OK Pagodafest encouraged me to post a mods/performance topic on our car

[russelljones48]

So we're finishing up with a pretty complete mech. refresh and several other performance enhancements "while we're at it".  The "we" in this case is Pedro Campuzano and myself, other vendors and machinists.  Before I get started I'd like to note that none of this will alter the car in a way that can't be reversed.  I had a desire for better handling,  better acceleration and more speed.  I'll start the list of mods and solicit comments, different ideas and perspectives and what others have done.  The one area that hasn't been addressed yet is braking so ideas please for possible later mods.
Engine/head: for the time being only head work.  New bronze guides, high performance SS valves with "modern" valve head design with thin stems (6mm). improvements with minor smoothing of ports, new MB valve springs, rockers, and studs.  a .0100 resurface of the head will add a few points of compression. The idea is to make small improvements to the stock system which will improve both intake and exhaust flow and maybe add a few rpm to valve train capability and response.  We will swap out the cam for a reground cam with slightly more lift and duration.  Sourced from an old grinder who has considerable experience with our generation of MBs.  New "blueprinted" injectors and a freer flowing intake/cold air system round out the engine mods.
Suspension/handling: 14X7 alum. wheels, Koni shocks, lowering springs, urethane bushings, and complete subframe refreshes (front and rear) i.e. new bushings and mounts everywhere.  Tyres/tires are being researched at the moment.
Ignition/spark: an electronic distributor with programmable advance curves  source from the EU - it was easier/cheaper/with better quality than rebuilding the original
Odds and ends: lightweight LI battery in stock location 

OK, fire away!! but please no comments on authenticity and I'd love your guesses on HP improvement over the tired old engine and over a stock fresh motor

[JamesL]

Just a question about the 7” wheels… will you have clearance from exhaust heat? I know someone tried 15x7 and had a bad outcome.

And a point of order.. re machining the head is difficult to undo (in a way that installing a 123 ignition, for example, is not)

[russelljones48]

Haven't tried the wheel fitment yet.. but they are 14X7 (not 15)  I'm told (famous last words) that they'll fit fine and eyeball fitment supports that..    on the head - agreed but that cut was the minimum to clean it up anyway and it will make a minor improvement to compression ratio...   so I added it to the story - every little bit helps

[rwmastel]

The exhaust issue would be with the 7" width, not the diameter.  And on that topic, if you're looking for better brakes, wouldn't 15" wheels open options for bigger rotors/calipers?

[russelljones48]

Yes, but I tried that 2 years ago and the real owner, my wife, nixed the 15's.  So, this is how I learn to compromise  .  Based on your comment I will pay close attention to the clearances and if the RR is too close to exhaust heat, either add shielding or scrap the idea...   last option, since no exhaust mods are on the table yet, might be to alter the exhaust system.  That's been contemplated so it might get added to the agenda..  increasing intake capacity may not boost performance as much if we don't do some commensurate changes to the other side... 

[mdsalemi]

So we're finishing up with a pretty complete mech. refresh and several other performance enhancements "while we're at it".  The "we" in this case is Pedro Campuzano and myself, other vendors and machinists.  Before I get started I'd like to note that none of this will alter the car in a way that can't be reversed.  I had a desire for better handling,  better acceleration and more speed.  I'll start the list of mods and solicit comments, different ideas and perspectives and what others have done.  The one area that hasn't been addressed yet is braking so ideas please for possible later mods.
Engine/head: for the time being only head work.  New bronze guides, high performance SS valves with "modern" valve head design with thin stems (6mm). improvements with minor smoothing of ports, new MB valve springs, rockers, and studs.  a .0100 resurface of the head will add a few points of compression. The idea is to make small improvements to the stock system which will improve both intake and exhaust flow and maybe add a few rpm to valve train capability and response.  We will swap out the cam for a reground cam with slightly more lift and duration.  Sourced from an old grinder who has considerable experience with our generation of MBs.  New "blueprinted" injectors and a freer flowing intake/cold air system round out the engine mods.
Suspension/handling: 14X7 alum. wheels, Koni shocks, lowering springs, urethane bushings, and complete subframe refreshes (front and rear) i.e. new bushings and mounts everywhere.  Tyres/tires are being researched at the moment.
Ignition/spark: an electronic distributor with programmable advance curves  source from the EU - it was easier/cheaper/with better quality than rebuilding the original
Odds and ends: lightweight LI battery in stock location 

Years ago, Motor Trend, or Car & Driver, or one of the mainstream American magazines took a whole bunch of these ideas of "improved performance" and better gas mileage etc. and put them all on a car. The results were, well, nothing.

Some people have had some clearance issues with stock wheel/tire sizes and exhaust. At this stage of life there is no stock exhaust system any longer. Anything original from the factory is long gone. Ever so slight differences in the bending of pipes can make the difference between fitting and clearance, and an issue that must be dealt with. I'd suggest that the difference between a 6" and 7" wheel, all else being equal, would not be noticeable in normal daily driving but more so in spirited driving as they would say. Remember for the day, the 230SL offered stable, neutral cornering. Exceptional road manners (when compared to other small roadsters). But it was never a "sports car" and more of a luxury touring car. See if you can find the book that has the test reports done in the 1960s on the model for some period-correct reviews. On my own car the first tires I had were Pirelli P6000, 205/70-14. I had a problem with rubbing in the front wheel well on lock turns, but others have not. I have since changed to the factory size and won't deviate from that standard.

