Alfa Romeo Forums banner

81 - 100 of 131 Posts

·
Registered
Joined
·
3,927 Posts
Discussion Starter #81 (Edited)
For the last three years I have had to adjust my idle up each year because it was dropping and causing a rough idle.

After the carbon removal treatments these last couple weeks i will need to lower it to where it was years ago.

In hind sight that was giving me a warning.
 

·
Registered
Joined
·
11,657 Posts
Is it normal for these old Nord engines to build up carbon like that?

When I replaced the head gasket on my Simca 1000 (that I had taken over from my sister) I was ~18 years old and once warm that engine was constantly hammered. It was as clean as a whistle inside ... no carbon anywhere. This was not a rebuilt engine that had just blown a head gasket but an old engine that I proceeded to thrash and rev often to 7000 rpm (even put a rev counter in it). And yes back then I'm not joking when I say I used to hammer it all the time. Poor thing, but it never gave any trouble. My Sud race engine didn't build up carbon either, but that was a race only engine and heck you are doing something wrong being on a race track if your engine is building carbon.

So I wonder, is it the old design, or as you say too much oil in the sump OR when you say hard for 200 miles you are like the 50 year old version of myself and hard is now soft (yeah I'm talking about our use of engines ... ;))?. I have only once since my racing days finished really lent on an engine and that was because I was late for what I thought was an important business meeting, but even that was for less than 1 hour so only a few miles. And as it was public roads and I was not 18 any more it was not that hard on the engine ... the 156v6 is lucky if I pull peek revs in 2 consecutive gears, that's not hard IMO.

Would be interesting to do say 5 proper laps of a race track and peek down the plug hole again ... ??
Pete
 

·
Registered
Joined
·
3,927 Posts
Discussion Starter #83 (Edited)
The track would do it!

Maybe the windex spray bottle water injection would be worth while thing to have?

I do need to describe how I was driving, what lead the to this problem and how I plan to drive from now on.

For the last 10 years I would take the Alfa to a hwy out of town and would cruise at 65 mph which is around 3,500 rpm for 30 to 40 miles and turn around and come back home, for a total of 60 to 80 miles per round trip.

Around town I would keep it around 3,500 rpms too. I was thinking that 3,500 rpm's would be enough to keep carbon from building up.

Well that and Techron ever other tank didn't do it. Carbon continued to build up!

Going to do the interstate freeways more now.

Now with the interstate speed limit at 75 mph and everyone driving at 80 mph - 85 mph I can get my cruising rpm's up to 4,400 to 4,700 rpms and the on ramps allow me to do full throttle 2nd and 3rd runs.

Game plan is to keep the rpm's between 3,800 and 4,400 rpm for street, hwy and interstates freeways.
 

·
Premium Member
Joined
·
3,878 Posts
Filling the oil up to the fill mark is just going to burn off the oil until its between the top and bottom mark on the dipstick. When you change your oil just put 7 quarts in it. Should bring it up to around middle between the marks. When it gets to the low mark add a quart. Anymore then that is over filling it.

Durning this week I plan to set the # 3 piston to the top of its compression stroke and fill it full to the brim, and top it off as needed for a day.

I also bought a leak down kit, compressor and a compression gauge so I can do the leak down and compression tests myself through this next year to watch for improvements.

You can use your leak down tester to force the fluid past the pistons to help get the mixture around the rings.

Last but not least you need to drive the snot out of it every once in awhile. Take it out and run it up the the redline every shift. It really will keep it cleaned out. Theres a reason its called the Italian tune up.
 

·
Richard Jemison
Joined
·
7,081 Posts
Stuff

I don`t recall the year of your Spider, Is it a late L-Jet or Motronic?
I ask only because the L-jet fuel pressure regulator is a 2.5 bar and the Motronic`s is a 3 bar. With L-Jet 4 cyl engines using the Mortonic`s 3 bar regulator improves fueling at higher RPM particularly with better cams.

