924Board.org

[kylekev]

We have been rebuilding our 78 924 motor this summer and it continues to be a learning experience. To improve performance, we were told to remove the emissions system and plug up the holes left by the lack of hoses. Unbeknownst to me, this included the breather tube. When we started the motor, it was hard to start and keep running, ran rough, and oil came out the dipstick. Research pointed me to excess crankcase pressure and I discovered a bolt has been JB welded into the breather outlet, why I do not know, but it was done. I need to get to the breather replaced, found on the website to run the breather tube to the air intake, and this will require more research.

The main question I have is what other issues has been cause by the advice to plug the breather? I am getting a lot of exhaust fumes in the engine compartment so where might this be coming from? Did we blow the head gasket? Is there another source I need to check? Ugh!

[Euro924S2]

No, you wont have blown the head gasket like that. The oil dipstick would blow out long before any long term harm comes to the HG.

If you've rebuilt the motor and honed the bores etc with new piston rings then they need to bed in so there will be a lot of blow by past the piston rings into the sump, so the symptoms will be even worse.

To solve the problem there is a funny shaped thing (looks like half a tennis ball but with a 3/4" short pipe coming out. Its towards the rear of the block, under the inlet manifold, about level with the brake booster. That should have a rubber pipe attached that runs to the intake pipe between the airflow meter and the inlet manifold. That hose should have a restrictor in it however, to stop too much oil spashing through it.

If thats the hole that hs been blocked, then it needs unblocking, if its not, then thats where the fumes will come from.

No other breather holes are needed on an NA.

The fumes are most likely from any newly repainted surfaces as they get hot, the paint is baking and burning off a little.... that will settle quite soon.

Hope you get it sorted.
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UK spec '83 N/A with 931 motor with Eaton MP62 'charger @ 15psi. EFI - 565cc inj. Standalone Adaptronic ECU. 951 FMIC. Ally rad. Twin throttle. Recirc valve. Custom manifolds and CAI. 232bhp

[kylekev]

Thank you for the reply. I know the breather is clogged because the emissions system was removed to improve performance and we were told to plug all of the holes. Will start to fix the breather tomorrow. Makes sense about the dipstick blowing out and glad to hear the HG is not blown. that would be an major UGH!. Did not know about the rings seating in and immediately makes sense. This project has been an education for both of us.