Engine Timing inlet camwheel - Page 2

Typhoon190 · 3rd January 2020, 20:22

I am fairly certain this is for traction control, as my cars have this free as well.

Rich in Vancouver · 3rd January 2020, 23:38

Correct assumption! My ZT is the same.
If the plug is a very nicely made BMW item that is exactly what it is for.
My car is also missing the cruise control so I have another mystery plug
to the right rear of the engine.
If only they had fitted caps to the unused plugs the learning curve wouldn't be quite so steep!

Fred Byrne · 4th January 2020, 10:20

Rover 75 2.5 connoisseur

Many thanks for that . It is a relief as i couldn't remember unplugging it. Hope to start the engine on Monday so fingers will be crossed. I always seem to have forgotten something. I notice John has a P4. I have a '100' and 105R also. This 75 is quite a change for me with all those wretched metric tools that it requires.
#
Fred

Fred Byrne · 22nd January 2020, 15:07

Tuesday became start-up day only it wasn't. When all was complete I turned the engine over through several revolutions and all seemed well. I then turned it over for about one minute with the self starter motor but with no petrol. I noticed a slight thump on every second revolution and thought about this for a minute or two. I thought something might be causing this in the valve train but decided to go ahead with fuel on anyway- the thumping was very slight and didn't cause any noticeable vibration. The engine started and ran for a second and stopped. There was a horrible clatter from somewhere under the bonnet. The engine was locked solidly. Catastrophe I thought immediately but I searched under the car and saw a big pair of pliers lying under the engine. Was this what caused the clatter or was it something inside the engine's guts? I couldn't be sure.

The following day I located the problem as being in the front bank of cylinders. I removed the cam cover and saw that it was the camshaft that had siezed up and further examination revealed that the two inlet valves on No.1 cylinder were stuck in the fully closed position. I had locked the engine in the safe position so both shafts should have turned freely but didn't. No amount of sensible persuasion would persuade these two valves to open. One inlet valve on NO.3 was also sticky but did open after a little pesuasion. All other valves were OK.

Today I removed the cylinder head fearing the worst of course. All piston crowns are unmarked and all cylinder liners are in perfect condition. I am beginning to think that the thumping I heard when turning the engine over with the starter was the piston hitting sticky valves on No.1 and thus persuading them to close. When the engine started perhaps it struck the valves more forcibly and bent them slightly but the impetus caused them to close. When the camshaft rotated to open the valves it found them to be bent and so locked up. What does anyone think of this. I am non-plussed.
I hope to replace the head next week after I have said my prayers of course!

Fred
2.5l Connoiseur.

chris75 · 22nd January 2020, 16:23

Quote:

Originally Posted by Fred Byrne

The following day I located the problem as being in the front bank of cylinders. I removed the cam cover and saw that it was the camshaft that had siezed up and further examination revealed that the two inlet valves on No.1 cylinder were stuck in the fully closed position. I had locked the engine in the safe position so both shafts should have turned freely but didn't. .........…
I am beginning to think that the thumping I heard when turning the engine over with the starter was the piston hitting sticky valves on No.1 and thus persuading them to close. When the engine started perhaps it struck the valves more forcibly and bent them slightly but the impetus caused them to close. When the camshaft rotated to open the valves it found them to be bent and so locked up. What does anyone think of this. I am non-plussed.
I hope to replace the head next week after I have said my prayers of course!

Couple of points of clarification , please

When you say the engine was locked in safe mode but the cams wouldn't turn , I take it the cambelts had been removed again ?
You have now removed the front head ; have you stripped it yet and got the No.1 valves out yet and what have you found ?
My gut feeling is that you haven't got "sticky" valves , more "bent" ones ! How , is another question yet .

Fred Byrne · 22nd January 2020, 16:52

Yes the cam belts were removed after I locked the engine in safe mode. Yes, my problem is why was everything apparently OK until I started the engine. My only theory is the valves were sticky and did not return to close when they should have done. Then the 'sticky'valve was hit by the piston and bent. The bent piston was jammed into the closed position by the force of the piston hitting the valve. Tomorrow I shall use a hydaulic press to push the offending valves out and see what happens.

Fred
PS thanks for reply

chris75 · 22nd January 2020, 18:52

Sounds like they are well stuck !

Good luck with the removal and the inspection pf the valve stems . Once you have the valves out , a simple test of rolling them along the edge of a flat surface will show up any wobble in the valve heads .
Speaking as someone who has managed to bend valves by brute force and negligence whilst working on the heads , I am thinking that perhaps whilst you had the cams free from the belts and the crank locked you may have been wrestling with the sprockets and brought the valves into contact with the pistons ?

Could that have happened ?
Believe me , it doesn't take as much as you might think ……...

