Mercedes-Benz Forum banner

1 - 20 of 24 Posts

·
Registered
1991 300D 2.5 - 1989 420SEL -2015 GLK350
Joined
·
26 Posts
Discussion Starter #1
Hello everyone-

Seems that a few years ago there were one or two people (well, at least one over in Minsk, anyway) making custom crank trigger wheels and sensor brackets for the M116 and M117 engines to use with Megajolt/Megasquirt/Electromotive conversions; but I haven't seen anything currently available either on the forums, ebay, or elsewhere online recently. I'm wanting to convert an '89 420SEL over to Megajolt, then possibly to megasquirt, but am having trouble sourcing a ready-made solution other than a generic/universal trigger wheel.

Have these dried up completely, or is someone still making them?

Suggestions? Sources? Have I missed something?

Thanks!
 

·
Registered
1988 560 sec
Joined
·
670 Posts
I am doing an efi conversion and am using a holley trigger wheel mounted to the pulley hub . Yes it is custom fit to that hub , it is a six inch wheel and i am using a hall effect sensor mounted where the air pump used to be.

I don’t know of any off the shelf parts ready to bolt on.

Elbe Engineering These guys have an efi conversion package that is very well sorted and ready to install.
 

Attachments

·
Registered
1991 300D 2.5 - 1989 420SEL -2015 GLK350
Joined
·
26 Posts
Discussion Starter #3
That's a nice, clean install. Did you do the machine work?
 

·
Registered
1988 560 sec
Joined
·
670 Posts
Yes i did the machine work , first i turned the pulley true then i made an aluminum adapter to hold the trigger wheel to the pulley. The trigger wheel bore is then enlarged to also fit the pulley and bolted to the aluminum adapter . Once the trigger timing is resolved it gets bolted to the pulley with two bolts through the aluminum and into the to be tapped holes in the pulley body.

I made a bracket to hold the sensor that bolts where the air pump used to be . Still a bit of work to be done on the bracket.

If you get to a point in your project where you need or want a setup like this let me know I would fab one up for cost if you sent me a pulley and a trigger wheel.
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
Very interesting especially with the ezl’s failing and getting costly. I also like the idea of not having to buy expensive ignition parts. It seems like the ford coils are the ones to use but wonder if there are cop options?

I still have my air pump so would have to figure a different placement for the sensor. Please keep up updated. If possible list parts, costs and directions. The machining looks great.
 

·
Registered
1991 300D 2.5 - 1989 420SEL -2015 GLK350
Joined
·
26 Posts
Discussion Starter #6
I will absolutely message you when I move forward on this- your work is the most practical and well-done I’ve seen so far.
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
Ok I am curious, and while I can use a lathe, I am not an expert my any means but how did you hold the pulley in the lathe to true it up? Jaws don’t open that much. Also go fihure, when I purchased the extra engine to do the head job, I tossed out a lot of parts I just could not see keeping due to space limitations. Front pulley was one.... still have the block, heads crank, pistons and rods. I think those parts are calling to me to do something with. Feel getting sucked into something if I am not careful.
 

·
Registered
1988 560 sec
Joined
·
670 Posts
To true the pulley body round to accept the trigger wheel I made an adapter that fit the center bore of the pulley on one end with a flange and the other end was turned to fit a collet , basically i mounted the pulley on the lathe the same way it mounts to the crank . The adapter fit to the pulley bore was a light press fit then held with bolts.

The two precision faces on the pulley from the factory are the pulley center bore and the mounting face so i used those as references to machine For the trigger mounting adapter .

Wish you kept the front pulley they are worth 100 bucks on ebay. Don’t ask me how I know.

So far this project is SLOWLY moving in the right direction , a little at a time ,to keep the project enjoyable a time line or deadline is not useful .

Next is turning the distributor into a cam position sensor so i can use coil on plug ignition and sequential efi.

The vortex is real beware you just might get sucked in .
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
Ok, I am going to ask this for others on here that don’t have your talents or access to machines so please bear with me. The ignition on these cars while good for their time are getting expensive to maintain and probably not as efficient as what you can do now. So when you do your journey keep us in mind but with an eye towards off the shelf parts that one could use do this. For instance could you use that useless front crank sensor in your build? So I am really trying to help out the weekend mechanics that don’t have a lot of money but can get used parts from a jy and do things to improve their car.

