Is the N62 An Interference Engine

[CapeX5]

All, I recently picked up an 04 E53 with the N62 motor. Was told that it started making noises and stopped running. I have started taking the engine apart to do the chain guides. See attached pictures. The driver side bank of engine had the chain come off the intake sprocket. There is evidence that the engine was spinning with the chain not turning the cam. I am trying to decide if I should gamble and just do all the guide replacement work and hope for the best or is it possible that I have bent valves? Looking for any help or knowledge of these engines.

[BigBody]

I’m pretty sure the majority of BMW engines are interference... if not all.

[BigBlack48is]

I doubt it... When I did the valve stem seals on my 06 N62 and of the valves fell into the cylinder ( luckily part of the stem was still in the guide ) We rotated the engine over at the flywheel and it still had a good solid 1/2" of travel to pull the valve back up into the head.

[crystalworks]

All BMW engines are interference. At least dating back to my knowledge base (>1975).

N62's are not known for guide problems or jumping teeth... I'd wonder what made this poor unit decide to do so. Would scare me.

Might be time to pick up another engine. Too bad you are so far away... I have a cheap N62. Would come with a truck too.

[andrewwynn]

On the M62 only the intake or exhaust I think interferes. I would use an inspection camera to check for bent valves, better use a leak down test to measure compression. I'm not sure about N62 though I'd bet they are similar. The added complexity with N62 is the valves change stroke so there's a chance they sometimes interfere

You don't need the guides fixed just get that loose chain on the sprocket and do a rough timing set so you can hand turn the crank.

I helped refurbish a few M62 heads with bent valves, we took about 5 heads apart to get 2-3 working heads; it wasn't that much more work once you are down to chain guides level.

[tmaxx445]

Originally Posted by andrewwynn

On the M62 only the intake or exhaust I think interferes.

The heads I pulled off my $750 project E53 say otherwise. Now maybe only with the Alpina/4.6is cams will all 32 valves kiss, but at least on my M62 they were all bent indicating both intake and exhaust are indeed interference.


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[andrewwynn]

That's a crazy picture.it looks like the valves are all parallel to the head face.

We only had to replace maybe 1/3 of the valves. I guess what matters is what type of chain failure happens.

In one case the chain broke and froze all the cams so only whatever valves were too far in at that point would be a problem and the engine killed so wouldn't keep spinning to cause more damage.

[tmaxx445]

Originally Posted by andrewwynn

That's a crazy picture.it looks like the valves are all parallel to the head face.

We only had to replace maybe 1/3 of the valves. I guess what matters is what type of chain failure happens.

In one case the chain broke and froze all the cams so only whatever valves were too far in at that point would be a problem and the engine killed so wouldn't keep spinning to cause more damage.

Yep it was a catastrophic failure. The PO said he drove for at least a tanks worth of fuel once he heard the noise. The chain eventually chewed up enough of the lower timing cover to completely come off the U guide and fall off the crank sprocket. It all back together now and running really strong though.










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[andrewwynn]

One of the m62 I helped bring back to life didn't get to derailing but there was almost no plastic left of the chain guides so it was very close to where the chain would derail. The engine still ran but sounded like it ran on marbles.

The second one had the chain derail, get caught between the crank sprocket and the lower timing cover and bind until it snapped! That was the one we had to comhine several non working engines into one working one.

Both started right up after resembling, and there was much rejoicing!

I love the gold color of the inside of the motor. I was not expecting it for some reason: it looks like it is anodized gold to make it look pretty not just that oil hat cooked on for 5000 hours.

[andrewwynn]

PS: outside the car on a motor rack not on your back under a car laying in antifreeze in a 45° garage is cheating.

(Good kinda cheating)


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