Main British Car:
1979 MGB 4.6L Rover V8
Dave's MGB with Rover 4.6
Posted by: RDMG
Date: June 26, 2017 10:00PM
Owner: Dave R
City: Northern VA
Car Model: 1979 MGB Tourer (roadster)
Engine: 2004 Land Rover 4.6L V8. Maybe carbed first, maybe EFI later, maybe EFI first.
Cooling: Stock Ď79 B radiator with Volvo electric fan
Exhaust: D&D Mild Steel 4-1 Headers with 1.5" Primaries, remainder TBD
Transmission: 1988-92 Camaro 305 V8 T5 WC, 1960s buick bellhousing, aluminum flywheel with 1990s Camaro V6 9 3/4Ē clutch (aftermarket stage 2 specs)
Rear Axle: Hoyle IRS with 1989 Merkur Scorpio (European Ford Sierra) 3.36:1 or 3.64:1 differential, LoBro 100mm CV axles
Front Susp.: Stock MGB, lowered, with a few uprated damper and brake pieces, FastCars IFS setup... someday
Rear Susp.: Hoyle IRS (still in the boxes)
Brakes: Stock MGB front with drilled rotors, Scorpio/Sierra rear discs, Stock master cylinder/booster
Wheels/Tires: 14" UK Minilites with ancient 195/60r14 Yokohamas now, soon to be 15" VTOs with 195/60r15 sticky tires
Body Mods: Partially backdated to Mk1 MGB spec with chrome bumper conversion, deleted backup lamps and side marker lamps, deleted door mirror holes, early steel dash, Frontline Developments fiberglass Sebring valance, 1970s period rollbar (maybe), color-matched fiberglass works-type factory hardtop. All will be painted Iris Blue very soon.
Interior: covered in mouse turds, piled into my garage corner. Can't think about it.
Electrical: stock MGB, still to be sorted out
Comments: Hi everyone, I've been surfing this site and the MGB V8 universe for over a year now, and finally I'm committing to a journal! I'm a technically minded guy with a taste for fabricating things, but this is by far the most involved automotive project I have ever undertaken. I drove a '73 B in high school, and have always loved the looks and feel of the car. My plan is to build the perfect driver's car with some track-day potential, not a trailer/garage queen. Everything on the car will have a factory-ish or period-racing look, using mostly MG pieces. For example, I'll use the later seats trimmed in leather, but with a steel dash and no center console. As little plastic in the interior as possible. No aftermarket add-ons where they show, except for alloy wheels. Underneath the sheetmetal skin, that's a different story...
I found a great stalled MGB project about 3 hours drive away, dragged it home in January, and admired the piles for several months. Here's the first photos I took:
Zero rust, straight shell, lots of go-fast (or just look fast) parts from Moss that I'll probably sell. At the same time I've been trolling craigslist for engine parts. I bought a late-model Rover Thor-type 4.6L v8 for a song (more on that to come), and cleaned out the garage of an old-timer Buick 215 builder in MD to end up with a 4bbl intake, 4spd bellhousing, Buick 300 Aluminum heads, a 215 flywheel, and a few other bits. Another guy in VA was selling off all his worldly possessions to buy a Macadamia nut farm in Hawaii, leaving me with a really great deal on some 90s mustang driveline bits, including two T5s (one rattles/jingles a lot due to a missed shift. More on that later too). In a moment of weakness, I bought a Hoyle IRS kit from the UK, and found a junked Merkur Scorpio to provide the rear axle. I also nabbed an RV8 GEMS EFI manifold from another junkyard. My garage is now stuffed with greasy and dusty junk, and I have to take some action. So far, I think I'm into this adventure for about $8,000, and I would rather not consider how much deeper I'm going to go.
I dropped the V8 into the engine bay for the first time, eased the trans tunnel near the firewall, and cut the holes in the wings for the headers. Here's where a Mustang 5.0 T5 shifter comes through the MGB trans tunnel:
The location is not ideal for a stock look with a plastic center console, but since I'm going for an early 60s look, I can fab up a new oval sheetmetal plate for the MGB tunnel hole, and cover the whole tunnel with carpet. The later trans tunnel is clearly not an early 60s tunnel, so its not like a perfect match for the original shifter location would fool anyone anyway. The rearward offset of the Ford shifter lever will put the knob about where the stock knob was, so the ergonomics are good.