Somewhere in the past there was a post on compressing the stock regulators to increase output pressure (increasing the spring tension)

I would suggest if you are continuing the MEK treatment (It`s the working chemical in Techron/Seafoam/and my choice of fuel additives, Berryman Chemtool. (My Porsche loved it, but I got over the Porsche stuff as I was not a big enough ********* to fit in with that bunch) that you put the pistons at mid stroke and fill the rest of the cylinders with MEK so a long soaking as it weeps past the rings have a better soaking effect. then change the oil (Shell Rotella T 15-40 non synthetic (diesel oil has more detergents/and additives to keep particulates in suspension as well as more zink)

Then after a good warm up run the car in 4th gear at about 5000-6000 RPM for 5 miles.

That heat load will clean the carbon.

Then pull the exh spring on the leaky one and replace the seal. If there`s not one pull them all and install them. (the Green Viton Reintz seals) If the builder used non stock guides with no provision for seals use the GM "umbrella" seals but cut the skirts a bit shorter.
 

·
Premium Member
Joined
·
13,094 Posts
For anyone who wants to see how MEK works, put a set of used spark plugs in a jar, pour in MEK and let them soak for 24 hours. Most of the deposits will have moved from the plugs and into the MEK.
 

·
Registered
Joined
·
3,927 Posts
Discussion Starter #87 (Edited)
Filling the oil up to the fill mark is just going to burn off the oil until its between the top and bottom mark on the dipstick. When you change your oil just put 7 quarts in it. Should bring it up to around middle between the marks. When it gets to the low mark add a quart. Anymore then that is over filling it.

You can use your leak down tester to force the fluid past the pistons to help get the mixture around the rings.

Last but not least you need to drive the snot out of it every once in awhile. Take it out and run it up the the redline every shift. It really will keep it cleaned out. Theres a reason its called the Italian tune up.
So I was way off, I said I was overfilling by a 1/2 quart when actually I was over filling the oil by 1 quart! With the high oil consumption in the over fill quart I bet my mileage per quart will improve?

Good idea on using the leak down tester to flush the rings out
durning the clean out, tried it today but no matter if I was TDC or short of it, anywhere in the compression stroke, when I hooked the cylinder to the leak down gauge set 100 psi it would rotated the piston to BDC, every time.

What am I doing wrong?

Thanks for the help!

I don`t recall the year of your Spider, Is it a late L-Jet or Motronic?
I ask only because the L-jet fuel pressure regulator is a 2.5 bar and the Motronic`s is a 3 bar. With L-Jet 4 cyl engines using the Mortonic`s 3 bar regulator improves fueling at higher RPM particularly with better cams.

Somewhere in the past there was a post on compressing the stock regulators to increase output pressure (increasing the spring tension)

I would suggest if you are continuing the MEK treatment (It`s the working chemical in Techron/Seafoam/and my choice of fuel additives, Berryman Chemtool. (My Porsche loved it, but I got over the Porsche stuff as I was not a big enough ********* to fit in with that bunch) that you put the pistons at mid stroke and fill the rest of the cylinders with MEK so a long soaking as it weeps past the rings have a better soaking effect. then change the oil (Shell Rotella T 15-40 non synthetic (diesel oil has more detergents/and additives to keep particulates in suspension as well as more zink)

Then after a good warm up run the car in 4th gear at about 5000-6000 RPM for 5 miles.

That heat load will clean the carbon.

Then pull the exh spring on the leaky one and replace the seal. If there`s not one pull them all and install them. (the Green Viton Reintz seals) If the builder used non stock guides with no provision for seals use the GM "umbrella" seals but cut the skirts a bit shorter.
It's a motronic engine and I'm running an aftermarket adjustable fuel pressure regulator.

I will be continuing the MEK treatment, I am waiting on another shipment of MEK and as soon as it comes in I will try what you suggested. When the last 4 days of cylinder soaking I'll change the oil to Rotella.

Trying to figure out what speed 5,000 - 6,000 rpm's in 4th would be in mph. I pulled my 4.10 differential and installed a shorter ratio differential from an earlier Spider, want to say a 3.86 but not sure?

Steve couldn't remember if he put seals in or not, he said he thought he did, so who knows.

Thanks for the help.
 

