collective wisdom on 'tilting' a bike engine at install..

ccrunner · **Posted:** Wed Mar 07, 2012 5:12 pm

Hey guys.. looking to install my 1998 VFR800 Honda engine into my build, and I have concerns about not being able to mount it as Honda did in the bike; level.

The bike engine is mounted sidways in the front of the car- car is RWD. Because of the way my rear diff/inline tranny (for OD and reverse) are set up, I'm forced to tilt the bike engine over on it's sprocket side a bit by about 6 to 7 degrees (this tilt is actually very close to how the bike would tilt on it's kickstand, so I'm not too worried about this 'tilt to the side' part of the install).. I'm doing this to match my inline tranny's nose-up angle, and laying the motor over a bit should help me avoid driveline vibration issues...

Onto the true question. For clearance/ease of install issues, it would also be nice to tilt the engine back by about 8 to 10 degrees (tilting it 'back' in the car's engine bay would be as if it were doing a perpetual low-arc wheelie if it were still in the bike). My big concern is lubrication/oil pickup... I'm going to pull the oil pan and learn where the oil sump is and move/adjust it if I must- but I'm wondering if any of you guys have had to fudge a bike's engine install angle to wedge it in, and what the results were.. Truth be told I can get away without tilting it back, but it sure would make routing the exhaust easier if I did..

thoughts?

thanks-

ccrunner

carguy123 · **Joined:** Sat Apr 05, 2008 2:25 am **Posts:** 2375

It's more than just the oil pick up. How does the oil drain back? Would the tilt affect whether the oil can drain back properly?

nufun · **Joined:** Sat Sep 11, 2010 9:26 am **Posts:** 91

It would also affect the clutch, since now its not sitting in oil at the right level. I would not change the angle. too many things could be affected.

Oil Return
Water Flow
Clutch

Kind of throws off the fung shway.

ccrunner · **Posted:** Wed Mar 07, 2012 10:50 pm

nufun wrote:

It would also affect the clutch, since now its not sitting in oil at the right level. I would not change the angle. too many things could be affected.

Oil Return
Water Flow
Clutch

Kind of throws off the fung shway.

I was thinking the same thing about too many variables.. I don't have a choice on the 'left tilt,' but the forward/backward tilt I can leave alone (leave level).. now I've got to get creative on fitting a few round pegs in square holes :lol:

ccrunner

xargs · **Joined:** Sun Mar 04, 2012 2:08 pm **Posts:** 6

I tilted mine up about that far to get the 'V' angle close to level so I could make the exhaust work.
Packaging wise, with the motor sideways in the car- it's kinda screwy anyways, since bike engines never have side loads.

The sump on the 800 is pretty square, and the pickup is right in the middle, so it really should get a FSAE-style sump/pickup extension. But the motor's so darn tall already it would be a pain. That's why I put a pressure gauge in place of the idiot light, so I'll at least be able to observe if it holds pressure under acceleration. The few 1st/2nd gear blasts I've done with it so far look promising.

Right now at the angle it's at (tilted back so the driveshaft has a straight run to the reverse box) and rotated to make the cylinders level leave it about 3/4 of a quart more than stock to fill the sight glass.

-xargs

This picture is from an early stage of development, getting the engine mounts in place and figuring out the instrument wiring...

Miatav8,MstrASE,A&P,F · **Joined:** Fri Dec 22, 2006 2:05 pm **Posts:** 3924

I suggest you leave the engine level or tilt the output shaft up a couple degrees above level, followed by tilting the diff pinion down a couple degrees below level. Set the engine output and pinion at the same height. If this sets the engine too high, you can use smaller diameter wheels to lower the diff in the frame yet retain the same ground hugging clearance, and/or set the engine lower than the diff with parallel shafts, creating a 1-2 degree angle relative to level on the driveshaft depending on it's length.

The pinion can be above or below level, but under load, the pinion tries to climb the ring gear, which pushes the front of the diff upward. Set the pinion angle below level, and the joints will be stronger under load when you need it, with a reduced operating angle.

