Finished! - PeachParts Mercedes-Benz Forum

#1 12-18-2003, 03:40 PM

Well we just finished my project two days ago. It was a long story. Here it is:

I just purchased a 1972 280SEL 4.5L that was smoking bad at start-up and when it was given a hard acceleration. We believed that this was a valve seal problem. When we started to take the engine apart, we realized that it was cylinders 3 and 4 that were fouling plugs pretty often. Cylinder 3 even had an extension on it. The car was also losing about a quart/1000 miles. I know that this isn't THAT bad, but I still wanted to fix it. We we were getting ready to do this "valve seal" job, we thought that it would take a day, MAYBE two, but boy were we wrong. We didn't know that we needed a special valve spring compressor for this car, because we did not know that it had overhead cams. We had no trouble replacing the intake valve seals, but the exhaust were getting to be a problem because you could not compress them very far with the tool that we made. We then called a mechanic. He came over with a special tool and took off all of the rockers and springs right away, as we were only taking off as we were working on them. He started to replace a couple of seals, while saying that he thought a valve guide would be bad on cylinder 3. Well, he was correct. He just pulled the valve guide out with two fingers. That is not good. So we had to wait for the new valve guide. I went ahead and bought a single oversize one. This was supposed to be 10 thousandths over, but when we tried to get it in we got it stuck. We then started to take the head off. After we got the intake manifold off and took all the bolts out of the exhaust manifold, the same mechanic called and said that he might have a way to get the valve guide out. He came over and sure enough, he got it out. Then we put an original sized valve guide in. Then back together everything went. Well I went ahaed and replaced just about every gasket and hose that even looked somewhat bad. I cleaned up the intake manifold, the valve covers, and the air box in some parts cleaner. Then, we were ready to put the spark plugs in and fire it up to make sure that the oil was getting to the camshaft correctly, since we replaced the cam oiler clips that break VERY easily. Well, we got all of the spark plugs in besides the one on cylinder one. It just would not go in correctly. We then went ahead and bought a tap and tried to use this to clean out the threads, but that did not get us any farther. The spark plug would only go in a little bit and would then get very hard to turn. Once again I called up the mechanic, and once again he had a special homemade tool that he put in the spark plug hole, and when he took it out, the spark plug went right in. While he was there, he helped me fix a gas gauge problem by sottering ( do not know how to spell that). Then we put on the plug wires, which we marked with black electrical tape so we would know which spark plug they went on. We fired it up and there was no smoke, and she sounded beautiful. We then took te plug wires off so that we could put the valve covers and the air box back on. Well, after this was finished, we put the plug wires back on. We then started it up for a test drive. Well as soon as we started it, we noticed thatthe engine was sort of pulsing. Well, when we took it around the block, it would not go over 40 and took about 30 seconds to get there. We then went back and checked the plug wires on the driver's side and the ones on cylinders 3 and 4 were mixed up. When we marked them, we put 0,1,2, and 3pieces of tape on them. My friend, David (WANT '71 280SEL), put in the last two on this side. When he saw the three pieces of tape, he just assumed that it went on cylinder 3, and he just put the last one left on cylinder 4. Well we switched them back to normal and fired the car up again. It sounded much better. We then left the garage we were working at so that we could go eat at this restaurant that closed in 30 minutes. David has a 1979 300SD TurboDiesel, and we decided to race at this one light just for fun on the way over there. He beat me. I knew something was still not right because my car should have killed him since we started from a stand still. Well, it was getting late so we decided to just eat and check it out later. When we went outside to leave the restaurant, I asked him if he had a flash light in his car. He did. I said "Let's just check the plug wires on the other side to make sure that they are correct. Well, cylinder 5 had no tape, cylinder 6 had one piece, but cylinder 7 had three, and cylinder 8 had 2! He had done the same on this side. Well, we switched them back to how they are supposed to be. We then raced at another light, with him driving my car, and me driving his. Well, when he hit the gas, the tires screeched and he murdered me while I was in the 300SD. She was finally back to normal. Well, I was happy. We could not belive that it still started with four plug wires mixed up! That was a miracle. Well last night, I took a road trip from Ft. Wayne, IN to Toledo, OH. She ran beautifully on the highway. The gas mileage was pretty good at around 17-18 mpg, and that is with a very dirty air filter on there. We did put this fuel injector cleaner/octane booster stuff in there that my uncle had recommended. The brand name is Lucas, and it come in a tall skinny 5 oz. plastic bottle. I recommend everyone use this at least twice a year. He said he uses it on his Harley all the time, and it makes the Harley run beautifully with improved gas mileage. Well that is the end of the story so far. We will have more to add later. I have to replace the window regulator, possibly the window motor, on the front passenger side window. I also have to get a new trunk seal and a new front windshield seal. There are some little spots on the bottom that are starting to rust, and I am going to spray the rubber spray on the whole bottom and in the wheel wells, since they salt her a lot. I am also going to put in a Kenwood CD player, 4 Kenwood 6" X 9" speakers, two old 10" Bazooka subwoofers (maybe), and a Bazooka amplifier. When I get this done, I am going to put an alarm on the car also, as vehicle break ins are pretty high in this city. I also need to fix the back seat. The bottom of it is sticking out, and when I push it back in, it just bounces out like the spring is holding it out. I will take some pictures and put them on here later. I am also waiting for the vacuum line that goes from the intake manifold to the brake booster. It is the one that has the check valve in it. If anyone has any questions about anything, please let me know.

