Sprint engine full specifications

[Nico Deltgen]

Hello
We are planning to rebuild our Doly Sprint engine. I am searching for full engine specifcations.
Any idea where I can find all dimensions and specificationd of a standard engine.
Specifically i am desperate need of following 2 standard dimensions
Connecting rod inside diameter ( without sleeve)
Inside diameter of main bearing housing in block
we need these diamensions to identify if modifications have already be made on the engine
Thanks for any info I can get and greetings from Luxembourg
Nico

[xvivalve]

The dimensions you ask for will not change. What you need to measure is the journal diameter of the crankshaft as it is from those that metal may have been removed. I’ll look this up for you later this morning…

[xvivalve]

The crankshaft main bearing journal diameter as standard should be 2.1260 to 2.1265 inches and the crank pin diameter 1.7500 to 1.7505 inches. If either is smaller than this it will have been ground (in increments of 0.010 inches) and you will need oversized bearings.

The dimension you have asked for, the diameter of the big end of the connecting rod without shells should be 1.8955 to 1.8960 inches, but this should not have been changed. I did have to replace a connecting rod in my TR6 once because the lugs on the bearings broke off and the bearing was able to spin in the journal which caused wear to the internal diameter of the connecting rod, but that would be a very rare occurrence and you could see the damage without having to measure anything.

Hope this helps...

[soe8m]

The dimensions you ask for will not change. What you need to measure is the journal diameter of the crankshaft as it is from those that metal may have been removed. I’ll look this up for you later this morning…

A good machineshop will measure and it's a common thing to skim the conrod faces a bit and roam the big end of the conrod to a perfect round hole to the exact size again. The same for the mainbearings when a line bore is wanted/needed.

Jeroen

[Nico Deltgen]

Hy Thank you for these helpfull info
hope that we will now be lined up to find out if our engine is still in good shape or
if more rework has to be done
Thanks a lot fro Lux