Upgrading a Supersprint 1700

[Graham Sewell]

There were times in the late 80's and early 90's when there was only one chassis - the DeDion - and you could have a x-flow, 1.4l K-series or 2l Vauxhall engine.

 

Then during a previous round of financial instability, they re-introduced the live axle to the Classic as a low cost entry model with only the x-flow engines. I certainly know of a few people who built 1600 DeDion's in that time frame. The choice of the 1600GT engine (single downdraught carb) will have been a cost saver in anticipation of later upgrades with the "better" chassis already in place.

 

Cheers,

 

Graham

------

Low tech luddite - xflow and proud!

[woodfell]

Thanks for the comprehensive answer.

 

I've considered a Zetec but would probably want to go to the 190 BHP Raceline route as it is not a huge amount cost wise over their 160 BHP offering.

 

I bought my one owner 1991 Supersprint from ebay at the beginning of this year - it's covered 19,000 miles and been to Europe a few times with the first owner. The engine runs very sweetly, so I think you have just been unlucky. I had a xflow in a Dutton Phaeton I built many years ago and thrashed it mercilessly and it survived. If my engine needed a rebuild I would either go the Zetec 190 BHP route or just rebuild the xflow depending on finances at the time.

 

 

 

[ashaughnessy]

I had my standard supersprint rebuilt and upgraded by Dave Brookes in Crewe (the newly built engine is great, so I'd recommend him). The new engine was measured (on a rolling road) at delivering about 150bhp, compared to its previous standard spec supposedly giving 135bhp, but after 40,000 miles probably giving more like 120bhp. Anyway, it now feels a lot more powerful and on a track day is at least 20 mph faster on the straight with more to come. The upgrade involved forged pistons, 244 cam, 45 DCOE carburettors (from 40), 4 into 1 exhaust (instead of 4-2-1 rear exit) plus a variety of other internal changes so max revs is now 7200.

 

Total cost of all this (including ALL the costs) is probably five or six thousand. When you add in a pair of new carbs (six hundred or so), new exhaust (five or six hundred), rolling road setup (a couple of hundred), plus the build, plus transporting costs to get the engine there and back, plus a variety of other bits. It all adds up, but I suspect that any price quoted for a zetec conversion would understated as well, so consider ALL the costs before you decide which way to go.

 

Was it worth it? Not sure. Its far better on track and based on the only track day I've done so far it keeps up with R300s. However its perhaps not as good on the road. This might be partly due to it being too fast, or it could be due to it not being so relaxed - perhaps a zetec engine in a lower state of tune would be both more relaxed and more powerful.

 

Considerable oil loss is standard behaviour if your engine breather goes straight to a catch tank. Losing a litre of oil in a hundred miles of hard driving is easy. Re-routing the breather back to the cam cover, with a secondary breather from cam cover to tank cures this.

 

Considerable "breathing" is also standard behaviour with an old standard spec supersprint. When revving you'll see considerable quantities of blue vapour coming out not just of the breather but also the filler cap and possibly the cam cover gasket. You'll see blue vapour coming out of the bonnet louvres when driving along slowly or at a standstill.

Anthony

[woodfell]

I can vouch for the xflow oil loss as oil was coming into the cabin during my last track day. It was venting via a hose from the crank case that was cable tied to the underneath of the car. I've now added a catch tank and rerouted the crank case breather hose to the rocker cover. Instead of adding a second rocker cover hose I bought an oil filler cap from Burtons that has a take-off pipe at the top. I've attached oil hose to this and have routed this to the catch tank. Not tried it yet so hope it works.

 

 

 

[LesG]

ashaughnessy; that's an interesting point re. the rocker cover breather system, does it actually work? And could you possibly post a couple of pics please?

 

Cheers,

Les.

[bstark]

Les - I have exactly the same setup and it works beautifully, a big difference over the previous 'straight to catch tank' setup.

 

Bob Stark

Supersprinter

[LesG]

Bob, thanks for that, would you be able to send me a pic or two?

 

Cheers!

[eric]

For me , the important thing is to keep the car original

 

So if I want R400 Rover engined I will not transform my car

I will sale it and buy the right one

after a road test of course

 

I have tested many model and if they are all Caterham, they are all different

In lowflying, it was, some years ago, a test drive between few models and the winner was the K1800 supersport with 140 HP and not the most priced 7

 

I like the book 's sentence : the most tuned, the more hassle it will give you

 

my Caterham is a 1600 sprint with 110 HP (and I will not transform it in a supersprint) enough power but some work on upgrade with later chassis mod

for a better roadholdind and a greater security

 

 

 

eric

[I.Mupferit]

Many interesting views here from the diehard X/Flow lovers and certainly there is merit in wanting to keep the car original if possible, but I'm surprised there haven't been more posts from the less traditionalist Zetec convertees. I guess it demonstrates how differently we each feel about the 7 and throws up so many reasons for owning one.

