Engine and Transmission Tech

Hello all, question for you engine guys out there. I originally bought the Olds 215 engine to work into the B but had issues finding pistons sized to fir the already bored engine, so picked up a Rover 3.5 and wonder if the bearings, crank, etc will swap or if the Olds issue factors in. The Olds had a bunch of new parts that came with it, which made me wonder if I would be able to use them or not. Sorry not lots of detail, broken arm and typing is great fun.

Thanks!

Most of the internal parts are interchangable except Olds rocker assemblies are unique. The main difference lies in the combustion chamber volume, as the 2bbl Olds heads have a larger combustion chamber. Rover uses the same size as Buick and varies the CR with different pistons. Olds varied the CR with the heads and used the same pistons for both low and high CR, so you could bump up the compression by changing the heads. These would be the same as the high CR Buick pistons and for a time they were unobtainable but I think suitable substitutes have now been found. The Olds 4 bbl heads have the same volume as the Buick and Rover and any of those pistons will work fine. The lower compression pistons will also work with the 2 bbl Olds heads but will give a much lower CR. Any 10-1/4 CR Buick or Rover piston will give 8:1 with the 2bbl Olds heads. The Olds Jetfire also used the same volume as the Buick head. Buick and Rover heads will work fine on the Olds block, but not the other way around as Olds used extra head bolts. The best thing is to CC the chamber. 37cc comes to mind as the number to be looking for. Aside from the heads everything else is interchangeable.

300 heads also fit and many other parts from the SBB line can be used. This includes 300, 340, and some V6 and 350 parts as well. But attention must be paid to the details. For instance, on the 340 thread '64 300 heads (52cc chambers) are used with a '67 340 block and 350 bore size. With a minus .005" deck (pistons stick up .005) and a 22cc dish this gives a 9.7 CR using a .050 gasket and .045" squish. But the pistons and rods are custom. The 340/350 crank has been used with the Rover P76 block, and the 300 crank with the 215. The 340 crank can be made to work in the 215 also but clearances are tight. The 300 and 340 blocks are 5/8 and 1-3/16" taller respectively and 80 and 82 lbs heavier. Not a bad trade off.

Jim

When I re-built my Rover 3.5 I ordered all the parts as if it was a Buick 215. 35000+ miles and no problems at all.

Also the gaskets in the Rover are used in the following engines. So if you can't find a part/gasket for a Rover try one of these instead.

Buick Skylark 61-63
Buick Special deluxe 61-63
Buick Special 61-63
Rover 3500S 69-71
MG MGB V8 75-77
MG MGB MK1V 75-77
Triumph TR8 80-81

Well, sounds like if I use the heads that came with the Rover I can use many of the parts from the Olds engine which is really great to hear. The Olds engine came with a set of high compression heads which I don't plan to use since I want to use it for more daily run around which means I want more gas mileage and want to run a lower grade of gas if possible. I believe it was being built to be a higher compression engine because it has a set of 300 connecting rods and the bore on the pistons was a different set up than a normal Olds engine. The pistons was where I was thrown off, I would need to send the Olds block back to the shop and have it sleeved and bored for another piston since I only have 5 of the 8 pistons that are usable and after calling all over the US I could only find 1 piston out there left in someone's stock.

You may have to do some calculating and measuring to see what will work best for you. Don't forget the old rule of thumb that an engine with alloy heads can generally run one point higher CR than iron heads, so if 9.5 is good with iron, 10.5 may be the same with alloy. If you have the high CR Olds heads they should be about the same as the Rover heads so I'd use the ones that are in the best condition. Also, consider things like valve covers. Olds heads use beehive springs and Comp Cams has come out with a line of those and may have one that will fit. But finding valves may not be easy. You can often find complete piston sets on ebay, Rover, Buick or Olds. Watch the compression height. Longer rods (300) can only be used with a shorter piston. This link shows some good calculators: [www.doverusa.com]