Timing Chain Slap after I replaced the Guides and Tensioner? E39 540i/6

[mvch427]

Hi everyone this is my first post but I would like to thank the community for all the extensive information which helped me with my motor.

I purchased a 02/2000 E39 540i/6 last spring with 143k and went about redoing everything I could on the motor. Took the cylinder heads off, got them reconditioned with new valve guides and stem seals, replaced the vanos seals and replaced the timing guides, all three tensioners and chains, as well as the entire cooling system. I even took every lifter apart and cleaned the old oil out of them with compressed air when I had the heads off.

When I bought the car, it had a seriously loud chain slap sound at idle once the oil came to temp. On a cold start it would purr like a kitten and then the slap would appear and get louder as the oil warmed up.

When I tore it down, the center u guide was shot and only the bottom clip was still attached so my guess is that it was pivoting (slapping) back and forth with the chain.

When I fired the car up after the entire rebuild, it clattered like a can of marbles for a couple of seconds until the lifters pressurized, and then the idle sounded like a quiet whisper. (I run Liqui Moly High Tech 5w-40).

1000 miles of driving the car and the idle was perfectly smooth. 2 months ago, I was driving and the chain slap returned. It was quiet and gradual at first but over the course of a week, it grew louder. It has stayed at the same volume for the past 2 months and it is not as loud as before the rebuild, but I'm stumped to why the chain is slapping. I'm using all FCP Euro Genuine/OEM parts for the guides and lower tensioner. I know it's a slap as the motor has an uneven vibration when I hold to motor between 700-1400rpm in neutral. It feels as if the chain is jumping around in the motor. No bits of timing guide in the oil pain, and all the guides are brand new.

When I am driving the car, I don't hear any slap above 1000rpm, it's only present when in neutral without load. The car hums along at 130mph at 4000rpm happy as a clam, but slap slap slap slap at idle.( I live in Montana, lot's of room to stretch its legs).

I've seen plenty of threads about chain slap and the verdict is replace your tensioner and or your timing guides. I did that, and it came back 1000 miles after the rebuild. The only moving part I didn't touch on my motor was the short block. Everything is new or refurbished. The car purrs at idle when cold, but the chain slap gradually comes on when the oil comes to temp. I'll be cruising on the highway to class for the day, and when I come up to a stop light and pull it out of gear, I hear the slapping.

Any possible idea as to what could be the cause of the slapping? Low oil pressure to timing chain tensioner?

I'd like to share pictures of the rebuild and the car but it says I can't post attachments..?

[JimLev]

Welcome to the forum Mvch427.
After 10(?) posts you should be able to attach pics.
Read the oil pressure cold and hot just to rule that out.
Post your findings.

[scubajim20]

I saw you mentioned OEM for guides and lower tensioner. What manufacturer did you use for the upper tensioners?

[JimLev]

I bought all of the guides and tensioner pads (cam to cam chains) directly from BMW.

[geargrinder]

Hmmm. I'd maybe try to pull the valve covers - or actually to start out, just the right one - and turn the engine over by hand and see how much slack there is in there and see if you see any slop. Maybe your main tensioner was a bad part? Despite much talk on forums about the spring length and spring fatigue, those operate primarily on hydraulic pressure aka they are 'lifters' really. Its possible you got a bad one?

[mvch427]

Where do I test oil pressure? Is there a mechanical port or do I buy a special scanner?

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I think the brand is febring

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Hmmm. I'd maybe try to pull the valve covers - or actually to start out, just the right one - and turn the engine over by hand and see how much slack there is in there and see if you see any slop. Maybe your main tensioner was a bad part? Despite much talk on forums about the spring length and spring fatigue, those operate primarily on hydraulic pressure aka they are 'lifters' really. Its possible you got a bad one?

I thought it could be a bad main tensioner so I replaced it with a genuine bmw tensioner from FCP. On startup it rattled for a second and then it pressurized and settled back into the same slap slap slap sound

[Chedley]

The correct oem brand of the timing chain tensioner should be BMW or INA. It has built-in the longer spring. Are you sure you did not install an old rebuilt tensioner with the short spring?
Also, when you rebuilt the engine, did you check or replace the oil pump chain ? Maybe that is where the slapping is..

[geargrinder]

As mentioned, spring length is nearly inconsequential once the engine is running. I stick to suggestion to take that right side valve cover off and eyeball whats going on under there.

[mvch427]

The correct oem brand of the timing chain tensioner should be BMW or INA. It has built-in the longer spring. Are you sure you did not install an old rebuilt tensioner with the short spring?
Also, when you rebuilt the engine, did you check or replace the oil pump chain ? Maybe that is where the slapping is..

The upper tenrionsers are febring. I replaced the genuine bmw lower tensioner with an INA lower tensioner from ECS after the slapping started again.

Now that you mention the oil pump chain, I did notice that it was a bit loose, but I foolishly ignored it as I was facing many other issues as it was my first motor job besides a big bore kit on a ktm dirtbike. Can I go in an adjust the oil pump through the lower oil pan, or does the lower timing cover have to come off too?

[JimLev]

You can adjust the oil pump chain by just removing the lower pan.
IIRC the newer chain tensioner has a longer spring but it isn't as thick as the old shorter spring.
99% of the time a new chain tensioner won't do squat.

[R Shaffner]

Hmmm. I'd maybe try to pull the valve covers - or actually to start out, just the right one - and turn the engine over by hand and see how much slack there is in there and see if you see any slop. Maybe your main tensioner was a bad part? Despite much talk on forums about the spring length and spring fatigue, those operate primarily on hydraulic pressure aka they are 'lifters' really. Its possible you got a bad one?

Great idea. In my experience, the tensioner will hold it's position for a while, as if it still has oil pressure. If you don't notice slack in the chain then isn't it likely you're hearing something else? (Asked by someone who is NOT an expert on chain slap.)

Hell, you could probably just remove the oil filler cap, put the car in 6th gear with the brake off, and have someone rock the car backward and forward while you look at the chain through the filler opening. If the crank moves without the chain, then you have chain slack w/o oil pressure, and MIGHT have slack w/ pressure. If not -- if there's no slack w/o pressure from the oil pump -- then my bet is the sound is something else.

I'd try this after recently running the car, to make sure oil was still in the tensioner. If you notice slack in the chain, I'd promptly pull the tensioner to see if it could be compressed easily or not. If so, I think something is probably wrong with the tensioner or the oil flow to it.