 

I was an early convertee from 1700 X/Flow to 2L Zetec with my first 7 back in the 90's and have to say I loved the bulletproof nature of the more modern engine and whilst it sounded different to the X/Flow, to my ears at least, the sound was less agricultural whilst still retaining the throaty inlet roar from the Webers.

 

I imagine you need to analyse the reasons behind wanting the 7 and make up your mind what to do after that. If you want a power unit with effortless performance, bulletproof reliability, oil tight joints and an easy upgrade path to over 200 bhp, then Zetec is probably the only economically viable option. If, however, you love the traditional feel and sound (and why not? ) of the X/Flow, are prepared to accept and live with it's shortcomings and are happy with up to a realistic 150 bhp whilst retaining reasonable road manners, then stick with a X/Flow.

 

If you need help changing to a Zetec, I'm sure there are many in your area who would be happy to lend their expertise. It really isn't difficult to do and Raceline (and BlatChat) will always be there with advice should you need it.

 

As for values, I'm not so sure it makes a significant difference for a car of this age. I sold my 7 year old live axle Zetec car for £13K some 4 years ago so it didn't seem to affect mine.

 

Anyhow, the choice is yours of course and only you can decide which suits you best.

 

Brent

(aka Arfur Nayo)

[ashaughnessy]

LesG, as Bob Stark says - the new plumbing for the crank case breather results in zero oil loss into the catch tank on my car, even on track days. Works perfectly. Sorry I can't post pictures - I'm in the stone age as regards photo technology. However its very simple in concept - take the existing crank case breather pipe and attach it to a union that has been fixed into the cam cover via a hole you have tapped for the purpose. Then add another breather to the cam cover to vent the pressure from there. The oil spat out from the crankcase goes directly into the cam cover, while the excess pressure is let out of the cam cover but without the oil.

Anthony

[Russell M]

Take a look here - there are photos of the set up posted.

 

Did the same modification myself last year & it works a treat

 

Previously was blowing lots of oil into the catch tank.

 

[Pezky]

I agree and disagree with Brent

I don't think it's worth upgrading to zetec for the sake of it, but if you want more power 150bhp+ then zetec will be a more cost effective way.

It cost me £2.5K to take my 1600 100bhp x/flow to 1700 140bhp 13years ago and then another £1k to make it unleaded 10 years ago!

Mind you I think my x/flow is a bit odd as it never uses/leaks any oil, even when I used to do track days

[ashaughnessy]

I think the chucking out oil thing is exacerbated by the standard cast pistons in a supersprint and/or worn bores, the combination allowing more gas to get past the combustion chamber and into the crank case (can any experts confirm this opinion please?). Moving to forged pistons and/or work on the bores and piston rings to improve the seal you would expect to help the situation. I don't know what pistons were used in the 1600GT spec engine - anyone? Q102 - when you rebuilt to 140bhp spec, what pistons were fitted?

Anthony

[Russell M]

 

Not an expert but my 1700 x-flow has healthy (215) compression on all cylinders & forged pistons.

 

Prior to the breather modification it chucked out loads of oil into the catch tank.

 

Edited by - Russell M on 30 Sep 2008 11:05:30

[Phil]

So 160bhp is a 25bhp improvement over the 1700 ss 135 bhp [ in your case a lot more possibly] for approximately three and a half thousand pounds.

 

What do you get for the money?

Modern power plant oil tight.

An engine at the beginning of it potential power out put.

Smoother engine, more refined and with the hood up a lot more peaceful.

Better fuel economy.

You get to keep your 40s.

A nice looking exhaust system over the standard rear exit.

A twin cam engine that looks the part in the engine bay.

Satisfaction of doing the job yourself.

Keeping the car you love.

Chance to clean the inside and underneath of your car.

Stacks more torque.

Better top end and comfortable motorway cruising.

Instant overtaking power and you can change down a gear if you really want to.

As said, years of experience from Raceline and Blat Chat to back you up.

It is an easy swap with most of the kit supplied with very little to source yourself.

 

I asked myself a question after buying a 7, why did I not do it ten years ago when I first had the chance, the same with the engine, why did I not do it the year before. Hindsight is great.

 

I miss the sound of my crossflow, but that is about it. It is hard to put into words how the car has improved.

It is only money, you only live once and its cheaper than carbon fibre.

 

The cost of a second hand Zetec could be anything from £50 to £300, the 1.8 is a good engine, with a change of cams it could easily see 150bhp. the engines are strong and a flush through, change of oil, cam belt and plugs will help to see it through to its potential of two hundred thousand miles or more.

