[vliegwielolaf1234]

If you replace the chain then also replace the pad's while you are there .

It is a one piece chain and they tend to wear , the pads get old and brittle due to age . And are not that expensive .

The camshafts have to come out either way .

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[jferraro17]

Thats the plan. Thanks for the advice!

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[Spyderman]

I just finished replacing the Variocam chain pads and the timing chain in my '92 Cabriolet. The car is currently showing 116,xxx miles, and the previous owner had zero maintenance records to pass along with the car. Judging from the grooves and the pitting of the old brown colored chain ramps, I may have 'dodged a bullet' with this R&R item. Here are some photos of the old chain pads and the new ones, as well as the re-assembled Variocam unit, and the new timing chain (aligned seven links apart between the 'blue' reference links) with the camshaft gears, back in place on the head. Also, will be replacing exhaust cam oil seal, spark plug tube seals, valve cover bolt seals, and valve cover gasket before buttoning things back up.

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[flash]

yikes - that was close.



this is what i was talking about way back when you got the car. there is a laundry list of this kind of stuff, all of which adds up. not a big deal, but it does add to the price of the car.

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[Spyderman]

The timing and balance belts are the next area I'll be tackling. I found a Continental sticker under the hood indicating that the belts were changed at 88,xxx miles, so definitely coming up on the recommended 30,000 mile change interval. New Gates belts will be going in, along with new rollers and tensioners. I actually enjoy working on this car more than driving it, weird as that may sound.

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[flash]

wow - you went and did the variocam, but not the timing and balance belts??? that means you have to pull the valve cover again. bummer.



time is more important than mileage on the belts. 4 years max if they are gates. 3 years if they are conti.

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[Bulti]

Huh? Valve cover to do the belts?

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[vliegwielolaf1234]

To set the cam timing you need to remove valve cover .

When replacing the belt your timing could be off , to get it a 100% you need to retime the camshaft .

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[Spyderman]

[quote name='flash' timestamp='1418333686' post='164408']

wow - you went and did the variocam, but not the timing and balance belts??? that means you have to pull the valve cover again. bummer.



time is more important than mileage on the belts. 4 years max if they are gates. 3 years if they are conti.

[/quote]

Not to worry, valve cover is still sitting on the bench. I try and plan projects like this out, and follow a logical sequence to avoid back-tracking and undoing completed work. Sometimes it actually works! <img src="/forum/images/smilies/968/smile.png" class="smilie" alt="" />

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[flash]

lol - kind of messy running the engine like that isn't it?



where's the extreme sarcasm icon?



bulti - view is absolutely right. many shops cheap out and don't time the cams, but that can cost you as much as 20hp. it's a pain in the butt, but worth it.

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[Cloud9...68]

What exactly is the reason for re-timing the cams when replacing the belts? Is it because of variations in length from belt to belt? By that reasoning, wouldn't it be necessary to periodically re-time the cams as the timing belt stretches over time?

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[flash]

it's more chain stretch and gear wear than belt stretch or variance, though that is there too. there is no way to lock down the cams and nail the timing either. the amount you move them is so small that any movement at all, including when you release things, changes the timing. even if you could lock it down, you have no way of knowing how much things have stretched or worn without hooking up the indicators. the belts don't have as much of an impact, but you would be amazed at how much the chain stretches, and how much of an effect that has on cam timing. a couple thousandths of an inch means a pretty big change.



every engine builder will tell you that cam timing is everything when it comes to getting performance out of an engine.



that's why cam timing is a part of the belt change procedure. it's right there in the manual. many shops skip it though, thinking "if it ran before.....". basically they are lazy, often because they don't want to buy the tools, but mostly because it adds up to 2 hours to the job. it's not like they dyno the car afterward so you can see if you got it all or not.

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[Cloud9...68]

Flash,



I followed part (maybe most) of your last post, but not all of it. I think my confusion comes from the fact that the topic of this thread is variocam pad and chain replacement, and the discussion of the need to time the cams after a belt change got interjected later. This is what I have some questions about, as I have a belt change coming up soon. Do you want me to start a separate thread on this topic, or can we continue talking about it here?

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[flash]

if one is doing the variocam job, then a belt job in conjunction makes sense, since some of the work is shared. that's how we got onto that. as for a belt job, this is simple. time the cams. period. it's a part of the job. check out the workshop manual. they put it in there for a reason. it makes a huge difference in how much power you get, and where you get it. you can swing it one way and get more low end, or the other way and get more top end. there really isn't a need for yet another thread about belts and cam timing. we've had this conversation here before. there is already quite a bit here about it, and it hasn't changed.

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[Cloud9...68]

OK, so in a pure belt job, without touching the variocam chain, the crank is locked, and the cams can't move, because they're under tension from the valve springs. So the only variable is the timing belt itself, right? So, is the need to re-time the cams after a belt change driven by the variance from belt to belt? And if the timing is that sensitive to this variation, shouldn't the timing be re-set periodically during the life of a belt as it stretches?



I'm not disputing the need to time the cams after a belt change, by the way - I've already done it once after the rebuild, so I'm familiar with the technique, and it isn't that bad of a job - just trying to understand the why's. Thanks.

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[flash]

slow down on the reading. post #52. first sentence. once again, it's due to CHAIN STRETCH AND GEAR WEAR. it really has little to do with the belts.

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[Cloud9...68]

OK, so then why time the chains after a belt change? If the timing changes primarily as a result of chain stretch and gear wear, then re-timing the cams is something that should be done on some mileage interval if you want to get the maximum power out of the engine. Is Porsche's recommendation to time the cams after a belt chain simply to ensure that it gets done gets on a regular basis?

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[flash]

it is on a schedule. it's not a recommendation. it's a part of the job. it's no different than torquing a bolt to a spec. they figured that to maintain performance, you needed to time the cams every 4 years or 60k miles (which we now know to be more frequent than that). that's why it's a part of the belt job. yes, there is a small amount of variance in belts, and this too needs to be accommodated, but really it's wear on the chain, gears, and pads that create a change in cam timing.

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[Bulti]

Ok, next thing to learn doing myself: cam timing. Obviously a very expensive thing to outsource...

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[flash]

well, if you are outsourcing the belt job, then not too bad. it's only a couple of hours more. however, if you were to send it out for just that, then it would be expensive.



the tools are the issue here. you need 2 dial indicators and a couple of other specialized tools to do it

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