formula SAE car...warping the block by forcing it in...

[legolyle]

I'm on a formula SAE team at my university, I'm brand new to the team
basically, this is the team's first year designing/building a car. They are using a straight 4 motorcycle engine (I honestly cant remember the specific one) aluminum block honda.
It has 3 mounting locations, but the front two are the ones in question. they lay parallel to the cylinders, one on each far side of the block, theyre simple thrue-bolt holes molded into the block.

so, heres the deal...they made the mounts using the block as a template...but when they went to drop the block in yesterday, only one side lined up correctly. so they put a bolt in one side, and then put weight on the other part of the block to force it into place and hammered the bolt in.

I was errr...against this...but im new...and not an engineer...yet

they didnt know if this would warp the block...
do you guys think it could warp the block?

im wondering if it would simply warp the chassis first...
the engine was already all assembled when dropped in.

thanks a bunch for your input

 

[hvyman]

Me thinks it would warp. Stress on the block especially extended high heat like racing from bad mounting would most likely distort it.

I'm no engineer tho.

 

[Polythamus]

Hey im also a student involved in the formula SAE at my university. Supras represent!!! I'm actually on the engine team, we run a 03-06 Honda cbr600, my guess is you run a similar engine.

Anyway i STRONGLY recommend you go and produce new mounts, I'm not sure about whether or not the block will actually warp but you could easily crack or damage the holes the bolts bolt into.

I did this to a 2jz-gte by trying to force a manifold on that didn't line up 100%. Machining new mounts is a hell of a lot easier than trying to fix any damage you could do to the block or the chassis. If you do things half assed or lazy in formula SAE your car aint gonna make it through comp...

 

[legolyle]

Hey im also a student involved in the formula SAE at my university. Supras represent!!!

hell yeah!

thanks guys, I'll try and talk some sense into them

if anyone else has any input, I'm still listening xD

 

[Typhoon]

Shim/elongate the mounting points on the chassis as needed. Most all motorcycle engines are stressed members in motorcycles these days, they'll handle a fair whack of load on them, but why risk it?

 

[te72]

If it doesn't fit, a hammer isn't the best answer, unless you're building a demolition derby car... Aluminum block? What's going to happen to that if the thing heats up (engines *do* do that sometimes...), and the steel it's mounted to doesn't wanna move? Something is going to want to give, and it would suck if that thing was your engine, right?

I'd say get back to the drawing board and make things right.

 

[legolyle]

well, they still have to paint the chassis, and take everything out, so maybe they'll fix it...
If they do, I'll be sure to let you guys know...if they dont...I'll let you guys know if the car survives or not xD

also, I had no idea the engines are a partially structural member in bikes. Thats crazy

 

[Freshmaker]

I was the powertrain team lead of my formula team. We used 600rr and f4i engines. I wouldn't recommend you guys run like that. It won't take much to fix. Do it right so you can worry about tuning the car, not fixing it.

More importantly, you need to learn from them so you can do it better next year. Each team can only make so much progress from the previous year. good luck!

Sent from my ADR6350 using Tapatalk

 

[bioskyline]

id think the bolt and/or the mount would warp before the block. the weakest link is going to be whats going to give first.

 

[legolyle]

yeah, so, I said I'd come back, I'm back

never had any issues with the engine, my fears were unwarranted. All went well with it, except when we were disqualified for leaking a few drops of oil from the dry sump system during the endurance event
Also, a little issue with our motor, which comes stock with ~100hp (CBR600RR), only made 33 hp, 21 torque on the dyno. O.O
with given restrictions, and poorly designed intake, I'm still surprised.

:icon_conf


the car was pretty popular, for anyone who may have visited the competition you likely saw it:

were looking into that little discrepancy with the engine though. I might be back on here for more help :icon_wink (yay?), I should be learning to tune an engine from scratch here eventually

anyway, I appreciate the responses guys, this is very much a learning experience for me, and well, guess I learned something xD

 

[te72]

33hp on the dyno out of the 600rr engine? Old roommate had one of those bikes, it dyno'd something like 103 at the rear wheel... I would think something is very wrong on yours.

 

[Poodles]

Warped block causing loss of compression?

 

[te72]

Haha, hmm... oval shaped cylinders don't give very good compression when fitted with round cylinders.

 

[legolyle]

yeah, well, during comp I actually thought it had a blown headgasket...that supra intuition
but, we did a compression check and engine had good compression across the board, between 160 and 170 for all of them. Next is a leakdown test, but, I no longer think compression is the problem. But, ya never know

also, I forgot to mention, when we did the dyno, we looked into possible problems and found that two cylinders weren't firing correctly. One was set a tooth off in the ECU and the other's coil wire had a short. So, that brought horsepower up some (we haven't dynoed it since though). The competition restricts intake to 20mm diameter. The real problem we've run into now is low power, poor throttle response, and a horrible power band. Which I think boils down to tuning (which is super rich right now) and intake design.

 

[te72]

Ouch man... 20mm intake restriction? Might as well use a coffee stirring straw. :nono:

160-170 compression seems low for a motorcycle to me, shouldn't they be somewhere in the 11:1 area?

 

[legolyle]

yeah really xD

well, 12:1 is what I read, but, all the same, some quick searching shows those numbers to be relatively normal, so, thus far, nothing points to a BHG or warped block

 

[MkIII FTW]

Good to see more SAE guys!! At my university I am the director of electrical subsystems for my SAE team. I have a twin brother who is heading up the powertrain design. Best of luck to you I know how daunting it can be.

 

[legolyle]

haha, nice man! I'll most likely be heading up electrical for my team this year as well
best of luck to ya!