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Engine Noise. Piston Slap? Herald 13/60 1968


Kev
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Hi everyone,  Is anyone able to identify this noise? I have had a local mecanic have a look at my car and he put a camera down the spark plug chamber and noticed a few marks on pistons 1 and 2 on the bore. He seems to think it could be Piston Slap. So when the car is cold and idling, it sounds quite loud (as shown in the video). Once warmed up, the sound at idle goes. However, when driving and putting load on the engine the noise comes back. Everytime when putting on load. I'm not a mechanic and my skills are limited to servicing and hope someone on this forum is able to help me in any way. Also, if anyone knows a good mechanic for these classic cars in Essex/Herts area, would be very grateful.

Thanks

Kev

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agree  exhaust chirrup  and   certainly not piston slap 

 also check the fan blades are not making contact    even run with the fan belt off as a short test 

split pullies and belts can generate a lot of noise 

Pete

 

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Thank you both for the feedback. I have run the engine without the belt and the noise is still there. The blades are not making contact with anything. I have ordered a new manifold and downpipe gasket and will inspect the manifold when removed. Fingers crossed! Keep you posted

Thanks, Kev

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  • 2 weeks later...

"Piston slap" is a side to.side movement of the piston in the bore, typically as it changes direction at the top or bottom of the stroke.    Did your 'mechanic' see marks on the bore wall?  That would indicate severe wear, that needs a rebore, or at least a hone and new rings.  So pursue all the alternatives first!

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Hi All... So I have finally removed the manifold gasket and it seems you guys were correct!! See attached two photos. 

However...

Putting everything back together again and not touching ANY of the electrics and only reconnecting the fuel line to the carb, it absolutely will not start at all! Started on the button before.

I have since tried the following...

Checked battery... No battery issues, fuel pump checked, spark plugs sparking, condenser changed.

The only thing I think it can be is the carb. Perhaps when removing the manifold (with the carb still attached), I have moved or dislodged something inside. Maybe a dismantle and clean up is in order.

So frustrating because I cannot even check if the engine noise has been resolved or not!

Kev

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If you 'threw' the carb about it has probably dislodged the float and therefore no fuel getting in. Check that first. Petrol smell?

Check needle is free and the piston is sliding up and down.

I'm shocked your 'mechanic' could not hear the exhaust blowing!!!

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Have taken the Carb (Stromberg 150) out the car... removed the float and cleaned the float needle valve. Seemed a little sticky but now moving freely. Whilst had it out, I removed the diaphragm. Upon taking the cover off I expected a spring to pop out, but its not there? What the heck. Where the hell is the spring!?

What issues could happen from a missing spring?

Also to note... when I removed the fuel line from the carb, the fuel spat out from the pressure. Is this normal? Also I could not see signs of fuel in the manifold and the plugs are not wet. So could there be a blockage in the carb somewhere?

Sorry for all the questions. 

Cheers

Kev

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fuel under pressure from the pump will spurt if the float needle is closed as fuel height is ok or  if the back of the float needle valve is blocked 

have you removed it and had a good clean ??

and a 13/60 stromberg does not use a piston spring thats quite normal and correct 

Pete

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  • 3 weeks later...

ok, update for those that are following my progress. The engine starts, with no chirrup noise. Yay!

But, listen to the video with sound up... I promise I am not touching anything! The revs are up and down and it doesn't sound happy.

I have messed about with static timing and the carb dismantle and rebuild etc etc, something I have missed?

I feel like I need to get a tuner?? if there is something I can do myself, please help?? otherwise i'll post a new topic asking for recommendations for a mobile tuner to come to my house in Harlow, Essex. Attached vid. All the best, Kev

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have you got the diaphragm located correctly there are lugs to fit in a relif in the body and also in the centre ring  

if you look with a small mirror or remove the top   the air piston has two holes in its base these must be the engine side of the piston 

Pete

 

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The fuel filter looks as if it is horizontal, not vertical, would this cause issues with fuel flow?

I know the filters don't have to be full, or anywhere near it, to work. Mine always has very little in but is vertical(ish)

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39 minutes ago, Chris A said:

The fuel filter looks as if it is horizontal, not vertical, would this cause issues with fuel flow?

Mines horizontal and works OK. 

It does sound like fuel starvation, try Peter's suggestions first. 

Iain 

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Taken out the diaphragm and taken some pictures as I have put it back together. I have made sure the two lugs fit in their appropriate place.

There is plenty of fuel in the filter and the fuel pumps out when disconnected. Perhaps it is a sticky float valve? or maybe the diapragm needs replacing. No sign of a tear.

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it could be the dreaded rubber hose slivers jammed in the back of the float needle valve  

has checking the diaphragm made any difference  was it all ok or a bit out of place

tip when playing with the diaphragm if its grown and gone baggy with oil etc  a wash in petrol will return it to NEW shape 

Pete

 

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I recently had the car stop dead because a rubber fuel line had collapsed internally and blocked the line. Symptoms were initially lumpy running/fuel starvation. Rubber was only a few years old and stamped R9, but sadly not bought from a reputable source. 

Doug

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