In my mind, there are three detrimental items in this car. 1) The brakes. They should have come with 4 piston calipers with a larger rotor. Corvettes had a setup like that from the early sixties so Mercedes certainly knew about a system like that. While the existing brakes are ok, they are not Up to a Mercedes standard. Unfortunately, I have not seen an easy and cheap upgrade for that.

The second item is horsepower/efficiency. These engines are dogs in both power and mileage. A 69 350 gm car could put out 365 hp on a carb engine. Why would Mercedes only put 240 hp in an Sec? yes not a fair comparison since hp ratings and emissions come into play over the different time frames but if you look I am sure other mfgs in 88 had more power per cubic inch than a M117. Fuel efficiency is not good either. The problem is most of the upgrades to improve things are very expensive. Try sourcing a couple of 300hp cams. Zowee. A hot Chevvy cam $100 all day long. Many of us on here simply can’t afford the high cost of upgrades just to get a few more ponies and I suppose its why many people shy away from owning these great cars.

Last , and its more about the times these were built but I the handling could have been better. To compensate I put new springs on, new b8 shocks and stiffer sway bar. All helped but its not optimal. BTW, I have a 99 SL and it still did not have a rack and pinion setup�� which underscores the Mercedes go slow philoshophy.

I sound like I don’t appreciate the car, I love it. Its just what I know what’s out there and I look to see what can be done reasonably to make things better.

Boy I wish they had an off the shelf good intake that you could use the existing Mass Flow unit.
 

·
SuperModerator
1986/1990 W126
Joined
·
13,367 Posts
At the time, the brakes on these were exceptional I believe, from reading magazine reviews. And also the handling. It was the firm ride at lower speeds that picked up criticism.
Before they rolled out multi link suspension so it was a compromise geared towards the handling I guess.

Time marches on and all that, there are improvements that can be made with what we have available now.
Handling wise I love mine actually and only replaced my shocks with standard Bilstein, trimming the springs to my liking.
Both the SE and SEC can be pushed really hard around corners and be a lot of fun while remaining neutral and predictable.

Weren't they able to out-brake the Ferrari 308 at the time or something?

They held their own until later in the production period when other cars started to catch up, like the newer 7 series etc. Then the next S finally came out.

I'm sure the fuel injection could be improved on now but I wouldn't change mine personally because it's so reliable and easy to fix.
Love the project though, well worth a try especially if you have skills like these to fabricate stuff.
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
Well I am lucky my memory is failing. While working in the garage I found out I did not toss out the main pulley so if you get yours to work just maybe you have a second guinea pig
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
Ok my curiosity, could you have drilled a hole in the front of the drivers side valve cover and simply installed a sensor in the cam gear? I don't think they are balanced and it might be more accurate. The distributor I think is driven from the oil pump. Now with that said I think you might have a small business here when you get done. Nice look on the distributor.
Did by chance you look for a place to mount the sensor on the other side of the crank? I ask since many people might want to keep the air pump. Liviu165, the teeth are supposed to tell the system what position the crank is in so it can time the spark. IF you look there should be one tooth missing. I suspect there are 36 teeth on the gear, one for each 10 degrees of rotational travel. If this works well, and its reasonable, it might solve the problem with the high cost and problems that go along with a distributor cap, and rotor.

I also have to say this, I am amazed at the skill of some of the people on this forum. Sooo Soo many brilliant home mechanics
 

·
Registered
1988 560 sec
Joined
·
670 Posts
It is a 60-2 tooth crankshaft position wheel that the new ecu will use for timing control. Used in conjunction with the cam shaft position sensor that was the distributor i will be able to run sequential injection with coil on plug ignition.
 

·
Registered
1991 300D 2.5 - 1989 420SEL -2015 GLK350
Joined
·
26 Posts
Discussion Starter #16
What exactly is the wheel with many teeth for (the first picture in the above thread)?
It's the subject of this thread: The trigger wheel for and Electronic Distributorless Ignition System (EDIS). Each "tooth" in the wheel is read by a crank-position sensor and transmitted into an electrical impulse. That impulse is then read by the ignition control module, which uses the information to accurately determine the crankshaft position and time the ignition pulses to the spark plugs. The wheel is part of an aftermarket conversion of the W126 ignition to EDIS.

While the 420 and 565 SELs already have an electronic ignition system, it isn't as sophisticated as a newer EDIS, which is more accurate and better at delivering more power and efficiency. And (in my situation) the OEM ignition parts for the W126 V-8 engines are getting scarce and extremely expensive to replace ($280-400, just to for an OEM-equivalent crank sensor, $2000+ for a new EZL, etc.). Sure, you can source used parts or cannibalize a parts car from a yard, but the longevity of the salvaged parts can be dubious.

