YC versus FH 1500 engine: significant differences?

[chrishawley]

I'm planning to build up a replacement engine for the Spitfire 1500. But the spare unit is YC (small saloom) rather than a Spitfire engine (FH) per se. Before I embark;are there any differences between YC and FH I need to take in to account? ?front plate/mountings, cam profile, valves, flywheel, mainfold etc etc. Any pointers to potential pitfalls would be much appreciated.

[thescrapman]

Differences? Sump.

Nothing else I can think of.

[Casper]

https://www.tssc.org.uk/tssc/uploaded_files/177 - March 1995.pdf  Page 28 should help you

C.

[Josef]

I’d guessed the cam profile would be different as it is between the Herald and Spitfire. But Casper’s courier link as proved me wrong and looks like all 1500s had the same cam. Rationalisation or emissions? Anyone know?

[Casper]

Yes the cam is the same.  I forget the part number but it did change.  I don't have my references to hand but I think the valves are also the same.

C.

Edited May 25, 2023 by Casper

[chrishawley]

Thank you. If I've got this right the the Spit1500 has a more sharply recessed sump at the front with the drain plug at left rear as opposed to right front on the saloon. So sump pan required. Different manifolds on the Spit but they would be transfered off the outgoing engine anyway. The chart in the courier indicates that the FWD 1500 engine had larger inlet valves but the size was common on the RWD 1500 saloon with the Spit1500. But I'd be wondering whether there was any carry over of the larger valves on early YC engine but I suppose setting that one aside depends on having the head off and measuring.

One further question: How about the front plate/engine mountings? The saloon engine I have has sort of cubic rubber blocks for the mountings rather the the spitfire type the with ears. Any insights into whether the front of the engine is different or whether it's just the rubber mounts that need to be change?

Thanks again.