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Post by tommydp on May 17, 2013 12:30:42 GMT
Hi all! I've not been very active lately, but hope to post more frequently in the future.
I've enjoyed the white 1800 for a month now, since I got it back on the road. Actually, the Rover has rested ever since as I've driven the 1800 every day.
The white one works very well. Ok, it's done almost 200 000 kms without an overhaul but it starts instantly and runs vey well. It really pulls like a train. Marvellous!
OK, there is a puff of blue smoke when revving after idling but nothing to be seen on the road. I don't really care.
One thing concerns me though. There is a noise from the engine now and then. A metallic, rattling kind of noise. I believe this is the dreaded sound of detonation... It can be heard at high rpm when driving also if revving hard.
I suspect the vacuum advance, as if I remove and block the pipe it goes away. However, it will then hesitate and be somewhat more jerky, especially at low speed.. I've tried retarding the ignition timing, but the noise remains as long as the pipe is attached no matter how far I retard it. I've checked the timing and advance with a strobe and a homemade strip of additional timing marks. The mechanical advance is spot on but when the vacuum is attached it advances waaaay off..
Funny thing is, I tried the rebuilt Distributor Doctor distributor, as the blue one is just standing in the barn anyway. Well, it makes no difference..
Any ideas of how to overcome this?
Is this a common problem on 1800? I've had at least two others with the same noise. Back then I didn't care and turned the radio up... I've never had this phenomen on a Marina 1800.
Could the sound just be due to a tired engine? Oil pressure is down to 50 driving when really hot. Idle is 25. The sound is rather identical to the "lack of oil noise" I get when I cold start it, before oil pressure builds up. This takes a couple of seconds. I sometimes wonder if it fires abnormally quickly! If it took some revolutions, the pressure would build up before start. Seriously, both when cold (with choke) and hot it fires the instant I turn the key. Is this really normal? The blue one is the same.
Update: BTW, it never pinks/ pings if my understanding of the phrases is correct. Pinking is the noise you get when you floor it up a hill if over advanced right? It never does that. The noise is at light throttle, if I floor it it goes away. This is detonation, right?
Ok. Updates to come! Really annoying noise. Please help:-)
Regards, Tommy
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Post by Penguin45 on May 17, 2013 18:02:30 GMT
Timing chain? You've had fun with them before...........  Chris. |
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Post by tommydp on May 17, 2013 20:13:03 GMT
No way I'll look into that! Runs and idles beautifully except for the noise..
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Post by threelitre on May 17, 2013 22:20:04 GMT
Hard to do a remote diagnostic. But the vacuum advance will not be working on full throttle or will also have no effect at max rpm - so I have a little doubt it is this. I once encountered a Spitfire (the one with four wheels, but no wings on it) with a tired engine. It had low oil pressure and when hot the engine rattled with the mains at higher RPMs. Cold and low rpm (particular under load) was fine. I think it may be that the bearings on the engine are on the way out.
Regards,
Alexander
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Post by Penguin45 on May 18, 2013 1:24:29 GMT
Do they rattle? I thought that if the bottom end was going you got more of a "thumping" sort of noise (Like when my Chevette estate let go on the M5 at Bristol back in the dark ages)?
Chris.
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Post by dave1800 on May 18, 2013 1:31:55 GMT
Hi Tommy I feel that the teacher is posing some difficult questions again! But this time I am really confused, easily done You are saying "A metallic, rattling kind of noise. I believe this is the dreaded sound of detonation... It can be heard at high rpm when driving also if revving hard." and later "Pinking is the noise you get when you floor it up a hill if over advanced right? It never does that. The noise is at light throttle, if I floor it it goes away. This is detonation, right?" At 200,000 miles your engine will be worn and the rattle you hear at cold start is the bearings before the oil circulates. I have run engines for tens of thousands of miles like this knowing that the only cure is a rebuild, just changing the shells is likely to only give a temporary result and is a lot of work on this installation as you know. Big end bearings send to rattle when worn whereas the main bearings produce a low down rumble. As Alexander has pointed out under high load there is no vacuum advance so the only thing you need to check is that the vacuum unit or the rotating plate in the distributor isn't sticking. But as you have tried the blue car distributor this probably rules this out. I don't understand why your timing changes as you connect the vacuum pipe. At idle the butterfly occludes the vacuum take off so there should be no advance until the throttle is opened. This needs to be investigated. I know you have a vacuum gauge  so you could check the vacuum advance against the vacuum to see if it is within spec. Your oil pressure is more than adequate, the B series engine needs only 30 psi when hot for normal driving - BMC even issued a notice for the 1622 Austin Cambridge engine on this. (I'm not suggesting it is a good idea for high speed Autobahn driving, Alexander!) You may