The 205 was Peugeot's attempt to really see off the other hot hatches such as the XR2/3 and Golf Gti. The power output is very high compared to other engines of the time and was a result of Peugeot paying a lot of attention to engine design detail. The legacy of this high output is that it is not as simple to improve the power as with other engines that are in a lower state of tune as standard. A great many modified engines that both I and colleagues in the trade see, have LESS power than standard and the companies selling engine conversions tend to boast the most ridiculously inflated power claims compared to companies specializing in other marques.
Let's compare the 1.9 Gti engine with the Golf 8 valve and see how Peugeot got so much power. The 1.9 has a claimed 130 PS (128 bhp) compared to the Golf's 112/115 PS (110/113 bhp) in 1.8 or 2.0 litre form. Firstly Peugeot made the bore larger at 83mm and this allowed them to fit larger valves - 41.6mm compared to the Golf GTi's 40mm items. This 8% increase in valve area is worth about 10 bhp. The head was given large ports and a decent shape and flows very well for a standard item. The induction system was carefully designed to flow well and flows enough to allow even well modified engines to breathe ok. Peugeot got the exhaust system bang on - it flows well, has good tuned lengths and an excellent manifold design - whatever you do, don't waste money on an aftermarket system - you won't get more power - you'll probably get a fair bit less. When it rusts away go and buy a genuine Peugeot item - not a pattern part. Finally Peugeot topped the engine off with a really good camshaft. Most 8 valve engines of this size have about 400 thou valve lift as standard and a fast road cam from Piper or Kent etc will add another perhaps 30 to 40 thou to that. The Pug 1.9 has 445 thou lift as standard and fairly long duration as well. Nearly 10 degrees more than most other standard 8v engines. It's already more than a match for an aftermarket fast road cam for most other engines. In fact it really wants more compression ratio than the stock 9.4:1 to work properly but more on that anon. The good exhaust and big cam add the other 5 or so bhp that similar engines lack.
So in effect the Peugeot engine is already the equivalent of a fast road tuned Golf. Given that the exhaust and induction system are so good what can we do to improve the power further? Well the main area left to improve is the cylinder head but it takes really well developed port shapes to give more flow and that takes flowbench time. There is also some power available from even higher lift/longer duration cams but at the expense of some tractability. We'll look at both areas later.
Both the 1.6 and 1.9 share the same 83mm bore and the capacity comes from different crank strokes - 73mm and 88mm respectively. The wet liner engine is strong and reliable with a few idiosyncrasies to watch out for. The liners have no shims underneath and must protrude above the top of the block by the right amount to seal properly. This relies on accurate machining at the factory as the clearance is not adjustable. 4 to 5 thou is the figure to look for - too much lower than this and leaking head gaskets and/or water in the sump can result. Over time the liners tend to distort to a slightly oval shape because of the constant piston thrust in one direction. However, if you remove the liners and leave them on a shelf for a while they seem to go back round again - weird but true. A good tip when rebuilding an engine that is still in good enough condition to not warrant new liners is to refit them turned 180 degrees round in the block. Most of the wear takes place on the thrust side of the engine and rotating the liners lets the relatively unworn side seal against the rings better.
Beware when removing and refitting the cylinder head not to turn the crank until the head bolts are done back up or the pistons will move the liners. The liners just sit on machined recesses at the base of the block and are sealed with thin rubber O rings. Move them and they are unlikely to seal again without new O rings and the consequence will be water leaking from the block into the sump oil.
Peugeot did a huge amount of messing about over the years with the number and arrangement of plain and grooved main bearing shells, the reasons for which have always eluded me. The Haynes manual comments on the complexity of it all and states that when they stripped their own test engine it didn't even have one of the bearing combinations listed in the official Peugeot charts. Other engines nearly always have 5 grooved bearings in the block and 5 plain in the caps for very good reasons of oil supply to the crank. That's the way I build the Peugeots too, regardless of year, and they run perfectly happily like this of course. Peugeot actually finally settled on this combination anyway for later 8 valve engines and the 16 valve engine. Maybe they read my tuning articles.
