The 1986 825 Sterling - Rebecca

[Very Tall Brad]

Stewart...you are a few days late but thanks anyway...


November 20th.

If you are changing the wings, remember that early MK1 ones were slightly different to later ones.

Not in terms of fit or appearance but the earliest cars have a different set up around the indicator. Compare a MK1 to a MK1B for example and you will see it.

Whilst aesthetically it won't matter, if the plan is to keep the car as original as possible it's just something to note...

[whitelion58]

Despite fitting a new rear exhaust box a few weeks ago, and Brad fitting a new centre section before I got the car, the exhuast note has a deep reverberation and is getting quite unpleasant, so time to investigate.

I could not find any gas leaks, or really locate the source of the noise, but it did seem to be from the front - so the front pipe is the obvious suspect.

As usual, the forward bend has had a hard life and is heavily rusted, paper thin. That was enough to convince me I had to do something.

Having changed four or five front pipes on 827's I was not looking forward to the task - it can so easily escalate into a world of pain.

I had a good look at the manifold studs and as expected - this car is 26 years old after all - they were at an advanced level of crudiness. I got a small wire brush up there and cleaned as vigourously as I could to clean up the exposed threads as much as possible. Experience shows that the nuts usually start to turn okay, then seize on the rusty threads and shear off the stud.

Next I invested in a tin of "Plus Gas Dismantling Fluid". This is much thinner that good old WD40 and far superior in penetrating and easing rusted up fasteners.

I left that to soak, spraying them liberally 3 times over 24 hours.

This morning I gingerly pushed on the best quality , 6 face - 14mm socket in my set and started to swing on them. Miraculously they offered no resistance at all. They came off as if they has been on for a couple of weeks - amazing!. Two of them actually unscrewed the studs rather than the nut, but I am not complaining!

Of course this is a non-cat car and the last time I looked, front pipes were hard to find, and £140. Later front pipes for cat cars are easily had for £35, so what is the difference?



Top pipe of from Rebecca.
Middle is an almost-new used non-cat pipe - see the curious bend near the end section?
Bottom is a new Mk2 pipe

They are all slightly different lengths too.

The non-cat are only a few inches shorter than the later ones - the middle section is longer to make up for the missing cat.

Here is more evidence of noise from the pipe. See the bodged filler in the join and the blackend and rusted section before the flex.



Another view of the ends of the three pipes



and finally the rusted front bend



The initial plan was to cut-and-shut the new pipe to match the one of Rebecca,but a little more thought produced this:
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I didn't want to interfere with the new front pipe, so just cut the end off the orig pipe, which was in very good condition.
I can confirm it was the original factory item - double skinned!



Some careful measuring showed the gap between the new pipe and the middle section is 3 1/4". A bit of hunting in the scrap pile produced another old front pipe, so just cut the flange of that and welded into the other piece - Voila a perfectly formed spacer piece.

Just need to wait for the hail storms to pass so I can bolt it all back up, if I can find some gaskets in the shed..


Tim

[CHR15E]

Front pipes are certainly fun.

I've only ever had one that has come off like yours did. Out of, hmmm. A lot.

[scoobyh123]

Got to do mine sometime between now and January, reckon i'd best start the Plus-Gas treatment soon as it also is the original double-skinned factory jobby!

Means after the MoT (in Jan) i'll have to make a new de-cat pipe (current one slides over a cut off front pipe, courtesy of fitting a flexi repair section some time back).

Just hope mine comes off as easily as yours did Tim!

[CHR15E]

Don't put money on it.

[ash]

Is it the front pipe to manifold bolts that seize and break, or the manifold to cylinder head bolts?

[scoobyh123]

Don't put money on it.

I won't! That said, i've been fairly lucky with the nuts/bolts etc on this car, even the ones i suspected would be rusted solid have usually come free quite easily. Then again, they've not been manifold to downpipe bolts which are potentially the worst on the whole car! Fingers crossed for when i do it!

[Richard Moss]

I have an electric (12v) impact wrench. When combined with a good spray of rust penetrant and a 6-sided socket it makes very short work of exhaust nuts.

