ROVER 4.6 HELP

[STEVE G]

Just bought a second hand 4.6(block,crank,pistons)

1st problem, Crank nose is about 1" longer then 3.5 to take crank driven oil pump. I intended to use timing cover from 3.5,as I dont have a spare inch infront of crank pulley.

Answer 1 machine off offending extra inch and tap thread deeper.Dont really like the sound of this.

Answer 2 Fit crank damper to the stop and make up spacer for the bit that pokes out to tighten bolt.Seems the easiest solution.

Answer 3 Fit damper using spacer inside instead of oil pump drive gear and fit P6 water pump and pulleys which dont stick out so far.A bit complicated.

Any thoughts from guys that have done the convertion, or any other potential problems solved would be a great help.

Also who do you recommend for Heads, cam , general spare parts and machine work
Regards Steve G.

[StuartH]

Steve,
My 4.6 doesn't seem any longer than the 3.5 I had (maybe I put the 3.5 together wrong!!) I have the original 3.5 timing cover and pulleys on mine, (the new type is much better but I didn't have one, and with the ancilliaries to match it was v. expensive!!) I'm not sure what RPi did to it to make it all fit together right though as I just gave it to them when they built the engine - I guess they wont mind if you ask (if they do I'll ring them for you!!).
As I bought the whole thing from RPi not sure where's good for other bits, though in the past I've also had good dealings with DJ Ellis, V8 developments, and someone else in birmingham/coventry area who unfortunately the name has slipped my mind.
I'll bring mine over (or as you said you could pop round) so you can take a look at it, though it doesn't really look much different to the 3.5!! - goes much better though Not sure the weather at the weekend's going to be up to much though unfortunately

Stuart

[STEVE G]

Stuart
Since my post I've dry fitted the damper and pulley just to see.The crank sticks thru the damper only 17mm and the pulley is the same distance as on my 3.5,so I think if I make a spacer to fit the crank with an OD the same as the bolt washer everything should be OK.Cant wait to get spending money on it.
Give me a ring I would like to come over and see your set up even if the weathers #####.
Regards Steve G.

[PeteV]

Hi Steve,

Congratulations on a good choice of motor !. I too got hold of a 4.6 block/crank/pistons last year & built a 4.6 for my Sumo. Heres a few things I found out along the way that may help :-

Crank – Easiest option is to buy a spacer from RPI for about a fiver. The whole SD1 front cover & crank pulley assembly bolts up perfectly. You’ll of course need a camshaft with the standard SD1 drive fittings. The only problem I noticed crank-wise is that there's an extra flywheel dowel fitted, which you’ll need to cut off (Holley at RPI says they’ve never managed to get one out yet). I cut mine off & was very careful to ‘machine’ back flush with the surface. Checked flywheel run-out with DTI when finished & was in spec. One thing I did notice was that compared to the SD1 set-up , by the time clutch/bell housing/gearbox were bolted back in place I had lost a smidgen of clutch travel – may just cause a problem if you were on the limits beforehand.

Other things to note with the 4.6 block –

- I don’t think anyone has started making oversize pistons or crank/big-end bearings so if you’ve got big problems then its new bits I’m afraid !. Mine was well in spec (76,000 miler)
- Real Steel now do the rings for this engine , and are a bloody sight cheaper that paying £125 as I did !
- I’m sure you’ve heard about the block-cracking problems on this block. The story is that the Range Rover engine management runs lean & the block tends to crack behind the liner on the back cylinders. I’ve found mine seems to produce a LOT of condensation but there’s definitely no emulsion in the oil. About the only thing you could do here if it were a problem is throw in a top quality engine sealer like Moroso Ceramic . But heck it’s a kit car anyway so just change the oil more often !

Heads – Don’t believe all that crap that people come out with about ‘you’ll have to buy 4.6 heads’, the SD1 heads fit a treat. I cc’d my SD1 heads that, from memory ,had had about a 20-25 thou skim. That in conjunction with the standard tin gasket (3.9) worked out as about 9.7 or so CR (IIRC!).Use some genuine ‘Wellseal’ on the tin gaskets, by the way. I had no major problems with lifter pre-load (use a shim kit from Real Steel). My heads had worn guides so I packed the lot of to Real Steel who fitted new ‘bullet-end’ guides & their own slightly large valves & re-cut the seats to my spec. all for about £250 !!. This combined with a home-port job produced a great set of road heads for little money. The good thing about going form the slightly larger valves is that you can take the valve throats out to where they should be. All porting was done with nothing more than a Dremel & some carbide burrs – don’t you just love aluminium heads ! ( but use eye protection or you’ll get a free trip to the eye doctor included, as I did – yes I was wearing all the gear, but it still got in somehow so be warned !!!!!)

