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tips, technology, tools and techniques related to vehicle driveline components

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Bland
Tim Bland
Oregon
(8 posts)

Registered:
01/22/2017 11:15PM

Main British Car:
1980 Triumph TR8 Rover 3.5

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: Bland
Date: July 23, 2018 02:22PM

Amendment to my previous post.

After further checking I have two Rover blocks and not a Buick block.


turbodave
dave cox

(13 posts)

Registered:
04/30/2018 03:00PM

Main British Car:


Re: Rover 4.6 V8 Triage
Posted by: turbodave
Date: July 30, 2018 10:35AM

These vids I took say it all...

[www.youtube.com]

The Later 4.6's seem to have the "loose liner syndrome" (not to be confused with "cracked block behind liner" or the earlier "dropped" liner issues). These are simply that there appears to be insuffient interference, especially on the centre four liners, for the liners to hold in place, especially at higher temperatures.
Pinning is the easy fix for what is otherwise a plenty servicable engine. If you do proceed, I'd go ahead and simply pin them all anyway, as its so easy to do with the engine on the bench, in pieces.

The "first 6 month production" 2003 4.6's had the well known issue of the dowel holes in the block for the front cover being machined in the wrong place (interestingly the bolt holes and even the countersinks for the dowels were right, someone just mistakenly offset the dowel holes). This is easy to see as the pump gerotor is likely broken when you pull it out, and ALL the bolts are biased to one side in the holes in the front cover. Fix for that is to simply pitch the dowels, align manually such that the gerotor gear "floats" and can be slid forwards/backwards using a magnet thru the oil seal, and drill a few 1/8" holes and knock in a couple of roll pins for holding that location. Just because it came out of an '04, don't assume it was an '04 motor. You'll see the countersink offset around the dowel very easily if it is there. If it looks ok, it is ok.


turbodave
dave cox

(13 posts)

Registered:
04/30/2018 03:00PM

Main British Car:


Re: Rover 4.6 V8 Triage
Posted by: turbodave
Date: July 30, 2018 10:39AM

Finally, if you do pressure test the block, I recommend setting the block on your grill, and warming it up, at least to 180 deg. If it doesn't leak at that temp, you've definitely got a goodun.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: August 01, 2018 10:22AM

Loctite should fix that also.

Jim


roverman
Art Gertz
Winchester, CA.
(2901 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Rover 4.6 V8 Triage
Posted by: roverman
Date: August 01, 2018 08:08PM

Warning: If you convert to head studs, reduce your torque # by 30% ! 20 tpi vs 14 tpi. Just about any cast aluminum thread will fail,if 30% too much torque is applied . FWIW, roverman.


RDMG
Dave R
Northern Virginia
(103 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Re: Rover 4.6 V8 Triage
Posted by: RDMG
Date: September 07, 2018 03:05PM

Well, my levels of optimism are now much lower.

A pressure test through the coolant passages passed at 30psi for 24 hours, and I thought I was a brilliant finder of decent RV8 engines in the wild. Just for kicks I pumped up the pressure to 50psi, and within a few minutes cylinder four sprouted orange, oozing, bubbling stuff all around the top of the liner. Definitely looking at a cracked block. Center head bolt hole is stripped too, and I think thatís not coincidental. I havenít yet tested the crank journals for wear, but I will. Heads just had a valve job, so they should be ok.

My only leads on a replacement used engine are from suspect trucks: either from no-body-damage Landys in the junkyard for about $300, or from a guy parting out his Rangie after an ďinterior burnĒ for $1500. No way to test either before buying them, so it feels like a real dice roll either way. All are high mileage and likely need rebuilding anyway.

Iím inclined to invest in the block I have, to be reasonably sure it will last a long time.

Local top-hat install costs are $1200 labor, plus $500 cost of sleeves, plus $100 to tig-weld the crack. The might-as-wells add $2000, or maybe much more.

Iím now wondering what to have the machine shop do:

1. Stock bore (94mm ID liners) and replace all worn bits with new Rover 4.6 spec bits, or

2. Overbore (96mm ID liners) and go with Chevy 305 or Ford 4.6 pistons and appropriate con rods.

It seems like option 2 gives me more power, a free-revving engine, and perhaps tougher and lighter pistons for the same labor? Do I lose anything? Iím guessing the parts and machining costs are similar either way?


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: September 08, 2018 07:34AM

I'd be looking for an iron block.

Jim



7sand8s
Dennis Miller

(24 posts)

Registered:
09/21/2008 10:47PM

Main British Car:


Re: Rover 4.6 V8 Triage
Posted by: 7sand8s
Date: September 08, 2018 07:41AM

A different brand same idea...
[www.hotrod.com]


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: September 09, 2018 11:59AM

Yeah, see with an iron block there's no messing with sleeves. No cylinder wall cracking. No threads pulling out, ever. And a 3.8" bore (96.5mm).