A second hand unit, missing out on water rails and special sumps would keep the price down, many have done this with great success, it was my plan at first to do this but it was time thing so the Raceline package won.

 

FreeRange7

 

[a7bca]

finally got some answers on my crossflow engine.

 

apparently my piston-pin (there is a more technical name for it) has come out and has deeply scored my bore. essentially wrecking it. The engine would need pretty much a full rebuild which will also likely need lining of the block. This will likely come in at the top end of a rebuild cost, maybe £3k or there abouts. ☹️

 

This is a double whammy though as the scoring will have reduced the value of my AX block possibly rendering it of very low value. i wont know the value until it is out and properly looked at. so my p/ex value of my xflow has likely just halved. ☹️

 

so the zetec option now seems like the best option. the £3.5k level is also low by the time all the little bits and bobs that are needed on top then labour for removing old engine, fitting etc, realistically i have been told to budget 4.5-5k ish and then whatever part ex my crossflow is worth to come off that.

 

so had better get a great winter with loads of sunny days to get the most driving!

 

James

 

 

 

 

 

-----------------------------------------------------

Caterham Red 1991 De-Dion 1700 X/FLOW

 

my car habit...

 

 

[I.Mupferit]

Sorry to hear it is so badly damaged James (it's a gudgeon pin by the way) but at least I guess that makes your mind up for you now. I would still consider doing the swap yourself though, and recruiting some local 7er's to help if necessary, which will all keep the cost down. Bacon sarnies and endless drinks are a lot cheaper than paying to have it done.

 

Doing it yourself, I would still say it is possible to bring it in for around £3.5K.

 

Brent

(aka Arfur Nayo)

 

Edited by - Brent Chiswick on 30 Sep 2008 12:05:56

[a7bca]

yes i guess it has made the decision.

 

not quite what i had in mind when i started this thread on upgrading a supersprint ... lol

 

i dont think even if it thought i could do it i would have the room, and is garaged at my girlfriend's dads house, so i am already imposing a fair bit, without turning the garage into an engine bay

 

james

 

 

 

-----------------------------------------------------

Caterham Red 1991 De-Dion 1700 X/FLOW

 

my car habit...

 

 

[alan c]

James,

Sorry to hear that the engine is as bad as this.

Not sure where the car is housed but there are at least two of us within walking distance of your house who could help and others close by. I dont have space in my garage for work on this scale even if I take my car out!

X Flow engines may not be your favourite right now but dont rule out finding one for sale by someone else upgrading.

Alan

[a7bca]

hi, thanks for the offer

 

it is garaged near hazlemere.

 

james whiting said he could prob source an engine also, i might have a quick scout too. but it concerns me that i might end up back in the same boat with an unknown engine, with potential problems etc. and if i do that and pass the car on and change it is only going to end up costing more probably. i dont think i would change for an older car, i would go for a much newer one.

 

james

 

 

 

-----------------------------------------------------

Caterham Red 1991 De-Dion 1700 xflow soon to be .... 2.0L Zetec

 

my car habit...

 

 

[ashaughnessy]

Given its a de-dion does that mean you have a five-speed gearbox? Zetec makes even more sense in that case - would others agree?

Anthony

[a7bca]

it is 5 speed yes.

 

-----------------------------------------------------

Caterham Red 1991 De-Dion 1700 xflow soon to be .... 2.0L Zetec

 

my car habit...

 

 

[MusCat]

I'd agree that now you're looking at £3k+ for a bottom end rebuild, the extra £1,000 for a Zetec looks the best route.

 

Having been in the same boat it's depressing, you start the process hoping you'll get away with spending £1.5k and you end up 3 times that!

 

I'd still consider doing a "quick and dirty" x-flow swap, if you're finding it hard to justify the spend on the Zetec. Put a thread in the wanted section, one will turn up.

 

Tim

[a7bca]

funny thing is it has had a bottom end rebuild in the last 4 years (according to the paperwork) and has not done too many miles in that time. equally over the years it looks like it has had 3 broken pistons. maybe there is something just a bit bad in the engine, who knows.

 

i will probably only find it hard to justify until i get in it and give it a good drive ...

 

james

 

 

 

 

-----------------------------------------------------

Caterham Red 1991 De-Dion 1700 xflow soon to be .... 2.0L Zetec

 

my car habit...

 

 

[Roger King]

Broken pistons are common on the Supersprint due to their being asked to do way more than they were designed for. Forged pistons completely solve the problem.

 

There is nothing wrong with linering an AX block provided it is done properly with a stepped parent bore to stop it moving.

 

If you take a standard Supersprint and fit forged pistons + change the distributor to one with a more sensible advance curve, the engine becomes MUCH faster thanks to lower reciprocating mass, much lower internal friction, better ring sealing, better combustion due to better ignition timing, etc. Of course, you can go further.........