Blown out an inlet manifold gasket(s)!

[WydRyd]

My intake vacuum leak & whistle has gotten progressively worse over the last week or so and the car is now struggling to idle. She's now gasping for air at around 300-400rpm's and finally stalls.

Looks like I have to rip off the entire intercooler assembly, AFM & intake manifold and replace the intake manifold gaskets. Judging by the idle quality, it may be a number of inlet gaskets have been blown out

Anything I should be warey of before tackling such a job? Things I should prepare for?

Any advice appreciated

[Lukesportsman]

Is this before you started worrying about head gaskets or did I misunderstand your email? Do you think we're talking just intake gaskets or something deeper? Why the change in thought?

[john walker's workshop]

try tightening all the intake nuts first. most 930s have loose nuts.

[WydRyd]

Luke, I had a chat with Todd of Protomotive and he said he'd be extremely surprised if I blew out a C2T head gasket at only 1.1bar of boost (he runs them up to 1.4bar without any problems), so he recommended checking/replacing the inlet gaskets. The whistling from the intake is typical of a leak around the intake area, not really a blown head gasket.

Thanks JW, I think I'll try tightening all the intake nuts first and see if that makes any difference. If it does, then the problem points to the inlet gasket(s). My motor is actually a Carrera engine. Only my setup is now running 930 P&C's and C2T head gaskets.

[Lukesportsman]

Just let me know down the road if you decide to move foward again. Who knows, I might still be in the market at that point. Good luck with your engine diagnostics.

[WydRyd]

Luke, once I get this addressed, I'll move forward. I need the setup intact for now until I get this problem addressed. Sorry for the delay

[john walker's workshop]

if it's a carrera intake, there's a phenolic spacer between the intake and heads with a gasket on each side. the bottom gasket gets sucked in all the time, and that kills the cylinder function at idle and low rpm. disable one injector at a time and see which one does not drop the idle.

[WydRyd]

Hi John, yup, it's the factory Carrera intake manifold. The gaskets are just paper I'm told, so I guess their lifespan would be even shorter in an aftermarket forced induction setup like mine.

I'm told I don't need any loctite between the surfaces, just the gaskets themselves, right? I guess as long as the spacer you refer to is clean of any old gasket residue, the surfaces should mate reliably under proper torque. Can you confirm that the torque setting should be 18lbft for these bolts?

The engine barely idles now as it literally pulsates between 300-400rpms and then dies shortly after, so I don't even think I'd get time to go disconnecting injectors sequentially to identify the dead cylinder

[WydRyd]

BTW, how much fuel can I expect to leak out once I disconnect the fuel lines from the fuel rails? Never done this before, so I want to be prepared

[Lukesportsman]

I'd say about a spray can lid worth. 40psi vents off pretty quickly from such low volume fuel lines. I've never found it very much fuel as long as you let the engine "sit" and vent off some residual pressure. My return lines always vent off the pressure within a short time ( I have a gauge on the fuel line).

[john walker's workshop]

18# should be close to or at the max for a 8mm bolt. those carrera allen bolts loosen up too, just like 930s.