inlet manifold not sealing

Post by **timmo** » Sun Dec 27, 2009 4:32 pm

Put stainless 3 branch on and metro inlet manifold....Inlet wont seal, leaks petrol. Tried half washers etc, are there supposed to be ferrules in the inlet manifold...shows them on the somerfords website..what do they do? Could this be the reason for leaking? Also when fitting the new manifold gasket, noticed it was thinner than the original that came off....the new measured 1.2mm and the old one was near 2mm thick...would this also make a difference?

Cheers Tim

Post by **bmcecosse** » Sun Dec 27, 2009 4:42 pm

The flanges all need to be the same thickness - you may need to file down the ones that are over thick. I don't use 'half washers' - but I have used washers that have been filed down on one half - to compensate for the uneven flanges. Thicker gasket would help - although thin one should really be ok.

Post by **timmo** » Sun Dec 27, 2009 4:59 pm

Yes, also filed down flanges....Thing i noticed is that on the old gasket the outline of the maniold flanges were deep impressions...the thinner gasket didnt seem to have much of a depression, and none at the bottom

Post by **bmcecosse** » Sun Dec 27, 2009 5:01 pm

How strange! All nuts done up tight I suppose ? Any fouling between manifolds - to stop the inlet seating in correctly ?

Post by **aupickup** » Sun Dec 27, 2009 5:03 pm

maybe the train is getting in the way

Post by **timmo** » Sun Dec 27, 2009 5:04 pm

Yep, all done up tight....cant do any more now till i get another manifold gasket....

Post by **bmcecosse** » Sun Dec 27, 2009 5:07 pm

You say it 'leaks petrol' - are you sure that is from the join manifold to haed - and just some petrol running down from the carb - and dripping off at the lowest point ? Normal problem would be hopeless inrush of air - not allowing the engine to run - or to run so fast it's uncontrollable!

Post by **timmo** » Sun Dec 27, 2009 5:21 pm

Deff coming from manifold joint.....when i 1st ttied to start it, had big backfire and wouldn't start so knew there was an airleak....Im sure last time i tried it was only coming from the left port, but as i said the gasket is sopping wet now and not much good...so will need another gasket before i try again....but did wonder if it needed the ferrules in the manifold or not?

Post by **bmcecosse** » Sun Dec 27, 2009 5:26 pm

By 'ferrules' - do you mean the location rings? Half fitted in the manifold and half in the head ? Only the 295 head has provision for these - I have never used them. Still don't see why there is this leak of petrol - where's it coming from ? The carb shouldn't be leaking fuel like that - unless the fuel delivery pipe is connected to the wrong inlet on the carb .........<br>

<br>

#4 is the fuel inlet - #5 is the vent/breather - and #6 is the connection for the crankcase breather pipe.

Post by **timmo** » Sun Dec 27, 2009 5:47 pm

There are recesses for the ferrules (locating rings) in the manifold and in the head...1275 Ital engine. Im sure the fuel is coming from the manifold joint and not from the carb...will check tomorrow if i can get a gasket from somewhere

Post by **bmcecosse** » Sun Dec 27, 2009 6:12 pm

Right -couldn't remember if some 940 heads have the location rings. But - the fuel has to be leaking from somewhere - to collect and run out of the manifold joint! Can't just be the normal flow of fuel into the engine -surely?

Post by **MarkyB** » Sun Dec 27, 2009 7:07 pm

none at the bottom

Sounds like the exhaust pipe or something else is stopping the manifold sitting flush to the head.

Post by **Stig** » Tue Dec 29, 2009 9:43 am

The location rings won't help it seal, they're just there to (slightly) improve the air flow.

I had a problem with one particular head and alloy manifold where part of the head casting protruded such the the manifold wouldn't sit flush and left a slight gap along the top. Filing it off fixed the problem.

the thinner gasket didnt seem to have much of a depression, and none at the bottom

Sounds like something's stopping it underneath then, more difficult to see. I'd suggest assembling it without a gasket and without the exhaust first to see if it sits flush, then with the exhaust too.

Erm, like MarkyB just said then (sorry, didn't see your post).