Gerabox and Engine Rebuild – Page 2

25 October 200917 June 2018

25-Oct-2009

A very successful weekend. The gearbox has been put back together and now all that’s left is to make a start on the overdrive. The covers of the gearbox still need to be removed one last time so the gaskets and oil seals can be fitted but I wanted to make sure the selector mechanism worked before I did this. The other issue left is I still need to buy the correct oil seal for the front of the gearbox as the one supplied in the overhaul kit was the incorrect size. This shouldn’t be a major problem as a bearing company in Norwich stocks them and while I’m there I will also need to get a replacement bearing for the overdrive as one of them feels a bit worn.
Hopefully if all goes well I can get the overdrive back together tomorrow afternoon.

23 October 200917 June 2018

23-Oct-2009

Spent the day stripping down the gearboxes and overdrives. Overall this was relatively easy job and the only difficulty part was dismantling the gears on the main shaft. The problem was the shaft from the Type 5 gearbox was too long so it was impossible to use a bearing/hub puller to remove the bearing so the individual gears could then be removed. To overcome this the only option left was to pop down the local machine shop and use their hydraulic press (cost me a fiver). Once the gearboxes was stripped I gave the items a quick clean so I could check the condition of the parts. The parts will still need to be cleaned more thoroughly before I can start reassembling.

The selection of parts can be seen in the photo below, hopefully I can remember how it all goes back together!

20 October 200917 June 2018

20-Oct-2009

One of the biggest issues with the 1970 3 Liter V6 is the gearing, basically it was all wrong from new. With the ratios in the original 4 speed gearbox and overdrive along with the 3.77 axle ratio it is impossible to reach 60 mph with out changing into 3rd gear (this is probably why the quoted 0-60mph times are worse that really should be.

In my opinion their are two issue with the gearing. One is the final ratio of the axle is to high and the second is the ratios in the gearbox are not very well space. As my car is fitted with the ford English axle with a 3.77:1 differential there is not much I can do to improve the ratio in the axle. It is possible to get a 3.54:1 crown wheel a pinion for this axle but from the opinion of other owners it really needs to have a ration of 3.09:1 or 3.22:1 (this is what the 3 Liter Capri had fitted. With is in mind I eventually plan to replace the rear axle with the an Atlas Axle from the Ford Capri(this will be a future project).

The other area that I think is correct is the ratios of the gear box. I think there is a large jump from 2nd to 3rd which is far from ideal (especially on a race track). The list below shows the ratios shows the ratios of the original gearbox along with some other ford gearboxes that could be fitted. As you can see from the table most of the ratios are similar with the exception of the 2nd gear ratio.

Ford Gearbox Ratios	1st	2nd	3rd	4th	5th (4th + Overdrive)
Zodiac Mk4 4spd	3.163	2.21	1.41	1	0.82
Capri V6 Type 5 4spd	3.163	1.94	1.41	1
Sierra Cosworth type T5	2.95	1.94	1.34	1	0.8
Sierra five speed type 9	3.65	1.97	1.37	1	0.82

There are several advantages and disadvantages of the different gearboxes. The Type 5 4spd would be a straight swap but you would loose the 5th gear(overdrive). The T5 and Type 9 would be stronger by I would require a different bel housing. The Type 9 also had a cable clutch which would also require further modifications. The Type 5 and Type 9 are cheap and easily available second hand unlike the T5. I was actually having problems trying to decide which gearbox to go for when I discovered that it would be possible to take the gears from a type 5 gearbox and fit them to the Zodiac Gearbox this would solve the problem of the 2nd gear ratio, the car would still look original, wouldn’t require any modifications to the car (e.g. clutch and gearbox tunnel) and it would be cheap as Type 5 gearboxes can be found for about 70 on ebay. The only downside would be that the gearbox would not be as strong as a Type 9 or T5 but as my engine isn’t tuned I can’t see this being a problem.

With this being my forward plan I’ve actually bought a Zodiac Mk4 gearbox and overdrive as well as a Ford Type 5 gearbox. This means I can spend time trying to make a hybrid gearbox out of the two with out having to take the Marcos car off the road. The Phot blow shows my Donor Type 5 Gearbox along with the 4 speed gearbox and overdrive that I plan to upgrade.

17 October 200917 June 2018

17-Oct-2009

After traveling over 2000 miles in the Marcos since I completed the restoration I decided it was about time to fix the rear wheel bearings that have been rumbling away, even as loud as the engine and exhaust is I couldn’t keep ignoring it as I’m sure it was getting worse. Stripping down the rear axle and removing the half shafts was relatively easy but removing the old bearings from the shaft was quite a bit harder than expected. I really should have expected this as on the Ford English Axle ford rely’s on a friction fit to hold the bearing in place.

The bearing is kit actually consists of two part, one is the bearing and the other is a metal ring that is also pressed on the shaft to help keep the bearing in place (see photo below). The first step in removing the bearing was to place the bearing in the vice and squeeze the bearing across its diameter. As the bearing is made out of hardened steel (and it’s slightly worn) the outer race will shatter just leaving the inner part still on the shaft. Luckily the metal ring is made out of normal steel so it was possible to carefully cut about 80% through this ring with out damaging the shaft. once this was done i hammered a chisel into the cut causing the ring to open out making it slip off the shaft. Once this was done it just left the inner section of the bearing on the shaft. this was the difficult part to remove. First I tried brute force of punching it of when this failed I tried grinding through the bearing but gave up on this approach as I feared I would end up damaging the shaft so the final approach was using the oxy acetylene bottle to heat it up and then knock it off. This worked in the end but it took me and my father over 2 hours to remove the old bearings.

Once the old bearings had been removed the next challenge was to fit the new ones. As they had to be pressed down over the entire length of the shaft I ended up using a piece of scaffolding pole and a large sledge hammer. This worked well but yet again was a two man job.

With the wheel bearings replaced the next job was to remove the diff while the half shafts were removed so I could to check the differential as I believed their was slightly too much back lash. Once this was removed The backlash was measured at about 0.4mm (should only be about 0.13mm) The job of adjusting this is quite simple so now all I’m waiting for is a replacement gasket to arrive so the rear axle can be reassembled.

22 August 200717 June 2018

22-Aug-2007

Today has not been very productive as I was trying to fit an alternator to my car. However after spending the best part of the day I admit defeat. The problem was caused by the alternator body having a larger diameter than the dynamo so it causes the alternator to hit the rocker cover. If I was to use a slightly longer fan belt or make a different bracket the alternator would fit without any problems but the fan belt would then hit the steering column. After a day of trying different brackets, and fan belts I’ve given in and decided that I’ll keep my car original and fit the dynamo to the car. The only other bad thing to happen is I managed to repeatedly scratch my rocker covers trying to fit the alternator so these need to be removed and painted again.