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RDMG
Dave R
Northern Virginia
(129 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Update on 4.7L Toyota/Rover v8 Project
Posted by: RDMG
Date: December 13, 2019 01:23PM

Hereís an update on this thread a year or so ago:

[forum.britishv8.org]

My goal was to build a better-than-stock Rover v8 long block for parts and labor expenses under $5,000 using used or off-the-shelf parts only.

Donor parts include a 4.6L and a 4.0L engine from the last generation LR Discovery, a set of 1964 Buick 300 aluminum heads, and a Buick 215 4bbl intake manifold. My initial 4.6L engine was beyond repair due to several thread repair failures, so I found a junkyard 4.0L engine with a better block.

Engines: $700
300 heads and manifold: $450

I bought the following new parts:

8 oversized 95mm Toyota Tacoma 2.4L 4-cyl 2RZ-FE pistons from NPR (OEM supplier) $300
Lighter 24mm piston pins from JE $200
8 Melling top-hat cylinder liners $180
16 oversized, hardened Ferrea intake and exhaust valves for Buick v6 engines, plus hardened valve seats and Z28 springs $550

I had Jon Carls port and rebuild the Buick 300 heads with the new valves and seats. $1,400

Crankshaft grind .010 under: $150

Soooo, Iím in for about $4,000 before the machine shop costs even start, and I donít have a cam, lifters, pushrods, head studs, or front cover sorted out.

Machine shop costs to install liners, balance and blueprint, and assemble are in the neighborhood of $4,000.

Looks like $8,000 will be my minimum cost.

That price point gets me a hopefully durable, 4.7L, free-breathing, lightweight engine, loosely consistent with MG factory heritage.

The above engine has basically the same bore as the Buick 300, but with a shorter stroke. The ported 300 heads should make the engine perform better at higher RPMs, but the cast pistons and valve spring type limit the redline to 6000rpm or so. I have a set of coated tubular headers, so I suspect that the 215 intake will be the performance choke point.

In retrospect, I recommend anyone contemplating a conversion to consider 1) a bone-stock RV8 that needs no rebuild (performance potential limited), 2) a stock Buick 300 (good upgrade potential down the road with TA heads, 350 crank, etc), or 3) a Ford 302.


minorv8
Jukka Harkola

(190 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: minorv8
Date: December 14, 2019 03:06AM

I completely agree! I have collected parts to build a stroker engine. Crank, SBC rods, stroker pistons etc. Some very good deals, some less. My crank is a TVR specific item that has narrower crank pins than e.g. typical Rover. So more machining on rods. When I finally had all parts ready and block bored for trial assembly I found out that my pistons were sticking 60 thou out of the deck. Pistons are short stroker items so machining 60 thou off was not possible. SBC rods were 6 inch ones, shorter ones at 5,850" would leave the pistons 90 down in the cylinder at TDC.

There are 5,950" SBC rods for 350 pin size. I bought a set and machined them to fit the crank. Next issue: bearings. There are specific bearings to fit 350 rods to 327 sized cranks. Thick as hell ! Of course these are too wide to fit TVR crank so they had to be narrowed as well. Naturally on both sides. After a several months delay I had the second set of rods and did another trial assembly. I found out that physically larger rod big ends made the rod bolts hit the block at main oil gallery. Some grinding fixed that. Pistons did stick out some 15 thou so I got to do some more machining.

So, now I have a short block assembled. Bore is 94,5 and stroke is 92 mm. Price ? Not sure. Is it worth all the hassle or problems. Hard to say. Does the car need it ? No, power to weight ratio is already more than enough. Any other issues ? Sure, heads are Wildcats so I need to sort the intake. It will be a sheet metal, it's halfway done. I hope to get everything sorted next year.

Finally, I would add a 4) 4.8 or 5.3 LS on the option list.


tr8todd
Todd Kishbach

(367 posts)

Registered:
12/04/2009 07:42AM

Main British Car:


Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: tr8todd
Date: December 14, 2019 08:00AM

I too wish there was a way to put together a cheap reliable 4.6L or better Rover. There just isn't. I will freshen up a 4.6, but thats as far as I'm willing to go now. Bought a salvage 2010 Camaro 3 years ago. It had 11,097 miles and after fees, it was $9800. Honestly it should not have been auctioned off as salvage, but there were performance mods and it had never passed a state inspection, save for the initial one. I think that is the main reason it was written off. Anyway, I got the whole car. Sold off around $5K in parts and still have some stuff to sell, just have not bothered to post it yet. I'm into a beefed up LS3, and Tremec TR6060 with clutch and every conceivable piece to complete a build for under $5K. I have since purchased engine plates, oil cooler delete, headers, etc. to the tune of around $1000. That includes a used K&N fresh air intake from an LS7 Corvette. Now that LS engines are getting even easier to find, there is no way I can justify building a 300 plus HP Rover. Now I just need to figure out what to do with a garage full of Buick/Olds/Rover stuff. Literally 30 obsessive years of hoarding, ahum, I mean collecting. It is so refreshing to just turn on a computer and find exactly what you want and need. Instead of spending hours trying to figure out what's out there that might work in a Rover, I spend half that time trying to find something I know will work for the best price. You can't beat the fact that these Tremecs are basically indestructible compared to a LT77. Plus, 6 speeds baby.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5868 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: BlownMGB-V8
Date: December 14, 2019 05:24PM

I cannot help but agree with the sentiments above, having built a number of 215's at all performance levels. I just don't consider them durable enough for any sort of a high output build. Exactly the reason I went to the 300 Buick. Start with a good basic foundation to get good results, and there is no more suitable foundation for the MGB. The block is much stronger than the Ford at the same weight and late model, there is no cutting required. It is cheaper to use than the Rover by a decent margin, and can go to 5.7L. LS's are becoming plentiful but still not cheap and you have to cut up the car. Plus the 300 has a very good reputation for durability and trouble free use.

