chewed up diff crownwheel & pinion

[CosworthCabrioLee]

Re: chewed up diff crownwheel & pinion

Dave if you decide to go down the Dolly route give me a call as I have a spare axle if its going to be of help to you.Number in pitstop of email me leezr160@hotmail

[stevejgreen]

Re: chewed up diff crownwheel & pinion

Did you order a nice outfit over the phone?

Congrats in advance on being a pioneer if you go the TR7 or rebuild route with Rimmers.

As you suggest, a second hand part never quite gives full confidence.

Please keep us posted on progress, it could keep several Marlins and perhaps Marinas on the road.
As a minimum, some quotation ref from Rimmers would allow others to refer to it again with a minimum of fuss, both parties being confident of the outcome.

A short dittie to Sue for Pitstop would ensure that it's always in the club history.

My Sprint axle was cheap (thanks Chris) but by time you have invested in all the necessary parts and new brakes and cleaned it up, it's close to a recon diferential price.

[beergutdave]

Re: chewed up diff crownwheel & pinion

Thanks for the offer Lee, I'll keep it in mind.
Regards Dave

[danny_nelson]

Re: chewed up diff crownwheel & pinion

Hi Alan, notes from my roadster days on axle ratios read
Marina 1300- 4.161, 1800- 3.636 Van 7cwt- 4.56 Van 10 cwt
4.556 Dolly 1500- 3.89 1850 manual- 3.63 1850 auto- 3.27
I did not record the differences in the Ital range, but I also have notes on the T R range. Look forward to meeting up with you soon. Danny.

[lil_red_roadster]

Re: chewed up diff crownwheel & pinion

Dolomite half-shafts (exc Sprint) are, AFAIK, a direct swap for Marina items. I recall a post or Pitstop article where someone went down this route...just can't seem to find it at the moment. The only thing to watch out for is that the keyways on Dolly shafts vary between 7/16 & 3/8...last time I looked Rimmers still listed them.

[dogoncrazy]

Re: chewed up diff crownwheel & pinion

Food for thought maybe?
Uprated Morris Minor conversions used the Marina axle but have it seems switched to more popular rear wheel drive Escort axles.I believe its also possible to convert the axle to the marina wheel Pcd. Memory is vague but seem to rember firm in Redditch that does the above [they may also have at one time supplied Caterham with Marina axles for the 7]

[stevejgreen]

Re: chewed up diff crownwheel & pinion

Ah, Alan, another can of worms and a book as a reply.
Working from memory. I know the risk in that, Escort axles are the same width, give or take a gnats. Yes the 4.25" PCD's are different and yes you used to be able to get different hubs to get to a Marina 3.75" PCD, you may still be able to. Perfectionists will swap all four wheels to 4.25" PCD so that means new hubs on the front, Hobsons choice!

BUT

As far as I understand, the greater offset of the Ford diff towards the drivers side make the use of a Ford axle almost impossible in a SWB Roadster and still needs some cockpit work for a LWB. Same 'sort' of problem as a Dolly sprint axle.
Cars like the Moggie and Marina have comparatively so much space underneath, Abigail could hold a party, around the prop. Some Roadster tranny tunnels barely clear the prop in an effort to accomodate a wider seat, so there is no way without serious surgery.
From memory Caterhams had enough space, just, but I have never compared them personally.

It is possible to take a wider, heavier duty Ford axle and cut them down in width and then weld them back together. Serious engineering as 1/2 shafts need shortening as well. I think it was done to suit the early Escort boys who were running silly power.
On that theory assuming you have an unlimited budget almost anything is possible, even a custom diff centred to suit a SWB Roadster that could take 200+Bhp quite happily.

On another track we could follow Jez Cox's thoughts of fully floating 5 link or de Dion setup welded under the back. If that could be done economically...................

I'm sticking with my Sprint Axle.

