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Duratec vs K series
DIY Si - 24/6/10 at 08:15 PM

Evening all.

I am about to embark on restoring and modernising an Austin Healey Sprite, but I am unsure when it comes to the engine choice.

The tried and tested route is the K series and type 9 conversion. It's been done before and will no doubt be done again due to the lightweight engine and a Sprite not needing much more than 230bhp to see it nicely along the road.

However, K series aren't all that new anymore, and I've been thinking about the Duratec. The power will be easy to get, but how heavy is it? The K series is used as it's about the same fitted weight as the A series that lives there normally. What I don't want is a big heavy lump ruining the handling in what should be a roughly 700-750kg car.

So just how heavy is the Duratec, and how much will 200 bhp cost me?

Unless of course, there is another engine that I haven't thought of that I can get and tune for peanuts that performs as well as the K series.

Oh, and it must fit under a normal Sprite bonnet too, as I don't want any bulges in it.

[Edited on 24/6/10 by DIY Si]

scootz - 24/6/10 at 08:24 PM

Duratec is about 10kg more than the 1.8 K-series.

For 200bhp on a 2.0 Duratec, then you're looking at a set of TB's, good ECU and a decent exhaust (not cheap - even if you go for bike TB's).

230bhp will be pretty costly in a NA engine!

britishtrident - 24/6/10 at 08:24 PM

K series really don't suffer wear problems --- piston rings, valve guides, crank bearings will all do interstellar mileages without problems. What causes problems on the k series is if they have been worked on by fools. Find a nice unmolested engine and you are off to a good start.

A K series is lighter than the A series --- but that is more than wiped out by the type 9 gearbox.

DIY Si - 24/6/10 at 08:32 PM

Sorry, didn't make that all very clear. Whilst it would be nice to have 230bhp, to start with, I'm aiming for about the 160 that the 1.8 VVC K series is meant to have had. A decent exhuast, inlet and so on should put that up a touch though.

BT, I had read the same thing on the 'net. Many have found that some engine builders actually do a worse job that the factory did with things like balancing, so a nice original is what I'm after. Well, that and the uprated HG and maybe some came whilst I'm in there.

StevieB - 24/6/10 at 08:54 PM

What model sprite are you restoring?

I have a Mk 1 Midget currently being converted to a BEC race car and I have a lot of parts that are common with sprite 2 (and maybe sprite 1) that I won't be using.

I do have the odd consideration every now and then about just putting car engine in - have you considered the XE?

wilkingj - 24/6/10 at 08:55 PM

quote:
Originally posted by britishtrident
K series really don't suffer wear problems --- piston rings, valve guides, crank bearings will all do interstellar mileages without problems. What causes problems on the k series is if they have been worked on by fools. Find a nice unmolested engine and you are off to a good start.

A K series is lighter than the A series --- but that is more than wiped out by the type 9 gearbox.



Yes... And Make sure the head gasket is a good one. K series are notorious for blowing head gaskets. Its a known problem. However this is the head gaskets problem, and needs to be replaced by a good one. (The silicon sealing ring slips out of place causing water loss and eventual engine failure if not repaired quickly. So watch out for signs of water loss or leaking.
Not sure if this applies to the smaller 1.4, but is an issue on the 1.8's


GeoffT - 24/6/10 at 08:58 PM

Also beware of the height of the Duratec - PPC mag did a feature on them a while ago and I think I remember them saying that it's something like 50mm taller than the Zetec...

StevieB - 24/6/10 at 08:58 PM

The problem is the same across all K Series as they're effectively the same engine with differing crank/pistons etc.

You can get a race gasket (try eliseparts.com) or, I believe the Freelander gasket was improved over the original due to early models experiencing problems and is maybe a cheaper option.

British Trident is probably the man to ask about the K

coozer - 24/6/10 at 09:05 PM

Rover V8.

DIY Si - 24/6/10 at 09:11 PM

It's a late MK IV, from '69. I had considered the XE, but it's quite heavy compared to the K and that's quite important on this.

I've also just found out that Frontline do all the bits I need for not too much money.

loggyboy - 24/6/10 at 09:57 PM

quote:
Originally posted by DIY Si
It's a late MK IV, from '69. I had considered the XE, but it's quite heavy compared to the K and that's quite important on this.


Reconsider it then.
The Redtop is bullet proof, has great torque figure, they re cheap as chips to buy, mod and repair.
If I could get a new one i would have one over the zetec ive chosen - even if cost twice even three as much as ive paid for the zetec.
Love the engine, mine served me well for 6 years of very hard abuse.

flak monkey - 24/6/10 at 10:41 PM

Theres nothing in the weight of a k series and duratec, both are approx 80kg bare.

But you get an extra 200cc with the duratec and the additional torque to go with it.

You would be looking at around £800 for a duratec install, plus whatever ECU you choose.

Engine, bellhousing, ST150 flywheel, zetec/rs turbo clutch and bike throttle bodies should be easily doable for £800 and you would expect to see around 190bhp on a standard engine. 230bhp with just a cam change.

Exhaust wise, buy a tubular pinto manifold and cut and shut. Readily available, cheap and lots of designs.

David

britishtrident - 25/6/10 at 07:20 AM

The head gasket problem on the K series was really related to the number cold starts, and how the engine was driven in the first couple of miles before the water circulated. Three modifications cured the problem (1) The stainless steel dowl pins introduced about 1999 (2) Improved MLF gasket designed by Rover but only introduced after Rover closed by Ford. (3) The external PRT or more correctly PRRT thermostat.

