Marina based Roadster rear diff/axle

[christopher.bogue2011]

Hi,can anyone help?
I have a Marina based Marlin Roadster(short wheel base) which has been off the road for ten years and is now being rebuilt. When I took it off the road back in 2000 I had recently fitted a Fiat 2ltr twin cam engine with five speed box but kept the origonal 1.3 rear axle. It is my wish to try and lower the revs by fitting either a 1.8 diff which is the easy option or to change to something else. I have heard that there were some Ford Capri axles fitted to Roadsters which would be stronger than the Marina. Is there anyone out there that has done this mod? I would be grateful for any info.

[CABRIOBOB]

Re: Marina based Roadster rear diff/axle

Chris, I understand that someone fitted a Capri 2.8 axle in a LWB Roadster in 2005. I am not sure if a Marina 1800 diff will fit a 1300 axle. Some members are fitting Dolly sprint axles when they can get them.

[stevejgreen]

Re: Marina based Roadster rear diff/axle

This has been discussed on and off on this forum a little searching for differentials or axles will turn up loads of info.
If you have an original 1.3 Marina differential it will have a 4.11 ratio. The 1.8 is 3.63. It is considered that the 1.8 is tougher than the 1.3.
The differential centre can be swapped by simply pulling the halfshaft and unbolting the complete centre assembly.
Some Trials Marlins were fitted with Marina Van axles but these were a very different beast and are now very rare.
Sources of Marina diff centres are from TR7 (4speed) Dolomite 1850 (not Sprint)

Other than that you are into axle swaps. The first problems are that all the suspension brackets will need removing and new ones welding in place, also the diff nose will vary so the prop shaft will need shortening.
Possibly the best is to use a Dolomite Sprint primarily as the wheel PCD is the same as in the track. This has a ratio of 3.45:1.
I have completed and documented this on fastmarinamagazine.co.uk.
Other axles can be fitted but there may other problems as the diff centre castings will be larger with a greater offset so will not fit between the seats on a SWB car.
If you would like more help contact me direct at stevejgreen(at)btopenworld.com

[CosworthCabrioLee]

Re: Marina based Roadster rear diff/axle

Chris the way to go is a dolly axle route, I have fitted one of these to my Lotus powered Roadster LWB, would also recomend anti tramp bars and a panard rod too and for good measure a rear disc conversion. I have a couple of spare dolly axles so if you want any dimensions let me know.

[danny_nelson]

Re: Marina based Roadster rear diff/axle

Hi Chris,
Escort axles have been used, there is a member in Evesham with a Fiat swb using an Escort axle. There have been several using a Capri,one of these had the axle machined for width. I have a Roadster at present using a Toyota axle which is 4 inches wider than the Marina, the wings have been made wider, and the front adapted. It all depends on how much you are prepared to change.

[listerjp2]

Re: Marina based Roadster rear diff/axle

Hi danny
Interesting!
As you are aware I have a toyota 1.6 engine and 5 speed box from a Corolla. Do you have any pictures of said vehicle and can i ask what mods appear to be carried out (other than bodywork) to make it fit? If not I could come and have a look for myself. Let me know when you are available.

[danny_nelson]

Re: Marina based Roadster rear diff/axle

Hi Adrian,
Have a look on powell cars.net. This was built by Gwyn Powell, it has the 18RG Twin cam engine and everything came from a Celica. Are you going to Exeter this year?

[CosworthCabrioLee]

Re: Marina based Roadster rear diff/axle

Hi Adrian did you get your parts ???

[tim hawkesworth]

Re: Marina based Roadster rear diff/axle

Hi Chris,
Please see my posting to Paul on the "Roadster Mirrors" posting above
Tim

[christopher.bogue2011]

Re: Marina based Roadster rear diff/axle

Thanks guys for all your comments and advice regarding the rear diff.It is greatly appreciated.
Steve, does the 1.8 diff fit the 1.3 casing without any mods and if so any ideas apart from the Marina O.C. where I can get one?
Lee I am not a million miles away from you so would love to pay you a visit sometime to have a look at your roadster setup.
Tim, it is my intention to subscribe to the MOC soon. Call my absence from the club a sabbatacle - Career and stuff!!
Regards

[listerjp2]

Re: Marina based Roadster rear diff/axle

Hi Lee
Yes thanks, heavens knows where the other one went? oh well. Many thanks. Adrian

[CosworthCabrioLee]

Re: Marina based Roadster rear diff/axle

Hi Adrian dont forget the 1 million pounds please

[CosworthCabrioLee]

Re: Marina based Roadster rear diff/axle

Hi Chris welcome anytime.........

[listerjp2]

Re: Marina based Roadster rear diff/axle

Hi Lee, its on its way + a little bonus of another million. How about double or quits. If you can answer this simple question -What is a Pissal Stick?

[cameronfurnival]

Re: Marina based Roadster rear diff/axle

Adrian! Im shocked! A farmer question on here!!! lol