Vanos now or later?

[Dafoe]

Hey fellas!!! I’ve done well over a hundred Vanos jobs and have always done the cam bolts... I wouldn’t want to do all the work getting everything apart and not replace them with loctite. I will say that I’ve personally seen only two cars with loose bolts.

I’ve logged 150k miles on my last set... put new ones in during the rebuild.

Glad to see some familiar names in this forum.

[mrgizmo04]

There was never much of a misunderstanding on the failure mode. Even when I bought the car a decade ago it was common knowledge that the issue was that they’d back out and ultimately let the cam gears spin without the cam itself spinning.

Being able to torque to a higher spec will make it less likely for the bolt to back out on its own. Using loctite should make it less likely as well. Doing both together will give the most security. And even if you shoot for the stock torque spec, a 10.9 or 12.9 bolt will give you the margin of error necessary to tighten without risking over tightening.

We’re all here to provide information. I will call out information that I think is likely to result in engine failure.

This is now somehow on a whole other level. Information that I provide (which is researched and confirmed/backed up by people who specialize in either working on these cars and VANOS (shops and mechanics) or those who are constantly making parts for the VANOS problem areas (ala Raj/Beisan)) is deemed dangerous. And fixing the underlying problem and the mode of failure is now likely to cause engine failure? With all due respect, Terra...

[terra]

There was never much of a misunderstanding on the failure mode. Even when I bought the car a decade ago it was common knowledge that the issue was that they’d back out and ultimately let the cam gears spin without the cam itself spinning.

Being able to torque to a higher spec will make it less likely for the bolt to back out on its own. Using loctite should make it less likely as well. Doing both together will give the most security. And even if you shoot for the stock torque spec, a 10.9 or 12.9 bolt will give you the margin of error necessary to tighten without risking over tightening.

We’re all here to provide information. I will call out information that I think is likely to result in engine failure.

[Albertan]

When I was doing vanos, I did 4 cars. I used grade 10.9 bolts. I set up a bit of a test rig. A 6mm 10.9 bolted into a 10.9 grade nut could torque to 20 ft lbs before failure. So if grade 8.8 is supposed to be 6 ft lb and you change to 10.9, no one should be able to twist them off if they are aiming for 6 ft lbs (72 in lbs). Personally, I think I did 8 or 10 ft lbs plus loktite Blue. These will give a measure of safety.

[mrgizmo04]

Honestly, I think you're giving dangerous advice in this regard. It'd be one thing if we were talking about a major expense, but it's pennies. Guarantee you most shops are going to just "good and tight" bolts that call for 6 lb-ft. It was very well documented on the old forum that numerous shops and individuals overstretched the stock bolts. Coupled with loctite and some residual oil, it's extremely easy to torque them beyond what they can handle. I think it is very short sighted to not replace them, let alone not go for a higher class bolt.

Beisan does recommend replacing the bolts rather than reusing the originals. And I would go a step beyond and get stronger bolts.

My intention is not to be dangerous, but to provide some background, information and insight. Sometimes attempt at the "why".

I agree they are cheap, and there is no harm in replacing the bolts.

To me the topic we are discussing is somewhat parallel to understanding and knowledge that existed years ago about subframe failures and that plates were the solution. Until Vince and later Cayn from CMP did further analysis to better understand actual underlying modes of failure and how to best reduce/prevent the issue. Some people still think plates are enough because they have not followed latest info and r&d.

For the bolts in discussion, I can definitely see the panic ages ago as the bolts were shearing and the proposed solution would be to make stronger ones. Sure. Until better understanding about the actual mode of failure became apparent (loosening up and backing out which resulted in shearing).

Beisan procedure was written about 7-8 years ago I don't know what revisions have been made to that particular section on bolts. I actually discussed the bolts with Raj as recently as 2 weeks ago, because I told him that as I find folks that I need to help with VANOS, we inadvertently need to order the cam bolts just in case, and since he does not carry them we have to source them from dealers or Lang. He reiterated the underlying issue of the bolts backing out and there was no issue with reusing them with locktite.

On my car when I did vanos 3 years ago, mine were tight so I reused with locktite. Im almost 30k hard miles later, at this point which include everything from daily with baby, autox, canyons and track.

Like I said, I'm here to help and to provide info, which I think is valuable for folks to know. What you do with that info is a choice. If everyone sleeps better at night replacing the bolts, awesome.

[terra]

I don't think we need to keep going back and forth, but I'll just add this.

Hopefully whoever takes on the job (especially a shop) has proper tools and torque wrenches and understand the actual mode of failure to fix however they decide to fix at the end. Also, there is a reason why Beisan doesn't sell the bolt kit (it is not omitted by mistake).

Honestly, I think you're giving dangerous advice in this regard. It'd be one thing if we were talking about a major expense, but it's pennies. Guarantee you most shops are going to just "good and tight" bolts that call for 6 lb-ft. It was very well documented on the old forum that numerous shops and individuals overstretched the stock bolts. Coupled with loctite and some residual oil, it's extremely easy to torque them beyond what they can handle. I think it is very short sighted to not replace them, let alone not go for a higher class bolt.

Beisan does recommend replacing the bolts rather than reusing the originals. And I would go a step beyond and get stronger bolts.

[mrgizmo04]

Yeah, and in comparison to the rest of the cost, $24 is nothing. Other issues with stock bolts is that they're extremely easy to overtorque if you don't have a well calibrated torque wrench. Safer to just use stronger bolts (and they should be less likely to back out if you can torque them more anyway).

I don't think we need to keep going back and forth, but I'll just add this.

