timing issue

[merrill]

This is a frustrating issue.  I have been having timing issues with my 230 sl for a long time. I had another post called can't stop this pinging which is related.

Dr Dan has been helping me with this issue and even sent me an 051 distro to see if that would solve my timing and pinging issue.
Well, I have not resolved the pinging issue and the 051 has not resolved my timing issue.

As of this morning here is some data

At idle 860 rpm timing is 7 deg btdc
at 1500 rpm     timing is 20 deg btdc
never gets to 30 deg at 3000,

vacuum at throttle body using t fitting between tb and vacuum retard
14 - 17 in hg  stable. If I barely open the tb the vacuum drops quickly to 8 then to zero if I open it a little more.

when I disconnect the vacuum line to the distro at idle the timing goes from 7 btdc to 17 btdc about 10 deg swing.

also, when I pull a vacuum on the line from the tb to the vac retard unit on the distro I have no leaks. the vacuum is solid.

per the mb tech book the 230 sl with an 051 should be at 2 +/- 2 deg atdc then, 12-19 at 1500 rpm and 30 deg at 3000 rpm.

does this sound like a vacuum issue at th tb or a linkage issue?
or is this an issue with dialing in the vacuum retard unit at the distro?

I'd like to figure this out rather than buy a 123 distro that gernold recommended.

thanks in advance
matt

[Cees Klumper]

Just a few thoughts, 'for what they are worth':

(1) as far as I recall, the timing specs are without vacuum attached, meaning your idle reading, without vacuum attached, would be about 17 btdc instead of the factory spec of 2 +/- 2 deg atdc. Also meaning that if you distributor cannot advance by more than about 13 degrees, adjusting it to 2 +/- 2 deg atdc at idle without vacuum would yield 15 degrees at 3000 RPM rather than 30

(2) whichever the case may be on (1), why does your car ping when the advance is not close to what it should be according to the specs

(3) which leads me to think perhaps the timing indicated on your harmonic balancer is not correct (if there is such a possibility). May be worhtwhile to verify whether the '0' on the balancer in fact corresponds to the TDC on cylinder 1 (I think)

(4) the 123 ignition also needs the vacuum input to 'know what to do', so if that is in fact the problem (seems unlikely but still) fitting a 123 unit may not resolve the timing issue either

Since you have tried now with two different distributors, and the timing is still a problem, it would appear that the solution lies elsewhere?

[merrill]

cees,
thanks for the reply any input at this point is valued.

for (3) what are the chances metric motors installed the timing / harmonic balancer incorrectly?  wouldn't that put the motor 180 deg off?  

for (1) If I back off the timing at idle to say 5 deg btdc the timing never gets to 30 deg period. The timing advances to say 25 btdc max.

I have been playing around with the timing. If I set it at 30 deg at 3000 the timing at idle is somewhere around 10 degrees btdc.

my observation is the distro or timing swing is not enough.

with my other distro an 009 I would set the timing and when I checked it the timing had changed.  I could not get the 009 to keep its setting.


Waqas has been kind enough to let me swing by his place tomorrow and
1. observe the timing on his 230 sl at idle, 1500 and 3000
2. let me try the 051 from his other sl which is in the shop.

Thanks again for the input

[stickandrudderman]

Never assume anything!
I have seen several engines where the front damper has been incorrectly installed, in fact I sacked someone last month for doing it!
You must check that with No 1 piston at TDC (you can drop a long thin screwdriver through the plug hole, you don't need the accuracy of a DTI for your purposes) the zero mark lines up with the pointer.
If, as it seems from the information you've provided, you're not getting enough advance, then the timing isn't the source of your pinging, you must look elswhere.
Worn valve guides/seals can cause pinging, as can poor quality fuel.

[glennard]

Bring this puppy (as is) to PUB 2009.  You'll get at least 426 solutions!!  From personal experience--it does help to have the crank, cam, fuel pump, distributor, etc in sync.  Is this the same engine you have had problems with for a year or so from a Metric rebuild?

