DOHC MT75 ground clearance

[deezee]

I chopped the two lower gearbox bolt holes out of my sump when i reduced it by 35mm. I'm using sierra dohc 8v sump on my engine. I'm using the type 9 gearbox though. Engine is solid. Its ok without using those bottom sump to gearbox mounts.

[voucht]

I second Deezee : assuming that the type 9 has no lower mount points, removing the ones from the MT75 for ground clearance seems to be OK. It is necessary anyway to shorten the sump.

Speaking of that Deezee, how did you shorten your DOHC oil sump? Do you have pictures of it you could post here please? Did you do it yourself?

Thank you

[Matthew]

Hopefully losing the bottom 2 bolts isn't going to cause a problem. There are another 2 just above that I've retained as you can see in this picture



Once the sump has been cut back the end of the bellhousing will be flush with the bottom of the sump.

Matt

[deezee]

Yeah, did it myself with a TIG welder. Not pretty, but doesn't leak. Its welded inside and outside.

Edit: I don't have a photo of it fully assembled, but the sump sits the same height as the gearbox bellhousing.

Sump offered up against the Type 9 Gearbox


Sump and oil pickup have had 35mm removed from them


Sump trial fitted onto the engine

[voucht]

Thank you very much for the pictures, very instructive.

So you actually reduced the oil capacity of the sump, as the part you removed is not compensated by increasing the volume of the front part of the sump, am I right?

I roughly calculated. The inside of the part of the sump you cut off is more or less a 15x15cm square. Height of the cut-off part is 3.5cm, the lost volume is 15x15x3.5=787cm3 = 0.787 litres, so about 16% of the 4.75 litres the sump is supposed to hold.

May be it does not make a big difference, but could you please confirm it is OK and why?

If it is OK, I will definitely shorten my sump in the same way

Thanks a lot.

[deezee]

I've not had any problem with oil surge since cutting the sump down. I can only say what my experience has been, which has been spirited road driving (that is to say quick enough to squeal the tyres as the car tends to lift a wheel on cornering)

I fitted an Accusump to the car to control oil surge, but its not actually kicked in as the pressure has never dropped that low So a rather expensive and heavy backup system. Whether it would drop low on a trackday, I couldn't say.

[rapidtornado]

Think I set mine up so the bottom of the sump was 30mm below the bottom of the lower rail? I was a while ago now.
I have modified the inlet plenum to take about 40mm out of the height so it doesn't stick out too much.

I have a couple of pictures, they are not great but you can kind of guage how the engine is sat from the position of the pulley when viewed front on, that should be able to give you a datum for how high it is sat?

I Guess if I got it wrong when the nose cone arrives then I'm screwed

http://i1142.photobucket.com/albums/...o/IMG_4145.jpg
http://i1142.photobucket.com/albums/...o/IMG_4152.jpg

[Matthew]

Hi

Looking at the pics and the position of the water pump pulley I think you have your engine quite a lot higher than I do



I checked the clearance by propping a piece of wood on the scuttle and I'm going to need a bonnet with a scoop to get it to clear the front of the engine as the wood sits 20-40mm above the top of the nosecone.

Matt

[voucht]

Originally Posted by deezee

I've not had any problem with oil surge since cutting the sump down. I can only say what my experience has been, which has been spirited road driving (that is to say quick enough to squeal the tyres as the car tends to lift a wheel on cornering)

I fitted an Accusump to the car to control oil surge, but its not actually kicked in as the pressure has never dropped that low So a rather expensive and heavy backup system. Whether it would drop low on a trackday, I couldn't say.

Yes, Accusump are very good devices, sorry for you it never had to work, but it was wise to put this security in the first place
It is rather a good news for me that you say you engine never suffered any oil surge, and as I don't plan to go on tracks with my roadster, I will certainly shorten my sump in the same way as you did. Very useful info for me.
Thank you very much for the reply

[big_wasa]

Mine is a zetec to mt75 but that also leaves the sump an inch lower than the sump so good or bad I cleaned the gearbox up to match.