Resurrection of my CQ20V

[K Simmonds]

Those V8's do sound great and I'm a big fan of those engines in general, best thing Rover ever made even though they pinched it off the Yanks. Yeah, in the summer it'll also be a lot of fun on the road for short trips with the roof off and perhaps some motocross googles, what's the chassis like for corrosion on it? I've spent a serious amount of time under Landrovers with a MIG and have totally re-chassised a couple, another job I wouldn't do for fun.

Well if the clutch is new I very much doubt it's the release bearing, as you say I'd double check everything rotating at the front of the motor, I'm doing a cam belt on a members 7A this morning as it happens, well's he's doing it with me as my elbows still poo.

[Bowie69]

Chassis is mint, this thing was built in the 90s, did a couple of races and then, I think, parked up, apart from being bought a couple of years ago by a friend and he tootled around Devon in it during lockdown.

Bulkhead is steel box/part of the cage so no corrosion issues there either, rest of it is fabbed in ali.

Will check the rest of the engine, weird thing is I can't reproduce unless car is moving....

Sorry hear about elbow mate, take it easy, won't you.

[K Simmonds]

Good to hear it's solid as they can be a total nightmare as I'm sure sure your well aware, hope you got it for a good price as that's worth a few quid.

If you can't reproduce the noise unless it's moving then it's almost certainly drive line related or it could simply be something rattling, heat shields, brake splash guards etc, let it develop I guess.

My bloody elbow is a PITA, I only chipped the end off a bone but it keeps catching me out. It's really irritating as an X-ray of my right arm looks like I'm cyborg yet I now have near full usage of it again, the left all looks fine but doing something simple can really hurt. At least time is one thing I do have and that's what I guess I've got to give it, think I tried to do too much too soon back in the spring so am being very wary of it now.

[John.]

Was under the impression it wasn't suitable for the 7A, but be very happy to be corrected....

Had blue in it when I bought it, manual stated glycol based G11 which is blue so i just kept it on the blue stuff. I'd think the later pink stuff will of superseded the blue ?

[Bowie69]

Good to hear it's solid as they can be a total nightmare as I'm sure sure your well aware, hope you got it for a good price as that's worth a few quid.

Yep, a good price , not unfamiliar with them at all, had 24V FFR Lightweight and a couple of RRCs all of which I have done extensive things including cages etc, so this is right up my street.

My bloody elbow is a PITA, I only chipped the end off a bone but it keeps catching me out. It's really irritating as an X-ray of my right arm looks like I'm cyborg yet I now have near full usage of it again, the left all looks fine but doing something simple can really hurt. At least time is one thing I do have and that's what I guess I've got to give it, think I tried to do too much too soon back in the spring so am being very wary of it now.

That's a shame mate, but seems like things are picking up -keep up the good work

[Bowie69]

Had blue in it when I bought it, manual stated glycol based G11 which is blue so i just kept it on the blue stuff. I'd think the later pink stuff will of superseded the blue ?

Quite possibly, TBH, I've got myself so confused over coolant colour changes in the last 10 years I don't know what to think! G13 definitely supersedes G11, G13 is pink, so using that FEBI's version of that now..

[John.]

Quite possibly, TBH, I've got myself so confused over coolant colour changes in the last 10 years I don't know what to think! G13 definitely supersedes G11, G13 is pink, so using that FEBI's version of that now..

Sounds about right
I did worry a bit when I first got it, and the fact it has an alloy head. Then checked the handbook and felt a bit better about it.
Checked the handbook on my slightly newer Jap motorbike, it stated glycol too.

[Tractor Dave]

They were designed to run on the blue stuff. I remember the B5 A4 was the first Audi I had with G12 red stuff which had turned brown when the previous owner had added blue. I had to flush it all out. The main advantage of the newer stuff is that it lasts longer. Blue or Green needs changing every two years aposed to red every 5.

[Bowie69]

Fair enough! I find the pink goes brown quite quickly, which can be a bit annoying.

Currently looking at a new header tank, again, thankfully only £20.

[Bowie69]

So... coming back to the weird noise....

