Technical Rocker arm sideways play

[StefP0342]

Hi!

My 1970 Fiat 500L started to run a little rough and noisy (noise is like valve clatter when clearance is incorrect) after about 2-3 minutes after startup, so I wanted to adjust the clearance to the correct settings. When adjusting the clearances, the bolts were completely worn so I had to order new ones in order to set the clearances. After I set them correctly, the engine still runs very noisy as if the clearance is too loose. I set the clearance tighter and wider, but the noise remains in both settings. I noticed that rocker 2 (counting from the flywheel side) has quite some sideways play on the rocker arm. If I move the arm in both directions quickly i hear the sound which i also hear when the engine is running. A local mechanic told me the play in the rocker arm did not matter, but I don't trust the noise when the engine is running.

Could the sideways play in the rocker arm be the cause of the noise? if so, what is the best way to fix it?

I could not really find the answer in other threads so I hope some of you have an answer.

 

[bugsymike]

Hi!

My 1970 Fiat 500L started to run a little rough and noisy (noise is like valve clatter when clearance is incorrect) after about 2-3 minutes after startup, so I wanted to adjust the clearance to the correct settings. When adjusting the clearances, the bolts were completely worn so I had to order new ones in order to set the clearances. After I set them correctly, the engine still runs very noisy as if the clearance is too loose. I set the clearance tighter and wider, but the noise remains in both settings. I noticed that rocker 2 (counting from the flywheel side) has quite some sideways play on the rocker arm. If I move the arm in both directions quickly i hear the sound which i also hear when the engine is running. A local mechanic told me the play in the rocker arm did not matter, but I don't trust the noise when the engine is running.

Could the sideways play in the rocker arm be the cause of the noise? if so, what is the best way to fix it?

I could not really find the answer in other threads so I hope some of you have an answer.

If there is wear/play in the bush inside the rocker arm where it revolves on the rocker shaft, that could give false readings of valve clearance.
If the rocker arm is moving sideways along a rocker shaft this is usually controlled by the springs and washes/spacer between the arms and the pedestals that hold it to the cylinder head and is less likely to affect valve clearance although it is important they align correctly with the valves etc.
Are you 100% sure the noise is from the valve/rocker arm clearance area?

 

[StefP0342]

If there is wear/play in the bush inside the rocker arm where it revolves on the rocker shaft, that could give false readings of valve clearance.
If the rocker arm is moving sideways along a rocker shaft this is usually controlled by the springs and washes/spacer between the arms and the pedestals that hold it to the cylinder head and is less likely to affect valve clearance although it is important they align correctly with the valves etc.
Are you 100% sure the noise is from the valve/rocker arm clearance area?

I am (almost 100%) certain the noise is coming from inside the rocker cover. Do you have an idea of what else could cause the noise? Also, when the engine is cold there is no rattling, after about 3-5 minutes when the engine warms up a bit the rattling starts.

 

[Bleeding Knuckles]

Hi Stef, if you have wear on the rocker shaft to the extent that oil temperature build up causes the noise you should remove the rocker rail complete, remove the circlips at both ends and strip everything off and check the rail surface for excessive wear marks. You also mention a lot of wear in the adjusting bolts this may be an indicator to long term use and wear. It is also possible that with low oil pressure the top end (valves) have been starved of oil and caused excess wear?
Ian.

 

[bugsymike]

When the cover was off was there any sign of lack of oil?
Just to prove it's the valve gear and nothing more internal, when engine making noise can you switch off, tip in say a 1/4 of a litre of oil in the rocker box and start it up straight away and see if noise has gone temporarily by over lubricating the valve gear.
I have come across engines that the rocker shaft had been reassembled wrongly blocking oil ways causing top end wear and noise, not on Fiat though.

 

[StefP0342]

Hi Stef, if you have wear on the rocker shaft to the extent that oil temperature build up causes the noise you should remove the rocker rail complete, remove the circlips at both ends and strip everything off and check the rail surface for excessive wear marks. You also mention a lot of wear in the adjusting bolts this may be an indicator to long term use and wear. It is also possible that with low oil pressure the top end (valves) have been starved of oil and caused excess wear?
Ian.

