[krashnbyrn356]

My engine idles a little rough. When idling the rpms will drop to 500 but never below. Acceleration isn't affected and it runs smoothly. I replaced the spark plugs 3000 miles ago and found that there was a little bit of oil on them. It ran without a hiccup for a week then it went back to normal.

After doing some searching I found that the valve stem seals can cause oil on the plugs and rough idle. It has 160k on the clock and I have only had it for 30k or so. It has been doing it since I could remember but now I want to make sure it isn't something serious.

Here is what I am replacing/cleaning tomorrow:

-Distributor Caps
-Distributor Rotors
-Fuel Filter
-Cleaning Throttle Body
-Fuel System Cleansing

Hopefully that will cure it but if it doesn't, how many labor hours does it take to do this job on an 8 cylinder? I don't have the skills or the tools to do such a job so this one will be sent to the indy.

Thanks!

-Daniel

 

[deanyel]

Your research uncovered problems with 400E valve stems seals, or some other model? Are you sure it's not just oil in the spark plug wells - which would point to leaking donuts on the valve covers, a much easier job.

 

[krashnbyrn356]

It was mostly on the m104 but my car is having the same issues presented in those threads. Since it is a V8 I don't know how much the configuration differs when it comes to seal replacement.

Hopefully it is something easy like the covers, but I haven't been able to look at them yet.

 

[tuttebenne]

It was mostly on the m104 but my car is having the same issues presented in those threads. Since it is a V8 I don't know how much the configuration differs when it comes to seal replacement.

Hopefully it is something easy like the covers, but I haven't been able to look at them yet.

M104 and M103 valve stem/seal failure is usually a result of the motor having to rev to 3,000 rpm to keep up with all the other cars that are running 2200 RPM. I doubt this is the issue with your M119 because they aren't as highly stressed as the I6 is. Look for other causes. How long after an oil change do you have to add oil?

 

[krashnbyrn356]

I use synthetic and I've never had to add oil. Once I ran the car 12000 miles between oil changes and never had a problem. Only when I changed the spark plugs I noticed there was oil where there shouldn't be.

 

[edcarls]

I use synthetic and I've never had to add oil. Once I ran the car 12000 miles between oil changes and never had a problem. Only when I changed the spark plugs I noticed there was oil where there shouldn't be.

If you didn't need to add oil in 12000 miles, valve seals should be OK. Oil in you spark plugs is due to faulty valve cover gasket. To check, clean the surrounding area of your spark plugs using highly absorbent rag or paper towel. Then, remove your spark plugs. The porcelain part may be oily but the thread and tip of the spark plug should not be oily.

 

[sdoherty]

M104 and M103 valve stem/seal failure is usually a result of the motor having to rev to 3,000 rpm to keep up with all the other cars that are running 2200 RPM. I doubt this is the issue with your M119 because they aren't as highly stressed as the I6 is. Look for other causes. How long after an oil change do you have to add oil?

My M119 runs at 3K RPM at 65MPH so it IS as stressed as the L6 engines...

 

[deanyel]

I think it's a generational thing - neither the 104 or 119 motors seem to be prone to the problem.

 

[scratcher]

sdoherty,

How sad are we (me included) that we know exactly how many rpm our engines are turning at any given speed.

Next year, as soon as I finish some projects, I'm gona get a life.

 

[tuttebenne]

My M119 runs at 3K RPM at 65MPH so it IS as stressed as the L6 engines...

Yes that's right the 500E doesn't have the same diff ratio as the 400e; sorry.

 

[samiam44]

RPM isn't a factor...

Design- M103's have more problems that M104's -primarly due to valve weight.
Age
Heat

Age and heat destroy seals with time. Ideal perfect clearanced valve/guide needs no seal.
It's sucked down the intake stem seal, and burnt in the engine. Bluish smoke at idle would be a first sign (possibly). Oil sparkplug would have to come from outside (leaky valve cover) or you've got something major going on. I've seen cars with lots of miles, burning quart/400 miles which had clean plugs.

M

 

[Bruce24]

i changed my valve seals on m103 engine very simple job and it was do to previous owners using 0-30W penzoil .Seals are cheap but if you take it to mechanic i am sure he will charge you good

 

[samiam44]

Bruce24,

M119 with variable cam-timing is going to be much harder than a 103.


M