[beergutdave]

Re: chewed up diff crownwheel & pinion

Steve. Here's the latest on my dress fitting, er I mean diff saga lol. I spoke Allan at Rimmers Triumph dept and he has no knowledge of the TR7 and Marina units being interchangeable and was reluctant to check my unit over, which I found strange considering Rimmers maybe able to add another vehicle to their range, anyway, after further discussion it was agreed the only way to check was for me to purchase a crown wheel & pinion on the basis that if they didn't match I would return the items and recieve a full refund. So i agreed to his suggestion and ordered the said parts, subject to me paying for the items tommorrow (6/11). I then began thinking about stripping my unit down but realised that it had been a very long time since I last stripped and rebuilt a diff, so I desided to phone Rimmers once again. I spoke to a differant chap, whos name I didn't get, I asked if I could have the same arrangment on a fully recon diff unit, suffice to say I will be purchasing the fully recon unit. Ths chap seemed more interested about why I wanted to try the unit and understood the implications if it worked. Here are the prices I was given, firstly the crown wheel & pinion, £169 + vat and £10 carrage. The price of the recon unit I'd already ascertained from their web site, £276.46p inc vat + carrage and a £50 surcharge, redeemed after returning old unit. I don't think the prices are too extravagant because I know I'd have to slash out alot more if I were to have items made at a local engineering company. I will post more news once I recieve the unit. Regards Dave

[stevejgreen]

Re: chewed up diff crownwheel & pinion

Dave: It's a shame you got a bit of a run around and that I can't remember who I talked to, otherwise you might have had a more amicable solution.
At least you have a sale or return deal. I would expect nothing else under the circumstances.
As I suggested at the start, it's never been done before to my knowledge, but it's not just me who thinks it can be done. Please don't shoot the messengers if it all goes Pete Tong.

I can understand their reservations they are Triumph, not Differential matching specialists.
I once got a blank look from a Ford parts man when I asked him for a reversing switch for a Type 9 gearbox. He wanted the model and year of my car, so I told him. He thought I was taking the P. I managed to look offended!
Even if you bought the crownwheel and pinion you would have extra work and parts to buy, so it's not totally uneconomic.

I am now eager to see the result but Halifax is a long way from the South Coast.

PS. At the risk of offending staunch Marlineers, any info you manage to glean will also be of use to Morris Marina Owners and perhaps others. I often dual post between here and their FastMarina forum. They are a friendly bunch (generally) and won't hold owning a Marlin against you. You might even learn, as I do, a few more tricks of the trade.
http://www.fastmarinamagazine.com/index.php.

PPS. When you start work and posting results it might be nice to start a new topic. That way we might keep it clean of Ford/Dolomite/Sprint/Womens clothing/Ratio debates and preferably any fading memory posts.

Good luck with the fitting.
Lots of photos please.

Don't forget to buy the right underwear, you can ruin the look of a good dress without it!
(apparently)

[lil_red_roadster]

Re: chewed up diff crownwheel & pinion

Steve, since when did economics play any part in owning a kit car (or any car for that matter)...????

[donsayers]

Re: chewed up diff crownwheel & pinion

The 1.8 diff is stronger because the pinion is bigger having 11 teeth against the 1.3's 9. I would advise against rebuilding any axle where the gear teeth have got chewed up. The hypoid gears run at a very extreme pressure angle and they and the ball bearings require absolute cleandlines of oil. Any grit, even microscopic will cause pitting and fatigue of the gear surfaces and in the bearings, the chances of removing all of the grit resulting from the breakup of the previous gears is slim.

[listerjp2]

Re: chewed up diff crownwheel & pinion

Diif for sale on ebay might be of interest item number 130343617437

[beergutdave]

Re: chewed up diff crownwheel & pinion

Hi all, my TR7 unit arrived today. I have checked it against my old Marina unit and it looks very promising. There are some slight differances with the housing casing but nothing that would impose any fitting problems. The pinion, crown wheel and planetry gears are as per the damaged unit, although there is a slight differance in the planetry gear carrier, agian shouldn't impose any problems. The next step will be to actually fit the unit into the axle banjo but before I do so I want to double check things because if I fit the unit and find a problem my "sale or return" agreement with Rimmer Bros is canceled. I will post further updates and pics. Regards Dave

[beergutdave]

Re: chewed up diff crownwheel & pinion

Sorry, I seem to have problems uploading pics, I'll try rectify it. Regards Dave

[cdow]

Re: chewed up diff crownwheel & pinion

Just found this thread and have been reading with great interest, looking forward to an answer to the 'ultimate question' at the end, but I was denied!

Are there any updates on this please Dave, I think myself and a lot of others are hanging on the outcome your ground breaking work.

Cheers