John Simister
John ponders whether to repair or replace his engine
John’s full of seratonin as he ponders whether to replace or to rebuild.
Admit it. You like spending money. Even when you’d rather not, the act of doing so makes you feel good. What I’m referring to here is the serotonin release in the brain, the feel-good buzz that happens when you’ve just ordered a shiny new piece of motor car from a specialist or, even better, you’ve found a part you think you need on ebay at a price hard to resist.
When caught up in this euphoria of parts purchase, it’s easy to act too hastily. Then, if plans change, you’re stuck with bits you now don’t need even though you bought them with the best of intentions. Here’s how it can go a bit wrong, using my recently bought 1972 Rover 2000 TC as an illustration.
As it happens, this speedy machine tailored for fast-moving executives of half a century ago soon turned out to be anything but. Despite an assiduous rebuild of its unfeasibly large SU carburettors and painstaking attention to every pace-influencing setting (except one, which I’ll reveal later), the Rover was getting ever more hopeless, embarrassingly so, at tackling hills. The fuel consumption – of expensive super unleaded, thanks to the high compression ratio – was also shockingly high.
Under pressure
A compression test showed every cylinder to be around 30psi down from the minimum figure given in the manual. Some say these engines are prone to burning exhaust valves, and some replacements don’t last long, so I jumped at a set of NOS valves of correct super-tough TC spec on ebay. There’s been an occasional bearing knock on start-up, although oil pressure is otherwise fine, so I swooped on a set each of main and big-end shells at a bargain price on the P6 Rover Owners’ Club stand at the NEC.
The engine’s steel side plates (a P6 oddity) had been re-made by the previous owner in flat steel, so I needed the correct deeply sculpted ones that would make the engine smoother and quieter (more rigidity, less noise radiation). Right-hand ones are hens’ teeth, but luckily I managed to find a NOS pair. Then I took the cylinder head off.
Hmm. The inlet valves were beyond grinding-in, so I needed a set of those, too. And eight new valve guides. And I’d better get new timing chains and tensioners as the old ones were clearly worn. I looked at the bores. There was an obvious wear ridge in each of them, more than I’d expect at 66,000 miles.
But it had been blowing no smoke and using no oil. To rebore or not to rebore? Oversize pistons for a 2000 are frighteningly expensive… and then I saw a set of standard-size Hepolite pistons for a 2200 on, yes, ebay for a fifth of the cost. I’ll get my block overbored to take them and get a more powerful engine into the bargain. Click. Done. It felt good.
The times they are a-changin’
I cleaned up the head. And at that point, everything changed. I could now see that the aluminium around number three exhaust valve seat was badly eroded, exposing the outside of the seat that could be in danger of dropping out. This called for a welded repair… or maybe a secondhand 2200 TC head that has bigger exhaust valves to make better use of the increased capacity. One of the P6 parts suppliers I use could sell me a head for £200 or the whole engine, believed ‘good’, for £300. I opted for the latter, not least because I had now discovered that the 2200 pistons use different conrods.
No sooner had I arranged this, carriage and all, when a lovely man on the Classic Rover Forum offered me a 2200 TC engine of unknown condition in return for a charity donation. This would have been perfect, but it was too late to abort the one
I’d bought. Too hasty, again. So now I have an engine that I could slot straight in, and if it turns out to be good, I have a pile of un-needed and expensive bits.
Or do I build up an engine as I intended, use all my new bits (I’m getting the exhaust valves exchanged for the bigger ones) and enjoy the perfection that would result? It would be far more work, but just think of the serotonin rush.
As for that other pace-influencing parameter hinted at earlier, I discovered the valve timing was retarded by as much as 10 degrees. It’s possible that the sluggishness and thirst were down just to this all along, but let’s not go there. It would be a shame to spoil the serotonin euphoria.