Best way to build a tough 5lt

[Dylbo52]

I've recently bought an immaculate vn 5 litre bt1 with 270 000 k on it, a 2 1/2 sports exhaust, stage 2 shift kitted auto and CAI. I want to build a mild streeter thst enters a few burnout comps and driving events, but not sure where to start with it, any suggestions would be great, I want to build it to be reliable and tough with enough power to turn the tyres easily so where do I start?

 

[someguy360]

The 5L are very tough motors let down by a poor lubrication system.

Best thing to do would be replace the oil pump, and clean the pick up in the sump (the pickup's get blocked as the engine gets older and in the end stops all oil pressure from the sump, destroying the engine)

IF you are going to be doing those sorts of events I would be getting a full engine rebuild with shaved/ported heads for better compression and a decent cam.

If you want to keep using the existing engine just give it a freshen up with oil pump, pickup, sump gasket, rear main seal, head gasket, timing cover gasket, dizzy cap, plugs, leads etc

 

[Darren_L]

as above, the 5L is a fairly stout engine.

biggest problem with the oiling system is the oiling priority and drainback
The factory oil pump (in good condition) actually works extremely well, so well in fact that fitting a high volume pump is not a good idea. High volume pumps compound the oiling problems. They tend to pump huge volumes of oil from the sump up into the rocker covers. End result is oil pumping out the engine breather/pcv and an empty sump which leads to oil starvation at the main bearings - engine grenades... Also high volume pumps tend to put excess loads on the oil pump drive shaft, which can result in a snapped oil pump drive shaft. So stick with a rebuilt or new standard volume pump.

As a street engine, usually it isn't a problem as you aren't sustaining higher rpm for any length of time. But do a bit of circuit work and/or burnouts where higher rpm is sustained for longer periods and you can end up with serious problems.

There are various fixes ranging from simple to complex - high windage sump, opening up drain back holes in the heads & block, fitting oil restrictors, modifying lifter bores, polishing the valley etc, rather complex priority mains oiling system mods right up to the ultimate fix - a dry sump setup. How far you go entirely depends on your budget and how serious you wish to get with the burnouts.

General engine performance mods are like any other engine. The Holden V8 responds well to exhaust upgrades. 304's have very low compression, so first internal performance mod is to increase the compression ratio with some higher compression pistons. Do your research on the right cam, valve spring setup. Look for a good aftermarket intake manifold and if the budget permits some head work. Should go without saying is the internals should be balanced.

The sky really is really the limit - depends on your budget

 

[Nut Kracker]

I had this done to my VT 304 and it gave me 341 Hp (255 Kw) at the fly wheel. An increase of just over 107 Hp (80 Kw) over the standard 195i engine.

Custom aluminium port matched high flow intake manifold (Approx. 2000 cfm) and mafless tuned VCM OTR cold air intake. Custom twin 60 mm throttle body. Heads ported, polished and shaved 10 thou. with Yella Terra roller rockers and heavy duty double valve springs. Crane 888241 roller camshaft.
Pacemaker extractors into a 2 ½ inch twin cat back exhaust system with high flow catalytic convertors.

The manifold I have was custom built, but C.O.M.E. Racing do an excellent intake manifold with a twin T/B. Intake Manifolds | COME RACING