View Full Version : Reliability of moding a 6 year old cossie

Andy Banks
3rd April 2000, 02:27
So people tell me it is quite easy to modify a (big turbo) escort cosworth to get 320hp (bigger injectors, fuel pump, chip, exhaust).

But for a 6 year old car is it going to be reliable? Wouldn't want it to go BANG!

Any thoughts?


[This message has been edited by Andy Banks (edited 03 April 2000).]

3rd April 2000, 09:31
Hi Andy

There are too many variables to encompass without seeing the car but a reputable tuner will always be able to advise. There is nothing wrong with modding an "old" car as when done properly new parts are fitted most of the time.

It is well known that the Cosworth motor is massively strong and tuneable.

Depending on where you are in the country you would try very hard to do better than Mark Shead at M.A.Developments. You can reach him on 01628 671056.



3rd April 2000, 16:12
Hi andy

330BHP on the big turbo escort cosworth is quite straight forward to achieve.

Age doesnt really matter, its more down to condition.

in order to make sure it is reliable you need to fit a group A head gasket before you do anything else, they are not expensive, about 90. If you are not doing the work yourself then expect to pay about 500 at a cossie specialist.

During the head gasket change it will be easy to see if any minor jobs need takleing, it is quite common to have a couple of exhaust studs missing for example. It is also a good idea to have a minimal skim done on the head to ensure it is totally flat for the gasket to seal. Make sure it is the minimum as you dont want to raise the compresion ratio during this skim!

once rebuilt you will need to fit 4 new green fuel injectors, 4 AGP601P spark plugs (these can be purchased from ford suppliers like quickco and are a group A spark plug) a 3 bar MAP sensor, a piggy back board and new chip for the ECU and a -31 actuator. The fuel pump also needs changing to a higher spec on the escort cossie, the sapphire cossie standard pump is OK on this spec.
The engine will also need to be de-cated for anything above 270BHP so you need to add this to your costs.

The upgrade kit will cost around 1200 if you are not doing the work yourself. The 330BHP conversion makes a huge difference to the car and is well worth the expense.

Another thing to bear in mind is that the clutch will probably need replacing as you will see clutch slip at max torque on the standard spec. I would suggest you use an AP Racing Group N pressure plate and organic uprated clutch plate on this spec again from AP racing. Dont fit a paddle clutch on this spec, it isnt needed and is a pain in the arse in traffic.

There are plenty of reputable cossie specialists who will do a good job of this upgrade, i would suggest you ask the question as to wether they have had there maps altered to take into acount the drop in SUL from 98 to 97RON. If not you will need to budget for running on SUL with 1% octane booster to prevent pre-ignition.

Dont ever run this conversion on 95Ron unleaded or LRP, you will damage the engine with 95 ron and some LRP fuel will damage the turbo exhaust turbine blades.

If you need more info on who i can personally recomend then please mail me, i intend to keep this forum free of specific tuning companies propoganda.

You should expect this conversion to give about 30,000 trouble free miles if done properly, usualy the head gasket gives up at about that sort of mileage and is simply a replacement job. If you want to have it more bullit proof than this then you can have the block studded and use a 3 layer metalic head gasket but the cost goes up considerably and is overkill on this spec of engine. When you get to the same sort of spec's as mike rainbirds 420BHP cossie then this sort of work is esential for reliability but for what you are trying to achieve it is not needed.

Andy Banks
4th April 2000, 14:10
Thanks very much for the tips both of you.

Only had the car for a week now so I'm going to keep it for a month or so before changing anything. Currently it is totally standard and appears to have been looked after quite well by the previous owner.

As for tuning companies, that's a bit tricky, as both the car and myself are in hongkong. I have found a cossie expert who seems to know what he's doing. But these cars are quite rare here so I wouldn't have much choice.

Is there a lot of setup/tuning required after adding the piggyback board/chip etc, or is it really just plug in and go. E.g. fueling mapping, isn't it very specific to each car? Fuel mapping on two cars, even the same model, may be different?

For now, 227hp is adequate, but when I step into the STi I really notice the difference. Turbo lag is quite excessive on the cossie, whereas the WRX picks up almost instantly and has a lot more punch.

I suppose this is due to the big turbo on the cossie, and the 330hp upgrade would still suffer from lag...but would the spool up time be improved?


[This message has been edited by Andy Banks (edited 05 April 2000).]

6th April 2000, 00:12

The escort cossie is an awesome car (STEF http://bbs.22b.com/ubb/biggrin.gif http://bbs.22b.com/ubb/biggrin.gif). The mod's that have been described here are exactley what I had done to mine.

Under no circumstances must you go to this level without changing the fuel pump to a high flow rate. It is also imperative to have the car rolling road tested after the conversion.

As far as having the ecu mapped to your specific car - I would say yes. I had a pre-programmed chip, but the fueling was way over the top. I then went back to the original tuner, and the fuel map re-mapped. This released 25 bhp.

On this sort of conversion (320 - 340 bhp)you would be running approx 1.6 bar of boost.

I would beg to differ that your GRP'A', headgasket would last 30,000 miles. From my experience 10,000 - 15,000 is more realistic - but then it does depend on your driving style. Again the clutch should not be a problem with this power (I had over 340 ftlb of torque). It was'nt with me, and I did over 30 drag runs as well (and that was on a standard clutch, that had covered 45,000 miles)

Apart from that I never had any problems with my K reg 93 escort - which had covered 10,000+ miles since the conversion.

