M44 Timing Chain Tensioner Replacement Input needed...

[RayBallen]

Hi, searched the forum for anyone with an M44 1.9 who has done this with details but couldn't because I'm guessing it's a fairly easy job. Doing this as a preventative maintenance.

I'm planning on installing my timing chain tensioner DECOMPRESSED, not following the Bentley manual, as I've heard stories of timing chain skipping tooth because of the Bentley method (30s at 3500 rpm). The scary part is the initial start. Most of the time it's good but sometimes it's not.

I found this: http://www.m42club.com/forum/index.php?topic=2925.0 but it's for an m42. I'm wondering if it's the same for an M44 engine.

So practically, installing it DECOMPRESSED, but not prepped with oil so it can be threaded into the insert hole then start and still do the 3000-3500 rpm at 30 secs to ensure oil pressure fills the chain tensioner and idle for 5 minutes or so.

Anyone here who has done this UNCOMPRESSED or DECOMPRESSED? I'm still not sure if I should rev it as such with the tensioner DECOMPRESSED.

Thanks!

[RayBallen]

bump

[Vintage42]

... I'm planning on installing my timing chain tensioner DECOMPRESSED, not following the Bentley manual, as I've heard stories of timing chain skipping tooth because of the Bentley method (30s at 3500 rpm). The scary part is the initial start...

I don't see any of that in Bentley. Page 117-27 just says to compress the old tensioner if re-using it. Where is the 30s at 3500 rpm part? Would not idling be a safer way to refill the tensioner?

[RayBallen]

I don't see any of that in Bentley. Page 117-27 just says to compress the old tensioner if re-using it. Where is the 30s at 3500 rpm part? Would not idling be a safer way to refill the tensioner?

If it's DECOMPRESSED, I'm guessing it should be okay to just let it IDLE at start. But I'm proceeding with caution as this can throw off the timing. I want to confirm if someone has already done this on an M44. Been holding this job off for a month now. A local indy is charging me $200 for something I know I can do.

Others did it compressed but had to rev high at 3500rpm for 20secs to 30 secs to ensure it won't skip tooth but there have been cases it did. Im guessing the revving thing is from master techs or others who have done it COMPRESSED, if it's not in the Bentley manual. The idling I heard is not safe for compressed tensioner because the slower it is, the more it jumps and create noise. (Like the ones who have a failing tensioner, the noise disappears when rev'd high.)

[Vintage42]

... Others did it compressed but had to rev high at 3500rpm for 20secs to 30 secs to ensure it won't skip tooth... Im guessing the revving thing is from master techs or others who have done it COMPRESSED, if it's not in the Bentley manual. The idling I heard is not safe for compressed tensioner because the slower it is, the more it jumps and create noise. (Like the ones who have a failing tensioner, the noise disappears when rev'd high.)

I really don't know anything about this but am trying to understand.
By jumping I thought you meant the chain jumping on the sprocket, which to me sounded unlikely.
I think a compressed tensioner, or a failing tensioner, causes noise by allowing the chain to slap the shoe.
I can see that a compressed tensioner would refill with oil faster, and make the chain quieter sooner, if the rpms are elevated.

[rf900rkw]

It's a five minute job. You are seriously overthinking this.


The reason for the 3500 (I use 2200) on initial start is it gets you past the harmonics caused by the spring pressure of a closing valve trying to drive the cam forward. Thus you have a steady "pull" on the chain. This is used for initial run-in of new cams and lifters and such, not normally the chain. It's unneeded here. Put the tensioner in and go, though I do not see why you would do this as purely maintenance.

The chain can not jump a tooth if everything is good. A guide would have to be broken to allow enough slack in the chain for it to skip over. My guess from over here is the ones that had the "timing jump". had other problems... say a horrendous chain noise caused by a broken guide that they tried to fix with a new tensioner.

[RayBallen]

I really don't know anything about this but am trying to understand.
By jumping I thought you meant the chain jumping on the sprocket, which to me sounded unlikely.
I think a compressed tensioner, or a failing tensioner, causes noise by allowing the chain to slap the shoe.
I can see that a compressed tensioner would refill with oil faster, and make the chain quieter sooner, if the rpms are elevated.

The chain, depending on the condition of the guides and the state of the tensioner, along with the speed of rotation, on some instances can cause for it to "slack" or "slap" and cause the chain to skip tooth. It's like in a loose bicycle chain, if there's a lot of slack then it can cause a different configuration, chain could jump (which is fine in a bicycle but not in a car with timing) or simply chain "thrown off" although very unlikely in a car. rf900kw is probably right that I may be overthinking this but it's more like an investment at this point. I just spend $3k reconditiong and restoring the car and it would suck if this results to a thrown timing.