Thanks for all of your help, especially David (WANT '71 280SEL)
Tim Bradfield

Tomguy · #2 12-18-2003, 04:46 PM

It's pretty good to hear that it turned out so well. You probably panicked quite a bit but now you realize what sucks us all into these beautiful autos. When they are taken care of, they are a pleasure to drive!

Good luck with future endeavors. May your wisdom gained someday pay dividends!

joshhol · #3 12-18-2003, 05:27 PM

Hopefully somewhat can expound on the replacement of valve guide with head in place. I bet that doesn't work on any but the loosest beat up guides.

I need to to a stem seal job as well. Did you remove the valve cone halves? Did you pump air into the cylinder to keep the valve up or just set that piston on TDC?

You didn't say anything about setting valve clearances, did you?

#4 12-18-2003, 05:49 PM

I don't know what you are talking about when you say cone halves. If you mean keepers, then yes, they have to come out. I would HIGHLY recommend finding someone with the overhead cam valve spring compressor. It is about two feet long with two arms on the bottom for grabbing onto the camshaft for leverage.
Tim

psfred · #5 12-18-2003, 10:05 PM

Tim:

Rear seat bottom cushion can pop out -- to get it back in, push rearward until the little hook goes back behind the crossmember and push down to hook it in place. It can be a pain to get back in sometimes. Rear seatback is held on by some nuts on the outside bottom corners and at the top inside the trunk with some nuts on the bolts attached to the seatback.

Fun car, eh?

Tim's W108 is chassis #7 of the SELs, a lovely silver with blue top (repainted) with MBTex navy interior in excellent shape. Even the wood is pretty good, floor shift. Makes me jealous!

Peter

#6 12-20-2003, 12:39 AM

Peter
Thank-you for the compliments. The top was not repainted, just the silver was. I will try the seat in the morning. It is very cold out and constantly snowing. This car does not handle well in the snow if the trunk is empty.

Tim

68greezr · #7 12-20-2003, 08:39 AM

great story,i use lucas as well good stuff.

psfred · #8 12-20-2003, 01:13 PM

No, the W108 isn't great in the snow with an empty trunk. Snow tires help a lot, so do something like Firestone Affinities. Not cheap, sadly, but you must have good M&S tires for this car -- way too much power.

You also need to learn to drive with a VERY light foot -- tons of torque available with very little throttle movement. I just barely crack it open, take some practice.

Peter

Renntag · #9 02-05-2011, 02:46 PM

Holy crap that first post was an Epic battle of Textual proportions.

I could imagine someone trying to read aloud with one breath.

JeffreyNMemphis · #10 02-05-2011, 04:32 PM

Tim,

Welcome to the Forum! Please join and keep coming back!!

We love pictures. Show us your car!

WANT '71 280SEL · #11 02-05-2011, 11:11 PM

Actually, that's just how it was archived. It wasn't actually written like that. I now have that car, and the smoking problem has, for the most part, returned. As for Tim's__Benz, well, he now lives in FL and drives a Charger.

Jeffrey, note that the original post was from 2003

Best Regards,

David

JeffreyNMemphis · #12 02-06-2011, 11:36 AM

Ahh... Are you ready to rebuild heads? Very likely that your valve guides are worn.

suginami · #13 02-06-2011, 12:26 PM

Quote:

Originally Posted by WANT '71 280SEL

I now have that car, and the smoking problem has, for the most part, returned. As for Tim's__Benz, well, he now lives in FL and drives a Charger.

Jeffrey, note that the original post was from 2003

Best Regards,

David

Your 4.5 has 450,000 miles? That's incredible.

What kind of engine work has been done?

WANT '71 280SEL · #14 02-07-2011, 01:44 AM

It had a head job done around 250k miles. I have all the service records and that was the only major thing done until recently when it got another new chain, rails, and tensioner. If you care for the 4.5, and to keep it really nice it will need the heads done every 200k miles or so, the bottom end will never break. I have 350k miles on my dd 450SEL with the exact same engine.

Best Regards,

David