·
Registered
Joined
·
3,927 Posts
Discussion Starter #90
I would suggest if you are continuing the MEK treatment that you put the pistons at mid stroke and fill the rest of the cylinders with MEK so a long soaking as it weeps past the rings have a better soaking effect. then change the oil.
What would be the max time you would leave the MEK in?
 

·
Registered
Joined
·
3,927 Posts
Discussion Starter #91
Update

Well I master finding TDC and working the leak down gauge today.

The leak down gauge I have is going back to Napa because the fine tune regulator on it is non functional. But it works good for enough to flush the cylinders. The replacement one should be in tomorrow.

Even though the gauge regulator doesn't work I was able to adjust the compressor's requlator to maintain a steady 100 psi long enough to take some cold readings to compare with the warm readings I have from the shop that did it back on 11/27.

...Cold Engine (today).........Warm Engine (11/27)
# 1 - 9% Loss (rings)....................9% Loss (combination)
# 2 - 20% Loss (rings)..................25% Loss (rings/intake)
# 3 - 10% Loss (rings)..................20% Loss (rings/intake)
# 4 - 55% Loss (intake)................70% Loss (rings/intake)

An improvement, and is showing me where I need to concentrate.

I can see the # 4 intake valve carbon, it's build up on the back side of the valves edge and on the stem. I feel if I can get that off I will get better leak down numbers on that cylinder. I'm hoping that it's just not sitting down in the seat completely and is not bent? There are no impact marks on the piston or valve bottom to point to impact.

My plan is to flood the # 4 intake track enough to cover the back side of the valve and as much of the stem as possible when filling the cylinder, when the new MEK comes in.
 

Attachments

·
Registered
Joined
·
5,269 Posts
I had one just like a few years back. Didn’t know the MEK trick so i pulled the head , cleaned it up, lapped the valves, checked guides etc and installed seals on intake side. Total cost was one head gasket and 4 green valve seals and about 25 hours labor. Took 6 weeks as I recall!
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
To be honest Murray, I think all this cleaning/de-carbonizing is a moot exercise since it is addressing a symptom, not the cause. Descriptions, testing and photographic evidence show oil cascading down the walls of at least two cylinders clearly indicating piston ring and/or cylinder wall issues. This engine IMO needs to come out and be disassembled.
Any oil visible on the valves is originating from the bottom end and therefore is a symptom so I'd pay the head no mind as a contributing factor.
 

·
Premium Member
Joined
·
13,094 Posts
I think that the objective of the MEK treatment is to dissolve gum on the rings and in the ring grooves. That could be the problem.
 

·
Richard Jemison
Joined
·
7,081 Posts
MEK /Oil from rings

The MEK will seep through the rings with enough time. After 24 Hours it should be in the pan. Spraying it through the intake and turning the engine over with the spark plufs in using the starter the starter won`t hurt either BUT REMOVE THE SPARK PLUG WIRES!!

Any oil visible on the valves is originating from the bottom end and therefore is a symptom so I'd pay the head no mind as a contributing factor.
I can assure you oil coming past the valves DID NOT come from the rings.

I don`t think a re-build is necessary. Stopping oil leakage from the valve seals or lack of needs to be addressed. With the factory spring compressor this can be done in the car.

If you are dependent on a mechanic to do this I understand, but if you can do it yourself, and need to borrow a factory spring compressor send me a PM. (this offer IS NOT open to everyone!)
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
I think that the objective of the MEK treatment is to dissolve gum on the rings and in the ring grooves.
Yes, that's the objective of the MEK; to dissolve any gum/carbon that might be in the rings/grooves. It's currently an unknown if there is any.
But the MEK procedure is not doing a thing to fix the root cause of why only 2 cylinders, on an engine with only 10k miles, are carboned up in the first place.
 

·
Premium Member
Joined
·
13,094 Posts
The root could be oil from the valve guides which caused the conditions which led to carbon build up and gumming.

This motor is a lot like a race motor and it was built by an esteemed race engine builder. It is possible that it has no seals on the exhaust valves. It must have very high lift cams to make over 200 HP at over 7000 rpm and it is possible that one or more of the intake valve seals have been damaged or dislodged.

There is little downside to what Murray is doing and the upside is that he might avoid an expensive rebuild.
 
81 - 100 of 131 Posts
Top