Out with the old.

So we started this project to install a new Megasquirt 3 computer controlled fuel injection/ignition by pulling out what currently existed.

That's also not entirely true- the project started by ordering ~$3k+ worth of parts and having to machine some of them (a fuel injection manifold off a 280SL we picked up on eBay).

So maybe it is more accurate to say the first shop day was getting the old stuff out- now if you've ever turned wrenches on old cars you know: taking the old stuff apart can be half of the job if not more. 

The most important thing here, is to make sure you have plenty of time to do work, because little surprise "gotchyas" are always what will slow you down for days if not weeks (think ordering unexpected parts from over seas, if you can even find them). I had been working multiple jobs over COVID and was ready for a nice long break- so time was (luckily) on our side. 

Starting at the beginning- here's our starting point:

 

 

 

On the 1971 Mecedes 250 you have dual INAT/Zennith 35/40s these two are in OK condition except the accelerator pumps are just hanging on by a thread on each. Thus the motivation for this whole project- $2k for carb rebuilds or $3k for a modern fuel injection/ignition system, I went with the latter- a bold move, we'll see how it pans out. 

Getting those carbs off was no joke, we putzed around with it for a full day- I can't emphasize enough to the DIY mechanic the importance of good tools- so much so that it is my rule of thumb, that the first time you do a job, expect to spend as much if not more than it would cost to take it to a pro for all of the tools you will have to buy on the first merry-go-round, your profit will be knowledge, and hopefully some good time with friends. This goes beyond cars- I have had great luck with Milwaukee tools for house stuff and have nothing but nice things to say about the ratchet and wrench as well. 

 

But yea, getting those carbs off was a bear- I should have bougtht the Hayes Manual, as it was all we had was the "Dealer Shop manual" which is all done in shockwave and just says "remove retaining" bolts- ok yea, thanks. Some crows feet here could have helped, as it was we ended up modifying an open ended wrench. 

One we finally got the carbs off (we plan to sell them, so didn't want to destroy them) we also needed to get the intake manifold. Now on this car- the intake manifold is bolted to the exhaust manifold and has some sort of primitive thing to heat up the carbs faster with exhaust gas. Unbolting the two apart- when super old rusty bolts are in play, it seemed could only be accomplished with everything out. (Please feel free to correct me in the comments). So we also had to unhook the exhaust manifold. And we had to remove the posts, since the manifolds couldn't clear the posts with the engine in (they ran up against the side of the engine bay), and we didn't want to pull the engine, if we could help it. 

We used an angle grinder...

A sawzall (not pictured), and an acetylene torch...

It was a long night- but the manifolds did finally yield. But it was well after the shop dog called it a day (pictured below).

You'll see ~6 studs there, note a bolt exists on the far right (behind the thermostat) and far left (behind the clump of wires). When extracting the studs we got 4 no problem, but two broke off and we're still working on. Hopefully we don't have to pull the head (or we do and there's another post). NOTE- the AC compressor also has to some out to get the manifolds so just beware

Stay tuned, hopefully the next post isn't an upper engine rebuild(since the motor is strong) and we can begin the Megasquirt3 install.