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Manta a series axles

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Hi all, does anyone know the difference between the Manta A series 'small' and 'big' axles? And what kind of power they can each handle?

Thanks for any help!

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I might be wrong, but as far a i know there is only one size of axel. Are you talking diff size or width of axel? There are different ring gear ratios. But i think the 1.6 and 1.9 had the same diff. They did a limited slip diff and this has thicker half shafts so can take more power but the original ones are hard to find.

This is from the Opel workshop manual

http://www.theopelproject.com/shop-manual/opel-manta-axel.pdf

Im sure someone else will know a bit more about them.

 

Andy

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I’ve found two for sale on German Ebay, one labelled as a small from a 1600 and one as a big from a 1900. I’ve also spoken to someone in the uk about a rear disc conversion who asked if I was getting the big or small axle. I’m mostly concerned about any difference in the width but it would be good to know if anything else is different, particularly if one has a lsd 😁 

Here are the eBay links 

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The only difference between a 1600 and 1900 axle is the diff ratios

Generally, the 1.6 has a 3.67:1 and the 1.9 a 3.44:1, But a 3.89:1 or 3.16:1were also available. ( very rare)

I also noticed that the first link for the 1.6 axel, has an ally torque tube from a Manta B fitted instead of the standard steel one fitted to Manta A's

Manta B axels are the same as the A axel except for the ally torque tube and they are 1 inch wider.

If you find a Manta axel with an LSD fitted, then you are a very lucky man.

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I thought the LSDs must be a rarity!

Thats great though, cheers for the info :thumbup

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Axles fitted to 1.6N and smaller engines are different to those that were used on 1.6S and 1.9.

Not sure on all the differences, but I know the smaller axle uses smaller wheel bearings.

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You learn something new every day.

In that case, the 1.2 (never imported to UK) has a 4.11:1 diff and the 1.6N has a 3.70:1 diff

5aa2af0d8ac71_MantaArearaxelratios.thumb.jpg.a15ac032631867a2c8399f447f4db60c.jpg

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If the axle is from a UK car it should be the large one as we didn't get 1.2 or 1.6N engines here.

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Small c.c a series has chevette axle same as cavalier mk1 1.3. Other larger cc has bigger diff unit same as manta b large unit. 

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So the bigger diff that came on the 1900 manta a/manta b is capable of handling more power? What are the power handling differences between the small axle and the big axle?

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Is there a way to tell if its from an A or B? would you just have to measure the width?

The one without the ally torque tube looks better but you have no way to tell what the internals are like. Is there not one you can get in the UK?

The LSD was not fitted as standard and was add if you specified it. And yes they are very rare and you could only tell if you took the diff cover off.

A little disc conversion here.

http://www.theopelproject.com/?p=105

 

Andy

What power are you looking at? I ran 150bhp on the old 1.6 diff that i had without any problem. 2.1 CIH engine. Im not sure what the 1.2 axel would take but as previously stated we never got that model over here.

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Ok so I am looking at running a x25xe through it (170bhpish) so am just wondering if the smaller diff could handle it or I'd need to go for the 'bigger' 1.9 diff?

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For 170bhp and v6 torque you would want the bigger axle to be safe. You might get away with the small axle if you only ever drive steady, but then if you do there is no reason to fit a v6 ;)

Big axle is capable of around 250bhp apparently (assuming its in good condition) ideally by that point you want either the steel torque tube or to improve the bush mountings on the alloy one to limit movement.

As for axle widths i got this a while ago but have not yet had a chance to check all the measurements, i really should as i have an A, B and HS axle in the unit currently:

Width between drum backing plates:

Manta A  1230mm  Manta B  1285mm  Kadett C  1230mm  Chevette HS   1210mm

Width across brake drum faces:

Manta A  1400mm  Manta B  1455mm  Kadett C  1370mm  Chevette HS  1380mm

Distance between centreline of trailing arm to axle mounts:

Manta A  930mm  Manta B 930mm   Kadett C  950mm  Chevette HS  950mm

Distane between centreline of damper mounts on axle:

Manta A  995  Manta B  995  Kadett C  1020mm  Chevette HS   1020mm

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I would look for a UK 1.6 or 1.9 to be on the safe side as then you know its going to be ok. I take it that you have an A series? what axel do you currently have?

Mine is up in the air at the moment while i sort the engine and fit new prop doughnut so i can measure mine if you want?

 

Andy

 

 

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This is actually for a Chevette project,  which is why the width is important (thanks @mantasrme for all those measurements, very useful!) unfortunately I’m finding it hard to find any A series axles in the uk, which is why I turned to German Ebay.. looks like the big axle will be the safest bet if you think the v6 will be too much for the small one

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If you're running the X25Xe engine, you will definitely need the big axle.

You could go for a 4HA out of the scimitar SE5, lots of Ratios and Jag LSDs will fit in them. Altho it is a 4 link axle, if you do not wish to modify the car body with a little modification the axle can be fitted using the original mounting points. (I have a 4HA in my A series mounted on original points.)

What gearbox are you using?  The Manta 1.8 box is OK, but if you use the car in anger it will not last long. R25( Carlton with Mec speedo drive & clutch cable) or R25/28 ( Omega with hydraulic clutch & Electic speed sensor) are a stronger box, but bigger in size.

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I have a Manta getrag box to use, I do still have the hydraulic clutch box that was on the engine but I don't really want to alter the tunnel on the Chevette to get it to fit, also means no hydraulic clutch and speedo mods. Not sure if this an R25 or R28. I'm assuming the R25 Carlton box has the same size bell housing?

I also managed to find a prop from a Manta B auto which is the correct length for the getrag/manta axle setup on a Chevette, so would be nice to get an axle from a Manta rather than a 4HA or something else, although they're stronger(?) I'm not planning on going above 200bhp any time soon.. can you get stronger internals for the getrag box?

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The Manta getrag box is a 240 , the only difference between a 1.8 and GTE box is the starter is on opposite sides. The R25 is a bigger box from the Carlton.

I am running an X25XE in my A, was using a 240 box but broke 3 so have now changed to an R25.

R25 getrag box.

R25.thumb.jpg.9c61838bde160d039dea86f4fd999961.jpg

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Any bmw boxes fit a CIH?

More importantly, any fit a 1.8 or c20xe or x25 or x30?

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The same getrag box used on manta's was used on some BMWs.

Almost any gearbox will fit if you put a good bit of effort into adapting the bellhousing. You can get bellhousings 'off the shelf' to fit ford type 9 boxes to a CIH.

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Is there any way to strengthen the getrag 240 box to handle more power?

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Not that I know off.

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The bmw getrag boxes shared the internals with some opel boxes, but have completely different cases. Also i do not think it was the 240 boxes it was the monza 265 boxes that had bmw m3 internals (or something like that)

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Found this link and page 70 has a bit about the Getrag 240 box torque limit. 250lb for motorsport and then probably the interesting bit for road use is on page 71 which is not included on the preview!!

 

https://books.google.co.uk/books?id=xUDzd9WCQ8wC&pg=PA70&lpg=PA70&dq=what+power+will+a+getrag+240+gearbox+handle&source=bl&ots=uNt6xNKQTG&sig=38i9Cri8ZnRm48qRsHEhi-1B-ik&hl=en&sa=X&ved=0ahUKEwjpi6n38OfZAhWpJsAKHQFVDx04ChDoAQg0MAE#v=onepage&q=what power will a getrag 240 gearbox handle&f=false

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