Chain Guides Replaced - PeachParts Mercedes-Benz Forum

wbain5280 · #1 04-19-2007, 12:59 AM

Today, I finished replacing the chain guides on my 420SEL. Some were actually missing or only a small piece was left. There were sone sections down inside the open area of the open area of the head where the chain goes and the chain wore out some material of the head itself. The chain had rubbed on some of the pins and wore a groove in them. I'm suprised this engine didn't self destruct. I will post pics of this operation as soon as I upload the pics.

I had to smash the distributor cap as the screws holding it on were frozen but the cap needed replacing anyway. I also have new wires on the way.

I also found that the passenger side sprocket is off by what looks like one tooth. I'll install the tensioner and check it the offset and realign it properly. I suspect I'll need a new chain.

Hit Man X · #2 04-19-2007, 04:52 AM

Looks like you saved the motor!

Did you do the tensioner lining too? The lining is very inexpensive and easy to swap.

wbain5280 · #3 04-19-2007, 06:54 AM

Yes, I did the curver tensioner chain guide, the old one was loose.

wbain5280 · #4 04-22-2007, 03:41 AM

jhodg5ck · #5 04-22-2007, 12:04 PM

that 2nd to last picture of your timing, is that where it ended up after all the work?

I'm going to wager your upper gears are quite worn (As well as the other gears but they're a PITA to get to).

How many miles are on that engine?

Jonathan

stevebfl · #6 04-22-2007, 12:16 PM

You have more than chain stretch involved with that timing issue. Somewhere the gear has been put on wrong. Move the gear forward a tooth. That gap is more than a tooth wide. Back when it was practical to dial indicate and compensate timing I used to see right side gears as much as 14degrees retarded after 250k miles. Fourteen degrees is a little over an 1/8 inch. A one tooth movement will change the timing 18 degrees.

Don't even think about offset woodruf keys unless you plan to do a real dial indicated measurement of timing.

wbain5280 · #7 04-23-2007, 12:37 AM

I have yet to install the tensioner. I plan to do that in the morning and check it again. I will then take off the gear and move things around until they are better aligned. I fully expect to replace the chain.

The engine has about 250K miles on it.

I am amazed the engine even ran and that the valves didn't bend.

More to come on this darling.

Thanks for your replies.

jhodg5ck · #8 04-23-2007, 01:08 AM

Curious how much oil are you using? Have you done valve guide seals? I'm assuming heads/valve guides have not been done yet, no?

Jonathan

wbain5280 · #9 04-23-2007, 01:37 AM

Quote:

Originally Posted by jhodg5ck

Curious how much oil are you using? Have you done valve guide seals? I'm assuming heads/valve guides have not been done yet, no?

Jonathan

I haven't driven it that much considering the guides were either broken or missing and it didn't start or run very well until it warmed up.

The valves and guides haven't been done.

Here's what I've done so far:

1. Fix intake manifold and assorted vacuum leaks. It passed the emissions test with flying colors.
2. Fix fuel pump problems, such as a disconnected fuel pump, replace check valves, hoses, accumulator, clean the rust off the bracket.
3. Replace ball joints.
4. Fix cold start valve problem, actually I added a diode to the fuel pump relay to energize the valve during starting which is what the FPR does anyway, and resolder the FPR.
5. Replace the O2 sensor but I cannot get a reading from it. I think a four wire would be better.
6. Clean the interior since it was really dirty.

wbain5280 · #10 04-25-2007, 01:03 AM

On Tuesday, I received a new dist cap, rotor and plug wires. I also got a door check strap device which is going into my 300SE.

I'll post more pictures when everything is replaced.

jhodg5ck · #11 04-25-2007, 11:02 AM

FYI, I hope the door check is genuine..the aftermarket ones do Not hold up nearly as well.

Jonathan

wbain5280 · #12 04-25-2007, 12:51 PM

http://i19.photobucket.com/albums/b177/wb300se/MB_420SEL/DSC_0004-1.jpg

jhodg5ck · #13 04-25-2007, 01:22 PM

can't judge anything by that picture. I would need to see total stretch in degrees as well as the amount of polishing on the rollers.

Jonathan

TOPGUN · #14 04-26-2007, 12:58 AM

Question For Steve. What Happens If An Offset Key Was Used On Right Side Cam To Line Up The Mark To Have The Left Cam Line Up At The V Mark, The Balancer On The Big Zero And The Right Side Cam At The V Mark I Realize The Dial Indicator Is The Way To Do It The Real Right Way. All Guides Have Been Replaced, The Tension Rail And The Tensioner. The Chain Has 8 Deg Of Stretch. The Engine Has 100k And Is Extemely Clean. Thank You.

wbain5280 · #15 04-28-2007, 12:07 AM

OK, so now I have a big problem. I had the kids over last night and they were helping me replace the chain. The chain slipped on the driver side sprocket and I set the chain back one tooth. We continued feeding the chain in and the engine stopped turning. It's basically locked right now, so it seems. I'm going to find the tdc mark on the damper and measure the angle and the marks on the cams and note their positions. Maybe someone car rotate their engine to the same crank position and tell me the cam positions.

I'm going to play with it in the morning as well.