Hopefully whoever takes on the job (especially a shop) has proper tools and torque wrenches and understand the actual mode of failure to fix however they decide to fix at the end. Also, there is a reason why Beisan doesn't sell the bolt kit (it is not omitted by mistake).

[terra]

It's like $24 for the kit (iirc from Lang) because they also come together with hub bolts (which I don't think are needed), and they still require threadlocker, since the main mode of failure is bolts backing out and thus sheering, not that they are weak/low grade bolts to start with.

Yeah, and in comparison to the rest of the cost, $24 is nothing. Other issues with stock bolts is that they're extremely easy to overtorque if you don't have a well calibrated torque wrench. Safer to just use stronger bolts (and they should be less likely to back out if you can torque them more anyway).

[mrgizmo04]

The cam bolt are such a small cost in the scheme of checking / locktighting them that I think it's asinine to not replace them. And for that matter, you really should just throw some class 12.9s or ARPs in there so you can safely torque them a bit more.

It's like $24 for the kit (iirc from Lang) because they also come together with hub bolts (which I don't think are needed), and they still require threadlocker, since the main mode of failure is bolts backing out and thus sheering, not that they are weak/low grade bolts to start with.

[terra]

Cam bolts are only needed to be replaced if yours are broken/sheared. If they are tight when removed and show no signs of damage they can be reused with threadlocker. If they need to be replaced, still apply threadlocker on the new ones. You won't know until you get in there (or the shop does).

If you are never going to diy vanos and have to have the shop do the work, start with work that requires timing tools which you likely dont have but the shop does - ask them to check/do cam bolts WITH threadlocker, Beisan chain guide and do the oil pump disc (only if your hub tabs are not intact, then you need the Beisan hub also).

The rest of vanos work - the seals in vanos unit, the sealing plate and the solenoid can be done later and are much easier to do. While you still need to remove the vanos unit from the head, you don't need to remove the hubs/splines and disassociate the timing.

The cam bolt are such a small cost in the scheme of checking / locktighting them that I think it's asinine to not replace them. And for that matter, you really should just throw some class 12.9s or ARPs in there so you can safely torque them a bit more.

[mrgizmo04]

The shop will probably question that you don't know what you are talking about and you should stop listening to forum wisdom (they are in the business of charging $110 per hour and doing things based on the tech's understanding and knowledge). This information doesn't just come from living room racers or forum wisdom, some actually work on these cars full time/part time/hobby and help others work on their cars and collaborate with those who make better solutions for the car (like Raj from Beisan).

[mrgizmo04]

Cam bolts are only needed to be replaced if yours are broken/sheared. If they are tight when removed and show no signs of damage they can be reused with threadlocker. If they need to be replaced, still apply threadlocker on the new ones. You won't know until you get in there (or the shop does).

If you are never going to diy vanos and have to have the shop do the work, start with work that requires timing tools which you likely dont have but the shop does - ask them to check/do cam bolts WITH threadlocker, Beisan chain guide and do the oil pump disc (only if your hub tabs are not intact, then you need the Beisan hub also).

The rest of vanos work - the seals in vanos unit, the sealing plate and the solenoid can be done later and are much easier to do. While you still need to remove the vanos unit from the head, you don't need to remove the hubs/splines and disassociate the timing.

[ATB88]

Yeah there labor rate is 110 a hr. I told them I will call them in the morning. Because with this amount of work they shuld In my opinion be able to replace those 3 things cheep/free. Just checked a video out and like you said they are easy access after going this deep into the vanos.
looks like il be doing cam bolts, solenoid, seals, oil pump disk, timing chain guide, and make sure everything is cleaned. If a tab is broken we will get a new hub but shall cross that road if we get there.
gonna be pricy but then the car is pritty much "done" hahahs

Yeah, it's a lot to swallow at once, but that's just the reality with this car. VANOS is really something you should do all at once and not have to worry about it. The car should feel awesome once it's all done :]

Don't forget about subframe reinforcement, though. That's easily the priciest thing to take care of and the longer you wait, the greater the potential for increased cost :/

[Mainman857]

Yeah there labor rate is 110 a hr. I told them I will call them in the morning. Because with this amount of work they shuld In my opinion be able to replace those 3 things cheep/free. Just checked a video out and like you said they are easy access after going this deep into the vanos.
looks like il be doing cam bolts, solenoid, seals, oil pump disk, timing chain guide, and make sure everything is cleaned. If a tab is broken we will get a new hub but shall cross that road if we get there.
gonna be pricy but then the car is pritty much "done" hahahs

[ATB88]

Right now there quoting me
553 for cam bolts and labor
350 for seals and labor.

He then brought up doing the exhaust hub but hasent gotten me a price yet.

I know zero about getting into the vanos area. if your doing bolts to me it sounds easy to swap the oil disk out at the same time.

Yes, the oil pump disc is very easy to do if you're already taking the vanos off, which you do to access the cam bolts. Again, definitely don't pay for a new exhaust hub if yours is not cracked/broken. This is really the only part that can/should be left alone if it's not damaged, the new oil pump disc prevents any potential future problems with the exhaust hub.

$350 (3ish hours labor) sounds a bit high for the seals, but not outrageously so?

If you're paying the above quoted rates for the cam bolts and seals, you should be able to get him to throw in doing the oil pump disc, solenoids, and timing chain guide for just the cost of parts ($150, $150, and $80 respectively) as they are directly accessible/already being removed if you're already doing seals and cam bolts. Maybe another hour of labor to clean the solenoid valve body? This is an important thing to ask him to do: at 129k the valves themselves can get pretty gummed up and decrease performance.