Hi all

I am thinking of fitting St 170 engine to my lotus 7 I have seen a few on e-bay they seem all have covered 60-80k miles
1) Should I be worried as long as I change the timing belt?
2) Is the black top better than silver top?

Your response will be greatly appreciated

Regards axle

 

ST170 is just that, block is very similar to a Blacktop and you can fit a Blacktop head onto a ST170 block.

Silvertop is the earlier variant of Zetec engines.

60-80k is nothing if the engine has been serviced and maintained.

 

Thanks

 

The 2.0 Duratec might be a good option too. It can be found in plenty of Fords from the noughties and is all alloy, so lighter than the ST170 engine. Only 145PS as standard but there seems to be countless tuning options available. Caterham use a lot of Duratecs in the current Seven I believe so, if it's good enough for them, it might do what you need!

 

I sell a lot of engines to kit car and retro resto mod enthusiasts and yet to have one complaint when they go the 170 route so its must be a good option

 

the 170 engines are very reliable when properly serviced and maintained. I would consider putting the 2.0 duratec in your lotus though, as they're around 30kg lighter.
what gearbox are you planning on using?

 

Hi all
Thanks for all your replies the gearbox I have is MT75 I am still to find out if this will mate up OK to ST 170, so please let me know if you know?

2ndly why would the Duratec a better option I know it is lighter but than you have not got as much BHP, again I would value your opinion in this matter.

Thanks Again Axle

 

as far as i'm aware, there are two different bellhousing patterns for the MT75. One of them fits the zetec pattern but you have to leave a couple of the studs out.
the reason for suggesting the duratec engine was originally down to the weight advantage. They do have a lower standard power rating, but 200bhp is achievable without too many modifications. Parts are also alot cheaper to buy second hand.

 

Weight is a big advantage for the Duratec. If it's 30kg lighter, that's a big percentage in engine terms and a good weight saving in a car as light as a Seven. The question you have to ask yourself is, in a car as basic as yours, where else are you going to remove 30kg from one component? As Colin Chapman said, adding power makes you faster on the straights. Subtracting weight makes you faster everywhere.

Tuning options are big for the Duratec too. There is piles of stuff out there for it as it's used so widely. Mountune did a kit for the Fiesta ST (which used a 2.0 Duratec) that took it from 150PS to 165PS. Think that was just an exhaust, intake and remap. Keep in mind that most ST170 are usually in the low 160s in terms of horsepower and it suddenly becomes very close. Don't get me wrong, the Zetec is a good engine, especially in ST170 form, but it's a bit old-hat nowadays.

It does partly depend on gearbox compatibility though, as I am not sure on how the bolt patterns compare. That being said, loads of people run RWD Duratecs, so it must be possible!

 

Its a lump of pig iron, hardly worthy of a real Lotus 7. I binned the Pinto out of my old Westfield and replaced it with an allow blocked Poxhaul 2.2. The difference to handling and steering was night and day. If you must do it go for a true 2.0 Duratec.

 

Hi all
Thanks for your feed back it will help me to make the right decision.
Yes you are right about the weight and the car handling particularly in a 7 and Colin Chapman's principle of weight on a car.
However one thing I need to tell everyone here is I am not using this car on the track and I am on a budget, I do not suppose the tuning kit for the Duratec can be cheap?

So what you all clever guys think?

cheers Axle

 

Unless the Mt75 is a Mitchell and Cots mt75 as per a Morgan it’s most likely to be the integral bell housing 2wd cable clutched 4 pot variety as fitted to the Sierra and Granada ?

This means your stuck with a Zetec/ ST170 or older unless you want to upgrade the drive train.

The ST170 will bolt up no problem. It is old hat but it is rugged and reliable if maintained.

A Duratec can be fitted on a budget but will need the same things as the St to get it to 200bhp

 

Thanks for your response
Please let me know If I got this right, if my MT75 box is from a Sierra than i have only the choice of ST170 OR Zetec?

Does anyone know the weights of St170 & Duratec?

Cheers Axle:

 

If Its a standard ford box you have the choice of any of the traditional four pots.

After the Zetec they are Mazda bassed.

What are you upgrading from ?

 

8v DOHC

 

Unless you're upgrading the whole drive train then it's between the zetec and the st.

I am guessing this is a robin hood ? So the 30kg isn't the be all and end all.

The above engines can be done on the cheap through to 're mortgage monies.

Another option could be a 16v doh with the Rs2000 or even the 2.3 from the galaxy / scorpio.

 

Thank you all this is a great help and much appreciated, after taking everyone's point of view and the weight disterbution into consideration I think I shall for Zetec

Regards Axle