High Torque 4.3

landrovernuts · Post by **landrovernuts** » Sat Apr 12, 2008 5:33 pm

Afternoon All

I am just coverting my 4.3 back to hotwire injection as it was originally before putting in my 90 and am planning on running it for awhile before whiping it out for a rebuild as it is getting on abit high mileage wise now and also because it is abit 'peaky' for the 90, also the compressions are uniformly dropping slowly, but it is using no oil. It was dyno tested at 282 bhp at 5225 RPM not long after it was built with peak torque at just over 4000 RPM which is abit high for a 90.

Just trying to go through in my mind what bits I was planning on using and would welcome any comments bearing in mind I am after low end grunt , but free reving to about 5000 RPM(if possible)

The engine as mentioned will be hot wire injection with standard trumpets and plenum. Originally it was on 72mm throttle plenum and 45mm trumpets, but I sold these awhile ago. The ECU has been 'spoken to by Mark Adams, but obviously will need to be done again after the rebuild. It currently breaths through an ITG filter and a 70mm id snorkle. The inlet manifold is cleaned up with a dremel and the ports are matched to stage3 V8 Developments heads. It is currently running a V8 Developments camshaft (unsure which) and adjustable pushrods. The rockers are standard with modified oil passages and the rocker shafts are standard with modified end supporting pillers (John Eales) fitted for no other reason other than I had them. The block has been skimmed by V8 D to get the compression up to about 9.75 and the pistons have been pocketed. The bottom end is balanced and other than that is pretty standard, other than oil feed to the distributer gear and an uprated relief valve spring. Hot oil pressure is about 3.2 bar on a calibrated gauge at 2500RPM. Ignition wise standard 35DLM8 dizzy with an RPI power amp. Exhaust wise it is now on standard Range Rover manifold which have been ported to the heads leading into a standard 3.9 non cat down pipe and a Landrover TD5 back end which seems to flow well with out being noisy.

The plan will be to keep the bottom end pretty much as I have, but use an ARP stud kit. It is one of the early blocks with the cross bolt bosses, but non crossboltable mains caps. If the pistons and bores are OK to use what I have already got, if not cross that bridge when I get there as I understand 4.3 pistons are getting rare now(?) Camshaft..... I am tempted to use a Kent H180 or H200, but would welcome suggestions. Use an ARP head stud kit and composite gaskets (which it already has) and use standard rocker shafts and rockers, but new items. Ignition wise leave alone other than some Magnacour leads, the dizzy was a brand new item not long ago.

Any comments/recommendations and torque estimates would be most welcome. I am hoping for about 280 lb of torque at 2500 to 3000 RPM and about 230 to 240 BHP. Does this sound reasonable?

Toby

ChrisJC · Post by **ChrisJC** » Mon Apr 14, 2008 7:57 am

If I had that block, I would get it modified for the cross bolted main caps and then line bored with the new caps. Then you know it's bulletproof down there.

I think the rest of it will hinge on the cam choice primarily.

Chris.

landrovernuts · Post by **landrovernuts** » Mon Apr 14, 2008 3:19 pm

Thanks for replying, just wandering what cam you would recommend for my appliction then?
It has crossed my mind about getting it modified to make it crossbolted, but thought it was not worth when the ARP stud kits are available as I have not intentions of reving it hard. I had also thought about top hat liners while it was out, as I had a friends engine done recently when his block cracked and was impressed, but having always run it with an 82deg thermostat and a huge radiator and the fact it has never used any water I though I would leave it alone!

kiwicar · Post by **kiwicar** » Mon Apr 14, 2008 3:40 pm

What is your budget? if it were me with a longstroke custom rover I would go for a comp cams 268AR on a buick 215 blank on 114 LSA and use the comp cams chevy mechanical roller lifters, a set of 1.6 roller rockers. Oh and I would cross bolt that bottom end before I did anything else to it.
Mike
PS forgot the compcams link http://www.compcams.com/technical/Catal ... 26-227.pdf