It costs you 80 lbs.
So worth it.

Plus a much cheaper bellhousing and a lot more transmission choices.

Jim


RDMG
Dave R
Northern Virginia
(103 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Re: Rover 4.6 V8 Triage
Posted by: RDMG
Date: September 10, 2018 07:44PM

Hi Jim,

I hear you on the iron block, but Iím irrationally committed to the Rover aluminum block. I had a chance to buy a 300 out of a remote junkyard about 6 months ago, but just couldnít go through with it. I have so many pieces (bellhousing, coated headers, factory flywheel with ignition trigger wheel, EFI intake, etc) waiting to bolt onto my RV8, I canít bring myself to go another direction. Maybe for my next project?

I am wondering what if anything I gain/lose by fitting 305-size pistons to the RV8 block. I found a set of ICON Premium Forged Pistons, IC834-060, that have a
3.796Ē bore, 1.433Ē comp height, weigh 522g, that should work with a 6.11Ē 4.0 RV8 con rod inside a 96mm (3.78Ē) liner from Turner Engineering.

On the plus side:
Slightly larger displacement, maybe 4.8L
Forged pistons with higher strength, allows for TA Perf heads down the road
Slight weight savings (maybe)

On the negative:
Totally custom approach, likely has higher failure risk
Have to rebalance the crank, etc
Overbore top-hat liners are thinner, maybe weaker
Longer 4.0 con rod (6.11Ē vs 5.90Ē) gives a slightly higher rod-stroke ratio 1.89 vs 1.83 (I think?)

Unknowns:
Cost of set of 4.0 rods and machine shop costs to bush the wrist pin and reduce piston comp height a few thou, vs high cost for stock-spec forged pistons

Am I missing anything important?

Dave



Edited 2 time(s). Last edit at 09/10/2018 11:23PM by RDMG.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: September 11, 2018 09:58AM

Well Dave, you could still use your coated headers and EFI intake (have to use spacers though, and might not fit under the hood then). On the plus side you could use a 350 crank in it for 5.6-5.7L displacement. That flywheel might work with some machining and re-balancing but I expect that'd be possible without much difficulty. You need to thin it out some anyway I expect. And I'm guessing you are going with the Rover 5 speed?

But I do get it, you're in love with the light weight aluminum 4.6. It's clouding your judgement right now. Just consider that for what you are talking about spending to make it work, you can adapt your parts to the 300 (or sell and buy different parts) and possibly stroke the 300. And it will easily outlast the 4.6L Rover. I'd go with one of the 4bbl throttle body EFI's though myself. Simpler, easier, and looks better in my opinion. That doesn't help with your Rover transmission though, does it. Hmmm... What do those sell for these days?

It is basically a math problem on the face of it but with other factors. I'd definitely do the full cost comparison though before taking irreversible action.

Jim


RDMG
Dave R
Northern Virginia
(103 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Re: Rover 4.6 V8 Triage
Posted by: RDMG
Date: September 15, 2018 04:26PM

Hi Jim,

Your argument is compelling.

I spent yesterday morning in the local pick-a-part, hoping to find another RV8 that might be sound, but the only safe bet was in a Discovery with 180,000 miles on it. Full rebuild territory. For $500. No thanks.

If a 300 Buick falls into my lap, I may shift focus. Iím ready to think a bit harder about the options.

I canít seem to find the ďrecipeĒ here for stroking the 300 block. Is there a parts list or a discussion thread anywhere?

I already have a decent Camaro V8 T5 and a set of aluminum 300 heads (need work).



Edited 1 time(s). Last edit at 09/15/2018 04:27PM by RDMG.


mgb260
Jim Nichols
Sequim,WA
(1914 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Rover 4.6 V8 Triage
Posted by: mgb260
Date: September 16, 2018 07:31AM

Dave, 300 Stroker info:

[www.mgexp.com]


7sand8s
Dennis Miller

(24 posts)

Registered:
09/21/2008 10:47PM

Main British Car:


Re: Rover 4.6 V8 Triage
Posted by: 7sand8s
Date: September 16, 2018 11:10AM

From BritishV8:
[www.britishv8.org]


88v8
Ivor Duarte
Gloucestershire UK
(607 posts)

Registered:
02/11/2010 04:29AM

Main British Car:
1974 Land Rover Lightweight V8

Re: Rover 4.6 V8 Triage
Posted by: 88v8
Date: September 16, 2018 02:10PM

Perhaps you could ship a Turner top-hatted block over? A consolidator wouldn't charge you too much.
Maybe ask Real Steel; they use a consolidator, just in the opposite direction.

