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MG MGF Technical - Tech help needed post headwork and RR


As some of you know, my car did "well" but not "very well" at the recent Emerald rolling road session.
It's had some Peter Burgess work done on the head.

Dave, the Emerald guy, was suggesting that there was something very wrong with the car to get the cuve I managed to get. He was even suggesting that the exhaust cam may have slipped a tooth. He didn't think that the head work alone could make an engine produce the curve I had.

I don't have the data yet (Dave? Rob?) but a remember that I was 10bhp down at the top end and had a big "chunk" taken from the torque curve between 2k and 3k rpm.

The car is at the garage today and has been looked at. It passes the compression test very well and the cam timing has been checked. In short, there seems to be nothing wrong at all! The garage are reaching the limit of their expertise.

While the car is still at the garage, is there anything that anyone would suggest looking at?

Cheers,
Paul.
Paul Nothard

Tricky Paul :o( I think that you are entering the realms of needing the expert advice of a professional engine builder - Peter might be able to make some suggestions (useful to touch base with him anyway) and David Andrews, who, of course built Dave's superb head.

The only things that I can think of that should be easy to check are:
1. inlet manifold leaks
2. sensor failure
3. VVC solenoid failure
4. loom problem

How is the VVC cam timing set? Is it possible that this could be wrong???
Rob Bell


Sensors check out ok. Mike is off into the depths of MEMS now to have a look about.
Cams are fine. He double checked all of them to be sure.

If there were a VVC solenoid problem it would have most probably shown up in MEMS and, more importantly, I don't think that it would necessarily have affected the torque curve at low RPMs while maintaining a perfect tickover.

Loom problems - again I would have expected anything electrical to show up in MEMS. But I may be wrong.

I'm flummoxed.

Think it may be a trip to a specialist. :-(

P.
Paul Nothard

You're quite right, all of what I've suggested would be expected to ruin tick over - and that is not a problem your car has got. :o(

Perhaps Dave Walker may also be able to help out? He'll be in the process of moving to Thetford of course, but I guess you'll be needing another RR session at some point in the future in any case. Plus, he may have some further pointers on leads to follow up.

Not sure where we are with regard to the RR data - Dave, have you heard from DVA yet?
Rob Bell


Hi all,
"power low at top end and missing torque between 2 and 3 k rpm" sounds to me as not enough fuelling due to dirty / clogged injectors or fuel filter. Regulated fuel pressure OK ? Is it possible for the garage to make a road-test with a lamdasonde in the exthaustpipe and on-board instrument ? Hope it getīs sorted without too much work.

BR, Carl.
Carl Blom


Interesting idea Carl.
I'll give them a call and see, but I suspect that they're too busy today. <sigh>

P.
Paul Nothard

Sorry I missed this earlier - just got back from a visit to TechSpeed :-)

I've chased DVA by email for the RR data, but have had no reply as yet. I'll pick up the phone tomorrow and see if I can get hold of him.

Carl's fuelling idea sounds a good one. A conversation I had today with Roy Forde at TS was around the fuelling and how fuel pressure can be critical. I've emailed Paul directly.

Dave
Dave

This thread was discussed on 16/12/2002

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