The rods are very sturdy and survive race use happily enough so road use is no problem for them even on tuned engines. Standard pistons rarely cause problems either except for sustained use over 7,500 rpm.
Early engines had an oil pump drive which relied only on the friction of the tightened crank pulley nut to turn it - no woodruff key or other locking system. This strikes me as one of the worst bits of engine design I have ever seen and the first time I rebuilt one of these engines I was convinced for ages that I'd lost a part somewhere. I know someone whose Mi16 engine grenaded because of not tightening that bolt up properly and after a few miles with no oil pressure everything came to a very expensive halt. You have been warned.
The centre main cap has two bolts holding it in from the side of the block. If you can't get the crank out do make sure you've removed these two first as well as the two nuts inside the block before you start hitting things with hammers and breaking stuff.
Early 1.6s had smaller valves than late models but then went to the 41.6mm inlet and 34.5mm exhaust of the 1.9 engine. From then on there is no difference between the cylinder heads of late 1.6 and 1.9 engines and in fact they aren't even stamped with the engine size. The exhaust valve is perhaps a bit small but little extra power comes from fitting larger ones and the expense is not warranted except perhaps for big budget race engines. The inlet valve can be usefully increased in size though and 43.5mm will just clear the bores although 43mm is the normal big valve option I offer for road engines. As I said above, more 205s get badly modified by so called "expert" engine tuners than any other make of car. The cylinder head doesn't escape their attentions. I've seen a £400 "fully ported" head from one of the less reputable Peugeot "specialists" where the badly worn guides hadn't been replaced, the seats hadn't been recut, the valves hadn't been refaced and the porting consisted of a bit of polishing with a flapwheel in the areas that could be reached with the guides still in the head. Not surprisingly it didn't make any more power although 160 bhp was the claim. It must have taken nearly an hour to do that head ! A properly ported one takes several days of carefully detailed work.
Cam bearing wear can be a problem on high mileage engines especially if there has been any bottom end damage. Bits of crank bearing material tend to circulate with the oil and chew up the cam bearings and as these are machined directly into the head there is not much you can do to rectify it. Guides wear out pretty fast too - especially on the exhaust side and any decent head mods should include new guides if they are outside the wear limits.
There is not as much scope for improving flow compared with many other heads because Peugeot did such a good job as standard in the quest for that 128 bhp. Port shape is critical to getting better flow and it is the seats, valve throat and short side bend that need the most work. The main part of the port is plenty big enough as standard and needs no enlarging but as it is the easy part to reach, inept tuners take huge amounts of metal out here to make it look as though something constructive has been done. This drops the port airspeed and hurts low rpm power without increasing total airflow at all. 3 angle seats are a must and reshaping the valves in the seat area helps too. The guides have to come out to do the work properly and one sign of a badly modified head is lumps missing from the guides where they've been hit by the porting cutters.
With the optimum port and valve seat shapes it is possible to squeeze about 8% to 10% extra flow and power potential out of the standard valve sizes. So about 10 to 12 bhp on a std engine and proportionally more in conjunction with other tuning mods. Polishing and enlarging the straight part of the port without removing the guides or cutting the seats properly won't achieve anything at all except to make the head look superficially pretty. Sadly most heads fall into this category.
Given how well the std head flows it is big valve heads that make the most sense and achieve the best value for money per bhp gained. With larger seat inserts, 43mm inlet valves and the port shapes properly worked to get the most out of the bigger valves it is possible to get an extra 15% bhp. That's about 18 bhp on a std engine and 20 or more on a tuned one. On a race engine a properly ported BV head can easily be worth 30 bhp.
With detailed flow bench work and multi angle valve seats it's possible to squeeze even more flow out of the head but we're now into the realm of race engines and costs of over £1000 for the headwork.
