73 450 SE for sale, parts, or valve job? - PeachParts Mercedes-Benz Forum

homeagri · #1 02-10-2006, 11:48 AM

I have been a proud owner of a 73 450 Se for close to ten years.I have done quite a bit of work its in pretty good shape. I think it needs a valve job . Number 5 cylinder is showing about 60 psi. Its running rough. I described the situation to my mechanic he says it sounds like a valve job at the tune of 4,000. I am going to school and run a homelss shelter for seniors and dont make much money . I live in san Bernardino County in California. I have a rebuilt Volvo someone donated to our charity that we could give to someone who could help us fix the 450 or if someone could offer advice we would appreciate it.
Jim

Tomguy · #2 02-10-2006, 12:08 PM

Was a leakdown test done to confirm it's a valve, not rings? Have the valve clearances been adjusted recently? If not, they might be too tight, keeping the valve open during compression (This car has mechanical studs, not hydraulic). It could be a simple adjustment, or it might need a huge rebuild. Remember, sodium-filled valves can NOT be ground, they must be replaced.

ctaylor738 · #3 02-10-2006, 01:35 PM

Get another quote!

To fix one side, you should be looking at about 12 hours labor and about $450 in machine shop charges which would be $1650. For both sides, add 5 hours ($500) and another $450. Then you need maybe $300 in parts and gaskets, for a total of $2900.

You could also throw on a used head ($200) on for $1500-1600.

homeagri · #4 02-10-2006, 03:42 PM

Thanks for the input no leak down tests were perfomed . i know very little about mechanics. Can nayone help refer me to where I can get precise directions on adjusting the valves? i have a strong suspicion the problem is there. I had someone adjust them and the car seemed to run worst after he was through. I tried to adjust them again but I am unsure where the position of the lobe must be to get an accurate reading. Thanks for the help what a great site.

homeagri · #5 02-10-2006, 03:46 PM

Whats involved in a leakdown test? Does it require special tools. I am maninly trying to see if the car is worth fixing or not to be honest. If it is I may attempt to do it as a long term restoration project or it may be something that i am capapble of fixing now.I am hopeful it is a valve adjustment but want to be sure what I am facing.

homeagri · #6 02-10-2006, 03:54 PM

I did put a little oil in the cylinder it was 10/30 its what I had it seemed to raise the pressure about ten pounds.

ctaylor738 · #7 02-10-2006, 06:37 PM

The tip/point of the cam should be pointing up to adjust the valve.

If you only got 10 psi additional with the oil, then it's not rings - the generally accepted standard is a 30% increase.

homeagri · #8 02-10-2006, 07:45 PM

Thanks Chuck I can now try to adjust the valves. I will do another pressure check afterwards to see if there is any improvement. Do you know what the pressure should be to be acceptable?

ctaylor738 · #9 02-10-2006, 07:48 PM

Anything over 120 would be good.

cth350 · #10 02-10-2006, 08:21 PM

And motors for these cars are dirt cheap. a used one from a a 280se 4.5, 450sl, 450slc or another 450se would work fine. -CTH

homeagri · #11 02-10-2006, 10:37 PM

I just looked at the valves the adjustment looked ok. The compression was zero in number 5. Doesnt look good.Any idea where I could get a good engine? The problem is do you know what your getting buying a used engine? Is it comparable when you consider the work involved in putting in another engine as opposed to rebuilding the heads?Thanks for the help guys.

ctaylor738 · #12 02-11-2006, 09:36 AM

There is not a lot of difference in the amount of work between an engine swap and a head job. The major difference is in the logistics of finding a hoist, getting the new engine picked up and delivered, and getting rid of the old one. Cylinder heads are smaller and more manageable. There is nothing tricky about either option - it's a lot of rather tedious work either way.

The condition and reliablity of a replacement engine will be directly related to its price. The ones that have a history or compression numbers or that you can actually test will be more than the ones that "ran when parked" two years ago. I would say that for $800-$1000 you can find one that is worth installing. Less than that is a crap shoot.

Given the age and value of your car and your financial circumstances, I vote for fixing only what is wrong. This is assuming that your engine has good oil pressure and that the compression on the other cylinders is good. Pull the head and have only the minimum amount done to it, like one new valve and seals. If you can do the labor (and you sound capable), then you should get out for $100 worth of gaskets and misc parts, and maybe $100 at the machine shop. If your head is trashed, find a used one probably for $100 and have the shop do the bare minimum maybe combining parts.

If you send me an email I wills send you a couple of sections off the CD that will give you an idea of what you are getting into wrt engine swap and head pulling.

