I've been searching quite a while now, and I've found the basic "line up the cam marks then read the marks on the crank" over and over, however I've also found posts (on a different forum) which asserts that on an '85, the test is completely innaccurat, and reference is made to a "2mm lift test".

It's not that I don't plan on replacing the chain & guides, but I'd like to know if I need to do it "right away" or if I can wait a month or so since I just got the car running yesterday (after sitting for 2 years) and I'd like to drive it around a bit and see what else needs attention.

It starts immediately and runs relatively smooth on a mix of 5 gallons of gas & a full can of GM top end cleaner, so I imagine it'll run smoother once it gets real gas.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Dear V8 owner,
If the timing chain is allowed to slap the chain rails and guides the impact will break the nylon into little pieces. The pieces lodge between the chain and sprockets. You know the story. Does the engine make rattling noises when started cold? If it is'nt started for many days the tensioner bleeds down and allows the chain to whap the nylon when cranked. Carefull now my friend.
Don

It doesn't make a single slapping or rattling noise on start-up; even after starting up after being 'dead' for 2 years...

I'll probably do it anyway, just to be on the safe side, but it would be nice to know just how bad it is...

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Rolling in a new chain is not a huge deal and could save your engine. These are interference engines and are not cheap to recover from a broken timing chain.

Well, I pulled the left valve cover, aligned the mark, and this is where it fell:



Looks like I'll be ordering a chain, guides, etc... ASAP.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

If it is indeed 7 degrees of stretch then you are borderline.

The way you properly test the stretch is to bring the #1 piston to TDC, compression stroke to check the crank mark. This procedure eliminates any wear in the dampener pulley.

You can't really check for TDC using the cam marks due to it turning at a different speed (1/2) than the crank and it doesn't take much to throw a 10 degree (only a 5 degree variance on the cam gear or 1/72nd of a turn) false reading.

Bring the piston to TDC, check the crank mark and then check the cam marks. Then you rotate the engine (clockwise from the front) to align the cam marks, read the crank pulley and subtract any variance you may have found from the TDC position.

I'll try that method when I get home.

If my guides are intact and look to be in good shape, are they worth replacing? Should I just replace the rail guide cover and be done with it?

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

If the chain is good then I'd definitely replace the guides unless you have paperwork showing they were replaced. I'd replace them even if I had the paperwork. As Larry said, after a chain/guide failure these aren't a cheap fix.

Do I need to replace all of the guides, or would just the top guides be sufficient? I'm probably just going to order the stuff and be done with it. There's not much history on this vehicle.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Ok, pulled valve covers, plugs & fan. Got TDC of compression stroke on cly #1, lined right up with 0 mark on pulley. Right cam was lined up perfect, had to rotate pulley 10deg to line up left cam (which also moved right cam).

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

Kinda OT, did they make a 380SEL in 1985? I thought that by 1985, that the 380 was only SWB model (380SE) only and the LWB in 1985 was only available with the 5.0L engine which was the 500SEL.

Maybe this is a Euro model we are referring to.

I had a '85 380SE and was told it had a dual chain (unlike the 81-83 380 models which had a single chain), but the guides and rails are still cause for concern on all V8 Mercedes and should be updated on that engine.

Yup - it's a euro model. I ordered the chain, guide rail, rail cover & the plastic guides, along with some other stuff...

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

How many miles are on the engine, the cam gears are usually worn as well. If your gonna keep it for a while then fix it that way. It is acceptable to use the factory marks to set cam timing, but to do it correctly you will need a degree wheel for the crank, a depth gauge to set TDC as well as a dial indicator with all needed hardware to measure lift at each camshaft, I ran a dyno for 11 years and on occasion did that procedure shopping for horsepower. To be honest the gain isn't worth all the effort. As for the chain with valve covers removed grasp the chain at the center of the gear on top between thumb and finger and lift, if the chain only raises slightly it is still in order. If it lifts a large amount the chain/ gear set no longer fits correctly. The gear teeth will also seem sharp at the upper edges from wear. Setting the timing of camshafts correctly and rolling a chain is the simplest but most dangerous procedure as the failure rate is high for mistake. If the gear is set a tooth late it will have low manifold vacum and be lazy, if it's early it might not bend a valve....... maybe.
Bill

I took possession of the vehicle last monday (after sitting for 2 years), got it running last friday, and got it titled Tuesday.

I did try lifting the chain off the sprocket yesterday and it barely budged, and the cam gears look pretty good - nice and round (and symetrical) at the top like they should be.

The ODO reads 137K, but it's also busted, so true mileage is unknown. This is a project car, not a daily driver, so right now I'm concentrating on making sure it doesn't self-destruct on it's way to get the state inspection. Once that's done, I'll put a few thousand miles on it, then see where I'm at. Having only driven it maybe a mile or so around the neighborhood, I don't know if it's got trans, diff, suspension, etc... issues that need to be dealt with first.

I've got all the gear you mentioned, plus some (I left the automotive field a few years ago for more lucrative pursuits but never sold my tools). If the car checks out on the whole, then I'll do a little exterior work and then start fine tuning the engine.

__________________
A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.

From what you have shared it doesn't sound like there is an issue with the chain. It is quiet imediatly after starting, there is no noise when running. What made you have concern as to the condition of the chain? From all the ASE credits you post you clearly have a good understanding of the mechanics of an engine. Go drive it for a bit and see if you like it enough to spend time and money in it. Good luck
Bill