Bear in mind that the standard cam is similar in duration to an aftermarket fast road offering for most other engines anyway and really needs more compression ratio than Peugeot used (9.4:1) to make it work properly so a skim up to 10:1 helps both idle quality and power. A 31cc chamber volume (stock is 34.5cc) which equates to about 0.75mm off the head gets the job done. The last thing you ever need on these engines is one of those thicker head gaskets Peugeot sell that are meant to compensate for a light skim and get the compression ratio back to standard. No one in their right mind would want to build one of these engines with less than the stock CR. Longer duration cams require even more CR as with any other engine. Mild rally cams of about 285 degrees duration like the Catcams 4900340 or my own Puma002 need about 11:1 which is about a 2mm skim. Full rally cams such as the Kent PT27 need 11.5:1 plus. Race engines will want 12:1 or more. For very high compression ratios in a 1.9 it's best to start with either the pistons from the 1.6 which have a smaller dish volume so you don't have to skim so much off the head or high comp forged items. Fitting 1.6 pistons into an otherwise standard 1.9 will raise the CR to just over 11:1.
Breaking the cam caps when refitting the cam is something amateur mechanics seem to do with monotonous regularity. The caps are numbered 1 to 5 from the flywheel end of the engine not the cam pulley end. Each cap and journal has a different diameter. Fit a small cap to a bigger journal and you'll snap it in half while doing it up. You can check which cap fits where quite easily first by matching them to the lower half of the bore before fitting the cam. Lay them out in order, and the right way round before fitting any of them. If you break a cap you can't just get one from another engine. They're line bored to suit that head only. Break one and your head is now scrap. The money you tried to save by doing the job yourself rather than entrusting it to a professional has just gone up in smoke.
The Peugeot recommended tightening sequence puts an absurd amount of stretch into the head bolts which weakens both them and the threads in the block.. It's not uncommon for the block threads to strip or the bolts to break when either fitting a head or trying to remove the existing bolts. When fitting a head it's essential to do the following. Make sure the threads in the block are clean and free from corrosion and debris. The best way to do this is run a tap through them with some oil on it as a lubricant. As the bolts are 11mm thread size very few people are going to have a tap. A serviceable alternative can be made by grinding flutes into the threads of an old head bolt on the edge of a grinding wheel. New bolts must be well greased with moly grease both on the threads and under the bolt head. Finally rather than use the Peugeot stretch method I tighten these bolts in three stages - 25, 50 and then 75 ft lbs or an additional 1/4 turn whichever comes first. Some bolts will take the full 75 ft lbs and some won't. This loads them sufficiently to clamp the gasket properly but doesn't unduly stretch them and allows them to be reused. I also find it a good idea to tighten them fully, leave the engine for 24 hours to allow any gasket compression to take place and then retighten them one at a time in the normal sequence i.e. starting from the centre of the head and working out. Undo a bolt, tighten back to 50 ft lbs and then to 75 ft lbs or 1/4 turn whichever comes first and repeat for the other bolts. Bolts which wouldn't take the full 75 ft lbs the first time often will once the gasket has sat a while under compression. It's a good idea to do this again once the engine is run in. Once the head is fitted it isn't a bad idea to fill the bottom of the external block thread holes with grease or silicone to stop water getting in there and working its way up and corroding the new bolts. That will hopefully ensure that at rebuild time the bolts will come out easily without breaking or stripping the threads in the block.
Favourite trick for newbs trying to replace the cylinder head themselves is to forget that one bolt has a long spacer under it to prevent the bolt breaking through into the cylinder block. Do please try and make a note of which spacer came from where before you add yourself to the long and growing list of plonkers who scrap their engine block while torquing the head bolts up. Basic common sense ought to suffice in that when you drop the bolts into the bolt holes one sticks up a lot further than the rest but basic common sense seems to be a commodity in short supply these days.