[merrill]

glennard,
yep, this is the same engine I have been working on for the past year.
Metric motors did the rebuild.

stickandrudderman
I will pull the #1 plug and check for tdc today.

thanks
matt

[glennard]

Check the cam, distributor, and pump while you're at it.  And the plug wires 153624(?).  In this age of 'diversity', it is 'fashionable' to rearrange any of these to your own personal preference for PC.

[Benz Dr.]

I set that distributor to run at factory specs. The mechanical part of the distributor will run aywhere from about 17 - 22 degrees. I then set the vacuum portion to give a total of 30 degrees advance. Only the vacuum portion is adjustable - the mechanical isn't although you can adjust the speed at which it does advance.

The pulley isn't installed wrong but the distributor drive gear probably is. To test this, turn the engine over by hand until both cam lobes are pointed up and the crank is at zero. Pull the distributor cap off and look to see if the rotor is pointing to number one spark plug wire on the cap. Number one is to the right of the clip that holds the cap on and also to the right of the tang that positions the cap.
If the rotor is pointed to the small notch on the top rim of the distributor everything is in time. If it's well past that point, either before or after, it's not positioned properly. Anything to much before will cause the distrbutor body to hit on the housing where the oiler cup sits and you will only be able to get somewhere around TDC at full advance ( at idle ). Too far, or one tooth too far and with a timming light you will be well back of TDC and somewhere near 20 degrees ATDC. The object is to be able to have enough swing on the distributor to adjust the timming while having your strobe light flash on the front pulley when and where it's puposed to.
If it's not in the right quadrant simply remove the distributor and turn the helical drive gear until the rotor points to number one position so that the cap and distributor are in sync.
 Move the distrbutor to see if you have the correct swing. If you do it will move well past the optimum position ( in either directio ) so that any setting you want will be available for fine tuning.

I set the timing pointer at the base of the distributor to the far right so that I can turn it back if needed withought using a timing light. The pointer at the distrbutor should always be set to full advance with the notion that it's the optimum setting using available fuel in your area. If you run 94 then set it to the full advance mark. If you have to go back to 91 then move it to the center position and move it back when you get better fuel. Later distributors don't have this pointer but there is some amount of adustment at the clamp by backing the screw out a small amount which will let the clamp move a few degrees.
 Never move your basic setting unless it's clear that you have a big timing problem. This adjustment is done on the back side of the distributor using the allen screw to undo the clamp. Always move it back ( retard ) if you hear pining.

[merrill]

ok, so I made some head way today
went over to visit Waqas to do some comparisons on our sls.

on his sl we found what I expected
idle - 850 rpm = zero deg
1500  about 15
30 deg at 3000

my distro
idle - 850 rpm - 7 deg btdc
1500 about 20 deg
27 deg at 3000

for fun, we remove the 051 Dr Dan sent me and installed the 051 from his Sl that is in the shop.  
started the car, set the base timing and viola!,  almost factory timing specs

idle - 850 - 2 btdc
1500 - about 15
30 at 3100 rpm

The issue has got to be the distro I have.

Thanks Waqas for your time and loaning me your 051

[merrill]

sorry, I forgot to add

I checked the tdc as well, pulled the valve cover, number 1 spark plug,
and distro cover

rotated motor till timing on dampner was at zero,rotor at number 1 hash and number 1 cam lobes both pointing up and out at about 10 and 2

I could see the top of the piston so I believe the motor is assembled correctly

[Cees Klumper]

quote:Originally posted by merrill

for fun, we remove the 051 Dr Dan sent me and installed the 051 from his Sl that is in the shop.  started the car, set the base timing and viola!,  almost factory timing specs

idle - 850 - 2 btdc
1500 - about 15
30 at 3100 rpm

The issue has got to be the distro I have.

In that case, I would spring for the 123 distributor ... it improved the running characteristics on my engine markedly.

[Benz Dr.]