I discovered that the late Rover serpentine 4.6 front cover fits over the steering rack and seems to provide enough space behind the radiator, but the stock oil filter angle fitting would place the filter in direct interference with the rack. I will need to either move the rack (no thanks), or do something different with the filter. If you remove the angled fitting from the serpentine cover, it looks like the thinnest available remote oil filter mount will attach to the cover with a 1/4" of clearance at the tightest point. In this pic, you can see the cover with the factory angle fitting removed. That fitting bolts onto another threaded tube that may also be removed:
Hereís the angle fitting I removed to make the engine fit:
The angle fitting is just an elbow with standard filter threads and filter o-ring surfaces at each end. Remote oil filtration isn't ideal for oil pressure reasons, but it may have to do. I researched various adapter fittings, and theres a 90-degree Ford Motorsports product that is the correct threading, but not the correct lateral offset. The Hummer H1 has a centered 90 degree fitting that may work, I definitely recommend some folks here consider it for their applications. Check thread size though. The Toyota Camry and Lexus es300 from the early 90s use a great offset piece that may be perfect for a serpentine RV8 to clear the stock steering rack, but will require an adapter plate and threaded center adapter to work. I'll continue to surf the web for other bits, but I'm prepared to buy a remote kit if I have to. The Rover serpentine cover also has bungs for an oil cooler. I can run that in parallel (not in series) with the remote filter, if I want to. My project car came with a new MGB spec cooler still in the packaging, so I'll probably use it.
The cast aluminum oil pan of the last RV8 4.6 engines is very deep, and hangs lower than the front crossmember, about as low as the stock rear differential housing. Not ideal. I will replace the drain plug with a flush-mounted one to hopefully avoid any snags. Iím also thinking about reworking the entire pan to make a wider, shallower sump that will be better protected. The cast sump has an integrated oil pickup that is specific to the crank-driven gerotor oil pump that I like, so I canít swap out the pan for an earlier Buick 215 type.
I pulled the engine out, made some of the sheetmetal mods for chrome bumpers, and found an aluminum hood for a fair price. I then decided auto body work was not something I was naturally good at, and was not something I wanted to develop as a skill. I found an auto and motorcycle custom shop that did good work and had the shell towed there for final tweaks and paint. Sometimes itís best (and least expensive) to pay an expert. Given the investment in paintwork, Iím now past the point of no return!
JAN 2018. A FEW CHANGES TO THE PLAN
I continue to collect parts. This is becoming a problem. I convinced myself that buying a gently used Millrite milling machine with a rotary table would be the most cost-effective way to obtain the custom flywheel, modified harmonic balancer, EFI intake, and other unique interior trim parts that I will want, and I'm now neck deep in manuals and tutorials on basic machining. At the end of the day, at a minimum, I will have new skills and experience, a few custom parts, and a milling machine I can sell for the price I paid, if not more. I'm surrounded by Porsche guys who seem to have every tool but a milling machine, so maybe I'll be able to trade some services. The "might as wells" of this project are getting ridiculous. At some point, I think my intent was to put a V8 engine into an MGB. Hard to tell by looking at my garage right now.
I decided that I wasn't happy with the Ford T5 for a few reasons, the main one being that I snagged a decent Camaro V8 T5 with 2.95:1 first gear on craigslist for $400. I then convinced myself that the 3.35:1 first gear in the Ford T5 was too low, the tail housing was 3/4" too short, and the complexities of hybridizing a Chevy-and-ford clutch were too difficult. I just sold off all my Ford parts for a nice profit to a guy in Boston. I now have a better set of gear ratios, which may be the only justification that matters. I also now have a Ford T5 bell housing adapter and pilot bushing that I have no use for.
I'm still occasionally thinking of the perfect setup of transmission parts that would place the shift lever closest to the stock MGB location. Using D&D motor mounts that place the BOPR engine cylinder heads as close as possible to the MGB rubber-bumper firewall, a Ford T5 shift lever comes almost exactly through the fore-to-aft center of the oval trans tunnel shift lever hole. (Stock MGB setup is at the rearward end.). Using the same mounts, a Chevy T5 will be slightly rearward from the Ford location, by about 1". (Ford T5s have a longer input shaft requiring a bell housing spacer but have a shorter tail housing, GM T5s have a short input shaft that requires a thin spaced for 3.9 and later RV8 blocks, and has a longer tail housing.) I cannot confirm this through the internet alone, but I think its possible to replace the very short GM input shaft with a much longer input shaft from an Australian Holden (Commodore?) T5, to push the gearbox backward a few inches. The first gear ratios in both transmissions are the same, and both are GM products, so the gears should mesh. Borg Warner only made one type of 2.95 counter gear, I think, for all T5s. It may then be possible to use the very deep automatic transmission bell housing from the Land Rover Discovery with an adapter/spacer to suit the T5 bolt pattern. An existing off-the-shelf spacer plate could be drilled and countersunk to suit a set of holes in the LR bell housing. All of that would put the shifter another 1.5in or so rearward, which would be nearly perfectly in the stock location. LR Discovery auto bell housings are basically free on eBay, and Holden input shafts are available in Canada for about $150 new. Such a rearward shift would also require a custom transmission mount, but so does every other setup. I believe the 2.95 gearset for ford and GM T5s is the same part, so the Ford T5z should also be able to accept a Holden input shaft, but then the tailhousings would be somewhat shorter than an equivalent GM setup. Anyway, it may be an interesting option for someone out there.
