Offenhauser options comparison; Revell vs ARM

[aurfalien]

Hi,

Curious if the community has an opinion on Offy engine comparisons between ARM and Revell?

ARM;

http://americanracingminiatures.com/?product=esca-3-125th-scale-270255-offenhauser-engine-kit

Revell;

http://manuals.hobbico.com/rmx/85-4267.pdf

 

I'm thinking the Revell both in terms of material and part count.

[Bill J]

No expert, but if I recall correctly they are different engines. The ARM unit is a 255 C.I. Indy engine and the midget engine is much smaller,97 C.I.displacement and the overall engine is smaller, I could be wrong on physical size but sure seems like the midget engine is much smaller physically.

Edited December 22, 2016 by Bill J

[Ace-Garageguy]

No expert, but if I recall correctly they are different engines. The ARM unit is a 255 C.I. Indy engine and the midget engine is much smaller,97 C.I.displacement and the overall engine is smaller, I could be wrong on physical size but sure seems like the midget engine is much smaller physically.

Correct...pretty much.

I just bought the ARM engine and it represents quite accurately the 270 cu.in. mid-1950s engine, and with a little work also does the later 250 engines through the mid '60s. It is a BEAUTIFUL model.

The main engine assembly (one piece), gearbox, and lower sump are very nice resin castings. The rest of the parts are white metal.

The only thing I don't like about it is the fact that the cam covers are cast in, so unless you make duplicates and remove the originals, it's difficult to get a nice polished-aluminum effect on the covers and an as-cast finish on the rest of the engine.

Interestingly, it is physically the same size as the 97 cu.in. engine in the VERY OLD Monogram midget kit...below...which is about 1/20 scale or so. The engine in the kit shown below only has two parts...left and right halves...but it CAN be detailed for use as an unusual hot-rod powerplant. It takes some work to make something nice out of it, but it IS possible.

                                                                                  

The more recent Revell 1/25 midget kit has a correctly scaled and very nice 97 cu.in. Offy.

                                                                                      

Also interestingly, the Offy engines represented in the old AMT Indy car kits are significantly undersized, probably done to make them easier to fit inside the plastic kit bodywork.

                                                                   

An interesting thing is that many (if not all) Offy engines could be built up with the induction and exhaust systems on either side to facilitate packaging in a particular chassis. Swapping these required different cams of course.

Here are engineering drawings of the 270 and 97 Offy engines. The dimensions are shown so you can get a feel for the relative sizes.

Edited December 22, 2016 by Ace-Garageguy

[aurfalien]

Wow, thanks for the GREAT info!

[aurfalien]

This one looks really bad a$$;

http://www.indycals.net/parts/indyparts/resinoffy.html

He also has the turbo/exhaust set for it here;

http://www.shapeways.com/product/FLRRCJ7JA/1976-mclaren-exhaust-and-intake?optionId=19247636

What do you think?