I need to clarify, it was engine speed related for sure, would happen in every gear while accelerating at approx 2.5K, was getting more and more annoying.... like a rattle/screech, sounds great

Eventually gor a chance to properly look yesterday, seems two alternator mounting bolts had come loose, one had left the building entirely, and the other was nearly read to go... doh. Replaced the missing one and tightened both up, not sure why that happened.

However, the noise remained

Bit more investigating and seemed like there were some witness marks on the driveshaft shield from the exhaust manifold, bit of pry bar action and moved that away a bit.

Then realised the manifold shield could also be considered a bit loose.... so intake hose off, throttle body off and find the little L bracket at the rear is missing a bolt. Bracket also slightly bent, so straighten things up and two new bolts:

20221125_130356.jpg

Put it all back together and the noise is gone

It was so loud it was embarrassing, so good to get this fixed.

[newsh]

So... coming back to the weird noise....

I need to clarify, it was engine speed related for sure, would happen in every gear while accelerating at approx 2.5K, was getting more and more annoying.... like a rattle/screech, sounds great

Eventually gor a chance to properly look yesterday, seems two alternator mounting bolts had come loose, one had left the building entirely, and the other was nearly read to go... doh. Replaced the missing one and tightened both up, not sure why that happened.

However, the noise remained

Bit more investigating and seemed like there were some witness marks on the driveshaft shield from the exhaust manifold, bit of pry bar action and moved that away a bit.

Then realised the manifold shield could also be considered a bit loose.... so intake hose off, throttle body off and find the little L bracket at the rear is missing a bolt. Bracket also slightly bent, so straighten things up and two new bolts:

20221125_130356.jpg

Put it all back together and the noise is gone

It was so loud it was embarrassing, so good to get this fixed.

Isn't it great when you fix an unwanted noise!

[Bowie69]

Yep!

It took me at least 3 months to pluck up the courage to actually properly look at it.... fearing the worst I guess.

Thankfully not as bad as it could have been, and got ahead of a probable side of the road breakdown (alternator).

[Obli]

Great thread. Nice to see you're keeping her up together and standard.

I haven't been able to read the entire thread but you mentioned exhaust resonance. I'm working on addressing that on my 90 20v. It has a custom exhaust. Is yours a custom system? Where do you experience the resonance? Mine is at 2 - 2.5k rpm.

[Bowie69]

It is custom stainless and 2-2.5K is worst for sure.

[Obli]

Interesting. If I manage to improve/eliminate the drone on mine, I'll post up what I did. I've got a Helmholtz resonator designed which I'm fairly confident about. It's going to attenuate (reduce) the low frequencies (booming) generated around 2,200rpm +/- 400rpm. The only unknown variable in the formula is the exhaust gas temp before entering a custom centre box. Obviously going to fluctuate but need a fairly decent idea when engine is warm and driven at cruising speeds. I've been guessing about 175 deg C (350 deg F) for now. I think I'll uncouple the exhaust and get a measurement on it and then rerun my calculations. Then I can order the materials, fabricate and fit

My 90 20v (early engine, 2 plug ECU, bag-o-snakes etc.) has developed a hesitancy around 3.5k+. Started doing it a couple of days ago. I'm going to replace the knock sensors as they're 32 years old and the most likely culprits. Thanks for the earlier info in this thread on the two Bosch knock sensors, very useful. Are the blue and green variants simply cable length differences, do you know? Has your car been running OK using the doughnut design? I've noticed the aforementioned Bosch part numbers cross reference the Audi part numbers for the 10v engine knock sensors, so forgive me but I was slightly skeptical. I wondered why the 7A knock sensor p/n would be unique, unless it's simply a cable length difference?

My issue could also be the old Hitachi injectors. Are you running the orange/red Bosch injectors? If so, how have they been? I've been looking for a good excuse to do mine but historically I've had no issues with the Hitachis in 209,000 miles so couldn't justify binning them while working.

I like the look of the Ultra Performance stainless coolant stub from the thermostat housing. Might have to acquire one of those Would like to replace the long, straight hose too. Did you use a generic silicone straight hose cut to length?
No further questions, your honour!

Cheers,

James