Engine mounting

GreatOldOne · #1 26th April 2007, 09:51

It's getting close to the point where I'm ready to put the engine in. Is there anything I should watch out for?

Is there any specific angle the engine should be at (North / South that is)? Or should it be dead level? I don't want to end up putting it in and drilling the holes for the gearbox mount only to find the prop shaft doesn't align later on!

Patrick · #2 26th April 2007, 09:58

Two things to watch out for:

Bumping the engine mounts into your freshly laid brake pipes (been there done that, replaced the brake pipes)

bumping into the battery tray with the head - did that but it only put a little ding in that was easy to fix!

As for gearbox height - the bracket is little difficult to fit in but it easier with the weight of the engine and gearbox attached to it. I put ours in pretty much level with the chassis - prop fits just fine.

When it comes time to spec the prop shaft we have all the measurements and the width of the doughnut. Unfortunately they made it the length between the diff and the gear box so we cant use it. Your probably best off giving the measurement between the diff and the doughnut!

MartinClan · #3 26th April 2007, 12:11

Give yourself plenty of time when doing it and preferably have someone else to give a hand.

If you haven't already done so install all the plumbing that goes along the transmission tunnel first. I didn't put the clutch plumbing in until after and it was a pita to do.

The only problem I had was that the gearbox mount was actually too wide by about 5mm. I had to get my friendly welder to cut and shut it for me. The position (up and down) of the gearbox mount is quite important as it effects things like exhaust clearance under the car etc. I had to lower mine in the end so that the exhaust would run under and parallel to the floor.

Other than that it all fitted pretty easily with no real clearance problems.

Robin

Patrick · #4 26th April 2007, 14:21

You can see the height on our gearbox mount here:

http://www.msportster.co.uk/detail.asp?cat=7&offset=96

GreatOldOne · #5 26th April 2007, 14:30

Thanks Patrick - So the bolting segment is about 10mm (ish?) above the fold where the tunnel becomes the lip for the floor?

GreatOldOne · #6 26th April 2007, 17:33

Right, I've just been out to the garage, and I've done some measuring (you know, measure twice, cut once and all that).

The distance from the centre point of the engine mount hole to the mating surface for the gearbox is 370mm. The distance from the lip of the gearbox bell to the start of the notch for the mount is 510mm. That gives an overall length from engine mounting to gearbox mounting of 880mm.

With aid of uber accurate wire strung across the engine mounting bobbins (who needs lasers!

), I've measured off 880mm down the tunnel, and marked it.

I've tried placing the mounting bracket at that point, but I can't - the tunnel is too narrow at that point. The closest I can get the mount is 20mm further forward toward the engine bay.

Just how accurate do I need to be on this? Some of the discrepancy will be taken up by the rubber mounts flexing, and I'm bound to me a few mm off in my overall measurements. Do I go with the furthest aft I can get it, or is my mount to big?

MartinClan · #7 26th April 2007, 19:07

Quote:

Originally Posted by GreatOldOne

I've tried placing the mounting bracket at that point, but I can't - the tunnel is too narrow at that point. The closest I can get the mount is 20mm further forward toward the engine bay.

Just how accurate do I need to be on this? Some of the discrepancy will be taken up by the rubber mounts flexing, and I'm bound to me a few mm off in my overall measurements. Do I go with the furthest aft I can get it, or is my mount to big?

I would strongly advise NOT doing it by measuring - you need to trial fit the engine and box. Just prop the back end of the gearbox up to start with and then try the fit of the mounting bracket. There is actually very little weight on the back of the gearbox as I remember - the engine almost balances on the engine mounts. As I mentioned I had to narrow my gearbox mount - but I don't think anyone else had this problem.

Cheers

Robin

peterux · #8 26th April 2007, 19:19

Jason,
Just install the engine and gearbox together and install the bracket afterwards. Mine was obvious once the gearbox is in place.

Like Robin says, the alignment of the exhaust is important and if I did mine again, I would leave a small scissor jack underneath until you've got the exhaust in postion. You can then tweak the gearbox up or down until it's right. The only advice I got from Mark was to set the engine almost level but tilting slightly towards the oil drain plug.

