Honda Engine Swap Questions: Sprockets forum: Grassroots Motorsports Magazine

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June 17, 2009 11:55 a.m. jpaturzo New Reader

I've been googling the hell out of this one, and I am repeatedly being defeated. It's not a sprocket question directly, but a sprocket motor question.

I have an old formula SAE chassis. It was built around a Honda F3 motor (1995-1998 CBR 600). A Honda F2 (1991-1994 CBR600) is a direct bolt in. I'm good with all this.

My question is, are there any other Honda motors of larger displacements that are a direct bolt in for the F2-F3 family? I have found some conjecture / hearsay on the intertubes that a 1992-1996 900rr motor will fit, but no real evidence. I'm visiting my favorite bike salvage yard this weekend and I've got a hair across my ass to finish this project. Thanks.
June 17, 2009 12:02 p.m. alex HalfDork

I highly doubt anything's a direct bolt-in aside from the F2/F3 family. But, they should at least be dimensionally similar, and if you're not using the engine as a stressed member, there shouldn't be a whole lot to engineering new engine mounts*.

Furthermore, I'm willing to bet - not real money, mind you - that as you get to later generation motors - 929, 954, etc - they'll get incrementally smaller, which may or may not make your life easier.

*Notice the profuse useage of 'should' in that sentence. Take that to mean: I'm speculating wildly.
June 17, 2009 12:05 p.m. mulluthuntur New Reader

In reply to jpaturzo:

They swap those old 900rr motors into F2/F3 Frames. I haven't done it myself, but I was contemplating it. It is said that all that needs to be done on an f3 is modify the front motor mount bracket to make the 900 fit. I'm sure it wouldn't be that hard on an SAE car either. If you want to hop up that 600 motor I have some 636 F3 pistons and some HRC cams that would add some good power......I might be persuaded to part with them.
June 17, 2009 12:08 p.m. mulluthuntur New Reader

In reply to alex:

The rear mount between the f3 and 900rr are the same. That's why they do it on bikes, and adding an intank fuelpump is a pain. But on an SAE car I think it is much more possible to add a FI motor.
June 17, 2009 2:12 p.m. jpaturzo New Reader

Thanks for the replies. My motivation for this project is the only bike engine I have laying around is an '01 GSXR 600 motor (its mid rebuild). Adapting that to fit the frame is serious engine mount surgery, and a lot of oil pan modification to drop its height. I don't have a TIG welder so I was trying to avoid changing engine mounts. Though if I just stop being a wimp I guess I could MIG new mounts in.

I'll get a quote on a 900rr motor for the hell of it, and If I can get a F3 car kit cheap I'll go that route.....I can rebuild my GSXR motor and stick it in something crazy if it comes down to it.
June 18, 2009 1:38 a.m. Opus Dork

jpaturzo wrote:

I've been googling the hell out of this one, and I am repeatedly being defeated. It's not a sprocket question directly, but a sprocket motor question.

I have an old formula SAE chassis. It was built around a Honda F3 motor (1995-1998 CBR 600). A Honda F2 (1991-1994 CBR600) is a direct bolt in. I'm good with all this.

My question is, are there any other Honda motors of larger displacements that are a direct bolt in for the F2-F3 family? I have found some conjecture / hearsay on the intertubes that a 1992-1996 900rr motor will fit, but no real evidence. I'm visiting my favorite bike salvage yard this weekend and I've got a hair across my ass to finish this project. Thanks.

I had a 94 F2 that had some miles on it. Back in the day in motorcycle mags, there were companies that would put 900 motors in the 600 frame and the plastic would cover it back up. Always wanted to do it, but never got the $ before the bike was stolen. Looking at the links below, you will need the wiring and black box to go with it. Not a direct swap, but can be done.

Did find a few things though

http://austin.craigslist.org/mcy/1212533685.html

http://www.customfighters.com/forums/showthread.php?t=18491

http://cbrforum.com/forum/showthread.php?t=63882 search 900f2

http://cbrforum.com/forum/showthread.php?t=79563
June 18, 2009 12:50 p.m. wherethefmi Dork

I tihnk this is all way over your head, I'm going to let you ship it to me on your dime and I'll get rid of this evil for you.
Aug. 12, 2009 11:32 p.m. suzuki2903

if you still have them hrc cams id be interested in buying them
Aug. 13, 2009 6:07 a.m. 44Dwarf Reader

flat stock for the mounts with angle iron bolted to the end then bolt the angle iron trought the frame rail. You can put any motor in with out a welder.

theres off the self shorty oil pans availible for most bike motors..but there not normaly cheap. One that is cheap is the 89-92 gsxr units to get shorty pan by using the 86-88 gsxr pan.

44
Aug. 14, 2009 8:05 a.m. Gonzo_Bmod New Reader

Speaking of oil pans, remember you need to somehow correct the oil pick up as cars and bikes corner differently. A pan baffle or sometimes just an increased oil level (or both) can assure you don't lose oil pressure while cornering. Here is a FSAE site with good info:

http://fsae.com/eve/forums
Aug. 14, 2009 8:51 a.m. 44Dwarf Reader

Most engines do okay in cars but there are some that just go boom with out work. Early kaws did not like sideways mounting with out by-pass hoses ect.

Newer GSXR's need cut pans and extended gaskets. Gaskets extend in to the crank area like a windage tray and a pan baffle rolled in to one. It help keep the oil from sliding up the motor.
Aug. 14, 2009 9:06 a.m. nocones Reader

also be aware that Most FSAE cars are marginally engineered to handle the ~80hp MAX that an SAE car generates. Although it seems like a great Idea to bump the power to 150-180 you WILL break the custom axles, hubs, uprights, diff, A-arms, etc. that most SAE cars feature. I'd recommend just putting a Stock non-restricted F3 or F2 motor in. the 90-100 WHP that you would have should be great fun without guaranteeing that you break things. even a heavy SAE car weighs <700lbs So performance should be adequate.

Daniel
Aug. 16, 2009 12:41 p.m. jpaturzo New Reader

nocones wrote:

also be aware that Most FSAE cars are marginally engineered to handle the ~80hp MAX that an SAE car generates. Although it seems like a great Idea to bump the power to 150-180 you WILL break the custom axles, hubs, uprights, diff, A-arms, etc. that most SAE cars feature. I'd recommend just putting a Stock non-restricted F3 or F2 motor in. the 90-100 WHP that you would have should be great fun without guaranteeing that you break things. even a heavy SAE car weighs <700lbs So performance should be adequate.

Daniel

I didn't realize this thread came back alive. Yes the original components will asplode with increased horsepower, but when you had the foresight to design everything to swap out and be compatible with beefier stuff its not that bad. I'm waffling again, and I think an NA 600cc will do just fine. More than 100hp will just make lots of tire smoke, even with my fat ass in it.

We ran unrestricted cars like this, literally for years with no problems.