Fred Byrne · 22nd January 2020, 21:27

That is a possibility that hadn't occurred to me. Only I should have expected them to jam when I turned the engine over by hand also on the starter motor. All will be revealed tomorrow. I'm just relieved I didn't see a holed piston. As a matter of interest can you insert pistons and liners without removing the engine. Mind you the engine seems a lot lighter than the P4 engines I'm used to. I take them in and out whenever the whim takes me. Since I am now approaching my 83rd birthday I don't relish heavy weights anymore but hydraulics are a great sustitute for good old muscle power. Do you take the heads on and off with the two manifolds attached?

Fred

chris75 · 23rd January 2020, 11:24

Quote:

Originally Posted by Fred Byrne

Do you take the heads on and off with the two manifolds attached?

Fred

I removed the inlet manifolds from the heads to make it all smaller , but I left the exhaust manifolds on as I believe is general practice . I think you are just working on the front head ( ? ) , which is relatively easy to lift out

The rear head is a long stretch and I needed help to wrestle that one off !
It's a lot of parts that need to come off , isn't it !

Fred Byrne · 23rd January 2020, 12:41

Well! this is extraordinary. I gave the tappet a few taps with a 7 pound persuader. It freed up and I removed the valves. That is inlet valves on No 1. They are absolutely fine and i checked the seats were seating properly via the old lead pencil trick. This left me puzzled so I examined the two tappets. No.2 had scuff marks on one side of its skirt. I checked all the other tappets but none showed scuff marks. I then examined the tappet bores and No.2 tappet bore had scratch marks down one side. When I tried to reinsert the tappets on No1 cylinder neither of them entered easily. Whereas all the other tappets on the head just slid in beautifuly. I checked the offending tappets for ovality and No. 2 always came to rest on a piece of plate glass with the same orientation with the scuff marks uppermost so perhaps some ovality but the micrometer showed very slight ovality and could have been measuring error (.02 mm). More careful examination of the bores showed up tiny spurs iof metal projecting into the tops of the two bores. These two tiny imperfections caused the tappets to go crooked sideways and jam. Probably if I had given the starter motor another go it might have cleared on the other hand it might not and goodness only knows what damage might result. I am hoping this will solve the problem. You are quite right nothing is ever simple. I do have suspicions that at some time some one did have bent valves on this engine because there are indications that the head had been removed previously. My brother who was the precious owner says he did have the timing belt changed by a garage but no enormous bill resulted so it remains a mystery. Could it have been there since the car was manufactured- I doubt it because no machine would have left burrs like that. Tomorrow re-assembky starts in hope but not with great confidence.

Fred

3rd January 2020, 23:38	#12
Rich in Vancouver Gets stuck in MG ZT-T Join Date: Jun 2016 Location: White Rock, BC on Canada's Pacific Coast Posts: 849 Thanks: 338 Thanked 367 Times in 210 Posts	Correct assumption! My ZT is the same. If the plug is a very nicely made BMW item that is exactly what it is for. My car is also missing the cruise control so I have another mystery plug to the right rear of the engine. If only they had fitted caps to the unused plugs the learning curve wouldn't be quite so steep! __________________ ZT-T190, Anthracite, LHD, Left the Line on June 24, 2002, Sold new in Switzerland, spent time in Germany, Imported to Canada in September 2021

22nd January 2020, 18:52	#17
chris75 same car since 2005 2001 Rover 75 2.0 v6 Connoisseur Saloon Join Date: Nov 2006 Location: Ellesmere Port , Cheshire Posts: 3,811 Thanks: 379 Thanked 549 Times in 466 Posts	Sounds like they are well stuck ! Good luck with the removal and the inspection pf the valve stems . Once you have the valves out , a simple test of rolling them along the edge of a flat surface will show up any wobble in the valve heads . Speaking as someone who has managed to bend valves by brute force and negligence whilst working on the heads , I am thinking that perhaps whilst you had the cams free from the belts and the crank locked you may have been wrestling with the sprockets and brought the valves into contact with the pistons ? Could that have happened ? Believe me , it doesn't take as much as you might think ……... __________________ Who said it was simples ?

3rd January 2020, 20:22	#11
Typhoon190 This is my second home MG ZT-T 190 Monogram Typhoon Join Date: Jan 2009 Location: Oxfordshire Posts: 4,704 Thanks: 328 Thanked 557 Times in 443 Posts	I am fairly certain this is for traction control, as my cars have this free as well.

