Cam shaft problem

arcturus · Jun 14th, 2020, 10:05

Hi,what would be the symptoms of a damaged lobe on shaft. I have a horrible feeling that i am experiencing a problem there. I am getting an disturbing metallic rattle from the front of engine. I had to fit the old lifters on the new shaft as replacement lifters were unavailable at the time. I may be paying the price now!

kishor · Jun 14th, 2020, 10:53

Quote:

Originally Posted by arcturus

Hi,what would be the symptoms of a damaged lobe on shaft. I have a horrible feeling that i am experiencing a problem there. I am getting an disturbing metallic rattle from the front of engine. I had to fit the old lifters on the new shaft as replacement lifters were unavailable at the time. I may be paying the price now!

Hi

You might have a timing gear problem. These give way and makes a knocking noise.
Warn lobes will cause a 'miss'

Ta
Kassie

blueosprey90 · Jun 14th, 2020, 12:30

I think camshaft or lifter wear would manifest as a performance problem, not a metallic noise. My B16 timing gear is quite noisy for what that may be worth. Is your noise screeching or banging. Mine is of the banging type. If fan belt is too loose, that will make a screeching noise. If too tight, it might affect generator bearing due to side load. Screeching metallic. If it is rhythmic metallic with engine revolution, is it possible a bolt has backed out and is hitting a rotating part? Any metal in the oil?

Since misery loves company, my test run of my new race engine was not without major problems. At least it ran and didn’t explode at 6,500 rpm. So I can fix!

Derek UK · Jun 14th, 2020, 13:03

B16 fibre timing gear doesn't have the star shaped metal centre that allows it to break "safely. The B16 is just moulded onto a knurled metal centre. When it fails, the gear just stops and centre carries on turning. When I had mine go way back when, the engine just stopped and I free wheeled onto a space off the road. It was in town. Of course I tried to start the engine but found that the distributor wasn't turning. Replaced the gears with a set off the shelf at the dealers. Someone had ordered the set and not collected them. Mind you that was back in 1966!
Can you remove the followers via the side plates after taking off the rocker gear and removing the push rods? It's the only way to inspect them properly.

arcturus · Jun 14th, 2020, 15:01

Done that. The followers seem ok. and from what I could see of cam also.The timing gears seemed OK when I rebuilt engine but could have failed with the higher compression load. At least I can inspect the gears without removing engine. . I'm reluctant to pull out the engine again but will do if i can't find source of noise.If a big end or small end failed what sort of noise would that make?
When the timing gear failed on my B20 it started with a ticking noise which became louder and then complete failure.

arcturus · Jun 14th, 2020, 19:31

Posted a video on the facebook B16 site where you can make out the noise I refer to. https://www.facebook.com/groups/1778957228856655/

blueosprey90 · Jun 15th, 2020, 01:36

You have a lot of engine shake in that video. Verify your firing order. Then check valve clearances. Seems you have two different sounds. Is it possible cam timing has shifted or slipped? One sound sounds like valves. I think second of the sounds might be piston slap, or rod knock. But this is internet, I’m not a mechanic and shooting from the hip.

arcturus · Jun 15th, 2020, 08:46

Valve gap from 0.50reduced to 0.40mm. Will probably check timing gears next.Can do that with engine in situ. However,beginning to suspect a big end bearing problem.

Derek UK · Jun 15th, 2020, 14:47

I don't do Facebook so I can't listen to your noises. YouTube better for me. As I said the B16 just fails with no warning noises so if it's running the gear is OK. Plug wires on wrong easily checked. Dizzy runs clockwise the opposite to that on the B18/20. If that is fine you could try pulling one wire of the plugs at a time to see if you get a difference between each "running on 3" sounds. Have you had it running "smooth" since you did the last engine work? If so did the noises and wobbly running occur all of a sudden? 50 thou is correct for B16B inlet and exhaust.

My bad timing gears.
https://www.youtube.com/watch?v=iXxSRQ0johk
https://www.youtube.com/watch?v=nGykPiE43Ik

arcturus · Jun 15th, 2020, 15:08

I was thinking more on the line of a broken tooth

Jun 14th, 2020, 10:05	#1
arcturus arcturus Last Online: Apr 10th, 2024 08:21 Join Date: Mar 2006 Location: Sagres Portugal	Cam shaft problem Hi,what would be the symptoms of a damaged lobe on shaft. I have a horrible feeling that i am experiencing a problem there. I am getting an disturbing metallic rattle from the front of engine. I had to fit the old lifters on the new shaft as replacement lifters were unavailable at the time. I may be paying the price now! __________________ life's too short to drink bad wine

Jun 14th, 2020, 15:01	#5
arcturus arcturus Last Online: Apr 10th, 2024 08:21 Join Date: Mar 2006 Location: Sagres Portugal	Done that. The followers seem ok. and from what I could see of cam also.The timing gears seemed OK when I rebuilt engine but could have failed with the higher compression load. At least I can inspect the gears without removing engine. . I'm reluctant to pull out the engine again but will do if i can't find source of noise.If a big end or small end failed what sort of noise would that make? When the timing gear failed on my B20 it started with a ticking noise which became louder and then complete failure. __________________ life's too short to drink bad wine Last edited by arcturus; Jun 14th, 2020 at 15:04.

