2019: September part 1. Trying out new sprint motor

With the engine in and running I had a little tinker to tidy up and check settings etc.  The fancy (and expensive) Mangoletsi throttle linkage seems to be well engineered and was easier to fit than it looked. The engine idled quite nicely and I set the ignition advance at tickover to 10 degrees BTDC as a good starting point.

10 degrees BTDC using the Snap-On timing light.

Driving the car it felt good and responsive and with that fantastic growl from the carbs when you floor the pedal.  Almost worth changing the engine just for that sidedraught roar!  I booked a test in a couple of days time with Martin at Maynard Engines on their rolling road in Nailsworth to check what was really happening with mixtures etc.  A couple of days later I took the car over there and we strapped it down on the rollers.

First run showed it was actually set up quite well.  I had used the carb settings recommended by Matt at Eurocarb who are the Dellorto main agents in the UK. For the anoraks amongst you this is what he suggested as a starting point:-

Dellorto 45DHLA
Chokes    36mm,
Main jets  145,
Emulsion tubes  7772.5,
Air correctors  180,
Idle jets  60,
Accelerator pump jets  42.

I have been reading up on the carbs to try and get a better understanding of what all these numbers mean and how they all work together. This book was my main source of information.

I wouldn't claim to understand them now, but I do have a bit more of an idea than when I started.

Martin found it was running a little rich at the bottom end then went a little lean at the top so he made a few changes. We were not trying to achieve ultimate power but needed it to be a nice engine to drive on the road.

Turns out that folks have differing opinions about setup, Martin prefers to run bigger spec emulsion tubes so changed them from the recommended 5 to an 11 which gave a richer acceleration phase. They have more holes and in different places - see picture - and it certainly worked to make the top end mixture much better.

Dellorto Emulsion Tube Range from 1 ti 17

Driving the car afterwards it certainly felt smooth, with plenty of torque at low revs and pulling all the way up through the range.

Final carb settings are:-
Dellorto 45DHLA
Chokes    36mm,
Main jets  175,
Emulsion tubes  7772.11,
Air correctors  135,
Idle jets  60,
Accelerator pump jets  42.

2019 August, New Sprint engine going in!

With the engine built I could now call a friend to help with putting it in the car. Engine swaps are a proper two man job so help was needed.  Fred Brunsdon is an old mate from my rallying days and who has serviced for me on lots of rallies was available, so he called by on a Saturday to get the job done.

I had already got most of the old standard motor connectons undone or ready so it came out easily  and the new one was readied to go in.

Ready?

Steady

It's in

The exhaust lined up nicely and it was then just a case of connecting all the usual pipes and wiring.  There was one different pipe because the manifold is not water heated like a standard one so the heater feed goes directly from the water pump outlet round to to the heater inlet. This picture expleins it, sorry about the greasy lens on the camera!

Heater feed direct from the water pump outlet

The carbs could now go on with the fuel feed an I included an inline filter as an extra precaution.  I had decided to fit an electric fan so that was attached to the radiator using the normally supplied fixings through the radiator.  (These fixings later turned out be a poor choice - see Lombard Rally Bath 2019 report).  But it was beginning to look like a proper job

Dellorto DHLA45s on

Air filters and electric fan fitted

View from left side

Filling a new engine with oil and water is always an exciting but nervous moment but nothing ended up on the floor so that was a good sign.  Testing the Lumenition prior to try starting the motor revealed a snag when I found that I couldn't turn the distributor quite far enough, maybe because I had the jackshaft timing a little out, so what to do? Taking the distubutor out and turning it one tooth was too much so I came up with a Plan B.  I decided to modify the distributor mounting adapter plate by adding some additional threaded holes so it allow the distibutor to be turned a little more. Cunning plan, and it worked !

My distributor mounting plate with additonal threaded holes

With the Lumenition all connected I could now get it to produce a spark at around 10 degrees BTDC and I felt comfortable to try and start it. I had already spun it over with the plugs out to get some oil pressure so replaced the plugs and it fired up without too much trouble.  Excellent stuff, so now I let it warm up briefly then cool down overnight so I could re-torque the head bolts/nuts with it all cold.

Next morning I re-did the head bolts/nuts but also found a couple of problems. Main thing was several water leaks.  One seemed to be coming from the temperature sender, one from the usual water pump slot in the block but the main one was on top of the block and seemed to be coming from the pump link pipe.  The minor leak from the water pump slot was not too big a worry as it is quite common with a new water pump and usually settles down.  But it still meant I would have to take the carbs and inlet manifold off - curses!