Converting the cars to a more modern EDIS using commonly-available parts is sort of becoming the more-reliable and sometimes more cost-effective solution.
 

·
Premium Member
1991 560SEC
Joined
·
2,643 Posts
Thank you for the explanations guys. I’ll have to do some studying aside to catch up on this thread. I asked because I noticed few things and had few questions in my mind, but I did not bring them up because I am not familiar with this system. Never had a reason to become familiar with such a system, so …

Here is what went through my mind:
1) The weight of the harmonic balancer is determined based on the moving parts. Will changing the pulley weight influence the balance of the system and allow for some undesired vibrations? The pulley is also balanced with weights. Is its individual balance altered by the additional installed parts?
2) Could a custom toothed wheel of smaller dimensions be installed in the same housing with the new cam shaft position sensor? I am referring to a wheel/sprocket that is above (or below) the cam (with two bolts) and the sensors would be at the corresponding levels. Furthermore, I am envisioning curved slots for fine independent adjustment of each (the cam and the sprocket) with respect to the sensors. This solution would not require modifications to the pulley and would place the adjustments in an area easy to be accessed and keep it more compact.

At any rate, the above are few things from someone unfamiliar with the new system (yet).
 

·
Registered
1988 560 sec
Joined
·
670 Posts
Some thoughts and clarifications on my project .

1 the pulley mounted trigger wheel will be aligned to the sensor at the proper timing position then bolted to the pulley at that position. Any further timing adjustment will be done in the software. The sensor could be mounted directly under the trigger wheel if you wanted to retain the air pump.

2 the pulley trigger assembly will be sent out for balancing once the timing position is resolved. The weight is irrelevant the balance is not. The balancing is probably close enough as is ( the added parts were machined accurately and symmetrically in all dimensions) but balancing a pulley is inexpensive.

3 the cam position sensor does not need extreme accuracy as its only fuction is telling the ecu number 1 cylinder is on its compression stroke. So slop in the gears is not a factor.

The problem with mounting the cam trigger on the cam is lining up the sensor to the trigger through the valve cover. I am sure it is possible but the distributor seemed the easiest way for me .

4 if you are only attempting an ignition upgrade the crankshaft position sensor that is already in the engine is enough to run a wasted spark four coil ignition system like an Electromotive brand.

5 the distributor can be converted to sync both the crank and cam positions ( it has done that for over 100 years in an analog fashion ) a lot of efi swap kits use dual sync distributors but crank triggers have zero slop and was not terribly hard to fabricate.

I hope people find some of this info helpful. Any question, comments and suggestions are appreciated.
 

·
Premium Member
1999 500SL, 1988 SEC
Joined
·
1,068 Posts
So are you tellin me that one could simply use the existing crank position sensor, two Ford 4 coil packs that any jy has and the locic box and you would have a newer system?
 

·
Registered
1988 560 sec
Joined
·
670 Posts
So are you tellin me that one could simply use the existing crank position sensor, two Ford 4 coil packs that any jy has and the locic box and you would have a newer system?
If only things were that easy, I am saying that the car already has a crank sensor that puts out an ac signal every 90* of crank rotation that can be used to trigger an ignition and determine crank rpms. This is the basis of the factory ignition.

To make this signal work on an aftermarket or alien ignition system the following must take place. I am not an expert on these matters so take this for what it is worth.

1 the ignition control module lets call it the ICM must be able to read that particular signal. I doubt the ford can.

2 the ICM must be programmable so you can install the ignition map for your particular vehicle.

3 the ICM must also be able to read the other sensors that make up a modern ignition system which are
A coolant temperature
B throttle position and or manifold pressure
C motor rpms and vehicle speed

There are companies that have ICMs that can do these things MSD ignition Electromotive and Megajolt are a few but they are not cheap.


The stock ignition does all these pretty well and installing an ignition system that doesn’t take those conditions in account when determining an ignition curve would be a step back.

To me swapping the ignition without swapping out the whole efi seems to have little gain as the replacement efi ecu controls the ignition.

To me swapping out the efi without swapping in a new intake manifold doesn’t make much sense as the Bosch system is fine , it is all or nothing imho if you want to upgrade and modernize the m117 motor.
 
1 - 20 of 24 Posts
Top