[CHR15E]

Is it the front pipe to manifold bolts that seize and break, or the manifold to cylinder head bolts?

Front pipe to manifold.

I have an electric (12v) impact wrench. When combined with a good spray of rust penetrant and a 6-sided socket it makes very short work of exhaust nuts.

I use a proper air gun on them usually. Very rare they all come undone.

[whitelion58]

So I have been using this to commute this week, and thoroughly enjoying it too, a really nice drive.
Some interesting statistics from the VCM

Miles Covered 402
Time in car 9.39 hours - which is a lot
Average speed 41.6mph - which is pretty good
Fuel used 12.5 gallons
Average MPG 32.0 - which is amazingly good.
I have seeen the instantaneous mpg down to 5 when booting it hard, but that's not toooo often.

Now of course I know VCM figures must be taken with a pinch of salt, and I will do a brim-to-brim calc sometime soon, but its pretty encouraging.
The mpg figure has been steadily creeping up one or two points every day - which does lead me to suspect there is an error there. See if it continues, and get the real figures later.

Tim

[scoobyh123]

Good figures there Tim!

If the average mpg figure continues to rise then i would also expect an error, however if you reset it at the beginning of the week then as you've done each commute it will have improved the average figure slightly each day. Bear in mind when it was reset, your average mpg would have been 0.0 mpg and it takes a few days to reach the true average with things like hoofing it, cold starts, stop/start driving all making a hole in the figure then nice straight, steady speed driving boosting the figures up again.

There was a slight error on the VCM on my Mk1 Sterling too but it was a long time ago (10 years) and only a very small error (something like 1%) so i can't remember the exact figure but i think the best i got from that one was 33mpg on a sensible run.
Conversely, my Mk2 was at one time pretty much the same wherever and however i used it. Now it's a bit thirstier to/from my local town and around the village (about 23-25mpg) but on a longer run (did an 88 mile round trip yesterday) seems to be nearer 43mpg as a guesstimate. This is higher than i had previously managed of a smidge under 40mpg although i did have a very good run last night - good roads, no traffic and a warm engine to start with!

Be interested in seeing your brim-brim figures and what the error is on the VCM.

[whitelion58]

The ABS light has been coming on during most journeys for months now. For MOT prep I removed and cleaned up the sensors, which were in great shape anyway. It made no difference though. Still passed the MOT as the light stayed off long enough for the test.

Been using the car a lot lately - over 500 miles in the last few days - and the light now stays off all the time. Odd. On the downside, the Speedo has stopped working . The VCM is also showing 0 mpg, so it must be the gearbox sendor, or some related wiring, that has failed. Another fun job. Hope its compatible with an 827 sendor unit...

[scoobyh123]

Try this little trick before you condemn the sender Tim - remove it (one clip, one plug) and put it in the oven at about 70C for 40-60 mins. Then replace it and give it a try! Has worked for me several times now, usually i have to do it after short runs in cool/damp weather so there's a bit of empirical evidence as to cause and effect there.

How are the mpg figures doing? Been looking forward to seeing them!

[Alex SBY]

The ABS light could be down to the over volts relay. This lives behind the plastic panel in the boot (near side). Remove it and you'll see it clearly.

My 825 Mk1 had a dippy ABS light and replacing this relay with a good spare solved it. I *think* that they are the same as used on early Jaguar XJ40s (up to 1989), and the relay for them is still available (at an eyewatering £50), but try resoldering the relay first. It's usually down to your old friend, Mr. Dry Joint...

[whitelion58]

Thanks for the replies. I will try cooking the speedo sender - the needle flicked a couple of times for a day or two before it died, and I was ploughing through torrential rain when it finally died. Where is it by the way? I assume tucked round the back near the starter someplace. The long-term-average mpg, according to the VCM, had stabilized at a little over 34mpg, which is quite good enough for me.

I will have a go at the ABS relay if the light returns, thanks for the suggestion. My Mk2 saloon had an ABS light that was cured by a fuse box re-solder, though that is not supposed to be an issue for Mk1.

Cheers
Tim