Hey guys . I have just put my 1600 together from pieces I gathered up . It has a l18 that came out of a rally car and has sat for years . It has a datrally manifold and twin 45 webers ( that have sat for time as well ) . It started up easy a bit rough but ok . The timing is at 10% advanced , I thought that would be a good starting point . It has the odd backfire through the carbs but runs ok . Compression is 175,170,170,165 . When I put my hand in front of 1,2 and 4 trumpet they suck a fair bit of air but number three does not . If I block number 4 then release it fuel comes out of the trumpet . I took the manifold and extractors off and sealed the gasket and put it all back together because it had an air leak , it runs better but still no suction on 3 . I swapped webers front to back and still not sucking at 3 . I took the rocker cover off and all the valves are operating fine ( did not check with gauge though ) . This is my first car project and am running out of ideas . It drives ok and the engine feels like it will be quit strong with the carbs in tune . Could the intake valve on 3 be stuffed ? Head gasket ? ( no water in oil ) any ideas ?
Thanks .

Compression test ?? Maybe it's down on comp so not sucking fuel?
Is it getting spark to fire as well?

Yes has 175,170,170 165 compression , 170 on number 3 , has good spark to . If I take Leeds of 3 while running it does not make any differance !
Cheers

I had the same problem not long ago. Take the lead off and no change but take it for a drive and it would appear to be fine. It turned out that there was a blockage in the weber idle circuit, no fuel or suction near idle but as soon as you opened it up the main circuit came on. It took several attempts at clearing it out by removing the top and then blowing out all that could be removed.

is your break booster connected to no:3 runner?

Hey guys , the brake booster is connected to no3 and have tried disconnecting and blocking on manifold and still no different so I left it blocked . I will try cleaning inside weber again although when I swapped the webers from the front to the back it was the same cylinder not sucking , not the same trumpet . I will try clean it though as it does drive well .
Cheers

Thanks for the ideas guys . I gave the idle circuit on both carbs a really good blow out put it all back together and now it sucks through 3 . Still needs a bit of work to get it running better but have fixed one problem . Thanks Crumb .