New engine startup

[Dtjaden]

Next week I should complete the build of my new 2056 cc 914 engine. I have the option of making the initial startup and break-in of the engine using dual Weber 40 IDF carbs or MS3X. Even if I do the initial break-in with the carbs I will shortly after make the transition to MS for which I have all that I need. My concern about making the startup with MS is the stress I may put on the break-in of the new cam and pistons and cylinders.

The MS build for this engine will start with the stock plenum and intake runners, a 50 mm Vanagon throttle body, stock injectors, stock CHT, Bosch TPS, GM IAT, Walbro fuel pump and a 36-1 wheel from Mario. I also have an Innovate o2 sensor but I'm not sure where to install it with the stock exhaust with a banana muffler.

It would be nice not to duplicate some of the work to go from carbs to MS suck as changing the fuel pump, intake system, deferent pressure regulator, etc.

Any opinions on carbs or MS for initial break-in?

[Piledriver]

I hooked a clacker pump up to the fuel return line and used IDFs for 1/2 hour break in, didn't bother with the linkage etc, you are just looking for a ~2K high idle, easy to do with the stop screws.

I had to use super short manifolds on the T3 or the carbs hit the body even wit the cover off.

The fuel side is usually the easiest for most folk, and very easy to tweak on the fly to get it running... you might consider just going there.
I used a spare distributor i had laying around,

Now I'd suggest install it all, go fuel only with a distributor for break in and once it was running well fire up the ignition side.
(same session)

Just make sure you have the rubber boot on for the fan intake if you have a T3.

[Dtjaden]

Thanks Pilrdriver. I hadn't thought about going fuel only but I like it! It does get rid of most of the duplicate work. As soon as the cam breaking is complete I can switch over to the LS2 coils and start tuning.

Anyone know about putting the o2 sensor in a banana muffler?

[Steve Arndt]

Since you have the option I would recommend starting and breaking in with your carbs and distributor. This also allows you to configure your ECU on a running engine. You can verify your trigger is good and set the timing offset so it is all correct before running the engine with the ECU.