TR6 1972 CP Full nut and bolt rebuild - (Chapter 9)

So whilst all the bodywork was happening, there were a few other aspects of the build which I thought would make sense to get moving on to save time later, one of these being the engine. Oh my God… how many options!?!I'm used to driving pretty quick cars, so my initial thoughts were that I wanted a fully race-prepared engine… forged pistons, uprated con rods, high lift race cam, ported and flowed Stage III head, aluminium lightened and balanced flywheel… etc. etc.. You get the picture, basically 'the works'. Upon further investigation though, it became apparent that not only are some of the above completely unnecessary for the road, some would actually make the car far less drivable in an everyday situation. Let me walk you through some of the major work done on the engine, and my choices and decisions…

Pistons – Forged pistons are completely overkill for road use from what I can work out, unless you are planning on running a turbo/supercharger or looking to run 200+ bhp from the engine. That's without mentioning the fact that you could buy a good set of Nural pistons for the price of 2 forged ones. Obviously we replaced the rings as well with the new pistons

Con Rods – Worthwhile investment to get a decent set I thought. I bought some for around £300 for the set. I also invested in some ARP bolts to go with these too.

Crankshaft – Reground and balanced

Flywheel – I swayed against putting a fully lightened aluminium unit in as again, for road use, carefully lightening and balancing the original unit seemed to be the preferable option from speaking with the experts in the field.

Cams – From what I can make out, there's a trade-off here… do you want the extra lift and potential power offered by a high-lift cam, but then it runs like a bag of nails at lower revs, or do you want a nice balance of power whilst also having a smooth engine when idling? I went for the latter and purchased a 150bhp cam from Newman Cams in Farnborough (http://www.newman-cams.com/)… Ken was very helpful and once I had explained what I was looking for, he guided me towards the less extreme option. I also bought a set of followers from Newman as I understand it's better to get cam and followers from the same source.

Timing chain and tensioner – For me, it made sense to replace with new items considering the extent I was going to with the engine rebuild.

Aluminium sump – I didn't think it necessary to fit an oil cooler as I wasn't planning on taking the car out on track, but I figured that the additional capacity of an aluminium sump, and the better cooling would probably be a good thing. I purchased the sump from SC Parts (although it's available from a number of sources), and I don't know whether it's just this model or all of the ones that are available, but it didn't fit that well and needed some modification in order to get it to fit over the new oil pump and sit properly.

Cylinder Head – I took the head down to Classic and Modern Engine Services in Bracknell (http://cmesuk.com/) and following a good chat with Toby, again decided that a fully-blown ported and flowed Stage III race head was probably overkill. I did however go for a Stage II skimmed and polished head with replacement hardened valve seats (unleaded conversion), bronze guides and new valve springs. I was very tempted with a set of roller rockers as they just looked fantastic, but decided against this as again, this was simply overkill for a road engine (I'd also need to find a Perspex rocker cover as it would be criminal to not have them on show). I therefore just reconditioned my existing rocker shaft assembly. I also invested in a set of ARP bolts for attaching the cylinder head to the block.

Once fully assembled, the engine was also balanced to try and reduce any detrimental vibration

Here are some pictures of the process…

Engine block stripped down and cleaned ready for painting