Wednesday 25th March 2015

Ford Escort RS Group 4: PH Fleet

Yellow Peril is (finally) up and running again, with competition set for this weekend

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It's back! The Yellow Peril has just emerged from a winter rebuild after a nasty engine failure last autumn and the first event is this weekend, the Cadman Construction Woodbridge Stages in Suffolk.

It's taken a while to get here!

So what happened to the engine? One word: 'detonation'. Three events into last season at the Brands Hatch Summer Stages, the engine started losing coolant. Following the last rebuild at the now defunct JRE Racing Engines, it had blown injectors partly out of the fuel rail twice, due to an ill-fitting rail.

We'll never know the exact cause but the general consensus is this may have leaned off the mixture on the relevant cylinders, as well as spraying petrol everywhere at high pressure. If that happens at full load on a racing engine, detonation can follow in milliseconds. Detonation is a bad and means fuel is literally exploding rather than burning progressively.

I took the cylinder head off and what greeted me was a mechanical catastrophe - 'sick' doesn't even come close. The head gasket was leaking into a waterway, but much worse, the alloy head looked like someone had taken a nail gun to the inside of it thanks to the explosive force of the petrol. The expensive new Omega two-ring 'slipper' pistons were also ruined and so I did what all grown up people do - cried and drank beer.

There was a way back though. I gave Simon Armstrong a call at Ultimate Performance. Simon is a former McLaren race engineer then the project managed the Mercedes F1 engine program for six years. Now he runs his own business producing CNC machined cylinder heads for the motorsport industry. He's done well over 220 big valve Vauxhall Red Top heads so far and if he couldn't fix mine, nobody could.

"I cried and drank beer."

Simon first had the damaged areas welded and then re-machined the combustion chambers (to achieve the correct compression ratio) and deck to shiny, new condition. I was all set to rebuild the engine myself and have it recalibrated on a rolling road. I'd got all the measurements from it before strip down, including measuring the compression ratio using a burette and thought I was all set.

Then I measured the cylinder bores and discovered they were no longer cylindrical so a new block was needed. To get maximum performance from the Omega pistons, bores must be exact to within a few thousandths of an inch and the bores need to be 'plateau honed' to get the right surface quality. So getting a new block wouldn't completely solve the problem.

I needed a new engine builder, so I got on the blower to experienced Vauxhall Red Top builder, Kieran Smale at KSP engines in Cornwall. He painstakingly rebuilt the engine with a fresh block and a set of the latest SBD taper throttle bodies. When remapped on the dyno by calibration guru Sandy Brown, the result was a realistic 268hp at 7,500rpm and 188lb ft at 6,000rpm and 7,000rpm. I had been quoted 287hp by JRE but clearly that was optimistic as the engine is exactly the same spec. The new throttle bodies should have improved the mid-range torque and contributed a couple of points to top-end power as well.

268hp, 188lb ft and ready to race!

While all that was going on, the rear axle went off to Gareth Lloyd at West Wales Rally Spares, to swap the 5.1:1 final drive for a slightly taller 4.9 crownwheel and pinion. I'd shortened the gearing with the change to bigger 15-inch wheels last year but had gone a tad too far. It's all up and running now, the engine sounds sharp and happy and the car is MOT'd and ready to go. This will be the third attempt at Woodbridge following two DNFs through mechanical problems, so it's third time lucky I hope.

 

 

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FACT SHEET
Car: 1978 Mk2 Ford Escort RS
Run by: Jesse Crosse
Bought: January 2010
Mileage: 1,000 (or so) stage miles since 2009
Purchase price: £36,000
Last month at a glance: The winter rebuild is finally complete - to the stages!

Previous updates:
Enter the Yellow Peril! An intro to Jesse's Escort
A solid early outing, or would have been if not for electrical gremlins
Abingdon stages a proper workout for Jesse and the Yellow Peril
Summer break? Perfect time for some upgrades then!
Brands Hatch Summer Stages gives the Escort a proper workout
The coolant issue returns and a winter project beckons

[Lead image: Andrew Manston]

 

 

 

 

[soad]

The purchase price must have gone up somewhat?

[confucuis]

Jesus, I hate to see the financials after that! Fairplay though love this article on the Mk2 though I'm not normally a fan of them as there bloody everywhere over here in Ireland. It's a nice aggressive looking one which I like.

[tr7v8]

Can you translate this line!
Simon is a former McLaren race engineer then the project managed the Mercedes F1 engine program for six years

[windy1]

tr7v8 said:

Can you translate this line!
Simon is a former McLaren race engineer then the project managed the Mercedes F1 engine program for six years

McLaren then to Ilmor perhaps?

Edited by windy1 on Wednesday 25th March 17:59