Jun 14th, 2020, 19:31	#6
arcturus arcturus Last Online: Apr 10th, 2024 08:21 Join Date: Mar 2006 Location: Sagres Portugal	Posted a video on the facebook B16 site where you can make out the noise I refer to. https://www.facebook.com/groups/1778957228856655/ __________________ life's too short to drink bad wine

Jun 15th, 2020, 01:36	#7
blueosprey90 Master Member Last Online: Today 19:09 Join Date: May 2017 Location: New Milford, Connecticut	You have a lot of engine shake in that video. Verify your firing order. Then check valve clearances. Seems you have two different sounds. Is it possible cam timing has shifted or slipped? One sound sounds like valves. I think second of the sounds might be piston slap, or rod knock. But this is internet, I’m not a mechanic and shooting from the hip. Last edited by blueosprey90; Jun 15th, 2020 at 02:20.

Jun 15th, 2020, 08:46	#8
arcturus arcturus Last Online: Apr 10th, 2024 08:21 Join Date: Mar 2006 Location: Sagres Portugal	Valve gap from 0.50reduced to 0.40mm. Will probably check timing gears next.Can do that with engine in situ. However,beginning to suspect a big end bearing problem. __________________ life's too short to drink bad wine Last edited by arcturus; Jun 15th, 2020 at 10:28.

Jun 14th, 2020, 12:30	#3
blueosprey90 Master Member Last Online: Today 19:09 Join Date: May 2017 Location: New Milford, Connecticut	I think camshaft or lifter wear would manifest as a performance problem, not a metallic noise. My B16 timing gear is quite noisy for what that may be worth. Is your noise screeching or banging. Mine is of the banging type. If fan belt is too loose, that will make a screeching noise. If too tight, it might affect generator bearing due to side load. Screeching metallic. If it is rhythmic metallic with engine revolution, is it possible a bolt has backed out and is hitting a rotating part? Any metal in the oil? Since misery loves company, my test run of my new race engine was not without major problems. At least it ran and didn’t explode at 6,500 rpm. So I can fix!

Jun 14th, 2020, 13:03	#4
Derek UK VOC Member Last Online: Yesterday 17:06 Join Date: Jul 2006 Location: Chatham	B16 fibre timing gear doesn't have the star shaped metal centre that allows it to break "safely. The B16 is just moulded onto a knurled metal centre. When it fails, the gear just stops and centre carries on turning. When I had mine go way back when, the engine just stopped and I free wheeled onto a space off the road. It was in town. Of course I tried to start the engine but found that the distributor wasn't turning. Replaced the gears with a set off the shelf at the dealers. Someone had ordered the set and not collected them. Mind you that was back in 1966! Can you remove the followers via the side plates after taking off the rocker gear and removing the push rods? It's the only way to inspect them properly.

Jun 15th, 2020, 14:47	#9
Derek UK VOC Member Last Online: Yesterday 17:06 Join Date: Jul 2006 Location: Chatham	I don't do Facebook so I can't listen to your noises. YouTube better for me. As I said the B16 just fails with no warning noises so if it's running the gear is OK. Plug wires on wrong easily checked. Dizzy runs clockwise the opposite to that on the B18/20. If that is fine you could try pulling one wire of the plugs at a time to see if you get a difference between each "running on 3" sounds. Have you had it running "smooth" since you did the last engine work? If so did the noises and wobbly running occur all of a sudden? 50 thou is correct for B16B inlet and exhaust. My bad timing gears. https://www.youtube.com/watch?v=iXxSRQ0johk https://www.youtube.com/watch?v=nGykPiE43Ik Last edited by Derek UK; Jun 15th, 2020 at 14:53.

Jun 15th, 2020, 15:08	#10
arcturus arcturus Last Online: Apr 10th, 2024 08:21 Join Date: Mar 2006 Location: Sagres Portugal	I was thinking more on the line of a broken tooth __________________ life's too short to drink bad wine

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