Dolomite sprint Block

[warrenphill]

Hi Guys

I am in need of your help and knowledge please .
I have bought a Dolomite sprint in disrepair complete with a number of engines that have been dismantled,
one of the blocks has a large threaded bung in the side of the block casting and the other two has round piece in the casting but no threads for a bung,
could anyone please tell me the difference.
I also have with the parts a Dolomite 1850 Radiator, fan and cylinder head free to good home if anyone is interested, in York area.

Many thanks
Warren

[Carledo]

If as I suspect, the bung is about 2" in diameter and in the upper horizontal surface near the front of the block, this is where the water pump (which is driven by the camshaft) normally lives. The bung is part of an aftermarket conversion to fit an electric water pump located in the bottom radiator hose.

A picture of the offending article would help confirm the diagnosis!


Steve

[soe8m]

Early engines have a threaded plug in the engine block and later castings don't but the bulge is still there.

Jeroen.

[Carledo]

Early engines have a threaded plug in the engine block and later castings don't but the bulge is still there.

Jeroen.

You learn something new every day!

Steve

[warrenphill]

Thanks for the information Steve and Jeroen, looks like I have both early and late blocks,do you
Know if that is the only difference please, and do you happen to know weather a 1850 block can be used for a sprint engine.

Again many thanks and yes you can learn something every day.

Warren

[gmsclassics]

Yes. Back in mid 2013 I needed a new engine for my race Sprint and we took the block and crank from a 1974(?) 1850 Auto that still had standard bores, bearings and mains. JE forged pistons (with block bored to suit), new conrods, plus 'Sprintspeed' lightened clutch, 7' twin plate clutch, centre release bearing, blockbrace and more. Happily revved to 7500rpm and was still going strong when I retired some four years and fifty odd races later.
I would be looking for another if I ever needed to build another Sprint engine and the old block couldn't be bored out any further.

Geoff

[soe8m]

Not all. Some 1850 blocks have liners fitted from new and these cannot be machined to sprint bore. Only the 1850 solid blocks can.

Be careful to note your machineshop not to bore too deep. Most blocks are machined too deep by the factory hitting the crankshaft webbing. These are also not suitable for serious power and will crack. About 10% isn't machined too deep and are much stronger.

An 1850 machined too deep will have a stronger webbing as an sprint that is machined too deep by the factory because of the smaller bore. It would be a shame a machineshop does rebore an 1850 to sprint accidentally too deep weakening such an engineblock.

Jeroen.