The standard induction is a plenum manifold with a single butterfly and Bosch LE fuel injection. The manifold has big runners and flows plenty of air to work nicely with even well modified big valve heads. The LE injection system measures the air flow by means of an air flap which opens progressively as more air flows into the engine. The ECU then hopefully injects the right amount of fuel based on what the air flap meter is telling it. This works fine except at low rpm with long duration cams. The reason is that the air flap likes the airflow to be steady and in one direction all the time. Big cams cause the airflow to pulse strongly at low rpm and this makes the flap vibrate which confuses the ECU and leads to erratic idling. At higher rpm once the engine has "come on the cam" everything smoothes out and works fine again. Even with the standard cam the engine isn't renowned for having the best idle characteristics in the world and if you want to retain a good idle then stick to short duration cams (under 275 degrees). If you aren't bothered too much about idle quality then hotter cams will work fine once the revs are up over 2000 or so. Fitting a mappable ECU controlled by a throttle position sensor and doing away with the air flap meter eliminates the idle problem but is costly. You might as well pay the extra and go straight to throttle bodies as mess with the standard induction system to that extent.
Fitting DCOE carbs is another way of eliminating the air flap problem and is worth a few more bhp. Maybe 10 bhp depending on how highly tuned the engine is. They are also easier to calibrate than a fuel injection system but won't get anywhere near the same economy or tractability. Note that the Mangoletsi DCOE inlet manifold, which is the most commonly available one, needs an awful lot of work to match its ports up with those of the cylinder head. As cast it only has tiny holes through the runners which are very restrictive. It takes a good couple of hours with a grinder to remove the required aluminium and port the manifold properly so be prepared for the cost of this if you want the engine to produce the power it should be capable of.
The ultimate induction system is throttle bodies with mappable injection and ignition. This will add 15 or more bhp just from the extra airflow and also allow you to use longer duration cams without losing tractability. The total additional power potential is therefore pretty high. Cost is around £1400 plus fitting and setting up.
This can be a nice short section. The standard Peugeot systems are excellent and on a standard or road tuned engine you'll be wasting your money fitting anything else. Only on rally or race engines with long duration cams might it pay to fit a tubular 4-2-1 type manifold and larger bore system but that's outside the scope of this road oriented tuning guide. Also beware of non Peugeot standard replacement systems. You might save a few pounds but also lose a goodly chunk of bhp into the bargain. I had one experience some years ago where a non standard system lost over 50 bhp on a tuned 1.9. Yes I did say 50 bhp. With a big valve head and rally cam the engine only made 70 bhp at the wheels until the small bore fast fit exhaust system was spotted under the car. With this replaced with a decent system power went up to 120 at the wheels.
Because the standard cam is a fairly rorty item anyway it pays not to go too mad in this area, especially if the standard air flap induction system is being retained and idle quality is important to you. The usual choices for a road car with the standard induction system are the Kent PT31/36 (same cam) or the Piper 270. Kent claim 14 bhp and Piper 20 bhp which I've said for a long time are fairly outrageous claims. Recently I took time out to do my own measurements of both those cam profiles which came up with pretty shocking results. The Kent PT36 actually has slightly LESS duration than the standard cam and the Piper 270 only has a degree or two more rather than the ten degrees you would expect from the quoted duration. Other than having a few thou more lift, both of those cam profiles graph out as more or less identical to the standard Peugeot cam. Close enough at least that in my opinion they can't materially affect the power curve. I calculate that the Kent one will just about match the standard cam and the Piper one maybe add 2 bhp at most.
My recommendation to anyone considering buying either the Kent PT31/36 or Piper 270 in the hope of getting a significant power increase over the standard Gti cam is simple - don't.
This is all pretty depressing stuff. You can form your own views on the ethics of companies that sell products that are so similar to the standard item and yet claim such huge power increases to get you to buy them. It has now given me cause to wonder just how effective the mild/fast road cam offerings for other engines are. Without doing detailed measurements or back to back dyno tests which are expensive and time consuming you have no real idea of whether the costly purchase you are considering is going to be a waste of money. I don't have the time or resources to measure every cam on the market but I'll be publishing on here everything I do measure.
