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VG30E Head Gasket.


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HI Bob here. New to this forum but been around. I am an old semi retired mech and auto elec. 40+ yrs of experience.

Recently replaced the RH head gasket on my old D22. 500,000km on the clock and first major repair ever. Old girl has been converted to dedicated gas 20 odd yrs ago. Was still running fine but dumping water like no tomorrow. Finally had to go in and work on my own and shops ride.

Rebuild went like a dream. Nice and clean inside being gas. Head dead flat and only required minimal work on the all valves to get them to blue.

After rebuild old girl was very reluctant to start. With some major coaching finally fired up. Ran a bit rough as was to be expected for a while but did not clean up. On further examination I discovered an amazing problem. She was only running on the 3 cylinders of the LH bank.

Have checked ignition. Great spark @ all RH plugs. Timing spot on. Valve timing on mark.(rechecked 3 times.} Compression good. Plugs wired correctly in sequence. System water tight to 20 pd.

 

So in essence. Good spark. Good compression. Timed correctly. Ignition and valve train, Good fuel supply. Runs a single point gas carbie. NO gas No go anywhere, NO POWER OR COMBUSTION ALL RH CYLINDERS. RH exhaust stone cold after a few minutes running, No variation to eng speed when plug leads disconnected either singularly or all together. noticeable power drop whenever any LH plugs dropped out. Various new plugs.

 

Now I normally get all the headaches to fix from the young guys around here so to have this occur on my own ride is literally doing my head in. Anyone else ever struck this type of problem or got any plausible ideas to remedy this one. HELP ???? ## ***

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Carbed vg30e correct?

 

Could it be possible that your cam lobes are flat so the valves aren't opening? I don't know why that would happen suddenly.

 

Are you sure fuel is getting to the cylinders? Are the plugs wet like it's flooding?

 

The only thing I can think of is that the fuel isn't reaching the cylinder. Did you have rags in the intake runners at any point in the rebuild and forget to remove them? That or valves not opening. This is a weird one.

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Hanks guys. No Im not sure on fuel reaching this bank. Car runs a single gas carbie(LPG) Hence no liquid or moisture to check with. Carbie is situated in the flex line between the throttle butterfly air cleaner. So if any cylinders get fuel then all should get fuel unless mthe is some way ti prevent this from happening. And NO I didn't leave rag stuffed in the RHB ports.

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Bizarre. Compression rules out a lot of things. Sounds like you've already checked firing order, though that's still the first thing I'd recheck if I had it in front of me.

 

The remaining three cylinders running worse with the plugs out of the dead holes is interesting. Resonance in the intake, maybe? I haven't had a chance to work on a propane powered anything so I wouldn't know. Is the gas you run in the truck scented like the stuff we have for barbecues up here? Seems like you'd be able to smell that on the plugs.

 

What I'd do, just to rule out fuel, is pull the plugs from the three dead holes, squirt some ether or gasoline or whatever in there, put the plugs back in, and see if those cylinders try to fire when you turn it over. If that gets a pop out of them, then I'm with Citron on this--either the intake valves aren't opening (easy enough to remove the valve cover and watch the rockers) or there's something between the intake and the head that shouldn't be there, like if the gasket had shrink wrap around it or something. Doesn't sound likely but I've been surprised before... like the time the loud ticking noise under the hood of my friend's Chevy turned out to be an exhaust manifold gasket installed backwards.

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