Hence, I'm considering the uncompressed route as opted by several M42 owners in the link I provided. An uncompressed chain tensioner lessens the probability of any slack or slap. But then again I could be overthinking this.

The 3500rpm at 20 seconds or 30 is to ensure the chain is constantly pulled like rf900rkw mentioned below so it won't cause any slack or slap. https://www.rimblas.com/tech/archive...d_m42_tim.html

It's a five minute job. You are seriously overthinking this.


The reason for the 3500 (I use 2200) on initial start is it gets you past the harmonics caused by the spring pressure of a closing valve trying to drive the cam forward. Thus you have a steady "pull" on the chain. This is used for initial run-in of new cams and lifters and such, not normally the chain. It's unneeded here. Put the tensioner in and go, though I do not see why you would do this as purely maintenance.

The chain can not jump a tooth if everything is good. A guide would have to be broken to allow enough slack in the chain for it to skip over. My guess from over here is the ones that had the "timing jump". had other problems... say a horrendous chain noise caused by a broken guide that they tried to fix with a new tensioner.

My Z3 1.9 is at 163k. The receipt book I got from the previous owner doesn't show the timing chain tensioner to have been replaced. From observing various youtube videos or forums, it can start making noise at 200k or earlier for an m42 version. I want the guides to last longer as some M44/M42 owners have cited it can last longer by replacing the tensioner even before it starts to "chatter." I know it's a non-maintenance but more of a preventative measure.

You're probably right that I'm overthinking this but l want to hear from someone with an M44 who have done this. If not then I'll go by the book.

[Vintage42]

... I'll go by the book.

If the book is the Bentley Manual, Page 117-27 just says to compress the old tensioner if re-using, it and nothing about rpms.
And new tensioners that have never been pumped full of oil are also in a compressed state.
If it was advantageous to install a tensioner uncompressed, why would Bentley say to re-use your nice uncompressed tensioner and compress it in a vice until the oil was squeezed out?

[RayBallen]

If the book is the Bentley Manual, Page 117-27 just says to compress the old tensioner if re-using, it and nothing about rpms.
And new tensioners that have never been pumped full of oil are also in a compressed state.
If it was advantageous to install a tensioner uncompressed, why would Bentley say to re-use your nice uncompressed tensioner and compress it in a vice until the oil was squeezed out?

I can't find the link right now but from what I read it says the old timing chain tensioner (M42) version tends to lock up or sieze if installed uncompressed causing damage to the guides. Second, it would be hard to thread it back onto the hole if it's uncompressed, thus compressed is the official recommendation. But others who have done it uncompressed with the new m44 tensioner said it wasn't that hard as long as it's not primed with oil.

[rf900rkw]

Hmmm. Replace the tensioner to save the guides. I thought that wives tale was only in the M62 forums I *had* a 318ti. And I have a pile of cracked M44 heads behind the barn from people that won't change the cooling system plastic... probably done 30 or more head gaskets in M44s.


But no, I don't currently own one. Forgive me. I will delete my post.

[RayBallen]

Hmmm. Replace the tensioner to save the guides. I thought that wives tale was only in the M62 forums I *had* a 318ti. And I have a pile of cracked M44 heads behind the barn from people that won't change the cooling system plastic... probably done 30 or more head gaskets in M44s.


But no, I don't currently own one. Forgive me. I will delete my post.

Did I say "to save the guides"? I said prolong the guides. I don't know if that's true or not but what I'm doing is practically for peace of mind.

LOL are you implying that I'm focusing on the wrong thing? I completely overhauled my cooling system (as in literally everything, including all the "while I'm there") including the cooling pipes by the block and the behind the engine. Also replaced all the hoses. If that's the case, sorry bro If I'm not as experienced as you are.

I wasn't saying "you don't know anything". Sorry if it came out the wrong way. I actually appreciate your post. Just want to confirm if someone with an m44 who has done this uncompressed for validation (just to confirm for an M44 because most postings I find are for an m42). If not then I'll go by what you do or by the book.

[Vintage42]

... Just want to confirm if someone with an m44 who has done this uncompressed for validation (just to confirm for an M44 because most postings I find are for an m42)...

In this post, there no differences mentioned between M42 and M44 in the tensioner area:
http://www.318ti.org/forum/showpost....00&postcount=6

[BladeRunner919]

I've removed and reinstalled the original one when I removed the head on my M44. I just compressed it a bit before reinstalling, because it makes it easier to get the retaining cap in place, and then started the car. You are definitely overthinking this.