Thursday, 9 May 2013

2012 Sprint engine project begins

So having decided not to spend money repairing the old 8-valve engine I had to find a complete Sprint engine more or less ready to go in.  Some asking around on forums turned up an engine in Chipping Sodbury, only a few miles from me, which sounded suitable.  Speaking to the owner I found out it actually came from a TR7 which had fallen apart around it!

When I went to collect the motor I found out just how heavy these things are - or it may be I am getting old!
My long suffering mate Chris came with me and we only just managed to lift it into the back of my estate car.

I had borrowed an engine stand so we got the engine set up on it to have a good look at it.

First impressions not too bad but a couple of concerns soon arose.
The seller had told me he could never stop it weeping oil around the back of the sump and I quickly found the two bolts into the aluminium crank seal housing would not tighten - the threads were stripped.  Easy to swap the housing but that needed the flywheel taken off and I couldn't do that on the engine stand.  I have since seen a neat trick using a modified engine mount on the side of the block so its possible to get to all parts with it on a stand - next time then.
With the sump off the bottom end all looked good so it went back together and I turned my attention to the water pump.
Taking off the cover I found a 12 vane pump, excellent - but it was a 6 vane cover !!!  Again easy to swap but I started to wonder about what else I would find.

The carbs looked pretty dusty so I decided to give them a good going over with an overhaul kit.
Grimy carbs as received

I also got rid of the old waxstat jets at the same time. It was quite a nice and satisfying job completely stripping and cleaning the old carbs and they ended up almost good as new with their new butterflies, jets, needle valves and gaskets.

One of the fiddly bits to putting the Sprint engine in a TR7 is to sort out the heater pipes. My new engine still had Dolomite heater fittings so the previous owner had obviously bodged the pipes somehow ( yes, another bodge) but I wanted to do it properly. 
One heater connection joins to the water bypass pipe that runs along under the carbs.  I just used a standard TR7 bypass pipe here, only had to swap the olive fitting where it screws into the manifold.

The real factory TR7 Sprints had a special outlet casting fitted on the back of the head but these are super-rare so most folks use a made up version. Rimmers or S&S Preparations will sell you one which is just a standard Dolomite Sprint blanking plate with a standard plumbing outlet screwed and/or welded to it, see picture below. It looks a bit crude but works really well.

The picture shows a standard TR7 heater outlet and the modified Sprint one. You will need to re-use the screwed in outlet from the TR7.  After one failure which came out with all the aluminium thread I found I had to heat it up on a camping stove to avoid stripping the thread of the outlet.
Now all you need are some standard TR7 heater hoses to join it all up - simple.

Looking at the distributor I found it already had a Pirhana electronic ignition fitted so I would need the amplifier module to go with it. I also tested the vacuum unit by the good old sucking method and found it didn't move at all.  Searching around the web I found a Pirhana module on Ebay at a good price but the vacuum units proved to be nil stock at all the usual suppliers.  More searching and I eventually found a new old stock one at Mick Dolphin. Nice genuine bloke and good to deal with.

So finally I had a Sprint engine fully assembled and ready to fit

Please ignore the Speedograph air filters, they were just some new ones I had lying around and put them on whilst the engine was being fitted.  The engine runs on K&N filters now its in the car.

( The Speedographs are new and for sale in case you know anyone wants any for a Spitfire/MG/ etc )

The engine came with a scruffy but OK mild steel exhaust manifold so that went on.

Having experienced how heavy the bare engine is  ( around 140kgs I read somewhere )  I decided to buy myself a decent hoist to install it, especially bearing in mind it would be going in with the gearbox attached to it as well.
I decided to buy a 1 ton folding crane which cost £150, because I think when you have 200kgs of metal swinging in the air above your shiny paintwork you want to trust it to stay there. It also came with one of those adjustable leveller gadgets which are essential to tip the engine to the steep angle you need.
Trusty mate Chris assisted again and it all dropped in pretty easily leaving me to connect up all the fiddly bits over the next couple of days.


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