Isuzu G-series Twin Cam

Regarding the spring tension, I have two assemblies and they are both set so that there is 10mm of thread remaining. IE: In a "neutral" position, approx 50mm of U-bolt protrudes from underside of the assembly. This consists of 34mm of spring + 2 nuts of 6mm (total) + 10mm free. (34+6+10=50...

I don't think they're taking the piss. In fact I think there's a few subtle tips there - like "a few laps hammering ... looser or tighter"; and "into the pits ... with the spanner". Granted, your flatmates have little need for a spanner due to a lack of nuts, and the hammer may b...

Just as easy to have them refabricate from the flange plate.
I supplied the usual "wrecker-oxy'd" section of outlet which were removed and replaced by new 2into1 section shaped as required (about 24-26" is recommended; my 30" is very torquey - ie, over 360Nm above 2000RPM).

Oops -

(or vice-versa - increase burn time hence temp etc).

Ignore that - retard means later ignition hence less burn time.
But the pollies bit still stands.

Retarded timing improves the burn. When anti-pollution measures started back in the 1970s, one of the methods was to retard the timing by typically 3-degrees (until engines were re-designed). I think retardation increased the temp hence the burn (or vice-versa - increase burn time hence temp etc). I...

Looks good! Similar to my 2L DOHC in a Florian usng a 2" system with about 30" of 2-into-1 section (very torquey) then into a hotdog and over the rear axle into the muffler. The manifold gasket etc is common to Shuttles and other Isuzus. I had my system made up years ago for a mere $200! T...

Sorry Nick/GeminiCoupe from 18Jan. The 100kW was at the rear wheels. Good point! It's at the flywheel for my other discussions (ie 150HP with 45DCOEs, 220HP with L1 & port) I guess that means then engine wasn't too worn after all. But it is now - my last comp test was 100psi & 120psi (2 each...

Sounds right. I had an aircooled motorbike that used a copper head gasket. Used to anneal it with an oxy (heat until it glows red). I can’t remember if I’d quench them (in oil or water) – though I think they’d just air cool. The annealing softened and expanded the copper so that you could re-torque ...

If you want good torque down low, try to keep a reasonable 2:1 section - about 24 to 26 inches is ideal (that's measured from the stock DOHC manofold's twin outlet). I'm selling DOHC 4:2:1 extractors for a Gemini if you're interested. It has a nice two-bolt flanged end. Around the$300 mark....? PeterA

Oh sht - here comes another short post.... For gearboxes, it’s hard to compete with $84 (Pick-A-Part; or about $93 with warranty) for a Gemini 5-speed box. Mind you, you have to find one! If you can do the work yourself, I agree with Nick (gemcoupe) – just swap the bell housing BUT note that there c...

If it overheats, paint the radiator black! Black (mat) is the best color to radiate heat. Light & reflective surfaces are the worst. Many hot-rodders used to chrome-plate their radiators until they found overheating problems (and the chrome made things brittle so they'd also crack up - as may b...

Apparently the L1 is a common race profile; normally too lumpy for road use except on Isuzu G-series twincams. I'd assume camshaft regrinders should know of them....
The L1 was recommended for normal aspiration - eg, 2 x 45mm DCOE. I don't know about their suitability for turbos or supers.
Peter.

BTW - I think the dizzy on Dave's G200W is off a Honda.
Dean modified and fitted it at my place many years ago.
From memory it involved shortening its shaft and/or body (with a hacksaw), and fitting the DOHC's drive gear.
Peter.

Apparently the stock pots handle 180HP. Try L1 profile cams. With the port job and new pistons (and 45mm Webers) this should give 220HP. BTW - a standard G200W should be 135HP. I'm curious why yours is less? My standard G200W but fitted with twin 45DCOE Webers and a 2" exhaust (with around 26&q...

Yep, that's the one.... And I guess you're the wild Bellett Racer? I'm the other ex-treasurer with the OHV Wasp (albeit with a Florian engine). Did ya see the Bellett on ABC2's LateNightLegends? I PC-captured mos of it (missed the first 2 of 5 laps). Did pretty well against a 186 Holden.... Ooops - ...

I have DOHC waterpump(s). I'll PM you....

Are you using the return line? IE - EFIs have a reticulation system - pumped from tank to the injector feed and back to the tank. Carby systems (usually) only have the feed from the tank. (There can be other tank pipes, but these breathers for vapours etc to the charcoal canister etc.) Maybe you got...

Sounds to me like fuel starvation - needs a bigger pump? (Or restrictive lines & filters etc.) Take her somewhere and run until she cuts. Then turn the ignition off (but not if it locks the steering etc!) and into neutral. Then pop the bonnet and check the carby bowl for fuel, or - if not visibl...

If it overheats, paint the radiator black!

Hey Dave - I presume the GT is an "ex-Camira" (ha ha - ie, Camira - Brisbane) unit? If it is, it was originally registered in Vic and later Qld. Surely that should be of some weight for registration? As to pollution etc - that's the beauty of it - it is pre-ADR (1974?) and hence any engine...

Some comments.... Below are the numbers and $RRP for gasket kits for the G200W (see viewtopic 164) noting that these are from NZ Gaskets as supplied through AA Gaskets (Melbourne) to Bursons – it is argued that the gasket width between the pots is a bit thin and prone to blow – but since you need al...

Not to my knowledge.

Certainly looks like carbon fibre to me: gunmetal-grey plain gasket with metal vaneer around combustion chambers and one O-ring in oil feed line; classic fibreglass/layered edge look.
Thumbs up.

Eli, I got kits for a G200W through Bursons (August 2006) as listed below. The prices are RRP - you might be able to screw a further (25%?) discount. The kits are xx203KC and are usually labelled "Head Gasket: Isuzu 4", or "G200Z 1984 on". These came from AA Gaskets who apparentl...

Hi Eli, Just some comments (many of which are repeats from earlier) - but please note that experts may spot the errors! Most G-series head gaskets have the oil feed hole separate to the bolt hole. Isuzu fit and supply an O-ring that sits in this oil feed hole – though maybe this is based on old head...