4th January 2020, 10:20	#13
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 194 Thanks: 69 Thanked 60 Times in 23 Posts	Rover 75 2.5 connoisseur Many thanks for that . It is a relief as i couldn't remember unplugging it. Hope to start the engine on Monday so fingers will be crossed. I always seem to have forgotten something. I notice John has a P4. I have a '100' and 105R also. This 75 is quite a change for me with all those wretched metric tools that it requires. # Fred

22nd January 2020, 15:07	#14
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 194 Thanks: 69 Thanked 60 Times in 23 Posts	Tuesday became start-up day only it wasn't. When all was complete I turned the engine over through several revolutions and all seemed well. I then turned it over for about one minute with the self starter motor but with no petrol. I noticed a slight thump on every second revolution and thought about this for a minute or two. I thought something might be causing this in the valve train but decided to go ahead with fuel on anyway- the thumping was very slight and didn't cause any noticeable vibration. The engine started and ran for a second and stopped. There was a horrible clatter from somewhere under the bonnet. The engine was locked solidly. Catastrophe I thought immediately but I searched under the car and saw a big pair of pliers lying under the engine. Was this what caused the clatter or was it something inside the engine's guts? I couldn't be sure. The following day I located the problem as being in the front bank of cylinders. I removed the cam cover and saw that it was the camshaft that had siezed up and further examination revealed that the two inlet valves on No.1 cylinder were stuck in the fully closed position. I had locked the engine in the safe position so both shafts should have turned freely but didn't. No amount of sensible persuasion would persuade these two valves to open. One inlet valve on NO.3 was also sticky but did open after a little pesuasion. All other valves were OK. Today I removed the cylinder head fearing the worst of course. All piston crowns are unmarked and all cylinder liners are in perfect condition. I am beginning to think that the thumping I heard when turning the engine over with the starter was the piston hitting sticky valves on No.1 and thus persuading them to close. When the engine started perhaps it struck the valves more forcibly and bent them slightly but the impetus caused them to close. When the camshaft rotated to open the valves it found them to be bent and so locked up. What does anyone think of this. I am non-plussed. I hope to replace the head next week after I have said my prayers of course! Fred 2.5l Connoiseur.

22nd January 2020, 16:52	#16
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 194 Thanks: 69 Thanked 60 Times in 23 Posts	Yes the cam belts were removed after I locked the engine in safe mode. Yes, my problem is why was everything apparently OK until I started the engine. My only theory is the valves were sticky and did not return to close when they should have done. Then the 'sticky'valve was hit by the piston and bent. The bent piston was jammed into the closed position by the force of the piston hitting the valve. Tomorrow I shall use a hydaulic press to push the offending valves out and see what happens. Fred PS thanks for reply

22nd January 2020, 21:27	#18
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 194 Thanks: 69 Thanked 60 Times in 23 Posts	That is a possibility that hadn't occurred to me. Only I should have expected them to jam when I turned the engine over by hand also on the starter motor. All will be revealed tomorrow. I'm just relieved I didn't see a holed piston. As a matter of interest can you insert pistons and liners without removing the engine. Mind you the engine seems a lot lighter than the P4 engines I'm used to. I take them in and out whenever the whim takes me. Since I am now approaching my 83rd birthday I don't relish heavy weights anymore but hydraulics are a great sustitute for good old muscle power. Do you take the heads on and off with the two manifolds attached? Fred

23rd January 2020, 12:41	#20
Fred Byrne Avid contributor Rover 75 Saloon Join Date: Jun 2018 Location: Ballynahinch Posts: 194 Thanks: 69 Thanked 60 Times in 23 Posts	Well! this is extraordinary. I gave the tappet a few taps with a 7 pound persuader. It freed up and I removed the valves. That is inlet valves on No 1. They are absolutely fine and i checked the seats were seating properly via the old lead pencil trick. This left me puzzled so I examined the two tappets. No.2 had scuff marks on one side of its skirt. I checked all the other tappets but none showed scuff marks. I then examined the tappet bores and No.2 tappet bore had scratch marks down one side. When I tried to reinsert the tappets on No1 cylinder neither of them entered easily. Whereas all the other tappets on the head just slid in beautifuly. I checked the offending tappets for ovality and No. 2 always came to rest on a piece of plate glass with the same orientation with the scuff marks uppermost so perhaps some ovality but the micrometer showed very slight ovality and could have been measuring error (.02 mm). More careful examination of the bores showed up tiny spurs iof metal projecting into the tops of the two bores. These two tiny imperfections caused the tappets to go crooked sideways and jam. Probably if I had given the starter motor another go it might have cleared on the other hand it might not and goodness only knows what damage might result. I am hoping this will solve the problem. You are quite right nothing is ever simple. I do have suspicions that at some time some one did have bent valves on this engine because there are indications that the head had been removed previously. My brother who was the precious owner says he did have the timing belt changed by a garage but no enormous bill resulted so it remains a mystery. Could it have been there since the car was manufactured- I doubt it because no machine would have left burrs like that. Tomorrow re-assembky starts in hope but not with great confidence. Fred