This LRO reader emailed LRO.email@example.com to ask Julian Gilling about fitting performance parts to her 4.6 V8 Range Rover P38.
I’m thinking of treating my P38 4.6 V8 to a new Piper 280 cam kit and Stage 3 heads, plus new pushrods and rockers. Some people think it’s a great idea but others think exactly the opposite. What’s your opinion? What bhp difference would it make, and would it need remapping afterwards?
Vanessa Taylor, Hale, Cheshire
If you’re planning this work without doing anything else to the engine, I would advise extreme caution. The 4.6 engine is known to suffer cylinder liner failure, a problem exacerbated by increasing the power demands on the engine. If you want to increase performance substantially, consider a full rebuild to include ‘top hat’ cylinder liners, new oil pump and new crankshaft bearings. You may need a crank regrind too. Talk to an expert – such as RPi Engineering – who can suggest the most costeffective performance increases, and any pitfalls to avoid.
To get the best from a newprofile camshaft and Stage 3 heads, you’ll need a remap to adjust the fuelling. About 300bhp is possible if it’s done well. Everything – including cooling and lubrication systems – will need to be in A1 condition to take it. To avoid costly, premature engine failure, don’t cut any corners.
This workshop advice appeared in the Feb 2015 issue of LRO. Back issues are available to download on digital devices here.