My 4.6 V8 Rebuild Thread

[101RRS]

For a while now I have been wanting to put a 4.6 V8 in my 101 but being retired I do not have the resources to go out and simply buy a fully built up engine so will have to do a rebuild as resources become available.

I am not after a high powered race engine but one that will be reliable and produce a good torque curve between 2000 -3000 rpm to give a bit more oomph on the road. The 101 gearing means that the standard 3.5 is OK offroad but runs out of puff on hills on the highway.

At this stage I have not decided on whether to stay with carbies or go injection and will work this out as the build progresses. Likewise whether to use the old 3.5 timing case etc and go electronic ignition with a dizzy or go the much later ignition coil pack ignition system. I do not need to make these decisions just yet.

It will be a dual fuel system and as petrol will have to be purchased in remote areas I will stay low compression - high compression would be nice but 91 ron unleaded will the norm for petrol.

So as things develop I will ask questions and post progress in this thread.

So to start.

I have an old 3.9 engine with most ancillaries still on it, I have a 4.6 block with at least two slipped liners but it has no main bearing caps, 4.6 crank, conrods and 8.3 pistons (thanks to the generosity of an AULRO member) and I have a very low km, never over heated 4.0 engine (thanks to the generosity of an AULRO member). This engine had a rear head gasket issue and was constantly leaking coolant so was replaced.

The plan.

The basic plan was to put the 4.6 crank and pistons into the 4.0 block. Now as the engine is low km and not overheated I was not going to top hat this block - a risk I agree but the 101 is not an every day driver and if issues came up later I would then top hat it. I have low water and engine block temp alarms so future chances of overheating are low. A risk but at this stage worth taking.

Block Preparation

The first stage in the rebuild is preparation of the 4.0 block - disassembly of the engine, cleaning the block, checking it right over, bore honing (cross hatching is still there) and most likely crankshaft tunnel boring.

Taking the heads off the 4.0 the reason it was not used has become apparent - the drivers side rear head bolt (next the coolant passage) had been over torqued and stripped out the thread so a helicoil was inserted (rather poorly) and as a consequence there is a crack between the water passage and the head bolt hole and then on to the out side of the block.







The crack goes down into the block about 3mm that is visible so probably another couple of mm that is not visible.

So the first major question is, given the position of this crack at the extremity of the block can this crack be ground out and the block welded and the head bolt retapped/helicoiled or is this a block killer?

Cheers

Garry

[bee utey]

That looks suspiciously like a top hat linered block. I would consider it worth trying to rescue that! You would have to find a very good alloy head welding expert though.

How much extra hole depth is there under the pulled out insert? A new specially machined (e.g M14 x 1.25 outer, 7/16 UNC inner thread) fitted full depth might be possible to seal into place without welding. Then fit ARP head studs.

[101RRS]

That looks suspiciously like a top hat linered block. I would consider it worth trying to rescue that! You would have to find a very good alloy head welding expert though.

How much extra hole depth is there under the pulled out insert? A new specially machined (e.g M14 x 1.25 outer, 7/16 UNC inner thread) fitted full depth might be possible to seal into place without welding. Then fit ARP head studs.

I think you are correct - the top of the liner is 5mm wide where the liners on the 4.6 block are only a couple of mm. Also the top of the liner on the inside is chamfered on the 4.6 and squared on the 4.0.

I was surprised that a helicoil instead of an older style insert was used for a head bolt. I do not know how much extra hole depth there is - likewise that head stud hole maybe has enough metal under it to allow the hole to be drilled deeper and tapped - but maybe not.

I agree - if this is already top hatted it will be worthwhile saving - so I will proceed in stripping this block right down and getting an engine builder with Rover expertise to have a look and advise.

There is no one in Canberra who can do this - can anyone advise of an engine builder in Sydney who is a Rover expert who I can get to advise how to deal with this and line bore and hone the block.

Thanks

Garry

[jimbob292]

I tend to agree, looks very much like its a top hatted, well worth the time in saving it. I know new ones are expensive, been looking at one for my next project, Turner engineering do a good one, but the shipping is a killer.

Try and remove the heilcol, give it a good clean up with De-greaser, try a Dye pen test to see how far the crack has propagated too.

If you cant find a good machine shop; where the water jacket is gently grind a channel down the crack with a dremel drill, and fill with Belzona, grind and refill, as to build up the layers. Like wise with the screw thread, then re-tap, as bee utey commented with a larger helicoil, the whole area needs to be really clean thou.

I've used Belzona Industrial Protective Coatings and Repair Composites - Belzona as good repair compound will stand up to most riggers of machining, cutting taping etc, tough stuff

[101 Ron]

Everlast engines nowra can do what you want.
Full machine shop with crankgrinder and they know how to TIG weld.

[101 Ron]

For interest sake.
Rough guide for prices
17/9/2010
gasket set VRS compose head gasket $166.30
gasket set block ( Payten brand) $49.10
Gasket sump rubber $36.95
Big end bearings (glyco germany) $73.15
Main bearings $70.10
8x piston assy 9.35:1 hepolite $952.00

The above was from AJ....all for 4.6 litre.

[101 Ron]

From Nowra spare parts
21/10/2010
8x top hat liners $57 each.....$456
1x ring set $249
1x set conrod bearings $149
1x main bearing set $204
1x camshaft, up rated billet..$450
16x lifters $210
1x timing chainset....$306.......I think that was a up rated one with spockets
1x full gaphite gasket set including seals $372


all prices plus freight.

[101 Ron]

Everyone is hotting up their 101s and I will be the odd one out !
The power race is starting !

I have been told it is worth while just getting the 4.6 heads done up and fitting them to the 3.5litre block...........suppose to add 20 horse power.
Anyone have any experience with this ?
The later heads flow better and have higher compression ??????????

[clubagreenie]

Wayne Smith - Smiths Engine Research in North Parramatta (North Rocks Rd) is a guru of engine building. If anyone could save it he could. Worked with him on some Toyo engine development that ended up in Grand Am and JGTCC cars.

[101RRS]

Everyone is hotting up their 101s and I will be the odd one out !
The power race is starting !

So when are you putting in your 4.6.

Mine will be a slow build - one bit at a time as funds become available.

Thanks for those prices - did you chase them up for your engine.

Garry