[www.realsteel.co.uk]

Ivor



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: September 16, 2018 10:58PM

Dave, by now a few 300 strokers have been done, and much depends on your expected redline. To be completely honest, in an MGB a 350cid Buick does not need to exceed the factory limits unless you aim to race it somewhere. You can get an easy 375+ ft/lbs of torque out of it with the OEM build, and that's enough for great gobs of silliness. OTOH, a set of NASCAR take out rods and forged pistons are a relatively affordable route to 7500+ rpm speeds and ridiculous power levels.

So far there is not any one established formula. However if economy is the goal then the 340/350 crank main journals can be lathe turned to .030" oversized before going to the grinder. (1/2" overall reduction. Bear in mind that is like at least 10 complete full crank grinding jobs if the grinder does it all.) and then the 300 rods can be reused with suitable pistons of your choice. (Making sure to check the fit of the oil slinger in the 300 block.) The key to the entire thing is the rod and piston combination. The 300 uses a relatively long rod, the piston has a significantly larger than typical pin height, which only works due to the tall deck, and then the thing that makes the stroker work is that pin height. You can easily decrease that to accommodate the longer stroke without getting into the ring package.

So, for a performance build, start with the rods and plan on specifying custom forged pistons so you can get everything the way you want it, such as CR and squish area. This method allows you to minimize weight in the reciprocating assembly for a truly free-revving engine, and there is a LOT of room for reduction. The wrist pins themselves are 200 grams and that can be reduced by half.

For the near-stock build, use the 300 rods and either one of the pistons used in prior builds, any one that you find you like better, or custom. Note, piston crowns can be cut to modify deck offset, CR and dish plus there are a lot of things that can be done with piston pins if you feel like getting into that.

Bear in mind here that the difference between cast pistons off the shelf and fully spec'd out custom forgings is in the range of about $300-400 which may sound like a lot but you get a lot for that and spread over the life of the engine it is peanuts. Still, if I was being dollar conscious I would look very closely at the pistons that Chris used. That's been the latest development, and to my mind one of the most sensible. (Disregard Chris' whining, he's just a bit too much of a perfectionist. ;-) ) However we are yet to find the perfect rod/piston combo. Bear in mind also that early SBC rods with the large end narrowed are a valid rod choice and are available in forged rather than cast. This enlarges the piston options as well. The largest limitation to piston choices in fact is the 3.8" bore size, but expanding the search to non-American engines may prove fruitful. It takes a little math to get the pin height for the selected rod/piston combo but not that much. Deck height, stroke,rod length and then pin diameter to make sure you aren't into the ring package. You can use up to a 6.3" long rod with no worries. In fact I think it would be possible to squeeze in the longer 340 rods if the ring package was very compact.

So while it may sound complex, what you actually have is a great deal of flexibility. About 1/2" of leeway on rod length and the same on pin height. If you can't find a rod and piston that suits under those conditions either you just aren't trying or you are being too picky. Well, not you personally of course. There may even be some motorcycle pistons that would work just fine.

But again, for simplicity follow Chris' build. It's the easy recipe. Have your block sonic checked for core offset before you start (you can get an idea of core shift by looking at the cylinder roots at the crank end of the cylinders. If there is a great deal of visible variance it isn't a good sign.) and try to stay over 3/32" on the thrust side if you can, try to stay within .050" on the overbore and do the oiling mods. Since you already have the 300 heads set up an automatic search for a 300/4bbl aluminum intake and ask around. Any old iron block 300 will do the trick.

I currently have a 300 block on the engine stand with a turned but not ground 340 crank sitting in it. It'll be a slow build but my next step is to find the best rod I can at the best price. This engine will likely get Venolia forged pistons similar to my 340.

Jim


RDMG
Dave R
Northern Virginia
(103 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Re: Rover 4.6 V8 Triage
Posted by: RDMG
Date: September 19, 2018 09:36PM

Many thanks Jim, Jim, Ivor, and Dennis,

I clearly have a lot of reading to do!

The 300 is a really neat idea, but Iíll admit the level of effort described in the mgexp thread is a bit overwhelming!

Some beautiful custom pieces in that car. Particularly the motor mounts.

Dave


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5627 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: BlownMGB-V8
Date: September 20, 2018 09:36AM

It can be done very much like a straight up Rover swap. Except no liners to deal with. Doesn't have to be a stroker, plenty of power as a 5L.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(3471 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
79 MGB, Buick 215

authors avatar
Re: Rover 4.6 V8 Triage
Posted by: MGBV8
Date: September 20, 2018 10:51AM

Mike Moor gets just over 300 RWHP with his stock stroke 300. So, one does not have to go to the trouble of stroking the 300 for it to be a very good engine.
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