuffety scrapy noise ? ?? Now that`s a different problem entirely !! As for all the loose bolts you have found , according to Mike Brewer and Ant Anstead on one of their live stage gigs at Silverstone Classic a couple of years back , I remember them saying that US restoration jobs were renowned for not having nuts and bolts torqued up tight .

 

[Mad4slalom]

Starter motor gear not returned down shaft?

No , as starts perfectly every time with no clicking or not meshing sounds.

 

[Mad4slalom]

Thats it exactly. It should all fit in theory but I couldn’t get mine to stop rubbing in that area so took the tin snips and trimmed that top edge away.

I will get it off and inspect, a couple og people have said when its off to put a bar behind fly wheel and see if its loose, which made me wonder if it could be linked to my shifter vibration . Sounds like something must have moved for it to suddenly start scraping. I am also finding a fair amount of loose nuts and bolts .

 

[Mad4slalom]

I will get it off and inspect, a couple og people have said when its off to put a bar behind fly wheel and see if its loose, which made me wonder if it could be linked to my shifter vibration . Sounds like something must have moved for it to suddenly start scraping. I am also finding a fair amount of loose nuts and bolts .

The po said the flywheel bolts were loctited and star washered and torqued up, he said to check the harmonic balancer, which again made me think of my shifter vibration which I have always thought seems that it could be more than just shift rod bushes as the vibration gets worse with more revs like an out of balance wheel, that could also account for the loose nuts and bolts I am finding ?