Thanks for your quick response! I think that this seems plausible, considering there is also play on the middle part of the rocker arm (the rocker shaft bore? i'm a car newbie so i don't know the correct terminology yet ) see the vido attached. I will strip it and check this weekend. Could a replacement rocker arm assembly be the way to go?
Edit: FYI the play was about .4 mm

 

[StefP0342]

When the cover was off was there any sign of lack of oil?
Just to prove it's the valve gear and nothing more internal, when engine making noise can you switch off, tip in say a 1/4 of a litre of oil in the rocker box and start it up straight away and see if noise has gone temporarily by over lubricating the valve gear.
I have come across engines that the rocker shaft had been reassembled wrongly blocking oil ways causing top end wear and noise, not on Fiat though.

Thanks for your reply! I checked and there was plenty of oil inside the rocker box. Tipping in more oil when the noise started did not make a difference. I have added 2 video's, one right after startup and one when the engine is a bit warmer where you can hear the difference very clearly.

 

[bugsymike]

Not sure about the noise, though didn't sound like valve gear to me and you say pouring oil in didn't quieten it.
The rocker movement is not the worst I have seen.
Does the noise sound get worse when you rev up a bit, or put the car under load, say pulling up a hill?
Just a thought, try putting a rag to block the tail pipe a little in case it is a "spitting" noise from a manifold gasket, as that can show a leak.
Locating noises can be difficult , sometimes using a long screwdriver to your ear as a stethoscope can help, though keep away from moving parts.

 

[Bounding Bambino]

What oil viscosity are you using?

Ill have to watch the video later to see if the tick relates to cam rpm or crank rpm.

If its crank frequency. Could be lower rod bearings.

 

[Toshi 975]

I have never seen a rocker set where that middle casting is loose like that on the rocker shaft, normally they are tight as.

 

[StefP0342]

What oil viscosity are you using?

Ill have to watch the video later to see if the tick relates to cam rpm or crank rpm.

If its crank frequency. Could be lower rod bearings.

I changed the oil last september and put in 20w50. The sound gets drowned out when revving

 

[fiat500]

Thanks for your quick response! I think that this seems plausible, considering there is also play on the middle part of the rocker arm (the rocker shaft bore? i'm a car newbie so i don't know the correct terminology yet ) see the vido attached. I will strip it and check this weekend. Could a replacement rocker arm assembly be the way to go?
Edit: FYI the play was about .4 mm

The number 2 inlet rocker arm seems to be seized to the central casting. The only way that the casting could develop that much play is if it has been rotating around the rocker shaft.....the shaft should be fixed by the cotter effect of the studs that hold it down.
The interference fit of the oil delivery pipe should keep it located. If it moves like that I think the oil supply could be compromised.
Can the rocke-arm be easily separated from the central casting?

 

[the hobbler]

Thanks for your reply! I checked and there was plenty of oil inside the rocker box. Tipping in more oil when the noise started did not make a difference. I have added 2 video's, one right after startup and one when the engine is a bit warmer where you can hear the difference very clearly.

I agree with previous suggestions----remove and strip the rocker-shaft assembly. Excessive play of the rockers on the shaft will cause them to 'rattle' as the load changes on the actual rocker-shaft from push-rod to valve-spring. Although a complete rocker-shaft assembly isn't cheap, renewal of might be the only answer; if the shaft is worn, there will be unacceptable wear also on the rockers

 

[StefP0342]

The number 2 inlet rocker arm seems to be seized to the central casting. The only way that the casting could develop that much play is if it has been rotating around the rocker shaft.....the shaft should be fixed by the cotter effect of the studs that hold it down.
The interference fit of the oil delivery pipe should keep it located. If it moves like that I think the oil supply could be compromised.
Can the rocke-arm be easily separated from the central casting?

Yes the central casting (central part of the rocker assembly?) can be seperated from the rocker arms on both sides and the play is about .4 mm

 

[Bleeding Knuckles]

Hi Stef, after listening to your two video clips I thought that I could note a change in the engine valve rattle when you rev the engine? It sounded to me like the oil supply is only getting to the valve shaft when the engine revs if this is the case I think you should check for good oil pressure (does the oil light blink on tick over?) The fear I have is that your engine is showing signs of serious wear and should be inspected completely.
Ian.

 

[Bounding Bambino]

Took a listen on my desktop speakers. Hard to really hear on a phone. i would say its 90% a valve train sound. Typically a valve train tick would be 1/2 the speed of a lower crank knock. However there is a chance that most of the rockers are worn, and thus you get 4x the sound frequency per rev ) Along with seeing the play in the center support casting. It is critical for that casting to have a snug fit on the rocker shaft as its the central pressurized oil feed to the rocker pivots. Due to this being sloppy, there's a good chance you now have oblong worn holes in the rockers, along with possible shaft wear. Best to completely remove the entire rocker assembly (luckily easy to do on these cars). and start doing some measuring. Again these engines being solid rockers and lifters do make valve train noise. Yours seems to have excessive play.