Koni adjustable shocks are something many have done before.

The 123 distributor with or without programmable advance curves is a fine addition, pretty much universal accolades for this unit. 10-20 years ago, parts were available to rebuild the older -051 cast iron distributor, but I'm fairly certain these parts are gone. Dan Caron in Canada used to rebuild these, but I don't know if he does any longer. The other guy who used to do this, Glenn Ring in NY, stopped. Any wear in an old distributor will not be corrected by any add-ons like a Pertronix. You didn't mention 123 by name but said EU sourced. If there's another distributor replacement, I don't know what it is.

Nobody might know more about engine mods than Pedro, and nobody might know more about specific engine changes to the M127 than Dan Caron. Once you get it all together and have it tuned properly for normal starting and operating and feel comfortable with its daily operation, I'm sure Pedro can point you to a dyno for testing to see how all these engine mods have worked out for you. I sure hope for your sake that you don't end up chasing gremlins all over the place, things like now the engine runs too hot and you need some additional cooling, or the mechanical fuel injection isn't quite what is needed. We have not heard of too many direct engine modifications on the three engines found in Pagodas. So your results will be interesting.

[mdsalemi]

Let me also add that what you plan on doing for the engine is definitely in this right category here of Research & Development. Modifying any of our engines is in that realm.

In the world of American iron, you can find plenty of "how to" books on modifying any number of engines for more horsepower and or torque. From the lowly slant 6 (170-224 CID) Mopar unit, to the small block Ford V8s such as the 260-289-302, there's a book on it, with how to...and many parts sources. Of course the larger ones such as big block V8s get more attention and plenty of how to on those as well, but my point is that even on somewhat humble smaller engines used on family sedans, the "more power" mods are there. Those of you who have been to any big American car show and seen an otherwise nameless and faceless sedan with some giant blower sticking out the hood and who knows what done to the engine knows what I mean.

Not so much with our engines I'm afraid. I've yet to find the book. While some things can be done with clarity (shaved head, oversize pistons, etc.) there may be a lot of fog ahead.

Your results will be of significant interest to many who harbor the same ideas as you but don't say much!

[russelljones48]

I would love to see the article if you (or anyone ) can find it

[russelljones48]

CORRECTION wheels are: 14 X 6" I think from a 240D

[Benz Dr.]

Years ago, Motor Trend, or Car & Driver, or one of the mainstream American magazines took a whole bunch of these ideas of "improved performance" and better gas mileage etc. and put them all on a car. The results were, well, nothing.

Some people have had some clearance issues with stock wheel/tire sizes and exhaust. At this stage of life there is no stock exhaust system any longer. Anything original from the factory is long gone. Ever so slight differences in the bending of pipes can make the difference between fitting and clearance, and an issue that must be dealt with. I'd suggest that the difference between a 6" and 7" wheel, all else being equal, would not be noticeable in normal daily driving but more so in spirited driving as they would say. Remember for the day, the 230SL offered stable, neutral cornering. Exceptional road manners (when compared to other small roadsters). But it was never a "sports car" and more of a luxury touring car. See if you can find the book that has the test reports done in the 1960s on the model for some period-correct reviews. On my own car the first tires I had were Pirelli P6000, 205/70-14. I had a problem with rubbing in the front wheel well on lock turns, but others have not. I have since changed to the factory size and won't deviate from that standard.

Koni adjustable shocks are something many have done before.

The 123 distributor with or without programmable advance curves is a fine addition, pretty much universal accolades for this unit. 10-20 years ago, parts were available to rebuild the older -051 cast iron distributor, but I'm fairly certain these parts are gone. Dan Caron in Canada used to rebuild these, but I don't know if he does any longer. The other guy who used to do this, Glenn Ring in NY, stopped. Any wear in an old distributor will not be corrected by any add-ons like a Pertronix. You didn't mention 123 by name but said EU sourced. If there's another distributor replacement, I don't know what it is.

Nobody might know more about engine mods than Pedro, and nobody might know more about specific engine changes to the M127 than Dan Caron. Once you get it all together and have it tuned properly for normal starting and operating and feel comfortable with its daily operation, I'm sure Pedro can point you to a dyno for testing to see how all these engine mods have worked out for you. I sure hope for your sake that you don't end up chasing gremlins all over the place, things like now the engine runs too hot and you need some additional cooling, or the mechanical fuel injection isn't quite what is needed. We have not heard of too many direct engine modifications on the three engines found in Pagodas. So your results will be interesting.

I still fix original disdtributors but rebuild kits are harder to come by. The kits I used were made for Porches but they're all very similar Bosch units. I used to do 3 or 4 a month but now it's a couple per year aside from the cars that come in the shop.

Rebuilding these engines isn't rocket science but there are a number of things to pay special attention to. I wonder how long parts will remain available. MB has discontinued a lot of things but they know where the money is and old SL's are the ticket.