The hotter cam offerings than the above such as the rally and race ones at least do have more duration than standard and so really will alter the power curve. However they aren't going to work happily with the standard air flap meter and so are best used with carbs or throttle bodies or in actual rally or race engines. My recommendation for a road car if you're going to retain the standard induction system is stick with the standard cam. There simply is no magic way to design any road cam that gives appreciably more power than this without losing the idle quality and the low rpm power.
I rarely see a 1.9 cam with lobe wear but nearly every 1.6 cam I come across has severe wear. Why this is I couldn't say. The 1.6 cams have chamfered edges to the lobes (the 1.9 cams don't) and often the wear is so great that the chamfer has worn away. Maybe they are also made from a different material. The buckets will usually have corresponding wear and be severely concave if the lobes are badly worn. Always put a straight edge across each bucket when a head is being rebuilt and make sure the surface is dead flat. Measure every lobe with a vernier. All the inlet lobes should be the same height as should all the exhausts.
Finally, note that Peugeot changed the bolt that holds the cam pulley on from a 12mm diameter bolt on very early engines to a 10mm bolt on later ones. As with the crank bearings, why on earth they messed around with something which was fine to start with I have no idea. Maybe the smaller bolt saved 0.1 of a penny per engine and they were going through hard times. All Kent and Piper cams use blanks with the original 12mm thread in them so if you have an engine with a 10mm bolt you'll need to go and buy the 12mm one from a Peugeot dealer to be able to fit the new cam. Catcams use the 10mm thread size on their cams so your existing bolt will normally be the right one.
The Peugeot specified exhaust valve clearance of 0.35 - 0.45mm is too large in my opinion and can lead to a noisy valve train. Similarly the recommendation of 0.25mm from some of the performance cam manufacturers is too small and an engine that gets very hot could see the valves being held off the seats and burning out. I use 0.30 - 0.35mm on exhaust valves and 0.20 - 0.25mm on inlets. That applies to any cam, performance ones as well as standard ones.
I don't normally have to go into so much detail about the claimed standard power output in these tuning guides but the 205 Gti is a bit of a minefield in this area and it has knock on effects on how some of the less honest engine tuning companies arrive at their own power claims. To restate the rules I use for equating flywheel and wheel bhp on front wheel drive cars. The simple equation is to deduct 15% from the flywheel bhp and the longer version is deduct 10% plus a further 10 bhp. The chart below shows the wheel bhp figures we would expect to see using those two equations on the claimed standard flywheel power.
|ENGINE||CLAIMED FLYWHEEL BHP||
ESTIMATED WHEEL BHP
ESTIMATED WHEEL BHP
|1.6 GTI||113 BHP (115 PS)||92 BHP||96 BHP|
|1.9 GTI||128 BHP (130 PS)||105 BHP||109 BHP|
So do we see those power levels from standard cars on the rollers? In the case of the 1.6 most certainly. A few cars even make a tad more power. 98 bhp is about the highest I recall seeing. Only a really bad one will show less than 90. As for the 1.9 a few of them show that sort of power but it's a lot less common. About 108 bhp is the most I tend to see. So we could say that on average the engines are split by closer to 10 bhp than the 15 that the factory claim. A good 1.6 will have its claimed 113 at the flywheel but only an exceptional 1.9 will show 128. An average 1.9 will show anywhere between high 90s and just over 100 bhp at the wheels (so about 120 bhp flywheel) and really poor engines as little as 90 or 95. Highly tuned engines tend to go out of tune easily and show the effects of mileage and wear and tear more than run of the mill engines. Factor in 100,000 miles of wear, injectors starting to clog up, non standard exhaust and air filters and it isn't difficult to shed 15 or more bhp from an engine that probably never really had 128 when it was new.
