The Triumph Dolomite Club - Discussion Forum

Hi all
A chap has just called me asking if tr7 and sprint blocks are same.
Also where are all the potential engine number locations.

I said blocks are same but all other its (crank head chain covers etc are different) exception being jackshaft water pumps, back plate rer crank oil seal housing).
Is this true?

Also engine number on top of block not far from distributor. Any other locations?

Last question can you get +50 sprint pistons??? I think not.

Thanks all
John

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ONLY A FEW LEFT !

I think engine numbers are not always where they are supposed to be but this is a Sprint one

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Russ Cooper
Dursley
UK

Sprint and TR7 cranks are the same dimensions but I may have read that some Sprint cranks have extra oil drillings?
The front pulleys are different length and the engine rear backplates are different. This is because the TR7 flywheel is thicker so the back plate fixing bolts have to be countersunk on the TR7.

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Russ Cooper
Dursley
UK

I’ve seen engine numbers anywhere from between the two core plugs in that photo, down the vertical face to even lower than the position shown. Some blocks i’m Still looking for a number on, but I have to say I’ve never seen one as clear, or as neatly applied, as that photo! I suspect someone has done that post factory...

While on that subject someone might find it useful to know that you can reuse an 1850 block and crank in a Sprint rebuild with no issues. When my race engine finally died in late 2012 we took the block from an old 1850 auto (that was still on standard size pistons, big ends and mains) and used it successfully for another four/five seasons until I retired from racing. Block was bored out to match new forged Sprint pistons, crank was ground to 10 thou under and balanced with flywheel (but not cross drilled further) and everything else from the earlier race engine was moved across. Completed a further 3100km of racing without any issues related to block or crank, despite revving to 7000-7500.
Also of note with using an completely fresh engine we used a fully synthetic race oil (Motul 300V 15W50).

Geoff

The one real difference between the Dolomite and TR7 blocks themselves is the tube for the dipstick.
The Doly's is flared to aid the stick going straight in, and the TR7's is straight for the tube that takes the longest dipstick in the world to run down.
I've never checked if there the same length so the Doly's dipstick will fit with less ease.
I'm reliably informed that the early Sprint blocks, to 1976 I assume, have a different alloy of casting iron to later Sprints and TR7s. Not sure what the difference was. Something about Nickel content I think.
Another difference in attachments is that the timing quadrant that bolts on the block (or chain cover is it?) and the front pulley are paired and shouldn't be mixed. I seem to remember that mixing the TR7s pulley and Doly's alternator, fan, and mounts ends with chewed fan belts too.
Graham

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The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).