Evidence of leak from temperature sender

Signs of a leak from by-pass pipe

The temperature sender just needed some PTFE tape on the thread so I did that first then took the whole manifold and carbs off to fix the bypass pipe problem.  I had used a brand new link pipe and obviously with some new "O" rings so that was a bit of a puzzle. Inspecting the link pipe and comparing it with the other used ones I had it appeared to be a few thou smaller diameter in the grooves where the "O" rings sit.  I decided to use one of the good spares and put it all back together with some extra magic gasket then let it set overnight before refilling the system. Everything crossed.

Next day I ran it up to temperature again and things had settled down with only a couple of tiny drips.

Now I needed to run the car for a while to put some miles on it and see how it all worked.

 

2019, July. New engine work back on track

When we got back from holidays I could get on with building the new engine. The pistons and exhaust manifold had been machined so I collected them from Alex at Maynards.

Modified pistons, height reduced and pockets re-cut.

 And now they don't come above the block face!

Modified pistons fitted and more like it should be.

I sorted through my various spares to find the best set of sprockets and guides to use and fitted a new tensioner making sure it was a trusted type - not one of the dreaded Rolon ones that regularly shed the rubber pad like the one is this picture.

Typical Rolon failed tensioner, the rubber pad has come off

I chose the best ones to use out of this lot

Chain fitted with new tensioner, note spacer to aid setting up.

 This was all to do a test fitting so I could make sure there was enough clearance between the valves and pistons when the engine turned over.  I used some Blutack in the valve pockets to act as a check, if it got squashed too thin I would have been in trouble, but all was well.

Blutack in valve pockets to test valve clearance.

Having checked the valves would not hit the pistons I could now fit the head and timing chain stuff properly.  This went well until I checked the camshaft timing marks.  I tried setting the chain in different places on the sprocket and also tried turning the sprocket 180 degrees but there was no way to get the cam lined up properly.

Timing marks are close but not correct.

Next thing was to try using one of my other spare cam sprockets to see if that would give a better result and look what I got, a perfect setting!

That is more like it! Spot on.

Starting to look like an engine.

Next thing with the head on and torqued down was the water pump and cover.  I had a new old stock 12 vane pump which slotted in very easily and a new cover to match so they went on with the gaskets chosen to give the correct clearance .

Heater outlet plate on rear of th head

The distributor that came with the ex rally car engine looked pretty scruffy but testing the shaft for play it seemed in reasonable condition so I thought it would be worth stripping and cleaning to check. Turns out it was in very good condition with no noticeable wear in the shaft so after a good clean up it all went back together and into the new engine.

Looks a bit rough?

But the shaft is in excellent condition.

And no wear in the bearings.

The distributor also had Lumenition installed and it tested OK when I connected it to an amplifier module so that is a bonus.

Distributor and water pump fitted.

Next job was to sort out the inlet manifold for the twin 45DHLA carbs that goes on the engine.Its a new one so has never been used before but a test fit found that it fouled on the water pump outlet. There should be a small gap between the top of the water pump cover and the underside of the manifold.  There is a short link pipe with O rings that fits inside them and joins the two together. I had to file about 1/16" off both the manifold and the pump cover to achieve the gap required.  Best to find out now rather than when the engine is in the car!

Picture showing correct small gap after filing.

I found a piece of steel in my scrap bin that fitted perfectly to hold the flywheel while I torqued up the bolts and fitted the clutch cover.

"special tool" from the scrap bin holds the flywheel

The clutch went on with a new cover and a new old stock competition friction plate that I had bought several years ago and the engine is now ready to fit in the car.

NOS competition clutch plate

STR 0415 NOS competition clutch plate

Engine ready to fit

October 2014, Gathering parts for new Sprint engine

Keeping track of bits with this useful gadget

Got a call from Mark Maynard that my block was ready to collect with its new liner installed and they have done a very nice job.  I spent an afternoon cleaning it off thoroughly in their wash tanks before bringing it home for a spot of paint. The bottom end has also been fully balanced which should help things along.

"New" block ready to start build

Started a little test fitting and tried the timing cover on the block - it was too tall!   Curses.  
Obvious really, they had to face the top of the block when they did the liner and now the cover was left about 10-12 thou proud so I had to take it back to be matched up.

The machine shop had also made up a few tappet shims because the re-profiled cam needs thicker sizes than the standard range so I can get on setting up the head.

  Fun job starts here.

And when all the valves were bedded in it looked like this

 I hope I put the valve springs on the right way up!

 

I don't need to add anything about this picture except the one you need is always missing!

 

The two pictures above show the differences between a standard TR7 flywheel and the Dolomite Sprint one. The TR7 has quite a bit more material on the rear face but the important working dimensions are the same. The Dolly one is also about 2kg lighter so guess which one I will be using?

Crank with the Dolly flywheel all balanced up.

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I bought some posh stuff for the motor as well

Adjustable camshaft sprocket.

 45DHLA Dellorto carburettors

Shiny new manifold for the 45's