Buick/Rover/TR8 Aluminum 215-V8 Conversion

By Will Bridges (USA)

Published: 22-may-98

See also extract from HOTROD magazine (Aug, 1985).

Date: Fri, 19 Jan 1996 21:15:40 -0800
From: bridgesw@ix.netcom.com (WIL BRIDGES)
Subject: TR7-V8 Conversion Details
To: tr8@mercury.lcs.mit.edu

Attached is a rough draft memory dump that I have intentions of
cleaning up and sending to Hot Rod Mag someday to see if they have any
interest.  Hope it is of interest to this group.

Wil Bridges
1977 TR7-V8 Rover Conversion   
19 January 1996
bridgesw@ix.netcom.com
 

In the summer of 1993 a friend presented me an article published in your 1985 ABC issue of ABC Magazine detailing how to rebuild the humble little Buick aluminum 215 V8 into a potent powerplant for street/race use.

Since I had been driving a 1977 Triumph TR7 for some 8 years and 280,000 miles, I saw a chance to build my own TR8 engine and convert the wimpy little TR7 to a real roadster.

I began the process of collecting three or four 215's. four sets of '64 Buick 300 aluminum heads and three 300 cranks. I could not bear to pass up on of these little engines in the local "Pick Your Part" salvage yards. As luck would have it, another friend told me of two 1980 Rover 3500 SDI sedans for sale as a pair. This engine is the 1961-63 Buick 215 with some minor block, head and rocker arm assembly changes. The nice thing is, it is multiport fuel injected and solved my problem of smogging in California. The friend that gave me the article decided he wanted a Rover to drive so we bought the pair, he got his driver and I got an engine, transmission, smog equipment and a 3:08 ring /pinion and cluster gear set to replace the 3:90 gear set in the stock TR7 rear end. Obviously, I now have a surplus of 215 parts!

This began a 14 month saga of my friend rebuilding his Rover and me building the engine of my choice based on your menu of part mix and match. I decided on the stock bore, 300 crank and heads, Chevy 283/327 rods, Vega pistons and Nova flywheel (more about this later on). This combination yields 4.3 liter displacement.

Since there is some machining involved with this project it gave a a wonderful opportunity to justify to the wife the purchase of a used 15 X 40 inch metal lathe from the local Maritime Academy Training School who was updating their machine shop.

The selection of engine internals was heavily influenced by the fact that this car would continue to be my daily commute vehicle in San Francisco Bay Area traffic. Of 32 miles one way, about 20 miles was stop-and-go clutch-foot numbing traffic, so, I wanted an engine that would behave decently in that environment but still have impressive go-power when stood on.

The choice of fuel system was the stock Rover (Lucas) system and control unit with the modification of machining a new adjustable top for the fuel pressure regulator so the fuel pressure could be increased from 36 psi to about 45psi at zero vacuum. The fuel pump is from a 280Z just because a new one was available at the right price. I also used a stock TR8 inertia switch in-line with fuel pump supply voltage.

The Cylinder heads selected were 1964 Buick 300 aluminum heads( slightly larger intake valves than stock Rover heads) milled .060 to produce a cylinder head volume of about 43cc and yield a compression ratio of 9.25:1. The rocker arm assemblies were from the Rover heads as the rockers are significantly beefier. I wanted to use adjustable Volvo rockers (a nice light-weight steel unit) and had machined a set of inserts to match the Rover shaft diameter but closer measurement of the rocker ratio showed t hey were 1.5 and not 1.6. The cam had already been ground based on a 1.6 ratio. The rocker assembly supports were shimmed .045 to give good valve stem end wipe geometry and about .050 preload of the hydraulic lifters. The lifters are aftermarkets that are supposedly good to 6800 RPM. The cam profile selected is identical to stock Rover and Buick 215/300 with the exception that lobe height (intake and exhaust) was increased to yield .440 lift at the valve and take advantage of the slightly larger intake valves and assist in venting exhaust through slightly smaller exhaust valves. To contradict the immediate preceding statement, the flow test of the Buick 300 heads show that between .300 and .440 valve lift that little gain in air flow is realized. The 300 heads have significantly larger diameter intake and exhaust ports than the Rover/TR8 heads-they must really be restricted. Original intake valves were retained and a set of exhaust valves were machined from used junk yard valves( gimme a break-I just bought a new lathe). Additional head work only included light port polishing, slight relieving in the intake port area for injector spray clearance and valve guide reconditioning (note no mention of replacing the valve seats---leaded vs unleaded).

Block preparation included usual cleaning at ABC Machine Shop in Dublin, Ca. and the machining of an adapter( oh darn) for the rear main oil seal. The Rover crank is larger in diameter than the Buick 300 crank at the oil seal area so the adapter/spacer is needed to house the Chevy big block rear main seal. The top of the adapter is screwed to the block and the bottom is secured to the rear main cap as in your article. I elected not to bore the block oversize this go round so the cylinders were only honed to assist ring seating. Using the Buick 300 crank required reducing main journals a total of .200 and was the single most expensive expenditure in the project ($200 at ABC Crank regrinding in San Leandro, Ca). The block was very slightly relieved in one spot to allow crank counterweight clearance. Not sure if this is necessary with the Buick/Olds block. All freeze plugs were replaced- since I could not readily obtain the rear cam plug I had to machine one (oh darn).