Also check and see if the studs for the rocker hold downs pulled out of the head. Might be a possibility also if someone over torque them and damaged the hold downs.

 

[fiat500]

Took a listen on my desktop speakers. Hard to really hear on a phone. i would say its 90% a valve train sound. Typically a valve train tick would be 1/2 the speed of a lower crank knock. However there is a chance that most of the rockers are worn, and thus you get 4x the sound frequency per rev ) Along with seeing the play in the center support casting. It is critical for that casting to have a snug fit on the rocker shaft as its the central pressurized oil feed to the rocker pivots. Due to this being sloppy, there's a good chance you now have oblong worn holes in the rockers, along with possible shaft wear. Best to completely remove the entire rocker assembly (luckily easy to do on these cars). and start doing some measuring. Again these engines being solid rockers and lifters do make valve train noise. Yours seems to have excessive play.

Also check and see if the studs for the rocker hold downs pulled out of the head. Might be a possibility also if someone over torque them and damaged the hold downs.

When measured my spare rockers and shafts prior to a rebuild, there were surprising amounts of wear even on apparently quite tight assemblies. They do obviously work really hard and I believe the main "secret" to getting a good runner is attention to detail with the valve-gear.
The rocker shafts have slight differences in oil feed arrangements between the 499 and the bigger engines and I think it's also quite possible to assemble them incorrectly.

 

[fiat500]

Bear with me on this...there may be mistakes; we are all prey to them when we rely on memory or the wisdom of others.

I have attached a main image of the dismantled rocker-shaft of a 110F engine. You will find this marked on the aluminium parts that support it. This is an important thing to note (and here is the memory bit), because the design of the shaft on the ones marked 126(A) may be different.

You can see the highly polished surface, which is the underside of the shaft when installed, where the rocker-arms are thrust upwards in the course of their work. Turn the shaft over and the shaft is unworn, but there is an additional oil supply drilling. In theory, this shaft can be rotated 180 degrees in the vertical plane and it may be possible to bodge a bit more life out of it. As far as I remember, I have handled one of the later shafts that had the oil-drilling on one side only. If this shaft was dismantled and reversed there would be no oil feed to the loaded interface between the rocker and arm, which would lead to disastrous wear or seizure. Is this a possibility in this case?

As an aside, I notice that the rocker-arms pictured, which are from separate assemblies, are marked differently and are slightly different visually. The chunkier (rustier) and in detail, less finely finished object is marked, "FUGINI", whilst the other has a symbol that is hard to decipher, but which may be a capital C with an E in the middle.

 

[bugsymike]

Regarding oil ways and different shafts etc. a friend obtained an ex army fully "reconditioned" BMC engine and gearbox, by REME from a military auction all in a wooden crate supplied in a sort of peppermint green, all totally genuine. However when started up after the first 15 minutes or so there was horrible noise from the valve gear which on inspection turned out to be the wrong oil way rocker pedestal and rocker shaft being fitted by the REME engineers. Apparently engines were totally stripped and cleaned and reconditioned and then if you wanted to build one they would just be supplied with a box of parts to assemble.
At the time in the early 90s at the same auction company I could have bought a REME "reconditioned" Rolls Royce Merlin V12 engine all in a palletised wooden box, I didn't and it sold for £500 hammer price. I often wondered if it was for a tank which could just stop or a rebuilt Spitfire which would have been a bit more concerning.

 

[Toshi 975]

Regarding oil ways and different shafts etc. a friend obtained an ex army fully "reconditioned" BMC engine and gearbox, by REME from a military auction all in a wooden crate supplied in a sort of peppermint green, all totally genuine. However when started up after the first 15 minutes or so there was horrible noise from the valve gear which on inspection turned out to be the wrong oil way rocker pedestal and rocker shaft being fitted by the REME engineers. Apparently engines were totally stripped and cleaned and reconditioned and then if you wanted to build one they would just be supplied with a box of parts to assemble.
At the time in the early 90s at the same auction company I could have bought a REME "reconditioned" Rolls Royce Merlin V12 engine all in a palletised wooden box, I didn't and it sold for £500 hammer price. I often wondered if it was for a tank which could just stop or a rebuilt Spitfire which would have been a bit more concerning.

Rootes group used a light green type of metallic paint on their factory reconditioned engines. The nearest I could get to it was a Hammerite shade for my old 1937 Talbot 10hp.