You need a fair old angle on the engine and box as you lower it into the engine bay, so make sure you have a enough room above the crane to get it high enough. And put some cardboard over the front cross member so you can rest the sump on there if you need to.

Good luck, it's a great milestone in the build.

regards

Peter

Patrick · #9 26th April 2007, 20:08

Have to agree put the engine and box in then mark the position of the gearbox mount. We did that with ours - had to take them out again to drill the holes.

peterux · #10 26th April 2007, 22:11

Quote:

Originally Posted by Patrick

When it comes time to spec the prop shaft we have all the measurements and the width of the doughnut. Unfortunately they made it the length between the diff and the gear box so we cant use it. Your probably best off giving the measurement between the diff and the doughnut!

The Marlin supplied propshaft won't fit the doughnut, even if the shaft is the right length because the flange fitted is a completely solid circular disc.
To fit the doughnut, you need a flange with cut-outs for the bolts that go through the doughnut.
I just fitted mine without the doughnut.

Peter

Patrick · #11 26th April 2007, 22:13

doh! I didn't get that far as there wasn't enough room to try it!

Alfie · #12 28th April 2007, 19:18

I must agree with the above advice. My gearbox bracket was a tight fit but managed to get it in without mods. Make sure hard plumbing is in and everything is protected........ I also ended up with a crushed brakepipe and I too know the feeling of having to do the clutch plumbing cos', like Robin, I forgot it before putting engine in!! What a b*gger of a job.
Alfie.

GreatOldOne · #13 30th April 2007, 12:11

Well, all the pipes are in place and ready to go - including the clutch! I'm just waiting on having some help available to help with the operation.

In the meantime, I'll start padding the vulnerable bits!

As for exhaust alignment issues - I'm going for the Marlin side pipes; Wouldn't this be a bit more tolerant on the angle of the engine?

peterux · #14 2nd June 2007, 20:41

Just an additional post note to anyone else about to fit their engine and gearbox.
I think my gearbox is mounted too high and my propshaft flange nearly touches the gear change mechanism.

With hindsight, I would fit the propshaft as well before finally fixing the height of the gearbox mounting bar. I would temporarly fix the bar with one 6mm bolt each side until your sure everthing is Ok before opening up to 8mm and drilling the other bolt hole.

Ignore this post, i later found that the gearbox mounting height had nothing to do with my propshaft flange rubbing on the gear selector rod.

Will5 · #15 23rd June 2007, 21:21

I have just tried fiting engine and gearbox, dinged the battery tray, dooh!

I should have read Patrick's comments before I started.

I have question, has anyone found that the gearbox sits at an angle? The bracket was attached to the gearbox before I raised it into the tunnel. It fitted into the tunnel, but an angle, it was about 1-2 inched higher on the dirvers side. I can see any obvious reason for it. Should I mount the bracket level and then try to pull the gearbox level, or should I leave it asis?

I am going to look at the engine mounts tomorrow maybe they arn't right.

peterux · #16 24th June 2007, 07:38

Wiil,
not seen that problem before? Mine was pretty level with the tunnel at floor level without any forcing. I think Robin's bracket was too wide and had to be cut down.

Just a thought, the bracket is not symetrical, so try turning it through 180 degrees and see if it fits better.

good luck in the rain,

Peter

Will5 · #17 24th June 2007, 17:55

Peter,

I have just tried to refit the engine/gearbox again, it fitted fine. I must have missed something yesterday, I suspect although I checked it wasn't on the mounts properly.

I now realise how tight space is, fitting the air cleaner is going to be interesting.

Thanks

Will

MartinClan · #18 25th June 2007, 15:18

Quote:

Originally Posted by Will5

I now realise how tight space is, fitting the air cleaner is going to be interesting
Will

Hello Will

Everyone uses an aftermarket air filter like Jetex - the BMW one is just to big. The fun and games comes when mounting the AFM (to which the filter is attached). Marlin make no provision for this so you have to make up your own bracket. Its quite heavy and has to be mounted sturdily. Take a look at some of the builder web sites - I think everyone has done it slightly differently! (Bit like the fuel system - but that's another story....)

Cheers

Robin