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Sump to gearbox plate
Posted: Sun May 29, 2022 1:35 pm
by martinclan
Does anyone know the purpose of the sheet metal plate, welded to the sump and bolted to the bell housing, when the B series engine is installed?
Considering the bellhousing is bolted to the substantial rear engine plate it seems rather superfluous to me.
It's also a pain to get the bolts in and out!
Cheers Robin
Re: Sump to gearbox plate
Posted: Sun May 29, 2022 2:28 pm
by balmy
martinclan wrote:Does anyone know the purpose of the sheet metal plate, welded to the sump and bolted to the bell housing, when the B series engine is installed?
Considering the bellhousing is bolted to the substantial rear engine plate it seems rather superfluous to me.
It's also a pain to get the bolts in and out!
Cheers Robin
It’s a bolt head grinding platform!

Re: Sump to gearbox plate
Posted: Sun May 29, 2022 5:28 pm
by martinclan
Ah - sacrificial skid plate. Like F1

Re: Sump to gearbox plate
Posted: Sun May 29, 2022 6:34 pm
by MarinaCoupe
Maybe like formula one, but also it’s a strengthening plate tying the engine and gearbox together, especially given that the 1.8 has its front mount is right at the front of the engine and the gearbox mount is at the rear of the gearbox. I’m guessing that BL had some strength worries.
Re: Sump to gearbox plate
Posted: Tue May 31, 2022 6:34 pm
by martinclan
Thanks Chris. That was what I was guessing. But odd that it doesn't exist on the MGB which must have similar engine mountings.
Cheers Robin
Re: Sump to gearbox plate
Posted: Thu Jun 02, 2022 5:34 pm
by martinclan
I now know the reason!
It turns out that the Marina back plate is about 1/8" thinner than the MGB one. Hence the sump plate to add some strength and rigidity.
Cheers Robin
Re: Sump to gearbox plate
Posted: Sun Jul 31, 2022 7:15 pm
by martinclan
For the anoraks (that includes me now) here is a picture of the Marina (left) and MGB (right) backplates.
back_plate by
Robin Martin, on Flickr
Can't see from this picture but the Marina one is quite a bit thinner than the MGB one.
And the refurbed engine.
engine10 by
Robin Martin, on Flickr
Cheers, Robin
Re: Sump to gearbox plate
Posted: Mon Aug 01, 2022 5:09 pm
by MarinaCoupe
Pretty, pretty
Re: Sump to gearbox plate
Posted: Sat Sep 17, 2022 1:36 pm
by PeterJ
Hi Robin, I sent you a pm but perhaps I can ask you (or others) here since I've found this thread. In a distributor thread, you mentioned that a Marina crankshaft'd engine is no good for an MGB. I'm hoping the reverse doesn't apply as I've just picked up an MGB engine. Chris had already advised me about the backplate and flywheel which I'm ok with (also the front plate due to engine mounting differences). Are there any other issues I will have to deal with?
Thanks in advance, Peter