ST170 Puma with 6 speed box

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Noobrider

New member
Joined
Nov 1, 2013
Messages
425
So after a good days track driving I was hooning down the start finish straight at Croft in my little 1.7 track car and spied a Mk4 Fiesta in my mirror - I says to the passenger I'll slow down and have some fun with this car only for him to pass me like I was stood still and me unable to make any ground on him at all - I later chat to him to find out he has Focus ST170 engine in it with throttle bodies and an IB5 gearbox - I was impressed and a thought seed was planted.

Turns out ST170's are cheap and plentiful and I was actually approached by one of our car dealers that had one that had a bent chassis leg but otherwise was pretty mint - £450 later I used it as a daily for a week or two in preparation for the swap

So the big day came and we whipped the old Focus engine out and completely stripped it of everything - the plan was to pretty much transplant everything out of the Focus into the Puma - how hard could it be? Budget wise we were going to keep it simple - use the Focus engine and box, ECU and wiring to start with - no need for throttle bodies and fancy ECU's
 
Next step and all too familiar one - engine out of the Puma - done this so many times it was a breeze and then drop the ST engine and box into the hole left
First big problem - the standard inlet fouls on the brake servo and it just doesn't fit - quick solution - remove the brake servo for now so the whole lot was stripped out including the pedal bar - we were thinking pedal box

So we get the engine and box in the bay and start to line up engine mounts and drive shaft angles - this was fairly easy and we did a bit of cutting and modified the ST gearbox mount, drilled a hole in the O/S chassis leg and made a lower mount from some box section and utilised the Puma lower mount

 
Thanks Barry, always good to meet up with you at SHerbourn - you inspired me to do this write up and get me back on the forum
 
So with the engine in the problems start to mount - first up is the exhaust. The ST manifold is at the front and has some really weird bends - it also fould on the fan and would be very close to the radiatior.

We started chopping up the original manifold and managed to make an equal length 421 to join into the oriiginal Hoffman pipe keeping the Miltek back box and joining the two with a short flexi

The sound is lovely and she pops, bangs and burbles on the over run.
 
Slightly relocating to radiator and using an aftermarket push pull fan solved the clearance issue finally on the exhaust front

Next issue was the power steering pump - it was touching the O/S headlight - a quick solution was to remove the actual plug and run a hard wired set up - Time to wire it up and see it runs
 
Wiring is not my strong point but my son seem to know what he was doing so all the Puma wiring was removed - the ST engine has 3 main looms, one on the engine and one for each side of the car. We knew we had to remove the heater matrix for the gear cables and do we set about working out where everything was going to go

At the same time I drilled a hole for the gear cables and fitted them in place. The pedal box had arrived and put in place loosely and other issues were now begining to show
 
The pedal box was a specific Puma made version but it was clear the seat had to go back a fair way to make it comfy. I'm only 5'8" but I had to move the seat as far back as it would go in order to have a decent leg set up. This meant the steering column had to be extended. Easy solution was a quick release boss and a deep dish wheel but the angle became stupid to the point you couldn't see over the wheel. I lowered the column by undoing the two bolts holding it and remounting about an inch lower - Perfect
 
PLumbed the pedal box up after removing the ABS pump - the pedal box has a brake bias screw system fitted with a single master cylinder for each front. back and clutch. Decided to mount the resevoirs on the front dash inside - I have been told that this isn't acceptable for motorsport but its only a track car so no issues plus it has proved useful to keep an eye on the levels.

new lines were run through the whole car one to the front T pieced and one to the rear T pieced - also had to make a clutch flexi pipe out of a front brake flexi
 
Now for one of the main issues using the 6 speed box - Drive shafts.

The Puma ones don't fit in the gearbox end but the ST ones do - however they are 30mm too long - spoke to a local engineering company who actually make drive shafts and gearboxes for those great gig wind turbines. One of the guys agreed to machine up the Focus ones. They were cut in half with the 30mm removed, then centre drilled and a carbon steel threaded bar screwed the two halves together. This was was then welded and a sleeve put over the top which was then drilled and welded again, finally they were balanced - these have not given me any issues whatso ever and considering they just cost me a free service on the guys car were my biggest bargain.
 
some finishing touches - fitting the IMRC and welding up some plates in the engine bay tidying things up and getting the engine running.


I had to wire all of the focus lights into the Puma plugs and also fit all of the Focus switches, indicators wipers lights etc

I couldn't fit the power steering pipes as the fittings were all different but not really a problem for now - she started up first turn of the key - time for a test on track
 
So she was looking good but in road testing was generating a lot of heat under the bonnet

I decided to fit bonnet raisers and certainly day to day driving these made a big difference. Out on track I was hoping there would be enough airflow to keep those temps down.



So we went to Croft and the drive there was great - I hadn't booked on but was going to do a quick swap with one of the guys we went with just for a trial run. Here is the video - I know sometimes these can be boring but this one has a bit of all sorts in it.

https://www.youtube.com/watch?v=txyZnMofoWg

you may guess by the video title - I had a problem.

Initially everything seemed fine but the brakes are not the best having no servo, takes a lot of leg power to stop it, however I was still on standard Puma brakes. The steering wasn't great with no power steering and driving the car was giving me a full work out. I was hitting some top speeds though managing 130 mph at one point and the increased torque was changing my style somewhat as it would spin the front wheels up if you didn't feed the throttle.

Then cam the big issue - the power steering pump needs fluid in it...it overheated and set fire to the grease I packed it with eventually snapping the pulley off and cutting a water pipe.
 
I solved the power steering pump issue by making a bracket and adding a bearing pulley .

One issue I didn't really take notice of but did happen a couple of times was not being able to select gears - this was not a problem when driving the car daily or to the track but the next time on track it would be a massive issue.

I had booked on track at Silverstone at Ford Fair and again the drive down was perfect out on track though a number of times I could not select gears watch the video as they pack up at crucial times https://www.youtube.com/watch?v=wSFq0gToKSw

Took me a while to figure this one out but after losing all the gears at 3 Sisters and having to drive home with no clutch I figured that the clutch fluid was boiling. Indeed I was running 5.1 in the brakes and having no issues but for some reason I just had DOT 4 in the clutch.

I have no idea why it boils the clutch fluid as the engine and gearbox was lifted out of the original car as one and it worked fine in the Focus. I have replaced the fluid with RBF660 but have yet to use the car in anger as the MOT has now run out and I need to get that sorted before going on track again.
 
yes I did but Barry pointed out to me I hadn't put it on here so I'm doing a review
Started it last July I think - we are up to date now so anything after the last post is new stuff
 
Pumajay - you have seen the Facebook updates lol - Brian' thanks very much - its all about setting it up now cage is the next bit to get sorted although I am currently painting the ST brake calipers after a full refurbish
 
as an addition to my work load I bought a Millenium to restore - its actually in very good condition as its been garaged for the last 18 months but needs a new fuel tank (ordered) and a few other bits including a coil spring ( also in stock)
 

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