find that the head is heavily carbonised after all these miles. Detonation is pre-ignition at any time in the compression cycle and can be caused by hot spots, eg the carbon build up, under heavy load when it gets much hotter in the combustion chamber. It is far less likely under light load as the engine runs cooler. The effect at low load sounds like pinking ie the effective ignition timing is too advanced. As this goes away by taking off the vacuum advance try again to remove this effect by retarding the ignition with the vacuum pipe attached. Record how many degrees you need to retard the ignition to stop this noise. If you succeed then this rules out other things like the timing chain rattle as suggested by Alexander and I know is your favourite topic! Not to worry you but I had a similar noise many years ago with my Wolseley 18/85 engine. Eventually I found it was the crankshaft thrust washers worn and this allowed one of the conrods to clip the camshaft but only at certain RPM and load. Dignosis - a sharp tap to the front pulley to push the crank back. Then get someone to depress the clutch and you can feel the whole crank move forward. There were other give away symptoms (in hind-sight) the clutch came in lower than it should but I put this down to wear in the thrust bearing. The clearance between the cam and conrods is very tight. Did I find this straight away or did it take me ages to discover the cause? A clue, I have never forgotten it! There are many reasons why you have never heard similar noises on the Marina engines. It maybe the Marina is better insulated from the engine noise as the engine is longitudinal and further away from you. Also the Marina uses a cast iron crankshaft whereas the 1800 crank is forged steel so maybe has different acoustic properties? I think a long thread is in the making regards David Hi all! I've not been very active lately, but hope to post more frequently in the future. I've enjoyed the white 1800 for a month now, since I got it back on the road. Actually, the Rover has rested ever since as I've driven the 1800 every day. The white one works very well. Ok, it's done almost 200 000 kms without an overhaul but it starts instantly and runs vey well. It really pulls like a train. Marvellous! OK, there is a puff of blue smoke when revving after idling but nothing to be seen on the road. I don't really care. One thing concerns me though. There is a noise from the engine now and then. A metallic, rattling kind of noise. I believe this is the dreaded sound of detonation... It can be heard at high rpm when driving also if revving hard. I suspect the vacuum advance, as if I remove and block the pipe it goes away. However, it will then hesitate and be somewhat more jerky, especially at low speed.. I've tried retarding the ignition timing, but the noise remains as long as the pipe is attached no matter how far I retard it. I've checked the timing and advance with a strobe and a homemade strip of additional timing marks. The mechanical advance is spot on but when the vacuum is attached it advances waaaay off.. Funny thing is, I tried the rebuilt Distributor Doctor distributor, as the blue one is just standing in the barn anyway. Well, it makes no difference.. Any ideas of how to overcome this? Is this a common problem on 1800? I've had at least two others with the same noise. Back then I didn't care and turned the radio up... I've never had this phenomen on a Marina 1800. Could the sound just be due to a tired engine? Oil pressure is down to 50 driving when really hot. Idle is 25. The sound is rather identical to the "lack of oil noise" I get when I cold start it, before oil pressure builds up. This takes a couple of seconds. I sometimes wonder if it fires abnormally quickly! If it took some revolutions, the pressure would build up before start. Seriously, both when cold (with choke) and hot it fires the instant I turn the key. Is this really normal? The blue one is the same. Update: BTW, it never pinks/ pings if my understanding of the phrases is correct. Pinking is the noise you get when you floor it up a hill if over advanced right? It never does that. The noise is at light throttle, if I floor it it goes away. This is detonation, right? Ok. Updates to come! Really annoying noise. Please help:-) Regards, Tommy |
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Post by tommydp on May 18, 2013 7:09:00 GMT
Hi all! Thanks for your replies!
I have to clear a thing or two, I see..
The car does NOT have the kind of noise you get with over advanced ignition, going up hill with wide open throttle under load. (What I possibly incorrectly refer to as pinking..)
The noise is evident at steady speed/ light throttle, so when the vacuum unit operates as I understand it. If I floor it, the noise goes away until speed is steady again.
The vacuum plate moves freely, and the unit holds vacuum.
No, the vacuum unit does not operate at idle. I was referring to a check I did on the ignition advance. It was 12* @ 600 rpm, vacuum disconnected. I then checked by the book what happened at higher revs. It seemed to match the book very well:
Book says:
4 degrees@1200 rpm This means 16 degrees I suppose? 12*+4*
12 @2200
20 @3200
26 @4400 (Which gives a max advance of 12*+26*=38*
At least, the car showed very close to:
16 degrees at 1200
24 degrees at 2200
32 degrees at 3200
38 degrees at 4400
...with vacuum disconnected. What I was meaning to say was, if I connected the vacuum at higher rpm while checking it advanced further, going way off my home made timing mark scale (which went to 45 degrees) I believe this is normal? At least it did the same thing with the new distributor..