Most distributors will reach full advance well before 3000 RPM which is the maximum amount that you should have before full advance. The place or spot where you reach full advance is determined by how quickly the fly weights open. The vacuum portion moves first and will advance the distributor on vacuum retard units within a few hundred RPM - it's very quick. You need this for off idle throttle response or the engine will stuble and fall flat. You also need very precise throttle linkage set up or you will get te same problem.
All of these numbers are simply numbers and are there as specs that were built into the car. It will still run well outside of these numbers as there is a certain amount plus or minus.

The cure for this is pretty simple. If you want more total advance you can remove the vacuum cell and turn the pull rod out about two turns. This will increase the total advance. Normally the vacuum will move about 10 degrees and by the figures provided it is doing that right now. The mechanical is pre set and usually gives 15 degrees but can be more on some units. It is what it is and short of grinding the pins inside there's little that can be done about that. It's possible to adjust the spring tension so that the distributor flyweights open more quickly. This is VERY time consuming and involves repeated assembly until it works properly. It is possible to do very fine tuning by reaching through the top of the advance plate and bending the arms in or out that hold the springs. You can knock the springs off doing this so I wouldn't advise this but I do ( because I know how. lol )

None of this can be done acurately without a distributor tester. My unit was built around 1973 and is one of the last ones ever made. After about 1975 most cars had some sort of elctronic units and the need for what was a VERY exspensive machine ( over 5K back then ) became unwaranted. In real terms it was state of the art at the time and only the best shops had them.
I've never had mine calibrated but I believe it works OK. There are a few places around that restore them but mine was like new when I got it from a trade school in NJ. Restoration costs are are high as would be expected.

[merrill]

Dan
Regarding the distro drive gear being installed incorrectly is correct.  After looking at Waqas 3 cars we found my distro clamp upside down. The allen bolt was facing the radiator.
When we corrected the clamp we found that we could not set the distro at the #1 hash mark with out the distro touching the clamp.

So, we just set the distro where we wanted it and then moved the spark plug connections one over counter clock wise. I can adjust the distro with out the interference.  One of these days I will re set the distro gear.

quote:
The pulley isn't installed wrong but the distributor drive gear probably is. To test this, turn the engine over by hand until both cam lobes are pointed up and the crank is at zero. Pull the distributor cap off and look to see if the rotor is pointing to number one spark plug wire on the cap. Number one is to the right of the clip that holds the cap on and also to the right of the tang that positions the cap.
If the rotor is pointed to the small notch on the top rim of the distributor everything is in time. If it's well past that point, either before or after, it's not positioned properly. Anything to much before will cause the distrbutor body to hit on the housing where the oiler cup sits and you will only be able to get somewhere around TDC at full advance ( at idle ). Too far, or one tooth too far and with a timming light you will be well back of TDC and somewhere near 20 degrees ATDC. The object is to be able to have enough swing on the distributor to adjust the timming while having your strobe light flash on the front pulley when and where it's puposed to.
If it's not in the right quadrant simply remove the distributor and turn the helical drive gear until the rotor points to number one position so that the cap and distributor are in sync.
Move the distrbutor to see if you have the correct swing. If you do it will move well past the optimum position ( in either directio ) so that any setting you want will be available for fine tuning.

[wwheeler]

Who is doing the rebuild on the 051?

[merrill]

Dan,
I was able to set the helical timing gear to the proper setting for use with the 051.
I was a little nervous at first but in reality it was easy.

1. remove distro
2. remove spring that is between distro and gear - I used a magnet
3. mark location of where one end of the gear is pointing on the clamp.
4. use magnet pull gear up, turn it a little in the direction you want it to go and then re install.
5. put back in spring

it took a few tries however I was able to get the gear to move clockwise about 10 - 15 degrees? 
anyway, re installed the distro and put it all back together.

note:  the gear and distro connection is off set.
If you pull out the gear to check it out, make sure to put it back in the correct orientation. 
If you do not the distro will not engage the gear unless you turn the rotor 180 degrees.
which is not what you want to do if you only want to move the rotor just a little.