Reliant Scimitar SE6A
Nigel treats the Scimitar’s engine to a bottom end refresh
While my Scimitar’s cylinder heads were away being converted for use with unleaded fuel, I decided to take time to delve further into the Essex V6 engine. The dear old Scimitar had been running pretty well before fixing an exhaust leak had escalated into a cylinder head removal job. However, it had been burning a bit of oil, suggesting the piston rings may be past their best. Examining the bores, all cylinders looked good, free from wear ridges at the top or signs of scoring. With the heads already off, I only needed to remove the sump for the pistons to come out.
I figured that after almost 90,000 miles, it made sense to overhaul the engine now, hopefully making it good for many more miles. It’s actually possible to replace all the crankshaft bearings and thrust washers without removing a Scimitar’s engine, so I pressed on into the oily depths of the Essex lump.
The sump dropped easily enough, exposing the crankshaft. Under the car, armed with a breaker bar, I cracked the big end bolts. One at a time, the six pistons could be pushed up the bores until they could be grabbed and pulled out from the top. The pistons and big end caps were numbered and kept in order. Following a good clean up, the pistons proved to be relatively unworn, but the oil control rings had lost their spring and needed replacement. The big end shells looked very slightly scuffed, while the crank pins appeared perfect. Checking crank end float showed no wear. Impressive after more than 40 years use!
New piston rings and big end shells were required, so I headed to Queensberry Road Garage. I’m lucky to have proprietor Nigel Palmer’s advice and parts store so near to home. He duly provided a set of rings and big end shells – all in standard size – and the necessary gaskets. Back home, there was a significant hurdle before the engine could be reassembled. For the new rings to bed in properly, the bores would need to be glazebusted or honed. I called Pacehigh, who import the Us-manufactured Flexhone. Looking a little like a hedgehog on a stick, its shank fits in an electric drill and numerous abrasive-covered balls project on flexible wires at the business end. I
ordered one with 120-grit silicon carbide, sized for the Scimitar’s 94mm diameter cylinders.
The biggest problem would be cleanliness, avoiding leaving abrasive all over the engine’s innards. With block faces and bores wiped as clean as possible, I masked across the top of the vee. Underneath, I stuffed the inside of the block with clean rags to protect the crankshaft. The Flexhone and the bores were coated with oil and I set to work. About 20 seconds in each bore did the trick and soon each cylinder had a dull grey appearance, with a good crosshatch finish, ideal for oil retention and bedding in the new rings.
Building the engine back up started with checking the gaps of the new piston rings in the bores, then fitting them to each piston. Thoroughly oiled, each piston was held tight in a ring clamp and tapped down into its original cylinder, then the big end was fitted before moving on to the next piston. The big end shells and journals were liberally coated with assembly lube, and the cap bolts torqued to 25 lb ft.
Next day, in went fresh coolant and a gallon of SAE30 running in oil. A short spin on the starter with the spark plugs out produced healthy oil pressure… then plugs in, and the big V6 fired up immediately. Having covered just 80 miles after its ‘dirty’ rebuild, the Scimitar is purring along. I can’t wait to get to the first oil change and complete the running in process! ■ practicalclassics@bauermedia.co.uk