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  #1  
Old 01-12-2010, 09:18 PM
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low compression

Well,
I finally got around to working on my 77 that will not start. and has a large oil leak in the rear seal.
Took a compression test. here are the results...
#1 120
#2 140
#3 100
#4 140
#5 140
I am assuming that it will not start due to the low compression, As I get ready to pull the engine anything else I should watch out for?
Also is it also easier to pull the engine and trans on this same as the one on my 83 300sd? Or separate?
Thanks
Doug

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  #2  
Old 01-12-2010, 09:31 PM
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Try soaking each cylinder with marvel mystery oil for a week. Keep them full.

I know people that have drastically improved compression numbers by doing that.

Was the car ever run on veggy?
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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #3  
Old 01-12-2010, 09:31 PM
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Ouch. My gasser has more compression than that. Assuming you've already checked the valve lash and the car hasn't been vegged, I'm thinking that motor is toast.

I would pull the engine and trans as a unit. I think it's a little easier that way.
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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 362,xxx miles
08 Triumph Street Triple 30,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
88 Jaguar XJS V12 92,xxx miles. I should be in the garage now.
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  #4  
Old 01-12-2010, 10:13 PM
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Quote:
Originally Posted by 79Mercy View Post
Try soaking each cylinder with marvel mystery oil for a week. Keep them full.

I know people that have drastically improved compression numbers by doing that.

Was the car ever run on veggy?
Worth a try.
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..I also have a 427 Cobra replica with an aluminum chassis.
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  #5  
Old 01-12-2010, 11:55 PM
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When you are done be sure to turn the Engine over without the Injectors or Glow plugs and blow out any extra oil; to rule out any possibility of a hydraulic lock.

I did the Marvel Mystrey Oil TX on my Volvo and it cured the Hazy Gray Smoke that I had been gettng at all speeds. And, I actually did not expect it to work but tried it because it did not cost much t do so.
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Old 01-13-2010, 01:31 AM
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I know it was ran on WVO by the PO as a Sr. project in school.
But it ran when I got it, and it just got worse. Would WVO cause that? I have not ran it on WVO, Actually removed the items.
I can not work on it till Monday, so the MMO soak might be worth a try. Still have to pull it due to the leaking seal.
I have a turbo engine, that I could put in it, but the throttle is different, or I guess I could just remove the turbo. I was surprised how low the compression was.
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  #7  
Old 01-13-2010, 02:20 AM
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MMO soak worked for an old veg 617 I had on the shelf, turns out that the motor ended up having a bad bore. But it does help to loosen stuck rings.
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  #8  
Old 01-13-2010, 02:31 AM
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I have a 93 300sd with 215,000 miles on it and it has oil consumption issues.I have been told by several people on here that this particular engine is referred to as a rod bender. While I have no doubts about that I wonder if the MMO soak would be worth a try,have not checked the compression but do not have any hard starting issues either.It does idle a little rough though but runs smoothly under a load or at cruising speeds.
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  #9  
Old 01-13-2010, 03:18 PM
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Quote:
Originally Posted by didntdoit View Post
I have a 93 300sd with 215,000 miles on it and it has oil consumption issues.I have been told by several people on here that this particular engine is referred to as a rod bender. While I have no doubts about that I wonder if the MMO soak would be worth a try,have not checked the compression but do not have any hard starting issues either.It does idle a little rough though but runs smoothly under a load or at cruising speeds.

It might help if you believe you have stuck rings due to carbon or other build up.
Remember we are speaking of pouring it into the cylinder. No one is recommending putting it in the Crankcas Oil.
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Old 01-13-2010, 03:21 PM
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Quote:
Originally Posted by blackestate View Post
I know it was ran on WVO by the PO as a Sr. project in school.
But it ran when I got it, and it just got worse. Would WVO cause that? I have not ran it on WVO, Actually removed the items.
I can not work on it till Monday, so the MMO soak might be worth a try. Still have to pull it due to the leaking seal.
I have a turbo engine, that I could put in it, but the throttle is different, or I guess I could just remove the turbo. I was surprised how low the compression was.
I came across this article concerning using vegatable Oil as fuel.
As the article progresses the speak of the chemical reasons why vegatable Oil causes problems.
Operational test of Elsbett system.
http://www.ncat.org/special/oilseeds_innovations4.php
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  #11  
Old 01-13-2010, 03:22 PM
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didntdoit-It sounds like your rods haven't bent appreciably yet. You may be one of the lucky ones who drives many miles in a rod bender that never bends a rod. Your rough idle could be dirty or worn injectors. Try a diesel purge or run a tank or two of B20 and see if that helps.
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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 362,xxx miles
08 Triumph Street Triple 30,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
88 Jaguar XJS V12 92,xxx miles. I should be in the garage now.
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  #12  
Old 01-13-2010, 04:14 PM
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I have seen MMO help engines that have never been run on veggy oil too. If the car was driven very slow all the time over the years carbon will cause the rings to stick, and lower your compression. MMO is worth a shot.

Im going to soak all the cylinders in my 76 300D because its kinda smokey when cold.
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1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #13  
Old 01-13-2010, 04:22 PM
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Do a leak down test. Harbor Freight sells them cheap which should work well enough for infrequent use. At least you can confirm where it is leaking.
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  #14  
Old 01-13-2010, 04:55 PM
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I believe this is what you are talking about?
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=94190
It only comes with adapters for spark plugs. Or is there another one?
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  #15  
Old 01-13-2010, 11:51 PM
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If you just want to hear were it might be leaking from you can just connect you pressurized air to one of the Compression tester adapters.

With either the Leak Back Tester or just hooking up and Air Hose you would need a water seperator in your Air Line Circuit.

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