markmad

Hi Iceberg, as you will notice I reply to you from the home of Birkin’s and Superferformance . Your question is not too specific but I will assume you want a traditional looking 7 which then means Caterham ,Birkin and perhaps Fraser comes to mind of which it seems to me Birkin and Caterham are better represented in your part of the world. Your post ‘’stated using on a track ‘’ so I will suggest based on that. Try buy a used example which is close to what you envisaged building. Don’t think you will build for less!! Birkin’s offer the better value for money technically speaking , better than Caterham. Birkin’s have a slight restriction with regards to power plants that are able to fit , but that said your most popular engines will fit properly. Birkin’s have a very poor marketing strategy so one is not aware of how many optional parts are actually available for the car If you looking for lap times then keep it 4cyl preferably N/A , The only alternative that I have seen work with regards to quick track times is a 13B rotary power If you not looking for a traditional looking 7 then please ignore the above.

The centre one is a Birkin with a couple of upgrades .

Red Duck,I ve driven two race cars with the 6 speed H and its a really nice gearbox and the one has been attached to 280hp 7 for a couple of years now without issues . Take the H pattern box its good ,besides its lighter as well.

My intension here was not really to compare the two engines but was rather shed some light on the pros of the engine as it has quite a strong following in probably most regions where 4cyl engine/cars are popular.Plus it has been used in touring cars so long now its probably known as the Dinosaur amoungst the other power plants .

The GM porosity issue is easily repaired though it is nicer to have the coscast head but no performance advantage .I must add the heads did vary ever so slightly, though you have to have be very familiar with the engine to notice the differences in heads. You won’t need any serious porting for power levels below 240-250 ish just a head clean up. And for a road engine or track day engine the hydraulic lifters are fine but would stop using them at any power over 220hp though I have seen 240hp on hydraulics but its unreliable in a race engine . I have a typical mid spec race unit lying loose here at home and will put it on the scale to put the weight issue to rest .From an aesthetic point of view the engine is good looking compared to its competition .

The vx/opel engine is one of the best production engines that have been made in the past 20 years .Proof of this is that it is still used in formula 3 cars and was used in the Chevrolet BTCC cars until they went to 1.6 turbo. This alone should indicate that it has cult status. The weight issue is exaggerated because the engine came for example with different flywheels which alone differed in weight by about 4kg’s .Like wise the crank alternator pulley can alone differ from model to model by about a 1kg .My point is the state of the engines tune can have quite a large effect on its final weight . The engine is ultra reliable but it depends on the state of tune ,if you looking for up to 200hp then all you need is a set of decent throttle bodies and a good running engine. (believe it or not ).If you looking for more power than yes you start adding some common sense safety mods . I would just change to a ITB setup and dump the carbs but it is costly .SBD are a good source for spares though I personally would use a ECU that is well supported in your area. cheers ,dont let Duratecs scare you

Best all round engine in a Birkin/7 must be and I believe they are available in the U.S is the Toyota 1600 20v .Its light ,powerful in STD trim ,easy to come by ,easy to fit and comes STD with ITB’s ,fairly light ,and cheap probably the first choice power plant when it comes to Birkins . Duratecs are largely over rated when comparisons are made referring to weight especially when it’s compared to the Vauxhall/Opel unit. I can go into detail here but will refrain from that.

I'll give the Cat a miss thanks . But Mike people under estimate the cost of preparing or converting the car to race ready standards .I understand your thinking .

Mike from what you have written you better off selling your Caterham and keeping the Birkin ,besides it has a much better engine .215hp will require more than just the ITB's you'll need some cams as well.

The EXV has been used but it's a far cry from a 20xe .In fact the 20xe's head is still available as new and used for the Spiess formula 3 engines and I believe one of the small European car manufactures will use a rebadged engine in rally cars. I think when it comes to turbo engines a weak n/a engine can be made to look good quite easily, and yes the blocks casting was increased in thickness as from the C20ex LN onwards to reduce noise hence LN.

Mike ,I was browsing last night and came across this forum and saw your car joined and will take the opportunity to say the work you have done is brilliant .

VX engine is very good and my favourite .Remember the Brits like saying it heavy but it’s no more than a Kent engine and they compare the engine to a handgrenade in any case ! It does depend in what stage of tune it is in because if its 250hp unit it will probably be about 15kg's lighter than a STD unit. Rods are ok for reasonable RPM under 8000, with ARP bolts, but for constant RPM rather go steel rods . SBD and QED will be your main source of parts, Swindon are too expensive and don't bother with other companies. You can see 250hp with mild head work, really the biggest problem with many is they think it needs major work. Cylinder heads can be repaired quite cheaply if they have gone porous so there is no need to panic if this has happened to a GM head.

VX engine is very good and my favourite .Remember the Brits like saying it heavy but it’s no more than a Kent engine and they compare the engine to a handgrenade in any case ! It does depend in what stage of tune it is in because if its 250hp unit it will probably be about 15kg's lighter than a STD unit. Rods are ok for reasonable RPM under 8000, with ARP bolts, but for constant RPM rather go steel rods . SBD and QED will be your main source of parts, Swindon are too expensive and don't bother with other companies. You can see 250hp with mild head work, really the biggest problem with many is they think it needs major work. Cylinder heads can be repaired quite cheaply if they have gone porous so there is no need to panic if this has happened to a GM head.

In my opinion a 7 must have a 4cyl engine so I would narrow it down to just 4cyl options. Given this the best and most economical is a Toyota black top 20v Toyota engine This engine is easily to come by ,has throttle bodies as STD and can be run with the T50 Toyota gearbox .Optional bell housings can be purchased to use it against a Ford/Quaife unit as well. Optional parts are available from Birkin to make the fit easy. Down side is of course it will remain a 1600 and power will realistically always be below 200hp,but in a Birkin this makes for quite a quick race car or even road car. Duratec is probably the best 2l option, or if you racing any ex touring car engine will do as is the case with many who race 7’s in South Africa. My personal favourite is Opel/Vauxhall c20xe, has almost 300hp potential as per Duratec though is a little heavier. Zetec ,nice option but not a engine that will easily give you more than 250hp.But 250hp in a 7 is enough in anycase. Honda is an option but apparently heavy. If you really like spending money and like being unique then a Millington Diamond would be a nice buy I guess. Rotaries are popular in Cape Town because it’s the cheapest way of obtaining 270+ hp. Down side is they heavy, sound like washing machines and if you racing will possibly exclude you from various categories . Turbos on any engine to make power prove to be more a pain in the rear end in a 7 . As said this is just an opinion ,but it the above tends to work well more many over here .