I'm also knee-deep in intake/inlet manifold parts, with no clear plan on how to best proceed. I have the Bosch/Thor setup that came with the engine, but haven't been able to sell it on craigslist. To my knowledge, nobody has used that hardware in an MGB conversion. I also have a GEMS intake setup from a 4.0 LR Discovery, and that setup has been modified to an MGB V8 several times as documented here on BV8. I also have a Buick 215 4BBL intake, which would use a 500cfm carburetor. My front cover has no provision for a distributor, and the process of backward-converting a 4.6L engine (replacing cam, front cover, oil pan, etc) to install one is not appealing. Since I won't be using a distributor, I'm committed to an EDIS8 controller and a MegaSquirt or MegaJolt setup.
I like the idea of a carburetor on the Buick intake, to really give the car a period-correct (choke knob on the dash, smells like unburned gas, can't start in the cold, etc.) feel, but I also like the idea of a fully customized application of the Bosch/Thor setup that came with the engine. I'm thinking I'll buy a MegaSquirt kit and use it at first just to control the ignition, in order to get the car running on the Buick intake and a carb while I assemble the pieces for a custom Bosch/Thor EFI setup.
MegaSquirt can control just ignition, but it still requires a few EFI-type sensors to operate properly. using an old-school carb intake, I'll need to figure a way to sense the vacuum from the Buick intake, or perhaps from the carb itself. Hopefully that's not more difficult than drilling and tapping a hole?
By setting up a carbureted engine first, I can ensure that the rest of the systems are working before I embark on a range of complicated custom issues with the Bosch EFI. The Bosch/Thor system is a returnless fuel system designed to run at 50psi all the time, which requires a different fuel pump than most return-type EFI conversions. I found a low-cost external returnless fuel pump originally fitted to 2004-ish Corvette LS1s that supplies a constant 58psi, that I think I can fit to the stock MGB fuel tank with only a few mods to the sender unit cap. I assume the 8psi pressure difference won't be too much for the stock LR injectors, but I don't know yet. Likely many more variables and requirements that I have yet to identify.
MGB is back from the paint shop, looking beautiful, but mostly untouched since. Iíve been focusing on drivetrain work, to the extent that Iíve been focusing, or working, at all. I splurged on a Pro5.0 shifter for my camaro T5, and I really like the way it feels. Very precise, satisfying movement. I also bought some temp sensor bungs and had them welded onto my headers, facing inboard just before the pipes make their 90 degree bend to the rear. Off for thermal coating soon.
A friend and I also finally tore down my cheapo 4.6 engine, to see what we could see. I discussed it in an earlier thread titled ďRover 4.6 Triage,Ē which I now think will need to be edited to be ďRover 4.6 autopsy.Ē As we took off the valley pan gasket, we found this:
Spotlessly clean inside, no sludge at all. Also some fine metal pieces scattered about. The entire internals were equally sludge free. Iím guessing water got into the crankcase and steam-cleaned everything. Dragging a magnet through the oil sump, we found these bits (next to bottle cap for size reference):
I assume an oil filter clogged and blew out at some point, causing some distress.
The front cover gasket was flaky and couldnít possibly have been sound. I do wonder if it was the source of the coolant leak that led to an unnecessary head gasket replacement, followed by massive over-torquing of the head bolts. The head bolts were a disaster. A few had no torque or clamping ability at all, and some others had threads pulling up above the deck. Of those that were solid, I could barely crack them loose with my 2-foot breaker bar. I havenít seen the bearings yet, but Iím pretty certain Iím in full rebuild territory. The gaskets looked good, whatever thatís worth!
Next step is to remove the crank and pistons and check block pressure. Not optimistic at this point, but I think the 4.6 crankshaft is prob still worth what I paid for the entire engine, so I canít complain.
