Rover Holic

An engine made for a lightweight car, the 215 was GM's first engine to use aluminium for both heads and block. It came in mild two barrel (155hp), stronger 4 barrel (200hp), and sporty turbocharged versions (215hp). It had an over-square bore/stroke ratio designed for high rpm potential (3.5 x 2.8). It ran compression ratio's from 8.8:1 up to 10.75:1. It had permanent cast iron cylinder liners that stayed in place and didn't leak. A complete engine including exhaust manifolds, intake carbs and all weighs in at a whopping 318 lbs in stock trim. You can carry the block around under your arm, and each head - complete with sparkplugs - weighs 19 lbs.

In later years it was produced by British Leyland for Rovers (called a 3500 V8), and was even offered under that marque in multi-carb and EFi versions. It was a design of sufficient quality and modern engineering that Rover used it until 1986 virtually unchanged from the original 1961 engine and then simply stroked it and continued to us it to current years.

So you say, why didn't GM continue using the engine? Why haven't I heard much about it for so many years (if ever)? Well...there's an interesting story about this. It seems that when GM started up-sizing cars in 1964 the 215-cube engine was thought to be too light and too small to push the larger Specials around . Since they planned to enlarge the engine (first to 300 cubes and then later to 340 cubes), they also looked at the cost of production before re-tooling. At the time the manufacturing techniques for aluminium were not as well perfected as today, and to get the quality and durability required, the cost was higher than using cast iron (the cast iron liners and valve seats are examples of additional steps and costs). So GM opted for the better production value and went to cast iron.

The new engines were quite similar to the 215's, using the same cams and valve components, and designed so close that even heads and cranks have some interchange with a little ingenuity. But now GM had an out-of-production engine on it's hands - along with all the tooling to build them - after a very short (three years) run. Even with the application of earlier components in the later iron engines, it was not very cost effective.

Along came British Leyland. They saw potential in the little V8, and calculated that it would fit nicely in a somewhat smaller than the average American car they produced called the Rover. The Rover was upscale enough to demand a well made engine that was smooth and reliable enough to please its higher-end buyers.

It was also a time when BL was not doing as well financially as it once had, and I suspect that the purchase of this little 215 looked to save them a ton in R&D, testing, and de-bugging common to new engine designs. A deal was struck and BL got ownership of the engine design and all the tooling to go into production.

As I understand it, years later (after the Corvair was killed by over exited polititians and panicky journalists) GM started looking again at producing another quality small car and before long the 215-cube engine was top of the list for power. When they went to BL though, GM hit a wall. BL was willing to produce engines for GM (at a cost of something like $1,250 per unit), but did not want to relinquish the whole deal. GM countered by offering to build engines for BL (around $800 per unit), but the state of the British economy and the strength of the labor unions made that politically out of the question. In the end used the old 231 V6 instead and BL used the 215 V8 engine untill 1986. In 1987 BL stroked the engine to get 3900 cubic centimeters.

New Life

Over the years there has always been certain groups that found the 215 to be the perfect item for use in a variety of rodding and racing forms. They've been successful in Endurance racing, Euro Sedan racing, Grand prix and sand racers. (The Repco-Brabham engines are DOHC-modified 215 Olds engines, which won a Grand Prix championship with Jack Brabham driving) The key has always been to use this engine in lighter vehicles where a lightweight but strong engine could dramatically enhance handling and suspension response without destroying high-performance potential.

While I would not want to pack a 215 under the hood of some rods, I can see definite potential in rods in the 2500lbs or less category. If you think about it this includes a lot of iron built before about 1935. It is a good looking engine with the smoothness of an aluminium casting, so appearance is not a problem. There are still performance parts available to get the most from the cubes. And geared right to suit the short stroke, it can offer surprising performance.

It can easily manage 200bhp with minor tuning and much more if you want to go with some extra machine work. for example, a 215 can be stretched with the use of a 300-cube crank and rods although it means a bit of machining costs. It's also safe to bore out to .060" over the stock 3.50". In fact if you do bore through the liner and expose aluminium at the bottom of the cylinder, it is still known to work fine as long as the rings remain above the cut through area. To go larger you simply cut out the liners, mill the block for larger dry sleves, and your ready to rock. (One version uses 305-inch Chevy liners - with 3.756" standard bore and pistons).

Valve size is limited, but when you consider the cubic inches they've got to handle this does not appear to be a major limiter of power. You can increase the size of the valves - especially the Olds using SBC exaust valves.

There were some early overheating problems caused first by the lack of quality anti-freeze suitable for use in aluminium, and second, the aluminium used for the heads was a bit soft and susceptible to damage from over torquing and failure to use anti-sieze. There is also a cooling problem that develops if the heater connection at the rear of the intake is blocked off - It won't allow the right circulation to the thermostat.

Gary Cross (Melling tech guy and life-long racer) has one of these baby Buicks in his 1,400-pound , mid-engine racing dunebuggy. it's bored .040", precision balanced with a 232/242 @ .050 and .501 lift cam, tri-Y tube headers, polished ports and runners and olds heads. Intake valves are 1.6 SBC's (.070 over stock), exhaust valves are 1.5 SBC's cut down to 1.4's (0.060 oversize). Springs, retainers, guides and seals are all SBC and the spring pockets are modified to fit. He uses a stock four barrel manifold extensively modified for use with a 600-cfm Holley. Compression ratio is only 9.1:1 but the engine puts out between 240 and 260hp depending on the tuning and weighs just 280lbs with carb,starter, manifolds and alternator included. He red lines at 7200 and it regularly sees the tach pegged.