Any idea what the total max advance is supposed to be, WITH vacuum unit connected?
I've tried retarding the idle (600rpm)timing to 10 degrees and even 8 without success.
Of course, the engine has done 200 000 kms so it's due for an overhaul. It could be the bearings, but will they really make noise if the oil pressure is 50? There is no drop in pressure when the noise occures. I'm happy with the oil pressure, as the service sheet (BL) says 15-25 at idle and 50-75 running.
Ok, no intention of a lengthy thread again:-) This car is not meant to be immaculate, at least not yet. It would however be good to get to the bottom of that noise, as it's otherwise really good.. It runs very well and has a beautiful idle too:-)
regards, Tommy
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Post by dave1800 on May 18, 2013 7:27:00 GMT
Hi Tommy I added a few paras to my earlier post that crossed with your reply, maybe worth having a look. The answer to your question about the maximum advance is that it would not normally exceed the 38 degrees other than on the over run with the throttle held open enough to unblock the vacuum orifice. I assume you are testing under no load stationary conditions. Under load there is virtually no vacuum advance over about 2,500 - 3,000 rpm. You can check this out. OK another line of thought (we have been there before). At light load steady speed the manifold vacuum is at its highest and therefore any air leak will potentially be at its greatest as a proportion of the low level of fuel being used. The effect of this would be to weaken the mixture at light loads / steady speed and a weak mixture will knock. So, look for the usual air leaks, top up the carb damper oil and try richening the mixture. Regards David Hi all! Thanks for your replies! I have to clear a thing or two, I see.. The car does NOT have the kind of noise you get with over advanced ignition, going up hill with wide open throttle under load. (What I possibly incorrectly refer to as pinking..) The noise is evident at steady speed/ light throttle, so when the vacuum unit operates as I understand it. If I floor it, the noise goes away until speed is steady again. The vacuum plate moves freely, and the unit holds vacuum. No, the vacuum unit does not operate at idle. I was referring to a check I did on the ignition advance. It was 12* @ 600 rpm, vacuum disconnected. I then checked by the book what happened at higher revs. It seemed to match the book very well: Book says: 4 degrees@1200 rpm This means 16 degrees I suppose? 12*+4* 12 @2200 20 @3200 26 @4400 (Which gives a max advance of 12*+26*=38* At least, the car showed very close to: 16 degrees at 1200 24 degrees at 2200 32 degrees at 3200 38 degrees at 4400 ...with vacuum disconnected. What I was meaning to say was, if I connected the vacuum at higher rpm while checking it advanced further, going way off my home made timing mark scale (which went to 45 degrees) I believe this is normal? At least it did the same thing with the new distributor.. Any idea what the total max advance is supposed to be, WITH vacuum unit connected? I've tried retarding the idle (600rpm)timing to 10 degrees and even 8 without success. Of course, the engine has done 200 000 kms so it's due for an overhaul. It could be the bearings, but will they really make noise if the oil pressure is 50? There is no drop in pressure when the noise occures. I'm happy with the oil pressure, as the service sheet (BL) says 15-25 at idle and 50-75 running. Ok, no intention of a lengthy thread again:-) This car is not meant to be immaculate, at least not yet. It would however be good to get to the bottom of that noise, as it's otherwise really good.. It runs very well and has a beautiful idle too:-) regards, Tommy |
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Post by dave1800 on May 18, 2013 11:41:31 GMT
Alexander I don't think we should upset Tommy unnecessarily! His car still has good oil pressure. While there is undoubtedly some bearing wear after 200,000kms the fact that the noise under light load can be stopped by retarding the ignition taking off the vacuum advance suggests it is not too serious. I have read that light load rattle attributed to bearing wear occurs because the pressure from the piston is insufficient to force the rod down on the crank and take up the play. It sounds sort of just plausible and if correct, by extrapolation, retarding the ignition would reduce the pressure and make the rattle more noticeable not stop it. Update: Thinking about my Morris Minor 803cc variety the big end bearings were noisy ie knocked but only under heavy load. Lifting off slightly immediately stopped the noise and the oil pressure was definitely not what it should have been. This doesn't accord with the above paragraph. I guess given the problems with the blue car engine rebuild that he would like to keep this one going as long as possible. Of course it is very difficult to accurately diagnose from a distance and you may well be correct about the bearings but I think he should only worry if the oil pressure start to fall significantly. I hope I'm right! Tommy No chance of it being fuel related? regards David Hard to do a remote diagnostic. But the vacuum advance will not be working on full throttle or will also have no effect at max rpm - so I have a little doubt it is this. I once encountered a Spitfire (the one with four wheels, but no wings on it) with a tired engine. It had low oil pressure and when hot the engine rattled with the mains at higher RPMs. Cold and low rpm (particular under load) was fine. I think it may be that the bearings on the engine are on the way out. Regards, Alexander |
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Post by tommydp on May 19, 2013 10:57:13 GMT
Hi! I run 98 unleaded. I had exactly the same noise many yrs ago on another 1800. Then I ran 98 leaded, so doubt it. If so I guess it would have made noise uphill too.. Ignition timing seems to change as I drive. Set it to 12 degrees and when returnong from a test drive it was 15. Distributor has not moved.. Gotta love these cars..
