Converting an L67 to NA?

[c&cberlina]

Gday all,
Long story short, is it possible to remove supercharger and fit the NA inlet manifold to a L67, is the inlet side of the heads similar to the NA heads, I realise the injected holes in the heads will have to be plugged but will all other ports line up?
Cheers.

 

[Immortality]

It will all bolt up but as you noted, you will have issues with the injector bosses in the heads.

If you wanna go n/a, just take the belt of the charger. Done.

 

[ducker85]

need to change heads and inlet manifold. Probably the computer too.

but why would you want to do that? just stick a $500 L36 n ECU in it and keep or sell the L67 and ECU

 

[_R_J_K_]

just stick a $500 L36 n ECU in it and keep or sell the L67 and ECU

Low comp on the L67 will probably make it run like ass though.

 

[c&cberlina]

Thanks for the replies,
I've got a L67 in the shed that I built over ten years ago, it's 90% complete, it's got ported heads, larger valves, roller rockers, balanced bottom end & custom camshaft.
Over the last couple of years I've built up a vs v6 race car to race in IPRA but I've left the standard L36 in it just to get the rest of the car sorted, well the engine only lasted 10 laps around Sandown last weekend. So I was thinking of turning the L67 into a L36 by hopefully bolting on the L36 inlet manifold, change camshaft, plug injector holes and up the compression. The rules won't allow me to run a supercharged 3.8L.

 

[_R_J_K_]

So I was thinking of turning the L67 into a L36 by hopefully bolting on the L36 inlet manifold, change camshaft, plug injector holes and up the compression. The rules won't allow me to run a supercharged 3.8L.

How do you plan to change the compression without stripping down the engine or skimming the heads (in which case you'd just put Ecotec heads on anyway probably)?

Honestly man, it sounds like you'd be better off picking up another Ecotec runner for a few hundred dollars rather than dicking around trying to devolve an L67.

What was it that failed on your track engine? Internally they ain't that different save for some stronger rods.

 

[Immortality]

I agree, you'll probably have trouble finding high comp pistons to suit the L67 rod (shorter with larger pin). either sell the L67 short and build a proper L36 bottom end or rebuild the it with ecotec rods/pistons and use your old heads.

 

[c&cberlina]

Not sure exactly what has happen to motor in the process of pulling it out. It's got an ugly knocking noise coming from bottom end from 2000rpm+.
Yeah plan A was to get another ecotec, pull it down, clean it up, get it balanced and maybe a new camshaft.

 

[Immortality]

Best thing you can probably do is pull out the balance shaft and plug the oil feed for the rear bearing. There are also a number of little mods you can do to the oiling system.

sounds like it's run a big end bearing when it's got hot. The Buick V6/ecotec have an odd oiling system when means the mains actually have a slightly restricted oil feed and the number 3 main has the smallest oil feed so it's most likely it would have run a big end fed from it.

 

[c&cberlina]

Looks like iam going to rebuild the L36. What mods would you suggest for the oiling system??