Another 215 expert, Charlie Thomas, has been playing with Buicks for many years, as well. He's used them in street rods - especially for T-buckets and has found them to be an excellent way to get good performance and surprisingly nimble handling. For that reason he generally has baby Buick parts and some complete engines ready to use at his rod shop -Rods-N-Racin' (Charlie was generous enough to dismantle one of his stock engines to make the photography possible).

He recomends using 3.90:1 or 4.11:1 rear gears with a standard transmission to bring out the best in these engines. The original cars were often sluggish because they were geared too high to let them really cut loose. The trans would shift before the engine got into the meaty part of its power curve unless you held the pedal to the floor all the time.

Thats the only shortcoming I've recognized: There are limited automatic transmission choices for these engines. The Buicks came with the Buick Dual Path trans; a two speed, air cooled automatic that few have found to be appropriate for anything more than a senile citizens Sunday sedan. The Olds used the three-speed Hydramatic, but it is also woefully outdated and unique to the F-85's. You can plan to find or make a trans adapter or opt for any of GM's fine standard transmissions to complete your drivetrain. Don't look to the later engines for help either, because the 1964 and later engines went to the B-O-P universal patterns on the bellhousings. Also keep in mind that this engine will not like to be lugged, so gear it up to use the fast revving potential inherent in the 2.8" stroke (Charlie says the crankshaft in this engine could be more aptly referred to as a wiggleshaft).

Building a Baby Buick

I've discovered that rebuild parts are still a common item and on current listings for such major quality suppliers as Federal Mogul, Clevite, Melling, Fel-Pro and many more. Obviously there is no shortage of parts except for Olds valves which are out of production, and those can be replaced with modified SBC parts.

On the other hand performance parts are less common. Offy still shows listings for both a four-barrel and a Tri-Power manifold for this engine as well as finned aluminium valve covers for both the Buick/Rover heads and the Olds heads. A lot of what you'll find will be used parts or one-offs. Trans-Dapt still makes adapters for a variety of standard transmissions including Flatheads and GM three and four speeds.

Among the OE parts that are interesting are the cast headers from the 340 engines which will bolt to the 215 and have a larger port size. This could be very helpful if you plan to enlarge the exhaust runners and pick up some flow potential

Buick and Olds heads will interchange but are different. The Buick head is a polysphere design while the Olds is a wedge-type. In either case only conservative machine work is possible because the casting is very thin.

As mentioned before, a 300 crank will fit into the 215, but requires turning the mains down to fit the 215's main bores. The rear main seal also requires milling or the crank modified. An alternative is to get a crank from the later 3900cc Rover engine (made from 1986 to current), or even the whole engine.

On the other hand, if you are planning harsh duty for your 215 you can use a set of SBC rods (same journal size but need a slight side trim on the big ends) in combination with a set of 194-cube six-cylinder Chevy pistons (available as a light-forged item instead of the full skirt cast OE pistons). It's a cheap way of getting less reciprocating weight and better strength.

Heads will technically interchange with later engines, but there are problems. First the 300 and 340 heads are cast iron. You'll find they add another 60 pounds to the engine. In addition, the cast iron heads were designed to use with a heated intake and have extra water passage openings on the intake face and the block face. While again these can be blocked off and re-machined, I question how the extra weight and expense can be justified.

Intakes also do not interchange as the blocks were modified from the separate valley cover design in the 215 to the integral style in the 300 and 340. Also you MUST use the heater port at the rear of the intake manifold. It is used to purge air from the system and if blocked can result in the thermostat not opening and the engine overheating.

Timing cover assemblies are a miss-match despite the use of the same timing set throughout. The oil pump is also in the front cover. It turns out that later V8 pumps and 231 V6 pumps will work fine as long as you use the relief valve assembly from whatever pump you originally had. Melling offers a rebuild kit that details how this is done.

The 215's have a separate valley cover which is also the intake gasket. This stamped metal part is held in place by the intake plus two bolted clamps(A and B) the 300 and 340-cube engines went to a combination intake and valley.

The front of the engine is simple enough with the fuel pump on the drivers side(A) the oil pump and the filter adapter on the passenger side (B) and three accessory mounting holes in each head (D,E,F,) to make brackets simple. Timing cover and water pump are also aluminium

The four bolt holes for the valve cover identifies this head as the Buick/Rover item.The Olds heads have five bolts and are a completely different casting. Notice that these engines use a rocker shaft assembly with aluminium rocker arms. The rockers were available with both 1.5:1 and 1.6:1 rocker ratios.

Angled plug heads? Yep. The Buicks had 'em a long time ago.Charlie added the Crane retainers and slightly stronger springs to work with the Crane performance cam. Other important items for street rodders: The starter is on the left a.k.a. SB Chevy and the motor mounts (A) are mid engine about where the X-member will be.

cast iron 340 head on the left has two additional water passages (arrows) and larger valves than the 215 head on the right. Other than that, the gasket surfaces are about identical. The fact that these must be plugged and the question of maintaining correct cooling flow makes me wonder whether the cast heads on the aluminium block is practical. The combustion chamber design is a polysphere on the Buick/Rover (shown) and a wedge on the Olds.

From the exhaust side, the cast iron 300 and 340 heads and the 215 aluminium heads are twins. The only obvious difference is the port size and the potential for enlargement. The less obvious difference is the weight: 19lbs comlete for the aluminium head and 49lbs for the cast iron. The added weight and machining will persuade most that the aluminium heads are the best for the 215-cube engine.
Look close at the area around the bores (arrows) and you'll see the evidence of the cast iron liners in this aluminium block. The liners are cast in place and will typically stand a .060" overbore. If you want to go larger there is a LOT of aluminium under it and you can use larger dry liners. Be careful cutting the old out though, as too big a cut can damage the boring tool or cause the liner to come out in chunks.