THE 160 BHP SCAM
Most of the tuning companies specializing in other marques, Ford, VW etc at least give decent value for money. Unfortunately, in the murky waters of the Peugeot tuning world there are a couple of real sharks lurking. One company in particular accounts for 90% of the horror stories I get told by colleagues and customers. I'd say that at least 50% of the 'lads' who phone or email me have either had a bad experience themselves or know someone else who has suffered at the hands of this outfit. Naming them here in print isn't possible of course but a trawl through the postings in the various online Peugeot forums might reveal one name based in the north west of England cropping up more often than others. Their most commonly promised power claim for a road tuned 1.9 is 160 bhp. A ported standard valve head and a fast road cam of some description (usually some mythical French made cam for which any further details are too secret to give out) are supposedly all that is required to get this increase.
Take the power output of a decent standard 1.9 as being around 120 bhp and you're looking at another 40 bhp to get up to 160. If a properly modified standard valve head is worth about 10 bhp and a tractable cam another 5 then something doesn't quite add up here - even assuming that the work was done to a high standard which it probably isn't going to be. Even with a rally cam the figures don't make sense. I've had the dubious pleasure of stripping one such supposed 160 bhp engine which the owner found to be very little faster than when he took it in for the work to be done and later showed 108 bhp at the wheels on an independent set of rollers - about the same as a good standard one. The head work is described earlier in this article so no surprise that it represented no power gain. The celebrated and rather secret "French" cam was perhaps even more interesting. It bore all the same casting marks as a standard cam which was intriguing. Putting a dial gauge on the lobes revealed the standard 445 thou lift. Measuring the entire lobe profile and drawing it out on a graph failed to spot any further differences. So almost certainly it really was made in France - and had been living quite happily in that engine ever since Peugeot fitted it on the production line. £300 for the pleasure of keeping the cam you drove in with is hardly what I call value for money. The best bit was the subsequent two page letter trying to justify how a "good" standard engine only made 90 at the wheels and so 108 bhp represented a huge gain due to their expert workmanship and equated to the promised 160 flywheel. I think anyone who has to rely on 52 bhp of non existent transmission losses to justify their work should be in a different line of business.
What this '160 bhp' engine actually delivers is about 108 bhp at the wheels which equates to the standard Peugeot claimed 130 bhp. Now that's about 10 bhp up on what an average standard engine really makes but a country mile off the claimed 160 bhp. In fact 160 bhp from the standard valve sizes and induction system with a road cam just isn't remotely possible. 150 bhp is achievable with a big valve head and mild rally cam (122 bhp wheel bhp) and high 150's (128/130 wheel bhp) with a hotter cam such as a PT27.
The customer had however failed to get a single thing established in advance or in writing. Such as the exact make and part number of the cam he was paying for, whether the valve seats would be recut, the guides replaced or any other detail. A Piper, Kent, Catcam or any other known cam will have a part number stamped on the end and a specification in the catalogue which can be checked against if required. If a company is reluctant to tell you the lift, duration and timing figures of the cam they are trying to sell you then ask yourself why. If you don't want to join the ever growing list of lads who have suffered at the hands of this company then get as much as you can in writing before paying for work - the exact scope of modifications, whether guides will be replaced, 3 angle seats cut, the cam lift and duration, the expected power output at the wheels as well as the flywheel. If your questions don't get answered then go elsewhere.
So what power outputs are realistically possible with best quality work?
The power outputs below are for 1.9 GTi engines. 1.6 GTi engines will show about 10 to 15 bhp less with the same mods and produce peak power and peak torque at higher rpm. Everyone claims much higher figures but it's up to you to decide what you believe. Obviously final power output will depend on the condition of the bottom end, having a decent free flowing exhaust system, manufacturing tolerances in various components and proper rolling road setup.
Average std 1.9 engine - 120 bhp
Std bottom end, ported std valve head, CR increased to 10:1 - plus 10/12 bhp
Std bottom end, ported big valve 43mm valve head, CR increased to 10:1 - plus 18/20 bhp
As above plus mild rally cam (Catcam 4900340 or similar) - plus 30 bhp
Full rally spec engine on std induction - As above plus 290 degree duration cam (PT27 or similar) and 11.5:1 CR - plus 38 bhp. Idle will be rough below 1200 rpm but otherwise this spec can work nicely for off road engines. Mapped ignition helps.
