MGB Engine and Gearbox Fitting

[Mike]

Re: MGB Engine and Gearbox Fitting

With regards the fan I had allot of problems last season with overheating which culminated in a new rad. I did however try moving the electric fan to the front of the car between the rad and the grill in order to give me more space, in hind site I think this is a little less efficient and I will at some point move it back, so if you can squeeze the fan inside the bay I would recommend it. these 'B' series engines do run hot.

Mark

Looking at your nose cone, I think you could improve your cooling by closing the gap in the nose cone above your radiator. Air will take the least line of resistance and so flow through this void.
Its a fairly easy job to make a triangular plate that attaches to your radiator, or bond a piece of GRP to the nose cone itself. This will then force the air to go through your radiator.

Radiator air dam.jpg

[velovol]

Re: MGB Engine and Gearbox Fitting

Hi Steve, I see that I have a message from you but again am unable to open it. Maybe you could e-mail me at [email protected]. Brian.

[listerjp2]

Re: MGB Engine and Gearbox Fitting

Hi guys

If I have the wrong end of the stick please accept my opologise.

Below are the extracts from the build manual and they state the differences between the A and B series instalations.

On both my cars they had the engine mounts for both engines.

You may have to do a bit of work on the gearbox cowl

Adrian

Page 1.jpgPage 2.jpgPage 3.jpgPage 4.jpg

[velovol]

Re: MGB Engine and Gearbox Fitting

Thanks everybody for all the useful stuff and photos you've posted.

With the gearbox mounting I've decided the simplest route is to mount it on a crossmember. I'm looking at 30mm sq tube at the moment with vertical plates on the ends fastened by four 8mm bolts at each end in tapped holes through the chassis rails which will make it easily removable. As this position is at the base of the screen hoop this looks to be right to me.

Propshafts should in their normal load positions run straight but it's not the end of the world if they don't. You just need to replace U/Js more often. Anybody remember Spitfires etc ?

My comment about wanting to fit a permanent fan (as well as an electric) is because I thought the under bonnet temperatures were excessive and a constant throughput of air would be helpful for carburation and lowering the general engine temperature.
I had been using an electric fan mounted on the front of the original Viva radiator which worked, but was all a bit touch and go. The original electric fan failed going through Salisbury on a one way street during the evening rush hour and was not a happy experience !
I've now got a re-cored Austin 1800 rad which is much more the right size which will be going in soon with both electric and engine fans.

[andy4]

Re: MGB Engine and Gearbox Fitting

My chassis had mounting points for the B series so I just used these - The metal brackets on the engine itself may be different between Marina and MGB - I got some Marina ones, so if it looks like it won't line up that might be worth a look. Cooling Fan wise I ended up fitting an electric one on the front of the radiator as well, but left the mechanical one in place - might not be optimal but works fine, and the electric one is good as it will run when the engine is stopped of course, should the electric one pack in for any reason I still have the mechanical. My mechanical plastic cooling fan has about 25mm cut off the ends of the blades for clearance.

Air filter wise I started with the very narrow pancakes shown in the pictures but these were a very tight fit - the original aim was to avoid cutting the bodywork. Now I have much wider K&N filters and the front one required a cut in the bonnet and side panel - it actually looks ok and is certainly better in terms of the running of the engine - I'll take a picture of the new setup when I have the car out on the weekend.

Like you are proposing I used the gearbox mounts cut from an MGB cross member, and was hoping just to use a simple box section across the chassis - in the end Chards fabricated me a cross member similar in design to the MGB one - this allows the mounts to sit slightly lower - again I'll try to take a picture under the car on the weekend. Rather than drill the chassis I used angle brackets welded to the inner face of the chassis - Have been a bit paranoid about drilling holes in the chassis as it is pretty rust free and I am convinced this is helped by the fact there are very few places water can get inside the Marlin chassis. The dimensions in the manual for the gearbox position off the tunnel of course assume the shorter Marina box.

[stevejgreen]

Re: MGB Engine and Gearbox Fitting

Standard MGB mounts are different from the Marina, whether engine or gearbox. So a bit of fabrication is required. I have never got to the bottom of the various gearbox mounts supplied by Marlin. Assuming all normal builds were fitted with rear axle spacers it seems unlikely to be as a result of propshaft angle, that tends towards the horizontal under normal loads. It may be as a result of using thinner engine mounts in order to give additional clearance for the SC 1800 over the A Series.
The 'ideal' for a propshaft UJ is horizontal but this is a rare occurrence in normal driving. More important would be the alignment between the output shaft of the gearboxand the input shaft of the differential. Again this may be a factor in the gearbox mounting.
I have heard that the nose of a differential should ideally be angled downwards but I have no information to confirm or deny this, perhaps someone can help.

I did detail a lot of info regarding the installation of a Chevette Radiator at http://kvisit.com/S1cb2AQ incuding the suggestion of closing off the surrounding airspaces around the radiator, not so easy to make a permanet fix if you need access to a top mounted pressure radiator cap. One suggestion is to use commercial grade pipe insulation that will tolerate the temperatures found at the top of a radiator. It must be remembered that this will only have an effect if the vehicle is in motion, absolutely pointless in stationary traffic without a backup fan.

[mark westbrookwhite]

Re: MGB Engine and Gearbox Fitting

Thanks Mike, at the moment I have a piece of pipe insulation stuffed in there to help but I do need to do something more elegant.

[mark westbrookwhite]

Re: MGB Engine and Gearbox Fitting

h.m.cumming1 sorry don't know your name can you please tell me where you got your remote radiator cap that looks fantastic.

[h_m_cumming]

Re: MGB Engine and Gearbox Fitting

Hi Mark,
I think this is the one I used

http://www.cbsonline.co.uk/category/Braking_and_Clutch_System/Braking_System_Tools/Header__Breather_and_Oil_Catch_Tanks/Header_Tanks__Caps___Necks,b.html?page=1

Hugh.

[velovol]

Re: MGB Engine and Gearbox Fitting

Hi Mark,
Sounds as if you have got a bit further on and I'd certainly be interested in any photos you manage to take of the gearbox mount.

One reason I'm doing belt and braces on the cooling is that I've got a 1950 Sprint engine which must produce a few more calories than the original design thought of.

[petermarlin1798]

Re: MGB Engine and Gearbox Fitting

I used an MGB gearbox crossmember and got it adapted sit horizontally, bolting it to the chassis sides. I'm very impressed with the photos of the installation. Certainly much tidier than mine. Re the tunnel, I made a mess of aluminium sheet rivnutted together and covered the sorry lot with carpet.

[mark westbrookwhite]

Re: MGB Engine and Gearbox Fitting

Please find below pictures of my gearbox support. I hope it is of use.
It was difficult to get a decent picture so if you need any specific info dimensions please let me know.
Mark.Support 3.JPGSupport 2.JPGSupport 4.JPG

[velovol]

Re: MGB Engine and Gearbox Fitting

Hi Mark, Thanks for doing the acrobatics, that looks as if it should do the job. I'll post some photos of mine this week I hope. Brian.

[velovol]

Re: MGB Engine and Gearbox Fitting

Finally got some time on the Marlin and finished the gearbox cross-member and fitted it, all seemed O.K. ! It's got to come out again for painting. I'll attach a couple of photos for the benefit of anyone else going down this route. I've also got an MGB gearbox cross-member surplus to requirements, free except for postage.Marlin Gearbox Support 002.jpgMarlin Gearbox Support 005.jpg