Have been offered today a 1.8 8v Kjet coupled to a 16v box, i am considering putting it in my 84 Mk2 GTI. The engine was taken from a mk1 which was used in the Slick50 championship around 10 years ago, it was run in then rolled in its first race, the only things salvaged from the car were the roll cage and the engine and gearbox. It has sat in a friends lock up for years however he needs to have a clear out. All i know of the engine at this point is that when it was last on the dyno it produced 149 bhp, cams/polish/ported/pistons, lighted flywheel. They have had it running recently in another 84 mk2 GTI, and it runs fine and pulls really well, apart from tick over due to the lumpy cams fly wheel etc. My question is has anyone had any experience with a motor of this type? and any cures for the tick-over? and how much would you expect to pay for a motor of this type with a 16v box? Thanks PS, I only use the car at weekends, as a hobby car.
Can't give too much help, other than the fact i went in a mk1 with the same engine round Llandow circuit as a passenger and it shifted! It also ticked over fairly roughly, i don't think this is something thats really curable. Hopefully others will have had more first-hand experience
Change the cam for a less hairy one, or learn to love the Thrump-Thrump-Thrump tickover. Making sure it's set up properly will help, but ultimately it's down to the cam.
Thanks for the advice Mike, do you have any idea on what would be a reasonable price for a motor of this type that has not done much work and comes with a 16v box?
The engine alone is worth around 900 quid plus whatever the box is worth. The general cam used in them is a Schrick 304, which will make it idle rough on the K-jet injection and give very high H/C readings for the m.o.t. One way around the idle issue is as per Mike's suggestion above... drop the cam down to around a 285 degree item, or the other option is to run it on open induction, carbs or throttle bodies... it totally transforms the idle and low speed running, and will gain around 10-15hp, subject to exact spec & settings. The general spec is... Ported inlet & exhaust manifolds, ported head on 40.5mm inlets/35mm exhaust valves (though some have been done on 41mm inlets), 11.5:1 c.r. If standard type cast pistons (KS) have been used they can (do) break up around the ring lands over time (too much c.r, rpm, weakened crown combination) if the piston has been heavily skimmed (the normal practise) to reduce the bowl size to raise the c.r . Standard crank & rods are normally used and are more than up to the job at this power & rpm level.
What he said However, modified 8v engines don't seem to have much of a market these days. I've got a professionally built 2.0 8v, with a pack D solid lifter head, 285 cam, vernier pulley, increased compression, balanced bottom end, that I know has changed hands for about 3-400 in the past. In general you'll make a lot less than it would cost to build. Selling it off in parts might be the best way to maximise the return on it, so long as you don't take the head off to find the pistons are crumbling. Sounds like it's a better engine to own than to sell, to be honest. If you intend to do any significant road mileage in the car, I'd suggest looking at mappable engine management, rather than carbs. Megasquirt might be a good way to release some more potential, although probably won't get you the peak power of carbs. My modded 8v engine is running on kjet at the minute, and it's seriously choked by it. I'm hoping the megasquirt route will help mine too, but it's yet to be proved. My first step will be to try to optimise the kjet - as much as an engineering experiment, as a serious tuning exercise - a 16v throttle body and modded WUR will be the next steps on mine. This should help the fuelling a bit, but won't cure the flap flutter with Kjet and lumpy cams.
Not at all - sounds like a proper race engine. Could cost you a lot of money if you're sat in traffic in it every day, though.
Thanks guys for all the info, i have done the deal on it with the 16v box, and am very pleased with the deal . I haven't seen inside this motor but I'm told by a good friend it looks like new. Not having had to much experience with the 8v, i am looking forward to messing about with it. What sort of power would you guys expect when its set up correctly, and what sort of rpm's would you expect to see? also would you use the 16v box or the 8v? (I'm going to keep my standard 8v in garage for a rainy day!!!) Thanks again Ps, I have a company car this will do a max of 2000 per year, no heavy traffic for this car, just for a thrash at weekends...
as said earlier around 150bhp mark, dont mess too much with a good engine, there have been too many tales of people ruining good engines recently
I'd say that's a conservative estimate for a 304 cam and high comp engine.... should get more like 170+ on carbs or ITB's - see Mr Hillclimber's power figs for a reference point.
As here, if bought it could be worth looking at converting to Digifant, binning all air flow meter and mapping on management (worth a thought for you too Mike).
As well as that, it's the hydrocarbons at m.o.t time you need to be carefull of. My hillclimb man used to struggle to get his through with the 304 on K-jet (the m.o.t man said there "must" be something wrong with the injection system for it to be that bad!)... no probs now on 45's.
Good call. A good one is normally around 130-135 at the wheels, 155-160 at the flywheel at around 6,700rpm. More has been claimed but I'd like to see it on a rolling road. As a guide, standard 1800 8v's used to show 89-90hp on the rollers where I worked, so around the factory figure of 110-112hp. 8v's can be cracking..
It is a touch. The last one (ex slick 50) I did made 144 at the wheels @ 7,200rpm on 45's with the old head & 304, 12:1 on custom forged JE's (guess why I changed the pistons!) and Carrilo rods. We later upped the timing (it would'nt take more than 24 degree's on the rollers) and I fitted longer trumpets. At the next sprint my man said it was much faster (he broke the class record so it could'nt have been too bad), and after driving it myself (he was right!) it felt like an honest 150 at the wheels from previous experiance, so a good 178hp at the flywheel. It's currently back with me for an "upgrade" () after a successful season last year, so I'll try and get some pics up time permitting.
Thanks for all your advice guys its been really helpful. I want this car to look as stock as possible but with some extra power, 84 gti's in this condition seem to becoming farly rare so will keep the k-jet for a bit but am seriously thinking about carbs. Which box would you guys use? I'm sure i will be looking advice very soon.
Skim reading but 149bhp from a 1.8 16 valver in Slick 50 spec strikes me as low. A decent 8V will do 150-160.
It's a 1.8 8v, Chris, with a 16v box - first post. @ Watty, if you want to run it on Kjet, I'd drop it down to a much milder cam. I've got a piper 285 in mine, and it doesn't work well on Kjet. Feels a bit flat.