In truth a lot of coolant loss problems on the K series were misdiagnosed water leaks particularly from the inlet manifold gasket, and water pump.

I have had 5 k16 series engines in the family fleet only one suffered a head gasket problem and that was just a slow leak between the water and oil due to the sealant tracks on the gasket becoming detached/shrinking.

My own 75 1.8 is currently approaching 90,000 miles without any engine problems.

It isn't actually a very big job to change the gasket on these engines anyway, the longest part of the job is usually trying to get the alternator drive belt tensioner locked back.

The K series suffered because it was really the first hi-tech high volume car engine from a European manufacturer, the mechanics of the day tended to treat it like an old B series or Pinto engine when it had more in common with a motorcycle engine.

With the K series meticulous attention to detail and following the book procedures to the letter pays off.

[Edited on 25/6/10 by britishtrident]

bitsilly - 25/6/10 at 09:21 AM

A friend has fitted a K-series to his midget and is it superb.
Frontline are always good for a chat and advice. They also sell some serious up grades for the suspension and just about everything else!
My mate swears by the anti-tramp (sp?) bar set up thingy for the back suspension, but I have driven the car on a track and I would spend any money I had, first on brakes, then an LSD.
Great conversion though, real wolf in sheeps clothing stuff.

coozer - 25/6/10 at 10:01 AM

Re K series head gaskets. They aren't the only problem. I've had two where the head gasket has blown on both and it trashed the head. Basically the head gasket goes, it overheats and warps the head.

First one happened at 55K on my 214, a new head cost £400 but it never used another drop of coolant after that and I sold it with 110k on it.

Other one had done 278K and was a total wreck, didn't bother repairing as the gearbox was loose as well and dropped into neutral when I took my foot off the throttle.

iank - 25/6/10 at 11:42 AM

quote:
Originally posted by coozer
...
Other one had done 278K and was a total wreck, didn't bother repairing as the gearbox was loose as well and dropped into neutral when I took my foot off the throttle.


Head gasket went at 278,000 miles, shockingly unreliable. Are warranties worth nothing these days

tigertom - 25/6/10 at 12:14 PM

would love to have the balls to do a duratec install as well but the fear is that i spend the £1500 and install not complete.then more money.have put the foot down at 1500.no more.but its still tempting.

atspeed racing - 25/6/10 at 04:02 PM

We had a customer here that had a Frog eye sprite and he had fitted a Suzuki swift engine with a pair of webers on it.
it went like the clappers and is a super light, reliable engine..and its different

StevieB - 25/6/10 at 05:11 PM

quote:
Originally posted by atspeed racing
We had a customer here that had a Frog eye sprite and he had fitted a Suzuki swift engine with a pair of webers on it.
it went like the clappers and is a super light, reliable engine..and its different


Was it silver with a red interior? If so it was featured in PPC a while ago - really nice motor with great attention to detail.

rusty nuts - 25/6/10 at 06:30 PM

Back in the late 60s early 70s there was a company supplying Midgets fitted with a Ford x flow , the Toyota 4AGE is around the same size so should fit under the bonnet without any bulges?

MikeRJ - 25/6/10 at 08:37 PM

quote:
Originally posted by coozer
Re K series head gaskets. They aren't the only problem. I've had two where the head gasket has blown on both and it trashed the head. Basically the head gasket goes, it overheats and warps the head.


Only if you keep driving it after all the coolant has escaped. If you stop immediately that the temperature gauge starts dropping you are unlikely to do any damage.

britishtrident - 27/6/10 at 04:33 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by coozer
Re K series head gaskets. They aren't the only problem. I've had two where the head gasket has blown on both and it trashed the head. Basically the head gasket goes, it overheats and warps the head.


Only if you keep driving it after all the coolant has escaped. If you stop immediately that the temperature gauge starts dropping you are unlikely to do any damage.


Part of the problem was on the post 1996 Rovers the coolant temperature gauge was driven by the ECU, and the ECU would simply ignore any temperature reading it considered out of range and pass a default reading of 87c to the temperature gauge. Having said that you have to be a pretty insensitive driver to really cook one of these engines as if the coolant isn't circulating due to low level they starting pinking and the heater stops working long before the engine boils.

I have never seen a warped head on these engines ( the head with the cam carrier bolted to it is very stiff) but I have seen blocks with sunken liners due to gross over heating. Normally if an engine has been driven to that stage the plug leads and plastic covers on the engine will have started to melt.

But these engines are no problem with the latest parts and provided any minor external water leaks are not simply not ignored. I would however say a proper temperature gauge or just a warning light ( http://www.locostbuilders.co.uk/forum/5/viewthread.php?tid=121137 )is a wise thing to fit.

[Edited on 28/6/10 by britishtrident]

DIY Si - 28/6/10 at 07:34 PM

Given how easy it is to find a K series, I think I'll end up going that route.

BT, is there a preferred aftermarket ECU for the K series at all, or will just any 4 pot version do?
Also, is there any real advantage to getting the VVC engine over the stock 1.8? All gauges will be the old Smiths/mechanical types, so I don't have any worries on that front. And the plumbing will be of the more normal/non-Rover variety!

scootz - 28/6/10 at 07:37 PM

The Emerald ( LINKY ) was always one of the favorites amongst the Lotus tuners during the 'K' years.