How straight does the engine have to be?

Crazy · Post by **Crazy** » Fri Feb 25, 2011 6:15 pm

I was just wondering how straight the 3.5 RV8 needs to be in the bay? Reason I ask is my engine in the Volvo points a bit to one side (the pulleys would have to be moved about 2-3 inches to the left as you look at it from the front for it to be perfectly inline with the transmission n propshaft.

It also sits a bit nose high at the moment too but didn't know if this was an issue or not.

The engine is all bolted up to the gearbox which is all bolted up to the propshaft.

The tail end of the gearbox has the usual CV joint on it so I thought that this would allow for a little bit of an angle / tilt on the engine.

Cheers

kiwicar · Post by **kiwicar** » Fri Feb 25, 2011 7:41 pm

Hi,
in an ideal world you have a slight off set from the drive comming out the gearbox to the centre line of the drive into the back axel, on a live axel setup at static ride height, 1/4 to 1/2" is about right on a 4 foot propshaft . If you have about the same side to side then so be it but yuo can tollerate up to about 1 1/2 to 2" with the same length prop. You can also tolerate a skew of the drive lines up to about 3 degrees on a prop of about 4 feet, it is not ideal but then again not a big issue.
Best regards
Mike

Crazy · Post by **Crazy** » Fri Feb 25, 2011 7:58 pm

Thats cool. I think I have too much skew then as the engine, from an aerial view, is at about a 10 or 15 degree angle from the propshaft. So I guess that's way too much of an angle then?

I've only ever tuned engines that were already in cars, not fitting them so didn't have experience of fitting engines like this.

unstable load · Post by **unstable load** » Sat Feb 26, 2011 6:30 am

I recall from helping on a marine installation that about 2 degrees out of line is desirable to keep the joints working and prevent premature failure of the joints.

If you take them to bits, remember that the joints need to be out of phase to counter the losses and vibrations inherent to the system.

Crazy · Post by **Crazy** » Sat Feb 26, 2011 9:58 am

Thats cool. This gives an idea of how out from central it is at the moment. The fag is the central mark.

ChrisJC · Post by **ChrisJC** » Sat Feb 26, 2011 6:18 pm

The factory LDV V8 vans have the engine offset towards the passenger side to allow clearance of the steering box. I would think the offset is a couple of inches.

They use standard UJ's on the prop.

If you get into a problem, you can always use CV joints on the prop, then you can run at whatever angle you like.

Chris.

Crazy · Post by **Crazy** » Sat Feb 26, 2011 6:27 pm

Cheers mate. Very helpful

I gave a UJ on tge prop anyways (I call them CVs though but all the same thing)

Time to get on the engine mounts then

kstrutt1 · Post by **kstrutt1** » Fri Mar 04, 2011 10:32 pm

I had to offset the engine on my TR7V8 to one side by about 15mm to allow me to use SD1 exhaust manifolds,. I used a combination of mounting the engine at a angle and translating it sideways, It seems to work fine.

Kevin

Crazy · Post by **Crazy** » Fri Mar 04, 2011 10:42 pm

Cheers guys. I managed to get it a bit straighter, so I'm now onto the mounting stage. Well, my mate is for me LOL

DEVONMAN · Post by **DEVONMAN** » Sat Mar 05, 2011 11:07 am

As ChrisJC said, if you have CV joints at each end of the prop then you should be ok. The engine looks like an SD1, so if you have the standard gearbox (LT77) and prop, it will have CV joints and not UJ's.

Ideally, when viewed from above, the angle of the prop at the gearbox should be the same as the angle of the prop at the axle flange.
Ditto when looked at from the side. However, if you use CV joints then the errors will be acceptable. If you can move the back of the gearbox over as well then this would help to reduce the angles
With regards to the nose up situation, the RV8 engine is deigned to be installed with the nose slightly up and all the inlet manifolds are set to allow for this so as to make the carbs level.

Regards Denis

Crazy · Post by **Crazy** » Sat Mar 05, 2011 4:15 pm

Cheers for the info. It's actually a Volvo ZF gearbox I'm using but it has tge UJ at each end of the prop rather than cvs but the 2 cvs work as a UJ so it's all good really then