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Post by dave1800 on May 19, 2013 11:14:11 GMT
Oh no! Timing chain tensioner  Hi! I run 98 unleaded. I had exactly the same noise many yrs ago on another 1800. Then I ran 98 leaded, so doubt it. If so I guess it would have made noise uphill too.. Ignition timing seems to change as I drive. Set it to 12 degrees and when returnong from a test drive it was 15. Distributor has not moved.. Gotta love these cars.. |
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Post by tommydp on May 19, 2013 14:49:46 GMT
don't care... Strange the timing mark is steady at idle then. I fitted the rebuilt distributor again and it seems stable now. Just came back from a long trip to the sea, yes it's suddenly almost 30 degrees here... A friend followed and confirmed there was no smoke or smell from the car at all, so I'll just enjoy it as it is. This really is a well used 43 yrs old runabout.. AND perhaps I should put in a cooler thermostat than the 88 degrees:-) had forgotten that. I'll change the oil frequently and clean out the strainer. Perhaps there is a randomly blocked oilway, as the noise is a bit on and off. I'll watch the pressure closely. Noise seems worse when the car is hot and pressure is down to 50 running. Ok, this is merely an experiment om how much a B can take:-) i'm not going into this engine before a total rebuild is needed.
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Post by Penguin45 on May 19, 2013 23:43:34 GMT
I suppose......... If the temperature is normal, there's no smoke pouring out of the back and the oil isn't disappearing you might as well keep running the car.
I have an interesting regular "click" taking up the drive, which I suspect is a driveshaft flange. It all seems pretty tight to me. Then there is a little "knock" which comes and goes. I know it's a rack mounting bolt 'cos I've had it before. Some noises just become part of running the car. They may be largely harmless, but really ought to be sorted.
Chris.
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Post by dave1800 on May 20, 2013 0:53:29 GMT
For reasons I've never been able to fathom it seems you can run the B series engine in the 1800 almost for ever (a slight exaggeration  unlike the A series which in my experience starts belching out loads of blue smoke quite early on. I guess my worst 1800 engine which had a very high mileage didn't have a single completely intact piston ring in place. It used about 1 pint of oil every 200 miles if driven hard but didn't give out any noticeable blue smoke and amazingly still had quite good performance and idled smoothly. If you look at the John Twist videos you can see some MGB engines that have all kinds of damage eg rounded cam lobes and still managed to go after a fashion. Just keep the water hoses in good nick and see what happens. Regards David |
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Post by dave1800 on May 20, 2013 8:56:35 GMT
Tommy When the engine is cold and or has been standing for a few days why not turn the engine over a couple of times before you pull out the choke. This will allow the oil to circulate and pressure to build up and should stop the start up bearing clatter. If nothing else it will be better for your health . Maybe not a bad idea for everyone worn bearings or not? Thoughts??? regards David Is this a common problem on 1800? I've had at least two others with the same noise. Back then I didn't care and turned the radio up... I've never had this phenomen on a Marina 1800. Oil pressure is down to 50 driving when really hot. Idle is 25. The sound is rather identical to the "lack of oil noise" I get when I cold start it, before oil pressure builds up. This takes a couple of seconds. I sometimes wonder if it fires abnormally quickly! If it took some revolutions, the pressure would build up before start. Seriously, both when cold (with choke) and hot it fires the instant I turn the key. Is this really normal? The blue one is the same. Regards, Tommy |
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so you could check the vacuum advance against the vacuum to see if it is within spec. 
unlike the A series which in my experience starts belching out loads of blue smoke quite early on. I guess my worst 1800 engine which had a very high mileage didn't have a single completely intact piston ring in place. It used about 1 pint of oil every 200 miles if driven hard but didn't give out any noticeable blue smoke and amazingly still had quite good performance and idled smoothly.