Sexton R975-C1 a mess

[LRDG]

Thanks for the good information. As mentioned above, when I become a retiree in April, I will be in a much better position to follow up on all these tips.

[Bob Phillips]

Not sure if I should weigh in here but..here goes..
Before you do anything else you need to strip that engine right down and see what you have to work with. If the case, crankshaft, gear case etc are rebuildable- all the rest of the parts are easy to obtain. You will need to really check for cracks and damage carefully. Second, while some parts between the C1 and C4 interchange, many do not. The crankshafts are different and use different bearing retention in the front, slightly different rear mains etc. Third there are many aircraft engines that have been flogged to people to use as spares- notably the post war R975 -46 which was a helicopter engine- though it looks a lot like a C4. It is an entirely different animal with few interchange parts. Be careful you don't get stung! Fourth, it is easy to destroy a C1 engine. I recall the overhauled engine in Bill Greggs Sexton having the bottom jugs damaged when safe start up procedures were not followed. Most of the many engines I have seen had bad main crankbearings- hardly surprising given the design and the design expectation that this would be an aircraft engine. Finally lots of parts and core engines are available right here. Tear that engine down and see what you need!

[Andrew]

Andy over at northeast military is selling off everything he has. He has parts listed for this over at www.site.ww2mv.com/Engines-Parts_For_Sale.html

Andy (not the above andy )

[LRDG]

Bob, the engine is coming apart as we speak - a complete teardown. The bottom of most the cylinder liners have been mushroomed out by the broken rods (red arrows) so it will take some time to get them out without damaging the case.

The rotating assembly is scrap, badly damaged. If I have it straight, the output spline damage shown would have been from the engine trying to stop the Sexton dead when it locked up.

The case may be OK. We'll check it with dye penetrant when apart.

I take your point about carefully checking we are buying usable parts.

Are the very thin, closely-spaced steel cylinder fins as-cast? If so, they are very high quality castings. Spin casting maybe?

Malcolm

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[Bob Phillips]

Malcolm- for whatever little bits its worth- those splayed out cylinder bottoms may be a pain to disassemble but maybe they will have saved the thin cast aluminium that makes up the crankcase. Later engines (eg the -46 helicopter) has much heavier castings in it. It also rated at 600 hp with much more blower and carb action. I cannot tell you about the fins, I always thought they were machined in but I don't know..Bob

[daninnm]

last I heard he had lots of C1 cores avaiable and lots of parts....I even bought a C4 and a set of parts to rebuilt it but never had to do that.....I ahve his ph no if you need it....send me a note for the number.....

[lssah2025]

Good luck on your rebuild, glad they still have NOS Meteor engines in crates for my restoration!! When Rick had his original Meteor engine, the only known surviving example of a Mk1a Meteor, which was an aircraft Merlin converted to tank use but retaining it's original Merlin components, it sounds great. Not a radial but a V12.

https://www.youtube.com/watch?v=73u4GXB1TgU

https://www.youtube.com/watch?v=3sTt...re=c4-overview

https://www.youtube.com/watch?v=gYp1...re=c4-overview

[LRDG]

Originally Posted by Bob Phillips

Malcolm- for whatever little bits its worth- those splayed out cylinder bottoms may be a pain to disassemble but maybe they will have saved the thin cast aluminium that makes up the crankcase. Later engines (eg the -46 helicopter) has much heavier castings in it. It also rated at 600 hp with much more blower and carb action. I cannot tell you about the fins, I always thought they were machined in but I don't know..Bob

Good point, Bob. You are right, they did save a lot of damage to the crankcase.

It's pretty well apart now and disassembly has stopped as there is some angst about repair costs.

There is some interesting damage to the crankcase in the raised web that supports the lifter bores. It's shown below. It lines up exactly with the inboard end of the starter drive shaft (last photo, 6 o'clock position). It's like the nut on the starter end of the shaft had come loose and allowed the shaft and small gear to move inboard and wear into the web. And it doesn't look like old damage because there is wear debris coated on the web that's not shown on the photo. It's like the nut came loose and when it was spotted (or heard), somebody just retightened the nut to pull everything back into place and hoped for the best. The weird thing is there absolutely no sign of damage or wear to the end of the shaft or the gear. It's a bit of a mystery to me.

Thanks again for all the suggestions on parts but things are on hold for a while.

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[Stew Robertson]

Hey Bob ;
I think you should clarify your comments on Bill's 975

[Bob Phillips]

Hi Stew: I think you know this story ...so
Radial engines have a tendency to collect oil in the bottom cylinders and can create a hydrostatic lock up situation if you try to start them without first eliminating any collected oil. Usually you turn the engine through several revolution to evacuate oil from the cylinders or you could remove the spark plugs and drain it. In a tank engine your supposed to handcrank the starter 50 times to turn the engine over ( through the starter reduction) to clear oil. Oil is not compressible. If you crank or are able to start the engine without clearing the oil, you will have major problems- bent link rods, broken pistons, jugs that are fractured off the crankcase etc. The story goes as I heard it was, that once the radial powered vehicle in Bill Greggs collection got away from Rockwood (Bill and Stew), at some later time it was damaged when someone unfamiliar with correct procedures attempted to start it. Anyone familiar with a radial engine would not make this error. WW2 vets told me they would "bump" the engine a little at a time with the electric starter so they would not have to hand crank it.