Cam – I re-used my Real Steel Hurricane Cam from the 3.5. It’s a really nice cam for a basic 3.5 uplift but too mild to bother with in the 4.6. I find that you easily feel the motor go flat above 4000 revs. I’ve done a lot of study of rover cams & reckon that something like the Crane 218 (hydraulic) would be ideal for a 4.6 in a Cobra. I’m planning to swap mine over in the next 2-3 months so I’ll let you all know how well this works. By the way, I think RPI recommend a Piper 300 for the 4.6, which from the specs is a funny choice – I think I’m right in saying that its got 80 odd degrees of overlap which surely is a bit of a strange choice for a street motor ?

Carb – I run an Edelbrock 500 on top of an Offey 360 (reckon the Edelbrock manifold would be a better bet though). This works a treat, but could benefit from a RR session when I’ve finished to get the jetting spot on.

What’s it like – the first blast was quite an experience! – much more raw agressive power that the 3.5 I previously had – you can blip the throttle & it revs much much faster than the old motor would. Certain to put a big smile on your face too ! – and all for really not a great deal of cash !

Good luck !!


Pete.

[STEVE G]

Thanks Pete
This type of reply is wot this site is all about.
Excelent advice from someone who'se been there.

I have already on my 3.5
Edelbrock 500 on Performer manifold
Kenne-bell roller rockers
Cloyes true roller timing chain set(thanks Stuart)
Mallory electronic dizzy
Rimmers s/s tubular manfolds
MGBV8 remote oil filter set up(it works with 45psi+on tickover)

I've just stripped the engine down and apart from a bit of bearing wear crank looks OK.I will get it reground as long as o/size bearings are available.
As for increased capacity from initial investigation it looks like oversize(if available)is only economic route.Would have loved 300 ci.
As for heads I will buy performance heads but havent decided whose to go for,when I do I will get cam from same source.

Its just like Christmas again

Regards Steve G.

[TR Mike]

Hi Steve, just read your posting. I have a custom made 5.0 litre crank and piston kit for the 4.6 blocks. All you do is overbore a few thou and fit my stroker 90mm crank (which has the long nose ala 4.6). The nose can be left as is or cut off. My crank is fully counterbalanced on each rod throw, made from SG Nodular iron and cross-drilled with aluminium plugs. I'm trying to find a casing to build it into so that the kit can be evaluated and sold. I reckon it will work just fine and it will also adapt to the early blocks as well. Mike.

[russell_ram]

I wouldn't re-grind, it probably wont need it. Borrow a mic and measure it first. I've fitted 2 4.6's in Cobras and neither has been worn badly enough to warrabt regrinding.

The only way you can get serious oversizing (say 96mm) is by boring and re--sleeving with steel liners. The stock iron liners are notoriously fragile once you re-bore (and even in standard form occasionally).

I would go to the effort of finding some 4.0/4.6 heads. They ARE different even though all heads fit all engines. The new (10 bolt) heads have the fire face raised by 27 thou to allow the use of the composite OE gasket an stay at 9.35 ratio. The ports are much larger as standard, which means you have much more scope for removing metal without danger of breaking out. They also come with full hood Goetze stem seals which are a vast improvement over the old, inlet only, rubber washers. However you will need to re-do the guide with almost any aftermarket cam.

In terms of the BEST performance heads on the aftermarket, the are the Wildcat custom cast items, which outflow std race heads buy 50% or so, but ££££££££££££'s. Otherwise, the are all much the same, although I would personally go to DJE.

As for cams, I have tried a few. RS stumppuller works fantastically if you want torque over power, but you'll only make 230BHP. Otherwise 218 or 224 (needs piston pockets) would be a good choice. See my post on the 4,6 engine managemnet thread for more stuff.

Otherwise you have the basis for a really strong (and substantially lighter than US iron) engine.

[STEVE G]

Mike Sounds an excelent offer but after careful consideration I have decided to stay with a stock bottom-end as after a run in Stuarts 4.6 on saturday(thanks Stu) I recon 280bhp willbe plenty.Block is currently being pressure tested.Fingers Crossed.
Regards Steve G.

[TR Mike]

Hi Steve, Good luck with your venture. If you know anybody else with a cross bolted engine in need of an upgrade could you refer them to my web site. It's www.boostperformance.co.uk or www.chevroletls1.com. I can forward a picture of my crank kit. I really want to see it rev but can't find a casing! By for now, Mike Johnson.

[STEVE G]

Mike
Unfortunatly when I had the block pressure tested it failed miserably.Rpi took it inpart-ex on a new short motor(it wasnt them that tested it for me).They said it could be re-sleeved to a 5.0/5.2 safley but that was well beyond my budget.They might sell it to you for your project.
Regards Steve G.