VANOS Cam Bolts Replacement

[Bob Sacamano]

I am gathering my parts to bulletproof my VANOS. I am reading about the cam bolts which can back out and will order the Lang Racing replacements.

Question: assuming my exhaust hub is in good shape, I plan to use the Beisan disc. If I were doing just that (and seals), my understanding is that I would not need to mess with retiming the engine.

If I replace the cam bolts (not the hubs or sprockets), do I need to retime the engine? Or, can I replace one bolt at a time without losing timing?

Thanks everyone.

[Slideways]

No for pump disc and yes for bolts and/or exhaust hub

New factory torx style cam bolts with oil resistant medium threadlocker are fine. Even reusing the factory hex bolts that have not backed out and applying some blue thread locker would work.

Based on some questionable service Lang has provided to a few forum members and the fact that he is giving high strength threadlocker with those bolts (good luck getting those bolts out if cams ever need to be replaced), would pass on that kit.

[Cubieman]

I very much regret using the Lang bolts kit, and it has 100% to do with the red locite as noted above.

That was a while ago when I didn't know nearly as much, now if I ever have do remove the cams it could be an absolute nightmare. I'm sure the hardware is fine, they likely don't manufacture it.

Another vote for the new style BMW bolts and locite (blue) 243.

[bmwfnatic]

I don't like the "new" BMW bolts, they didn't do anything to prevent failure, just many bolts that were originally hex got updated to torx around 2007/2008, that's all, it's still a 8.8 bolt after all.
If you try to torque them up to 12Nm or even 14Nm like some people do this never feels good, you can feel them stretch.
I use 12.9 grade M6x16 bolts, I find they torque up nicer.

[Bob Sacamano]

Is this possibly a case where I should just check the cam bolts with my fingers, and if they are still tight, leave them be? And only replace if any are finger tight?

Most of the VANOS disc procedure I am comfortable with, but the timing gives me slight pause.

Motor has about 75k.

Thanks guys.

[maupineda]

You can check them with a torque wrench. Set it to the torque spec and slowly tighten them, if tight, it will click without moving at all.

but at that point you have removed the hubs so you need to retime. I guess if you are really lazy about retiming the engine, you can try what you said but there is no insurance policy.

[Slideways]

Is this possibly a case where I should just check the cam bolts with my fingers, and if they are still tight, leave them be? And only replace if any are finger tight?

Most of the VANOS disc procedure I am comfortable with, but the timing gives me slight pause.

Motor has about 75k.

Thanks guys.

Because it takes quite a bit of work to get to the bolts, it is worth it to add medium threadlocker to the old hex or new torx bolts. I have replaced the cam bolts on two engines and the original hex bolts were tight on both. I recently took apart the first one I did, and the torx bolts I put in with medium threadlocker were still tight.

[Bob Sacamano]

Okay, here's where I'm slightly confused. It makes sense to me that removing the hubs themselves requires retiming the engine. But, if I'm not removing the hub, can't I just replace the bolts one by one? For example, the image below shows only the VANOS unit removed with the hubs/sprockets still in tact. Is the problem that the bolts aren't all accessible without rotating the engine?

ETA: I was planning to do the Beisan exhaust chain guide. It looks like that requires removal of the chain/exhaust sprocket, so I may be stuck re-timing the engine no matter what. Maybe I am overthinking how difficult that is, I was just hoping to avoid it.

[Cubieman]

There is really no point at all to replace just the hub bolts, yes you could probably get away with doing them one at a time in star pattern, like a wheel.

The cam bolts are the ones that can back out and potentially smoke your engine so those are the ones to focus on.

Don't let timing the engine scare you away, if you follow the directions (Beisan directions are great) and have the correct timing tools you will be fine.

[sapote]

Is this possibly a case where I should just check the cam bolts with my fingers, and if they are still tight, leave them be? And only replace if any are finger tight?

Most of the VANOS disc procedure I am comfortable with, but the timing gives me slight pause.

Motor has about 75k.

Thanks guys.

You cannot get to the cam sleeve bolts without changing the timing, because the hubs have to be removed.

[sapote]

Question: assuming my exhaust hub is in good shape, I plan to use the Beisan disc. If I were doing just that (and seals), my understanding is that I would not need to mess with retiming the engine..

I suggest not to use the pre-drilled disk from Beisan as it might not match to the original 4 pump-pistons. Best is to have the original disk drilled with new smaller 2 holes.

[Bob Sacamano]

There is really no point at all to replace just the hub bolts, yes you could probably get away with doing them one at a time in star pattern, like a wheel.

The cam bolts are the ones that can back out and potentially smoke your engine so those are the ones to focus on.

Don't let timing the engine scare you away, if you follow the directions (Beisan directions are great) and have the correct timing tools you will be fine.

Thank you - I was being an idiot and getting them confused. Understood now. Appreciate the clarification.

[Bob Sacamano]

I suggest not to use the pre-drilled disk from Beisan as it might not match to the original 4 pump-pistons. Best is to have the original disk drilled with new smaller 2 holes.

I had read that Beisan was now drilling the factory discs and no longer sold their manufactured ones. Is that not correct? I can certainly send them my factory disc to be drilled if that's what you're suggesting.

[sapote]

I had read that Beisan was now drilling the factory discs and no longer sold their manufactured ones. Is that not correct? I can certainly send them my factory disc to be drilled if that's what you're suggesting.

Keep your pistons/spring and the small things behind them with you, mark your disk and send it to be drilled.

[Slideways]

I had read that Beisan was now drilling the factory discs and no longer sold their manufactured ones. Is that not correct? I can certainly send them my factory disc to be drilled if that's what you're suggesting.

Dr. VANOS will do this if you call ahead of sending it in. Beisan says they do theirs in batches, so not likely. Have used two swapped Beisan discs without issue and plenty of others have as well. The piston issue was with the discs they made from scratch which have since been discontinued. If you can wait and have the car sit for a week or two, then it is always best to have your disc redrilled.