43mm valve head, DCOE's/TB's, std cam, 10:1 CR - plus 35 bhp
43mm valve head, DCOE's/TB's, mild rally cam, (Catcam 4900340 or similar) 11:1 CR - plus 45 bhp
43mm valve head, DCOE's/TB's, full rally cam, (Kent PT27 or similar) 11.5:1 CR - plus 53 bhp
Ported standard valve head chemical clean, skim, 3 angle seats is £550. If the valve guides need renewing the additional cost is £6 per guide. Most heads require new exhaust guides. High mileage heads may need new inlet guides. Refitting of the valves and springs is included FOC if stem seals are being supplied by us as part of a gasket set or if you supply us with the new seals from your own gasket set. Otherwise the head will be returned unassembled for you to fit your own stem seals and valves.
43mm big valve head on big inlet inserts, £750. Other comments and valve guide prices as per the std valve head. However I always prefer to fit new inlet guides as well on BV heads because OE guides are usually not very concentric to the valve seat insert.
Race heads - big valves, specialised port work, multi angle valve seats - POA
The skim included in the basic head price is a light skim to clean up the gasket face. Different spec engines will need different compression ratios and heavy skims to raise CR will attract extra cost. Approx £20 to raise to 10:1 and £40 to raise to 11:1.
Measuring and balancing chamber volumes if required - priced on time spent.
Complete head gasket set £35 - includes head gasket, cam cover gasket, valve stem seals, inlet and exhaust manifold gaskets, cam seals etc
Head bolt set - £15
Valve stem seal set - £7
Shimming of the valve train to suit the cam used - £60 plus any new shims required.
Race Valve Spring System - uprated single valve springs and a thick steel shim washer to set the correct preload which replaces the 0.5mm Peugeot shim. Fits with the standard valve caps and stem seals and raises the rpm limit from the 7,200 rpm of the standard spring to 8,200 rpm which suffices for the vast majority of race tuned engines without using such high spring rates that abnormal cam wear is created. As easy to fit as the standard springs and avoids the cost and complexity of the double valve spring systems on the market which generate very high loadings and also require non standard valve caps to be used and machining done to the head. The cost of fitting these double valve spring systems will exceed the base price of the springs so our single spring system is a very cost effective option.
Supplied to fit with cams lifting up to12.5mm. Higher lifts can be accomodated with modifications to the shim washer. If used with cams with less than 12mm lift then also fit the standard 0.5mm shim underneath the steel shim supplied. In all cases the engine builder must check that there is at least 1mm free clearance before the spring goes coilbound as the fitted height will vary depending on the head casting, the valve length and how the valve seats have been cut - £75
Lighten and balance flywheel - £80 The Mi16/Gti6 type flywheels with timing teeth can't be lightened unless the teeth are machined off and you would only want to do this if the car is to be run on carbs or some other system which doesn't take crank timing references off the flywheel teeth.
Non standard cams with larger cam lobes can foul the inside of the lifter bore area. This needs to be machined before the valves are fitted and costs £20 to £30 depending on the cam profile if done during other head work.
I can't answer emails from people who want to know why their car won't start on rainy Tuesday mornings or why their engine blows smoke out of the exhaust every time they start it up. Despite the polite request on the contacts page I still get lots of "please help" emails from people who don't want to buy anything but think I'll be a good source of free technical advice. Newsflash - there's only me here and I don't sit at the pc all day waiting for emails to answer. I have engines to build. I used to at least try and find time to send a brief "sorry but I can't help" reply to these but nowadays they just get deleted so please don't waste your time typing. The place to ask is on the car newsgroups and when I have time I try to answer as many of these as I can.
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Last modified 3rd March 2011.