The Triumph Dolomite Club - Discussion Forum

I'm sure you CAN as you can fit a Sprint head to a TR7 block or use a TR7 block with Sprint internals and head. I gather it's also possible to sleeve an 1850 block and use it in a Sprint.

So it's POSSIBLE, but why would you want to?

You would indeed need to fit the Sprint timing cover, but also do something with the crankshaft timing gear as the 1850 only has a single row chain. Whether you can mix and match bits at the bottom end to match a 2 row gear and pulley to the single row 1850 crank is beyond my wheelhouse. You might also need to do something with pistons as the Sprint has valve cutouts not present on the 1850 pistons. Jeroen would probably know, he does this sort of thing for fun!

Steve

So it's POSSIBLE, but why would you want to?

Lack of availability of suitable Sprint blocks/pistons. Using an 1850 block bored or sleeved to 90.3 mm allows use of plentiful standard Sprint pistons. You'd not put a Sprint head on an 1850 block without bringing it up to Sprint bore as the combustion chamber would have a peculiar shape.

The cranks are identical between Sprint and 1850, so you simply replace the timing gears, chain and tensioner with the duplex varieties along with the cover, but you'd also need a sprint bottom pulley or machine the 1850 one down to size.

Con rods are also different between 1850 and Sprint.

xvivalve wrote: ↑Sun Apr 23, 2023 1:44 pm

So it's POSSIBLE, but why would you want to?

Lack of availability of suitable Sprint blocks/pistons. Using an 1850 block bored or sleeved to 90.3 mm allows use of plentiful standard Sprint pistons. You'd not put a Sprint head on an 1850 block without bringing it up to Sprint bore as the combustion chamber would have a peculiar shape.

The cranks are identical between Sprint and 1850, so you simply replace the timing gears, chain and tensioner with the duplex varieties along with the cover, but you'd also need a sprint bottom pulley or machine the 1850 one down to size.

Con rods are also different between 1850 and Sprint.

You misunderstand me! I fully appreciate the point of using a sleeved/bored 1850 block or a TR7 block to replace all the Sprint engines that been blown up, cracked, or bored to their limit. Or simply to compensate for the shortage of oversize Sprint pistons.

What I couldn't understand is why anyone would want to create an 1850 16v! Which is what Dave seemed to be implying!

Steve

Carledo wrote:
You misunderstand me! I fully appreciate the point of using a sleeved/bored 1850 block or a TR7 block to replace all the Sprint engines that been blown up, cracked, or bored to their limit. Or simply to compensate for the shortage of oversize Sprint pistons.

What I couldn't understand is why anyone would want to create an 1850 16v! Which is what Dave seemed to be implying!

Steve

The difference in cylinderbore and compression ratio won't make that work.

Jeroen