Diagnosing Noise in a 2000TC engine

D

dave61

New Member
Hi, I've recently acquired my first P6, a 1972 2000TC. It has been many many years since I got my hands dirty regularly with cars so I'm rusty, which I guess is preferable to the car being the same!

Anyway, this 2000TC has covered 90,000 miles and has a noisy engine. The sound is dependent on engine speed not road speed and appears to be top engine. Noises are always hard to put into words but this sounds more rotary than up & down, almost out of balance. Carbs, although worn seem ok & in reasonable balance. The noise occurs on both tickover and normal running, develops into a chirping kind of sound on the open road & can even almost disappear under light engine load when cruising at 50mph ish (I don't want to take her any faster until I know what the problem is!) . It is hard to localise but appears to originate in the head. People who have listened to the noise cannot agree on front or back, but top engine is not under dispute. Using a piece of wood as a stethoscope suggests most noise around one of the middle camshaft bearing caps. There is no obvious play in the camshaft but I did notice advanced wear to the camshaft lobes which is not yet terminal but would be a priority soon. Some valves are not opening as much as I would like. I have run the engine briefly with rocker cover removed (messy!) and oil pressure is very good indeed (said he wearing quite a bit !). There is also wear to the top cam sprocket and timing chain, but I wouldn't describe this as excessive for a 90k lump. The chain tensioner adjustment slot looks like it has reached the end of its' travel (viewed from front of car, adjusted fully to right of slot). Compression good. Spark plug colour normal & healthy.

My thoughts are 1. camshaft bearings then 2. wear to the trailing edge of the cam lobes not allowing the valves to close smoothly and 3. a breaking down of the timing chain tensioner bearing. The vehicle has not been converted to unleaded so I am using additive with every tank of Shell regular and every third tank gets 99 octane Shell Power fuel as a treat, again with additive. I am trying to decide on a plan of action for the old girl as I will need to save for extended periods prior to each stage of her restoration. Any help, comments or suggestions would be gratefully received, as would an experienced "ear" if anyone finds themself in Buckinghamshire. Also, suggestions please on the best camshafts to use for when I do get the funds to rebuild the head, and the best materials for valve guides.

Cheers, Dave
 
I think you have two options, wait for it to brake and then fix it or strip the top end / engine down and see what's what.
I don't think the 4 pot is prone to the cam shaft wearing so if yours has then either it's not had it's valve clearances check as it should, most awkward job on the P6 in my opinion or some other issue caused it, or maybe it had a poor rebuild in the past. With 99k miles then a good chance it has had a short or replacement engine. Back when the engine was designed 100k miles was excessive.
 
Is the timing chain tight? At RoverAmerica last weekend there was one noisy motor, which I rectified by adjusting the tension so it made the timing chain tight. You can feel if the chain is lose by taking off the oil filler and then feeling with you finger, if there is tension on the chain. The chain had none, so I got you an 1/8 inch allen key, and adjusted it. If yours is excessively worn, then the chain might be lose.
 
Chain noise will be "tinckly" and independent of throttle. Another possibility you shouldn't ignore is a minor blow in the built up exhaust manifold. Can't comment without hearing but you should be able to confirm / eliminate pretty quickly. The TC engines are prone to this.

It does sound like you need a pretty comprehensive top end rebuild. Others here are expert in the 4 cyl, but I wouldn't discount needing rebore and pistons as well. All of that would be really quite expensive. My suggestion would be to get hold of another 4 cyl lump, assess what you've acquired, and then rebuild the worst one out of the car at leisure. It might be an opportunity to convert to a 2200TC! The latter is more suitable for modern conditions because of the lower compression ratio. If it happened to come with a box these are a definite improvement on yours as well.

Chris
 
Hi Brian,

I'm in Drayton Parslow near Milton Keynes. Any chance of us meeting up one day?

Cheers, Dave


Brian-Northampton said:
Hi Dave,

Whereabouts are you in Bucks?

Brian.
Click to expand...
 
Hi Richard,

Thanks for that. I think I'll have to do both, ie wait for it to break (hoping that it doesn't) whilst saving up for the full rebuild. I always knew a head rebuild would be priority when I bought her anyway.

Cheers, Dave

richarduk said:
I think you have two options, wait for it to brake and then fix it or strip the top end / engine down and see what's what.
I don't think the 4 pot is prone to the cam shaft wearing so if yours has then either it's not had it's valve clearances check as it should, most awkward job on the P6 in my opinion or some other issue caused it, or maybe it had a poor rebuild in the past. With 99k miles then a good chance it has had a short or replacement engine. Back when the engine was designed 100k miles was excessive.
Click to expand...
 
Hi, Thanks for your comments. I've had the rocker cover off and the timing chain is tight at the moment but there doesn't seem to be any further adjustment available for the future. With rocker off, you see a plate with a smile shaped groove, which I assume indicates the current adjustment. The groove is showing all to the left when viewed from the front. Cheers, Dave

j_radcliffe said:
Is the timing chain tight? At RoverAmerica last weekend there was one noisy motor, which I rectified by adjusting the tension so it made the timing chain tight. You can feel if the chain is lose by taking off the oil filler and then feeling with you finger, if there is tension on the chain. The chain had none, so I got you an 1/8 inch allen key, and adjusted it. If yours is excessively worn, then the chain might be lose.
Click to expand...
 
