spark plug hole too loose

[mr benz]

I have a 190e 2.3 1987, i tried to give my car a tune up.
i made the mistake of overtightening the spark plug thus messing up the threading. the spark plug is so loose that when i started it it flew out the engine and the car has no compression, what shud i do? to get another spark plug to fitt or do i have to get another head, and what is the price?

You will need to take out the cylinder head, and install a Helicoil in the spark plug hole. If you do it yourself make sure you drill absolutely straight through the hole during the process.

[Jim Anderson]

You may not have to take the head off but you'd have to be careful of the metal shavings. Besides they are just aluminum and I don't think they could do to much damage.

[mr benz]

I was able to install a helicoil, i wasn't able to take off the head. i thought everything was ok after i installed the insert with the new spark plug. It seemed like everything fitted tight and snug without me takin the head off. so the i proceeded to let the sealant cure from a job that seemed well done.
but 2 hrs later when i went to start the car it , was shaking voilently. clould it be because the car need to rebulid compression.
why why was it shakin and stalling out so much?
I did drive it for like two minutes inially when the no#1 spark plug flew out the cylinder head could that have something to do with it.?
I also smell gas. Is that a bad sign?.

I do not see how you could possibly drill the hole without having aluminum shavings falling into the combustion chamber. that is why I suggested taking out the head. Even one very small shaving could possibly do two things. First it could get stuck between the valve seat and the valve head and not allow the valve to close completely. This could leave the valve protruding out of its position and consequently getting hit by the upward movement of the piston resulting in more damage. Secondly it could simply short out the spark plug which would mean no spark and consequent engine vibration. Lets hope that this is what happened. Also if that is what happened then the air/fuel mixture would not ignite but instead would pass out from the exhaust unburned hence the smell of gasoline (by the way, unburned gasoline passing through the cat will eventually damage it). I suggest you take the spark plug out and check it. If it is fine then go ahead and do a compression check on the engine.
Another very gross backyard mechanic way to clean any shavings from the combustion chamber would be to remove all the plugs (which you would be doing for a compression check anyway) and crank the engine to hopefully spit out any shavings if they are still there and loose (doubtful).

One thing I did not understand from your second posting is that the #1 plug got thrown out. Is this the plug you fixed with the helicoil, or is it another plug?

Also, the smell of gas can simply be a result of the fuel mixture coming out of the #1 combustion chamber since there is no spark plug.

[Silver Boat]

Could the sealant that comes with the heli-coil insulate the spark plug? I have heard of others using them for plugs so I would not think this was the problem. I agree that it would be much better to take the head off before doing the drilling. I do not think a valve would be down enough to be hit by the piston if there was a shaving from the drilling. It would have to be a big chunk. Have you pulled the plug out? how does it look? If you disconnect the plug wire from that plug does it change the way it runs? If so it is not getting spark or a good seal somewhere. Could you be getting blowby past the heli-coil?

Good luck

[mr benz]

could,it be that the sealant is really insulatin the plug too much and causing it to produce less spark.
I wonder.
anyway i did speak to few mechanics and i dont trust em but they are telling me i may have damaged the cylinder and may have to have it machined.
i mean they wanna do a whole new valve job on my car.
what do u think.I mean my car had 200,000 plus miles but it ran darn good.

I was also wondering, do u think i n my car will ever run the same after this, and do u think i shud get a valve job anyway.

Thanks
help.

[DALE DORIA]

From reading your postings and your progressive questions, it appears that you are in over your head. If not, then you would not have as many questions as you do. Perhaps it IS time to call in a professional........someone who will warrenty the work and get your car back on the road again.....Good Luck !

[mr benz]

yep i just had it towed to the shop. i hope they can solve this problem quickly.
On a car like that do thinkk i shud jus go ahead and get thevalve seals and every thing replaced. it has over 200,000 mile on it.

[Silver Boat]

It depends on how much you love the car. Kelly's Blue Book gives it a value of about 2400 in fair shape with the head repaired. Keep this in mind as this is what you should expect to get for it once repaired. For some reason some people seem to buy these cars for far more than they are worth. Add on to that above average maintenance expect there is no wonder they get a reputation for being a money hog. For me i would not have the head on my Mercedes done professionally (would likely do it myself) as I would never see a return on the money, and while I like the car I do not love it. My Miata I would do it in a hart beat even though I would never see the money out of it. So it is a combination of what the car is worth and how much you LOVE it. You might want to consider just finding another one with fewer miles and see if one of the mechanics wants to give you some money for the car. If your car had no other problems then you might want to repair it.

Just some things to keep in mind.

[Silver Boat]

It depends on how much you love the car. Kelly's Blue Book gives it a value of about 2400 in fair shape with the head repaired. Keep this in mind as this is what you should expect to get for it once repaired. For some reason some people seem to buy these cars for far more than they are worth. Add on to that above average maintenance expect there is no wonder they get a reputation for being a money hog. For me i would not have the head on my Mercedes done professionally (would likely do it myself) as I would never see a return on the money, and while I like the car I do not love it. My Miata I would do it in a hart beat even though I would never see the money out of it. So it is a combination of what the car is worth and how much you LOVE it. You might want to consider just finding another one with fewer miles and see if one of the mechanics wants to give you some money for the car. If your car had no other problems then you might want to repair it.

Just some things to keep in mind.

[mr benz]

the mechanic suggested that if the cylinder is damaged it wud cost almost the same to get a whole new motor as it wud to get the head serviced,and that it may be worth while just investin in another motor instead.He said that he would be able to get me a used low mile motor a 90 or 91 to go into that car. ill get more use out of tyhe car plus a more powerful engine . what do u think?