MK1 Astra 1200 to 2.5 v6 red top engine swap

"Lets see if a 2.5 v6 will make it go faster!"

Jake is the sort of guy that sees a big engine and buys it and then works out how to fit it to his car. Most people do things the other way round but let’s see if Jakes buy it and see what happens philosophy paid off.

He tells us that he’s pretty much always been into mechanics, “fixing and repairing... I picked up this Astra in August 2004 for a bargain price of £130 tax and tested. It was a 1981 mk1 Astra 1200s, in red (apparently), although in the trade it's called “shit brick orange”. The car was solid, 32,000 miles on the clock, and 4 previous owners.

It is my first fully legal car, and I wasn't really going to do anything to it... that is until I found ebay, I purchased one GTE steering wheel and i got hooked, as the guy i purchased the wheel off had a mate who is a fanatic about mk1 GTE's.

A 1981 mk1 Astra with a red top 2.5 v6 engine just didn't seem possible until Jake came along!

I drove down to pick up the item, and I saw all the other parts i wanted to buy, interior, seats, body kit, 1.8 8V engine, rear axle, mk3 discs all round, lowering springs, digi dash, koni adjustable short throw shockers and GTE wheels. That was just for starters.

Fitting all the items wasn't too difficult, springs, shockers, interior all went on quite nicely and obviously with the engine upgrade we had to change the wiring loom for the car, again this was quite an easy job. A problem we did have is that the GTE’s have a slam panel at the front of the car welded to the front valance, so when the engine was out we had to weld one in, also once we had the engine in and running, we found that the gearbox rubbed on the inner wheel arch a little, so nothing major yet... didn’t have to change any of the engine mounts.

The brakes were problematic, obviously with an engine upgrade you need to upgrade suspension, wheels, tyres, and brakes, but here the callipers were too big, as in they were an old larger version... so we could put the wheels on but the car wouldn't move anywhere. Not a problem as I went down to the breakers yard and picked up a newer set of slightly smaller callipers.

I drove the car around for about 8 months, until the bottom end went... the problem with 8v's I hear is that they are very dependant on oil, you’ve got to keep checking the levels. A month or 2 later I spied a 2.0 8v I fancied so bought it and put it in, but for some reason it just didn't want to run properly, changed the mass sensor, cleaned the injectors, changed the lead and spark plugs, checked the coil pack, changed the ECU... nothing would make it run as good as the 1.8 did....

Hacked off after about 4 months trying to get this freaking thing to work properly, I took it out and sold it, whilst I pondered whether or not I should go for a 2ltr 16v or a 2ltr 16v turbo.... until I was on ebay last summer and i saw this red top 2.5 v6 going for sale, completely unsure if the thing will fit in my car I bought it for £300.

I changed all the obvious parts, cam belt, spark plugs, gaskets... but couldn't use the gearbox that came with the engine as it's just too big and would require a lot of cutting and moving to get it in, so we pinch the f16 gearbox flywheel and clutch from a 2ltr 8v, which seem to fit nicely to the engine, although I was worried that the engine might tear all that apart (it hasn't.... yet)

Unhappy with the GTE wheels I purchased some team dynamics Monza 15 spoke, 16" white wheels, look very nice, a lovely red strut brace, some proper neon's (blue), upgraded the alarm, it's the Clifford concept 650, with call guard, remote start and black jax, roughly £1300.

After putting this engine in, it didn't run properly just like the 2ltr, so i up rated the fuel pump to one that delivered 3.5 to 4 bar and that's what the engine requires, still didn't run properly, checked the mass sensor, lambda sensor, couldn't figure it out, so on a whim i put some injector cleaner in and suddenly it woke up... but wasn't quite as fast as it could have been... had my engine tuning guy check it out and found out that it still wasn't fuelling enough, so I purchased 2 little resistors off ebay and put those inline with the engine temp sensor... that woke it the hell up....

I'm now awaiting delivery of the diagnostic plug, so my engine tuning guy can check all the engine for me, also waiting for the rest of the body kit...

I've more parts to buy as it's not quite finished yet, shockers for the back, imported springs from Holland to take the weight of the new engine, Quaife LSD, gte bonnet vents (not ridiculous Scooby scoops), Diablo doors coming in September and a super charger is going to be fitted at the end of the year...

At the moment the car is pushing out 170bhp, although it hasn't been on the dyno but that's what the standard engine produces, but with the charger it should push it just below the 300 mark... I know that's bad for tearing tyres up... but who knows maybe the next mod will be a 4 wheel drive kit.

I think that's just about everything, though there are some misc things I've done, like added electric windows, central locking, put nova mirrors on and I've got to cut off and replace the rear arches as the rust has gotten to them a little.

Obviously keep to the speed limit I've beaten 3 quick cars, a VW Corrado 3ltr v6 220bhp, a Jap spec Mitsi FTO Mivec 2ltr v6 200bhp and a Nissan 300zx 3ltr v6 300bhp, the benefit of my car is that it weights about 900kg much lighter that my opposition.
My younger brother has helped me every step of the way, he's 21 and is a fully trained mechanic.”

Impressive stuff Jake and it just goes to show that pretty much anything is possible if you work hard at it. To keep up with Jakes Astra, and the many other interesting projects of TorqueCars members please join our friendly forum which contains an exclusive members only gallery.

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