Thanks Chris,

That's helpful. Sounds like I can discount chain issues for now but will keep an eye on the advanced wear. As for the exhaust manifold, where and how should I look please? I'll keep an eye out for an engine to rebuild and use the time to sort out somewhere comfortable to work. I did plan to run her down to friends in Yate in the near future, if you were free, would you mind having a listen?

Cheers, Dave


chrisyork said:
Chain noise will be "tinckly" and independent of throttle. Another possibility you shouldn't ignore is a minor blow in the built up exhaust manifold. Can't comment without hearing but you should be able to confirm / eliminate pretty quickly. The TC engines are prone to this.

It does sound like you need a pretty comprehensive top end rebuild. Others here are expert in the 4 cyl, but I wouldn't discount needing rebore and pistons as well. All of that would be really quite expensive. My suggestion would be to get hold of another 4 cyl lump, assess what you've acquired, and then rebuild the worst one out of the car at leisure. It might be an opportunity to convert to a 2200TC! The latter is more suitable for modern conditions because of the lower compression ratio. If it happened to come with a box these are a definite improvement on yours as well.

Chris
Click to expand...
 
Hi Dave,

Every chance of meeting up when I'm down your way! I'll PM you my details.

Also, If your off to Yate - You need to drop in on Pilkie (another Dave), he lives in Yate!

Cheers,
Brian.
 
One more thing I thought of to check. Make sure that the heat shield beneath the carb is in good condition. They can split, and then can rattle badly. That happened to me, and the solution was to pop rivet it back together. It sounded bad, but was easily fixed.

James.
 
The exhaust manifold is fabricated from tube with welding at every joint. If it was badly cracked - usually at the joints - it would be very obvious, but when they are just starting they can sound surprisingly high pitched. Key clue is of course that the noise is throttle and engine speed related. Chirping is actually quite a good description of the sort of sound I'd expect. If this is the cause you can look forward to a succession of very minor but irritating repairs! Simply take the manifold (!) to your local blacksmith (!!) and get him to braze up the affected joint. Brazing is similar to soldering but at a higher temperature with a stronger "solder". Buying a replacement manifold is unlikely to be a solution. They failed when new and have carried on failing ever since! My Father actually sold a 2000TC and upgraded to a V8S primarily for this reason. The basic problem is that the actual manufacturing process introduces stresses into the joints, and even after long use and many repairs when the static streesses should have been eliminated, further stresses are created as the maifold heats and cools in use - you should be able to get it red hot if you try hard enough!

That heat shield suggestion is also a very good one!

Apart from further listening the most obvious first action is to check the valve clearances!

Chris
 
If it is the exhaust then one solution would be to get some custom headers/extractors made at a good custom exhaust shop. I had this done of my Rover 2000 automatic a few years ago, as there was a huge hole in the exhaust manifold. The cost was 600 Australian dollars for the extractors, plus 400 dollars replace the rest of the exhaust. It made the car run quite a bit better also.

James.
 
j_radcliffe said:
Is the timing chain tight? At RoverAmerica last weekend there was one noisy motor, which I rectified by adjusting the tension so it made the timing chain tight. You can feel if the chain is lose by taking off the oil filler and then feeling with you finger, if there is tension on the chain. The chain had none, so I got you an 1/8 inch allen key, and adjusted it. If yours is excessively worn, then the chain might be lose.
Click to expand...
I thought that ,once released, the hydraulic tensioners automatically adjusted outwards to take up chain slack. Turning the allen key will either pull back the tensioner into retracted position or release it fully.Am I wrong?
 
I thought that ,once released, the hydraulic tensioners automatically adjusted outwards to take up chain slack. Turning the allen key will either pull back the tensioner into retracted position or release it fully.Am I wrong?
Click to expand...

I'm with you Organ Doctor. I didn't understand it properly either for the 4 pot engine. I assumed that maybe the tensioner hadn't been properly released following some work.

Brian.
 
So,perhaps, by tuning the allen screw (clockwise as I recall) the tensioner has been pulled back from the chain, and the disappearance of noise is because the tensioner is no longer in contact with the chain. Or, as Brian has suggested, the tensioner was never fully released.
Also note in the Service Manual how the addition of a rubber washer to the tensioner will also eliminate noise.
 
Sometimes after fitting new chains, they are so tight that the tensioner won't start auto ajdusting even though you've backed off the allen key (if it has one) to get it started. Other than that it's normally the bottom one that's noisy, rather than the top.
 
Hi all,

I thought i would bump this post up as i know Dave has been busy recently,

After making contact via Pilkies Classic Carnuts it was decided to bring the car to my house so we could diagnose and repair whatever the problem might be,
The first thing that struck me was the noise,(i could here it from inside the house :shock: ) the only way i can describe it is a clacking,tapping,squealing type of noise, the clacking got noticably louder as the revs built up and was coming from the area around No 2 piston,
Our original plan was to fit the recon head that i had spent a few days working on,but after removing the head we found that No 2 piston was somewhat floppy in the bore,so off came the sump and out with the piston, we suspected it may be broken rings but we weren't expecting this,.... :shock:

4169001421_a2cec3c423.jpg


4169002181_f0927b8440.jpg


It was the decided to remove the other three pistons to check if they to were cracked but the pistons themselves were OK only the top ring on No 1 was broken,...

The bigends were down to the copper as were the mains,....

4208975535_ea5c9682c4.jpg
 
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