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Author Topic: Scruffy red MK2 Road Rally car  (Read 503 times)

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Offline Tonyb

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Re: Scruffy red MK2 Road Rally car
« Reply #15 on: August 10, 2014, 07:06:22 pm »
Bit of an update, not had much time for forum posting but plenty has been going on.

Did Llandow sprint and Llys y fran hillclimb in the car. Won the road rally class at Llandow (by the skin of my teeth) and second at Llys y fran. The car was happy enough to rev and sat on the limiter at 6200 much of the time! The problem was it didn't do much while getting there and didn't feel much fun, despite having a 4.47 FD and VWMS ratios in the box (geared for about 95 @ 6000 rpm).

Took the car to Mosleys Rolling Road to see where the power was. We ran it up to see what it had and the result was 112bhp at the crank, pretty much what I expected.

We started to play around with timings, did two runs and then it spun a big end bearing and seized solid! Never mind, excuse to build a proper one I suppose [:s]

As its a night event car, no point in building a fire breathing monster, even though I'm hillclimbing it at the moment, in its class it should be competative anyway. First to strip the engine and see what went wrong and why (for the record I didn't build this one, its what was in it). Also have a look and see what was in it that was useful and salvageable.

Engine coming out.



Here is part of the power problem, makes you wonder if people check anything when the build cars!!



This is a problem lol, couldn't get the bearing off the crank even with a club hammer!



TSR C pack head as told by the seller, all looks good.



valve seats are all good, which is good news.



Head, cam and valves were all good. Replaced one lifter as it was slightly pitted on top (odd!)



Manifold being machines our to match ports, out of interest the pattern exhaust gaskets I purchsed were miles too small and were skipped. Re used original ones which were ok.



Decided the problem with the big end must have been oil starvation at Llandow as you do pull some G's with sticky tyres on the long sweepers there, even with limited power. Nothing else in the motor was dodgy, all looked good. Made some sump baffles and fitted a windage tray as well for peace of mind.



Didn't want to pull the bottom end out again so I replaced the oil pump and cooler, all seals and gaskets, new big end, mains and thrust bearings. Obviously fitted ABF head gasket (it did have one on it originally) plus ARP big end bolts and some heavy duty main bolts.



New forged 2E crank installed with hardwear.



Block was decked and pistons machined to get the compression right to suit the TSR 203 cam and get the squish correct. The pistons and rings were the nearly new ones that came out of the Tatty Golf Slick 50 engine. Just had the block lightly honed to bed the rings.



Head torqued up ready to time the ignition and cam up on the bench, plenty of assembly lube!



Engine, clutch and gear box assembled ready to go back in. VWMS box now in it plus a helix competition clutch and lightened flywheel.



Nearly all back in :thumbup:



Took two weeks as I had to get it back out for an event the following week - lots of work I could have done without.

Test drove it and much better, did Epynt hill climb the next week and it went well. Second on the Saturday and Sunday, 6 or 7 in the class so good result. The limited at 6200rpm is rubbish as the car is still not at peak power plus it still seems a bit flat. The spec says 140>145 BHP on paper, fells like 130bhp.

Looked in to sorting the Digi ECU, most info says you can't do much and they are rubbish, thought about fitting a stand alone ECU but I'd never recoup the cost. Eventually, through chatting to the guys on here, worked out that the chip can be changed but that only stores the fuel map, the ignition and rev limit are on the ECU's on board memory chip.

Found a company who could sort it, so had a new chip fitted for the fuel map, and had the on board ignition map and rev limit changed to suit the spec I supplied and had the rev limit adjusted to 7200rpm. Got it back and fitted and much better, quite sharp now, has lost the 'wooliness' it had before, probably around the 140>145bhp the spec is supposed to give now. The only issue was that it was supposed to have the limit at 7200rpm, which I'm told it has but he set the soft cut at 6800rpm which is too low. Soft cut limiters have no place on a race engine anyhow, hard cut is all you need. turns out it had a fuel chip in it anyway but as the guy said that's no good on it's own, just makes it run rich.



We've been racing all year and doing quite well so far, but that's another story.......................

Offline JMR

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Re: Scruffy red MK2 Road Rally car
« Reply #16 on: August 11, 2014, 11:04:18 am »
Great stuff...cheers Tony... 8)

Love the "block" table by the way!! ;D

 

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