Good luck and thanks for your services to the elderly and homeless.

homeagri · #13 02-11-2006, 11:59 AM

Chuck thanks again for helping.My email is homeagri@sisp.net if you want to send anything. The compression in number 6 cylinder is not great when cold its reading about 60 psi the number 7 has a helicoil in it that came out and I dont have an adapter to check it. The pressure in number 5 was zero yesterday when I checked.

I did remove the injector to that cylinder and had it checked by NAPA and they said it was ok. Do I have to run the car for awhile to get a more accurate reading or is is possible to drop compression without running the car after removing the injector?

It sounds like it makes sense to do as you suggest repair whats needed. I think the other head is ok but will check.Is it usual for the drivers side head to wear more than the passenger side?

Is it normal to have one side with low compression and the other ok? I think I was running a little lean for awhile can that be the cause of a bad valve? You mentioned that these valves used in this car is not repairable if the car has a number of bad valves I suspect it may be better to get a used head? Does the used head come with valves? Are the valves pricey?

When I remove dthe injector I noticed quite a bit of sand or grit around the injector but it turned out ok according to the NAPA people. I was wondering what the correleation is between a faulty injector and the possibility of it affecting the compression reading, can you answer that?

You made me laugh when you said that you think I am capable of doing the work. You have encoraged me to take on the task at hand. This forum and particularly you are providing a great benefit to your viewers.

From a personal level I would never have attempted this task without your support and guidance. I am not by any means a mechanic in any repsect. I am doing this because of not finding a commpetent mechanic thats affordable. I was taking it in a few omnths ago to a shop that specialized in Mercedes and BMW's. It broke down on the way to the shop. I had it towed.

It stayed in the shop 3 weeks . He finally said he had taken off the fuel pump and found it faulty. It was six hundree dollars he wanted for the pump plus another 140 to put in in. He said the new pump would mean more pressure in the fuel lines and would need to replace all the hoses another whatever. I decided to tow it 40 miles to the shelter where I also live.

I repqced the pump which I found for less that 400 . Probably could have gotten it cheaper. I repalced the filter at the same time and also most of the fuel line hoses. I thought maybe thats why it ran rough( maybe sucking in air ).
It still wouldnt start. I put a gallon of gas in it and it stsretd. I guess I just wasted that money for the pump. Thats when I decided to do it myself. I had a mechanic 120 miles away but wasnt too happy whn I thought I needed a valve adjustment and he never did it. Maybe that contributed to my compression reading so low. Thanks again. Jim

homeagri@sisp.net

Thanks for acknowleding my work. I just started the homeless shelter a few years ago. I have and still run programs for abused kids. What you are doing hepling me is also helpinh those who I serve. I am miles from nowhere in the high desert. Its tough without a car.

ctaylor738 · #14 02-11-2006, 08:41 PM

I did remove the injector to that cylinder and had it checked by NAPA and they said it was ok. Do I have to run the car for awhile to get a more accurate reading or is is possible to drop compression without running the car after removing the injector? I WOULD SAY IF WE ARE DEALING WITH READINGS OF 0 AND 50, THEN RUNNING THE CAR WILL NOT MAKE ANY DIFFERENCE.

It sounds like it makes sense to do as you suggest repair whats needed. I think the other head is ok but will check.Is it usual for the drivers side head to wear more than the passenger side?NOT THAT I HAVE OBSERVED, BUT THE GUYS MAY WANT TO COMMENT.

Is it normal to have one side with low compression and the other ok? I think I was running a little lean for awhile can that be the cause of a bad valve? POSSIBLE - LEAN MEANS HIGH COMBUSTION CHAMBER TEMPS WHICH COULD BURN THE VALVES. You mentioned that these valves used in this car is not repairable if the car has a number of bad valves I suspect it may be better to get a used head? Does the used head come with valves? Are the valves pricey? EXHUAST VALVES ARE $42 AND INTAKES $28. USED HEADS COME WITH VALVES, BUT ALL THAT IS GUARANTEED IS THE HEADS

When I remove dthe injector I noticed quite a bit of sand or grit around the injector but it turned out ok according to the NAPA people. I was wondering what the correleation is between a faulty injector and the possibility of it affecting the compression reading, can you answer that? NO RELATIONSHIP SO FAR AS I KNOW.

You made me laugh when you said that you think I am capable of doing the work. You have encoraged me to take on the task at hand. This forum and particularly you are providing a great benefit to your viewers.

homeagri · #15 02-11-2006, 09:15 PM

Thanks Chuck
I guess it makes sense to repair the head i have. I thought it made sense to take it to NAPA to do the resurfacing of the head, and do they put the valves back in by machine or is that something I would do? Replacing the valve would that be part of the resurfacing of the head or is that additional labor? I understand the valves would be extra.

Does anyone know where to find the valves and gaskets? i live in the boonies and not a lot of parts available here. Do the guides usually go with the valve fries?