Other block components were stock Vega pistons and rings, late model 283/early 327 rods milled a total of .100 for journal fit on the big end. The bore for the Vega engine is listed at 3.501 inches-between this and not too much cylinder wear in the Rover engine, piston clearance ended up at .0025-.003 inch. Main bearings are stock mail order Rover/TR8, rod bearings are stock 283/327 bearings machined (oh darn) to make a wide as possible bearing surface and chamfered for crank filet clearance. Th e stock Rover timing chain/oil pump/distributor housing was discarded in favor of an early model Buick V6 housing. This allowed using a high capacity '64 Buick 300 oil pump and direct replacement of the Rover (Lucas) distributor with a stock post '74 Buick HEI distributor. The stock Rover oil pump is about 25% greater capacity than the stock 215 but about 15% smaller than the high capacity Buick 300 pump. Pump by-pass pressure is set at about 50 psi hot at 2000 rpm. Oil delivery channels in the Rover block and pump housing were left stock dimensions. The rope oil seal in the Buick front cover was replaced with a press-in neoprene seal. The Rover pan did include a windage tray that was retained as was the stock oil pickup.

Using the 300 crank required modifying the flywheel as follows to accommodate using the stock Rover/TR8 5 speed gearbox and bellhousing. The Rover flywheel ring gear was retained and installed on a remachined surface on a Chevy Nova flywheel. This flywheel has an offset toward the block that made it easy to reposition the starter ring back into its original relationship with the starter. No starter mods were needed. The machined surface on the flywheel was left about .030 larger than i.d. of the Rover ring gear. The ring gear was heated in an oven at 450 degrees for an hour then shrink cooled onto the flywheel with no other means of retaining. The clutch disk side of the flywheel has a stepdown where the clutch disk mates. The step was machined off and the remaining groove in the flywheel surface was left. The stock Rover/TR8 clutch disk diameter ends at the groove and does not affect clutch performance. One of the flywheel-to-crank mounting holes was relocated (enlarged) about 1/8 inch to mate with the corresponding thread in the crank. The stock Rover clutch cover mates perfectly with the Nova mounting holes. The three clutch cover locating pins must be redrilled.

The 300 crank/Nova flywheel combo results in the flywheel clutch surface extending into the Rover/TR8 bellhousing an additional .200 in. from stock. There is adequate clearance inside the bellhousing to accommodate the flywheel/clutch cover combo with no interference and the hydraulic clutch actuation mechanism (slave cylinder,pivot pin,throwout arm,throwout bearing,etc) needs no modification.

The engine components were fully balanced by ABC Machine Shop using the stock Buick 300 harmonic damper and appropriate drillings in the flywheel for external balance.

I was lucky enough to find a TR8 in one of the Bay Area self service junk yards--needless to say I stripped it from bumper to bumper. This find shortened the install process immensely by using stock components vs fabricating many brackets, motor mounts, and other fasteners. I did not change to power steering as the increased front end weight is minimal and steering is not really much affected.

The Lucas alternator was discarded in favor of a GM 78 amp unit. Since just the radiator fans draw some 32 amps when running at high speed (80 amps on startup) a 100 amp unit probably would not be over-kill for an A/C equipped car in hot climates. For a couple of months I had both fans running at high speed any time they came on and they slowly cooked a 68 amp alt.

The distributor has 12 volts supplied through a relay that is energized from the ignition switch lead for the old distributor. This is probably overkill since I later measured only 2-3 amps consumption by the distributor. There is some interference between the dist housing and block at the front intake manifold hold down bolt. The bolt can be replaced with a oval head or hex head and/or the dist housing can be relieved slightly. There is just enough clearance for the sparkplug wires to clear the hood (touch lightly).

You can also use a Buick water pump and I even mounted a flex fan on the water pump to assist air flow in the engine compartment when radiator fans are not running. The radiator was custom built from a Saab (as I remember-checked out a lot of rad's). It has a high fin density and is a 3 core unit. It was already the right height and only had to cut about 3 inched off the length on the radial arm saw (50 tooth carbide blade) and resolder the end plate. Slightly reshaped the end tanks from a bad TR8 radiator and soldered them on. Used the stock TR8 mounting position for the radiator and stock electric fans wired in a low speed(series)/high speed(parallel) configuration based on radiator temp (180) and high speed if block temp exceeds 190.

I have been driving the engine for some 18 months and 37K miles with the following problems showing up.

  • At about 8K miles the #3 exhaust valve spring broke( yes they were the original '64 Buick springs) so I replaced them with aftermarket springs that at installed/compressed height have spring pressures of 95/200 lb.
  • At 18 K one of the bolts holding the even bank rocker arm assembly stripped out (increased spring pressure?) allowing some flexing and eventual breakage of the rocker arm shaft before I could get it home in commute traffic. I re-tapped the hole to the next larger metric size and reused one of the Rover shafts. I was very disappointed with this shaft breaking because I was lucky enough to find two NOS 300 Buick shafts to put the beefier Rover/TR8 rockers on and now have to go back to a used shaft. That's life!

The last 21K miles have been problem free as far as the engine rebuild/conversion goes--had to recondition a throttle position potentiometer that had worn through the resist compound and was causing a slight flat spot when running at steady throttle pressure. Also replaced the ignition module in the GM distributor (yeah it was used too), it would tend to quit entirely for about a half second on really hot days.

Of course, considerable time has been spent tweaking engine timing (currently 10 deg BTDC) and choice of sparkplugs. I would like to experiment with advancing cam timing some 2 to 4 degrees but it is such a pain to do. I don't have verified specs but, 0-60 mph seems in the 5.5-6 sec range. The engine winds 6000 easily and still has significant "set you back in the seat power" when accelerating from 100 mph. I estimate top speed to be 150-160 mph.

One thing is for sure--it is a kick to drive and it gets 20 mpg in commute traffic. I can't wait for the next rebuild, maybe bore and re-sleeve it to 5.0 liter!