As regards to your lag and spool-up times, believe me, since getting rid of the Cossie, I have never experienced a feeling like it. Lag all but disappears, and spool up time is damn sight quicker. The torque (that pushes you into the back seats), will be something that us Subaru drivers can only dream about!!
Believe me, you will be amazed - the car will pull as well in 2nd & 3rd, as it will in 5th!!!!

Have fun!


[This message has been edited by Shaun (edited 06 April 2000).]

[This message has been edited by Shaun (edited 06 April 2000).]

[This message has been edited by Shaun (edited 06 April 2000).]

Andy Banks
6th April 2000, 02:02
Thanks Shaun you're going to make my bank balance drop with talk like that!!!!

BTW, what subaru do you now have? Did you ever get change to compare an STi with your cossie?

Does anyone have any rolling road results
they could post on here for torque and power?


[This message has been edited by Andy Banks (edited 06 April 2000).]

6th April 2000, 08:59
10-15,000 miles on a head gasket!

i wouldn't like to meet your engine builder.

I doubt you would find a harder driven cossie than my old one, used on track regularily, in sprints and also my everyday road car with 20,000 miles a year.

As for the clutch, prepair yourself for a 350 bill for a decent one, it is very common to have slip on a standard clutch when going to 330BHP.

Mike Rainbird
7th April 2000, 07:35
When I was running 34psi on the standard bolts and Grp A gasket, I only got 8-10,000 miles between head gaskets. However, it gets thrashed all the time.....

I agree with Shaun on this one, if you drive hard all the time, the life expectancy of the gasket will reduce....

Andy Banks
7th April 2000, 09:42
...and what happens when it does go?

Mike Rainbird
7th April 2000, 11:16
Dear Andy,
Because I have had the Cossie for so long I know what signs to watch out for. Having an alloy heder tank also helps (as you will see in little while). When the head gasket starts to leak, it doesn't normally let go in a big way (not on a properly built engine anyway!). What will happen is that it will start to leak gradually and normally when it does, it will start to "pressurise" the cooling system. By that I mean that some of the boost that is intended for the engine, will escape through the leaking gasket and into the cooling system. As this is already pressurised anyway, it has a cap that will start to vent off excess pressure beyond a certain point (I think the standard cap is rated at about 15psi). Obviously if the pressure exceeds that, the cap will lift and expel the excess. When it does this, it tends to expel a little coolant as well and this stains the alloy header tank with water marks. Accordingly, whenever I get excessive staining on the header tank (providing I haven't over filled it), then I know my headgasket is possibly on its way out. This can then be tested by putting the "sniffer" that is shoved up the exhaust to test hydro-carbons near the header tank and gradually unscrew it to vent a little pressure. If the monitor suddenly reads lots of hydrocarbons, then you will then know for sure the head gasket has gone, as the hydrocarbons will escape from the engine though the leak and into the coolant....

If you ignore the signs and continue to drive the car, then the leak will get worse and worse. It can then start to do damage to the cooling system as it will pressurise it beyond its capabilities. You will know this has happened, as your radiator will develop a smiley face http://bbs.22b.com/ubb/wink.gif. By that I mean it will bow downwards at the bottom to form the "smile". Also if left unchecked then you run the risk of warping the head. Whereas if you catch it soon enough you will only have to clean the head surface with a very light skim to prepare it for the new gasket. If it warps, you will need to take loads off which may mean the head becomes useless, as the valves are hitting the tops of the pistons because you have had to take too much off to get it level again...

A Grp A head gasket is fine below 2 bar of boost and the head bolts can be used twice before they should be replaced. However, if you are having the engine and stripped down for any reason, get it long studded. This is where the block is machined so that bolts go all the way through and out the other side. This way extremely high clamping forces can be used without running the risk of the bolts pulling out of the block (and stres cracks ocurring).

Hope this helps.

7th April 2000, 11:33
mike, i agree with what you are saying when running 34PSI boost. However the conversion we are talking about is for 330BHP which uses just 24PSI boost, i would be very surprised if this caused gasket failure at 10,000 miles. Built properly 30,000 miles on this spec is not unusual.

8th April 2000, 05:36

I wish I had all that info a couple of years ago.I used to have a Corrado VR6 which had many of the symptoms you describe,however it took me two years to realise what the problem was.

I had loads of faults on the cooling system during those two years including a burst hose,weaping water bottle cap(leaving blue stains),leaking water pump,leaking O rings on all the temp senders,cracked plastic thermostat housing and ultimatly a very smiley radiator that had expanded so much it was stuck between the top and bottom crossmembers.

There was other evidence too such as having to top up the coolant,higher oil temps than my mates(due to oil/water exchanger) and when ever I fixed one of the leaks the old anti freeze was dirty compared to the new stuff.

With the benefit of hindsight a leaking head gasket seems obvious but with the car running fine and the faults occuring months apart I didn't realise

When I did eventually take the head off it was obvious what was wrong,the seal on the oilway between the head and block had leaked and the oil had destroyed the action of the gasket. The cylinder next to the oilway was much cleaner than the others.I have since found out it was a common fault on early VR6 engines which was cured with a new type of gasket

The coolant getting into the cylinder had also caused the porcelain insulation to break off the spark plug and leave dents on the piston top,I have heard about this fault on a few VR6 engines,has anybody else heard of this on other engines after head gasket probs??.

I was lucky as I read about an identical case where the ceramic had scored the bore so badly the block was scrap.If it happened on a turbo motor it would probably damage the turbo as well.

So to sum up if you have any of the symptoms mentioned get your car looked at,it will save you money in the long run.


[This message has been edited by AndyMc (edited 08 April 2000).]