The engine turned out to be a boat anchor. At 50psi during the pressure test, cylinder 4 started bubbling furiously around its sleeve. A detailed inspection of the bearings showed copper surfaces on all the con rod bearings, and flakes of metal everywhere. All bearings are shot, all bearing surfaces on cam and crank are scored, pistons are junk. The new valve job is probably shot as well. Clearly in rebuild territory. The last few minutes of the engineís former life must have been sad. I spent a few months looking for a suitable replacement engine. In my area, junkyards are full of Land Rovers with new radiator hoses and head gaskets (cheap repairs in the hope that the block isnít cracked, that didnít work) or with 250,000+ miles on them, which are likely to be worn beyond reason. All of those blocks would put me no further ahead, so I resigned myself to paying rebuild expenses.
I had the crankshaft turned .010 under for $150, and was very pleased with the cheap price until I got a $100 photo-trap speeding ticket while driving home with it. After all that, I realized I could have had the 2.15Ē bearings on my 4.6 crank offset ground to 2.00Ē size, and had a 3.40Ē stroke equal to the Buick 300 crank. Lots of Chevy 2.00Ē rods available too, with a more common wrist pin size. Oh well.
I just dropped off my engine at Darton East in Winchester, VA, for a short-block rebuild including re-weld of the cracked cylinder, with top-hat liners all around and time-serts as needed. Iíve been following a few recent threads here, and am building something slightly different: a 4.7L with Toyota pistons. The Toyota Tacoma 2.4L 2RZ-FE 4-cylinder engines have pistons slightly larger diameter than RV8 4.0/4.6 pistons, but otherwise similar in most respects, including a 24mm wrist pin diameter. Theyíre flat with a 4.5cc dish, and similarly meaty. 50g heavier than the OEM piston, partly due to the larger diameter. The higher weight can be offset a bit with aftermarket off-the-shelf wrist pins that are 26g lighter than the OEM Toyota version. Toyota modders regularly turbocharge and supercharge their blocks with few ill effects. I believe the OEM supplier is NPR, and I bought two sets of four for about $110 each in 95.5mm oversize. VERY cheap options for the Tacoma piston are available, but I wanted some sense that my new pistons would be as strong and reliable as an OEM set. Turner Engineering in the UK (actually Darton) makes a suitable liner for these pistons, and Mellingís 356F sleeve for GM engines is another, less expensive option. All things considered, the Toyota pistons and Melling sleeves will give me a similarly robust, larger displacement RV8 for less cost than I would have incurred using pistons and other OEM-sized parts from Rover suppliers.
The small dish in the Toyota Tacoma piston requires a big combustion chamber to realize a workable compression ratio. As mentioned earlier, I found a set of aluminum 1964 Buick 300 heads when looking for a manual trans flywheel. Those heads have a 54cc combustion chamber, which will work well to create around a 10:1 compression ratio with the Toyota piston. I sent my heads off to Jon Carls in Minonk, IL to be worked over with some Ferrea 1.75Ē and 1.5Ē valves, Durabond hardened seats, and Z28 springs. I hope the heads arenít overkill for this engine, but if youíre in for a penny on old heads, youíre in for a pound! If youíre considering a similar setup and donít have these heads on hand already, consider the TA Performance head. Assembling a set of those will likely cost less than $500-$1000 more than all the work required to make a Buick 300 head breathe well. I had to draw the line somewhere, and having the Buick heads in hand was a powerful motivator to stick with them. I also realize this engine isnít a max-effort performance build. The 300 heads will do all i need the heads to do. I also wonder if the overbore to 95.5mm and the cast pistons might put my engine on the wrong side of the safety margins for the HP levels that a TA head might produce!
Iím still pondering the front cover. Some other threads here show my ideas on how to use a late Buick v6 cover with a crank-driven oil pump, and an oil filter adapter for other GM 3.8 engines. Too soon to tell which way Iíll end up.
No firm plans for cam, intake, or exhaust yet. I have a Buick 215 4BBL intake, a Rover GEMS intake, and a Rover Bosch intake on hand. Lately Iíve been thinking a FI Tech setup with distributor to look old-school under the hood, but my mind may change again.
Iíve been sifting through the hundred or so ziplock bags of MGB parts I acquired with my project car, and am now humbled by the nickel-and-dime expenses required to reassemble a disassembled car. A rubber seal here, a bolt there, a few body plugs, and pretty soon youíre spending hundreds of dollars at Moss! Iím also struck by how much time it takes to do one thing that probably took the guys in Abingdon a few minutes when the car was first built. Iíve easily spent 20 hours on just the door internals!
Next update will have some pics, I hope!
Edited 19 time(s). Last edit at 01/08/2019 06:48PM by RDMG.