If you don't baffle the pan, add a T at the oil pressure switch for a sprung piston type accusump.

ccrunner · **Posted:** Thu Mar 08, 2012 4:07 pm

xargs wrote:

I tilted mine up about that far to get the 'V' angle close to level so I could make the exhaust work.
Packaging wise, with the motor sideways in the car- it's kinda screwy anyways, since bike engines never have side loads.

The sump on the 800 is pretty square, and the pickup is right in the middle, so it really should get a FSAE-style sump/pickup extension. But the motor's so darn tall already it would be a pain. That's why I put a pressure gauge in place of the idiot light, so I'll at least be able to observe if it holds pressure under acceleration. The few 1st/2nd gear blasts I've done with it so far look promising.

Right now at the angle it's at (tilted back so the driveshaft has a straight run to the reverse box) and rotated to make the cylinders level leave it about 3/4 of a quart more than stock to fill the sight glass.

-xargs

This picture is from an early stage of development, getting the engine mounts in place and figuring out the instrument wiring...

I see Anton you've had to overcome the same problem in virtually the same application... Did you fab/install a baffle into the pan?- I plan to do this no matter how I end up tilting/angling the motor- I'm so freaked out about oil startvation it may just be to make me feel better than anyting else.. Also, as I read your post, you tilted your motor in both directions as I'd like to do mine, and having done that requires that you now add an additional 3/4 of a quart of oil to get up to the marks on the sight glass?-- If so, I see this as a benefit; more oil= more cooling (these engines run notoriously hot in the bike-maybe an air flow issue?).. also, more oil would furthur submerge the sump- another gain methinks- if only by a few mm...

ccrunner

xargs · **Joined:** Sun Mar 04, 2012 2:08 pm **Posts:** 6

ccrunner wrote:

xargs wrote:

I tilted mine up about that far to get the 'V' angle close to level so I could make the exhaust work.
Packaging wise, with the motor sideways in the car- it's kinda screwy anyways, since bike engines never have side loads.

The sump on the 800 is pretty square, and the pickup is right in the middle, so it really should get a FSAE-style sump/pickup extension. But the motor's so darn tall already it would be a pain. That's why I put a pressure gauge in place of the idiot light, so I'll at least be able to observe if it holds pressure under acceleration. The few 1st/2nd gear blasts I've done with it so far look promising.

Right now at the angle it's at (tilted back so the driveshaft has a straight run to the reverse box) and rotated to make the cylinders level leave it about 3/4 of a quart more than stock to fill the sight glass.

-xargs

I see Anton you've had to overcome the same problem in virtually the same application... Did you fab/install a baffle into the pan?- I plan to do this no matter how I end up tilting/angling the motor- I'm so freaked out about oil startvation it may just be to make me feel better than anyting else.. Also, as I read your post, you tilted your motor in both directions as I'd like to do mine, and having done that requires that you now add an additional 3/4 of a quart of oil to get up to the marks on the sight glass?-- If so, I see this as a benefit; more oil= more cooling (these engines run notoriously hot in the bike-maybe an air flow issue?).. also, more oil would furthur submerge the sump- another gain methinks- if only by a few mm...

ccrunner

I haven't done anything to the sump yet, as a street car I think it'll be ok with the extra oil that's in it -> yes, the tilt gives some extra capacity... The pan is baffled a bit in the left/right orientation in the car:

The thing to worry about is having the oil level high enough that the trans froths the oil around, raising temps and overworking the stock air/oil separator. I think the raised level is pretty much a wash, since the pickup is forward of the sight glass

I've been able to keep the engine around 185-190* with extra radiator and a Swift thermostat to replace the famously 'fail open' Honda thermostat.

I think it'll work, but I'll let you know more shortly, once I get the Yahshuatwo reverse box. I still have a pile of DMV paperwork to wade through as well, but moving permits here I come!

xargs · **Joined:** Sun Mar 04, 2012 2:08 pm **Posts:** 6

Here's a shot of it on the car, still working on the oil cooler mount (80's 600 ninja)

The angle iron with holes was going to be radius rod mounts for the second iteration of the front suspension, which was Festiva lower control arms. That got superseded by the Metro steering knuckles with Mazda 323/GLC 'L' shaped lower control arms.

Here's another shot of the engine in place, not a lot of extra room...

LocostUSA.com

collective wisdom on 'tilting' a bike engine at install..

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