Rumble.

[Dougal]

The downside to my setup where I have full torque from about 1400rpm is vibration.

From about 1500-1700rpm under full boost (20psi) the engine vibration excites the rangie body, making everything shake. If I'm accelerating through it's fine, but it's surprisingly how many hills put the engine into exactly this rev range.
I've just replaced the crank main and thrust bearings which has helped a lot (these are about 50,000km old and have been starved of oil many times) in terms of engine smoothness and even idle noise. But it's still there.

My next plan (unless someone gives me a better one) is to try and stiffen up the engine mounts to see if I can shift the resonant frequencies apart somewhat. I'm using 3" cylindrical rubber mounts, the first tack is to put a 3" hoseclamp around them which should stiffen them a little in compression.

[Dougal]

So I found out today that my rev counter is a bit out.
The rumble is actually happening from 1200-1500rpm.

16psi boost at 1400rpm could be the reason why.:angel:

[Larns]

16 PSI @ 1400Rpm.......Love it!

[DRanged]

How do you keep head gaskets in it. i run 15psi boost and only got around 300 hrs out of it before the cooling system started to pressurise. I am going to change to head studs instead of bolts, but would love a better suited head gasket. What are you running gasket wise???

Justin

[rovercare]

How do you keep head gaskets in it. i run 15psi boost and only got around 300 hrs out of it before the cooling system started to pressurise. I am going to change to head studs instead of bolts, but would love a better suited head gasket. What are you running gasket wise???

Justin

Is your head gasket confirmed? you've had the head off etc?

[DRanged]

Is your head gasket confirmed? you've had the head off etc?

Head will be off on saturday. It must be as I cannot fathom where else the cooling system could pressurise from.

justin

ps will take some pics as well.

[Dougal]

How do you keep head gaskets in it. i run 15psi boost and only got around 300 hrs out of it before the cooling system started to pressurise. I am going to change to head studs instead of bolts, but would love a better suited head gasket. What are you running gasket wise???

Justin

16psi is only at 1400rpm, it hits 20psi at 1800rpm and holds that fine. Been running that much boost fulltime since last year, I was running 18psi intermittently for years before then.
Factory head-gasket seems to hold up fine, that's the laminated steel one.

Mine is a factory 4BD1T, the original turbo wastegate was locked shut (actuator started to move with 25psi of compressed air). But the fuelling levels back then would only produce about 18psi boost as the aneroid on the back of the fuel pump had a leak and it never got full fuel.

[DRanged]

levels back then would only produce about 18psi boost as the aneroid on the back of the fuel pump had a leak and it never got full fuel.[/quote]

Can you retro fit the aneroid to a standard fuel pump???

Justin

[Dougal]

Can you retro fit the aneroid to a standard fuel pump???

Justin

Yes. I have done it, before I found out the pump I retrofitted the aneroid to had a different size shaft and wouldn't accept the drive gear.
You need the aneroid and brackets, the pushrod with spring, drill a hole through the back casing of the pump and attach the flag to the rack lever inside so the pushrod has something to push against.

But the aneroids job is to decrease fuelling when off boost, it's a smoke control device and can't make your pump deliver more fuel.

[Dougal]

I've retarded the timing a little and the rumble is now minimised. It was advanced far enough that I was losing boost.

Still haven't stiffened up the engine mounts.:angel:

[rovercare]

Yes. I have done it, before I found out the pump I retrofitted the aneroid to had a different size shaft and wouldn't accept the drive gear.
You need the aneroid and brackets, the pushrod with spring, drill a hole through the back casing of the pump and attach the flag to the rack lever inside so the pushrod has something to push against.

But the aneroids job is to decrease fuelling when off boost, it's a smoke control device and can't make your pump deliver more fuel.

While we're at it, got any more info on the boost aneroid, as mine is very smokey off boost and like the idea of cleaning it up, Don't want to turn down the fuel:D

Pics?

[Dougal]

The aneroid is on a lever which has just one adjustment, a screw with locknut on one end of the lever. This adjustment point hides behind a cap about 16mm round beside the aneroid pressure can.

To getinto it you'll need a thin wall socket to loosen the locknut then a small flat screwdriver to turn the screw.

Winding the screw out increases fuel off-boost. Winding the screw in reduces fuel off-boost.
I went the wrong way the first time and had a 20 second 0-50km/h sprint.:D

Regarding the rumble. I have concluded that it's due to insufficient flywheel inertia for the torque I'm producing at such low rpm.
My 2.2L nissan work car has a flywheel of similar weight to the 4BD1T flywheel.
I do have a plan to add mass to the flywheel to cure this problem, but it's some time away.