Jim


RDMG
Dave R
Northern Virginia
(129 posts)

Registered:
04/07/2016 08:29PM

Main British Car:
1979 MGB 4.6L Rover V8

Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: RDMG
Date: December 21, 2019 01:54PM

I got myself into this mess by holding onto the idea that the Rover engine has some sort of historical/cultural/tribal significance to MGs. While the 3.5L engine was the original factory solution, Iíve found myself in a place where the only things on my carís engine that actually match the factory 3.5L v8 engine are some of the engine blockís minor specifications (head bolt, bellhousing, and motor mount hole locations and thread pitch, etc), and the type of metal used to manufacture it. Thatís literally it. The Buick 300 has the same bolt holes but for the bellhousing, and itís made of iron.

I paid a steep price for those aluminum bolt holes.

If youíre not building a period-correct factory tribute, the Buick 300 is the way to go.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5868 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: BlownMGB-V8
Date: December 24, 2019 10:14AM

Plus you can ceramic coat the block for under $100, making it indistinguishable from the BOPR except by an expert.

Jim


302GT
Larry Shimp

(207 posts)

Registered:
11/17/2007 01:13PM

Main British Car:
1968 MGB GT Ford 302 crate engine

Re: Update on 4.7L Toyota/Rover v8 Project
Posted by: 302GT
Date: January 08, 2020 04:41PM

I like the Ford small block: it is the narrowest V8 available and with the proper choice of water pump length is almost the shortest, it bolts to readily available modern transmissions, and with aluminum heads it weighs little more than a Rover 4.6. A big advantage is most come with factory roller lifters and early blocks can easily be converted to roller lifters. A wide variety of performance parts are available and are also relatively cheap, especially compared to Rover. Easy to use engine mounts are readily available; XJ6 or XKE. (I recommend mounting the engine to the crossmember because of the thicker metal. Using the chassis rail, I experienced cracking due to the engine torque.) The biggest disadvantage is that the oil pump is under the front of the engine so the crossmember needs to be notched to clear the front (oil pump) sump of the double sump oil pan.

After living with my Ford 302 crate engine for about 10 years, I decided, several years ago, to rebuild it to incorporate the characteristics I wanted (which I am aware might not appeal to everybody). I was looking for a wide power band as well as a much higher rpm limit, but not so much of a torque increase since there is only so much torque the tires and chassis can handle. This makes the engine sort of like a classic sports car engine, but with low down V8 torque when I want it. For the short block I put in an internally balanced, standard stroke, forged crank, forged long (stroker) rods, forged pistons designed for a long rod standard stroke engine, and an aluminum flywheel. Each piston/rod assembly weighs 180 grams less than stock, and the bottom end is safe to 8000+ rpm. For the same price I could have built a high torque 331 or 347 short block but that is not what I wanted. However, the light weight internals help acceleration in the lower gears just as though more torque were available. Heads are AFR 165 with a provision for manifold heat. Compression ratio is about 9.8:1 and the engine runs well on 89 or higher octane. The intake manifold is a Weiland stage 1. This is a ďnormalĒ design dual plane manifold; the Ford stock manifold is a weird design and the base Edlebrock manifold is just an aluminum copy of the Ford design. I blocked off most of the intake manifold exhaust heat passages, but a small amount of heat is beneficial for throttle response. The cam is a midrange hydraulic roller design. I am using a Summit 650 vacuum secondary carburetor, as received, except for a different accelerator pump cam. The original distributor was a mechanical advance, only, MSD unit. In this form a chassis dyno showed 328 hp at 6600 rpm and 311 ft-lbs torque. I have since raised the rev limiter to 7500 rpm and there are no signs of valve float, and still a lot of power at that point. With my gearing, I can hit about 80 mph in 2nd gear. For first, acceleration is so rapid that I only have time to watch the tachometer so mph at redline is unknown. (I also had to replace my VDO instruments with SpeedHut instruments since the car out accelerated the VDO speedometer and tachometer in first and second gears.) I originally had a carburetor heat soak problem which affected hot idle and hot starting. I solved this by making a stainless steel (polished) heat shield under the carburetor. Someday I might also check the air-fuel ratio and adjust the carburetor jets if needed, but I doubt it is far off; throttle response is excellent and highway mileage is about 27. Recently I went to a vacuum advance distributor (the Pertronix cast unit and Mallory are the only ones that fit under the hood). With 10 degrees of vacuum advance available the engine runs well at 1000 rpm in 5th gear; with mechanical advance only, the minimum rpm in 5th is about 1400. My only complaint is that the lifters are noisy which is characteristic of the Comp Cams roller cam I am using. I may change to a Luniti cam at some point since these are known to be quieter.



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