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Problem with manifold gasket?

MarioZg

Enthusiast
Messages
83
Location
Zagreb, Croatia
#1
So far I have this problem since about a month ago. Since last service (oil and filters), car is not behaving like it should. When I accelerate, there is gap between pressing the pedal and accelerating, even when engine is hot. I have a feeling that it is never get warm enough, but the ventilator turns on after some time, so it is ok. First I suspected on carb, but I cleaned it and even replaced it. Symptoms were the same. Then I suspected on ignition, but I checked sparks, contacts, point of ignition and everything was ok. Then I replaced the manifold gasket because car was running good on "winter setup"- when I connect hose from air filter to exhaust pipe. But then it was shaking on idle. So, I replaced manifold gasket (Victor Reinz), but no difference was made. Then I sprayed this new gasket with brake cleaner, and the car was choking. I contacted Slovenian R4 doctor and he told me that only original gasket would do the proper sealing, so I bought brand new Renault gasket. It is far better, but there is still small gap, and car is slightly choking while accelerating. I checked with brake cleaner, and now there is no leaking.
So everything is new or checked, there is no air leak, but the car is not like before. You have to notice that problem starts all of a sudden. Everything was perfect, but then, next turning the engine on, it was bad. Do you maybe have some advice? Thank you very much!
 
Messages
227
#2
Hi Mario

Have you checked to see if your carburettor is the type with a short hose at the back/base of carburettor/manifold? If so this hose has a one way valve inside, if the valve is not working or the hose is split, you would experience the symptoms you are having.

Best Regards
 

MarioZg

Enthusiast
Messages
83
Location
Zagreb, Croatia
#3
Hello!
Yes, I checked every hose around the carb, one was bas, so I replace it. All other hoses are in great condition. I sprayed all over carb and manifold gasket, there is no air leak, but the symptoms are still here...
 
Messages
227
#4
Hi

One short hose has a one way valve concealed inside it, it is not obvious from the outside of the hose, if you feel along this hose, squeezing with your hand you will feel the valve . To test the valve, take this hose off, blow into it, if air comes out of both ends, the valve is faulty.

I hope this helps.
 
Messages
194
Location
Poole
#5
The manifold cast iron can distort, so that the exhaust sections stop the inlet sections from sealing on the cylinder head correctly. I had this problem, and had my manifold skimmed flat again at a machinist's workshop to fix this when gaskets would not properly seal. Check with a steel ruler and a bright light to see if the face of the manifold is perfectly flat.
 
Messages
88
Location
France The Lot
#6
The manifold cast iron can distort, so that the exhaust sections stop the inlet sections from sealing on the cylinder head correctly. I had this problem, and had my manifold skimmed flat again at a machinist's workshop to fix this when gaskets would not properly seal. Check with a steel ruler and a bright light to see if the face of the manifold is perfectly flat.
yep, just had to have mine skimmed, about 3mm drop on the 2 inner inlet holes compared to outer, I'd tested for a leak too.
 
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