Looks fine!

Got some work done this weekend. I really need to buy Stomski's circlip tool. My thumps are killing me.

http://forums.pelicanparts.com/uploa...1548619620.jpg
http://forums.pelicanparts.com/uploa...1548619620.jpg
http://forums.pelicanparts.com/uploa...1548619620.jpg
http://forums.pelicanparts.com/uploa...1548619620.jpg

I'm always surprised just how much work it takes to make one of these. Especially if you need to customise some parts - and I hate working on old rusty oil lines. Twin plug is a lot of extra work - and money!!! I really like the twin dizzy look, but the price is pretty steep compared to coilpacks.

Also, I needed to order stuff from no less then 6 different shops, as no one has everything. Quite annoying.

I ended up with:

MS EFI, Holley injectors.
New Wössner 10.5:1 pistons in freshly honed cylinders.
SC Heads twin plugged and ported to 41mm, matched to 3.2 manifold. They were lightly flycut as well, to clean up some minor damage.
Tuthill converted twinplug dizzy (amazing guys, good price as well).
DC 24/21 custom grind cams 114LC.
SSI and two out Dansk exhaust.

I'll be using two standard Bosch CDI's and coils. Also, I'm using the standard 3.0 throttle body, which fits the 3.2 manifold perfectly.

Could this be restricting air flow at high rpm (the fitted airfilter is just for show)?

http://forums.pelicanparts.com/uploa...1549953118.jpg
http://forums.pelicanparts.com/uploa...1549953118.jpghttp://forums.pelicanparts.com/uploa...1549953118.jpg

So the engine is starting and running. No oil leaks. So far so good.

But at idle it has a high pitched whistling sound from the left bank and it's running rough. AFR's all over place (Lambda on the left bank), but mainly way too high. So I have a vacuum leak somewhere. Took me some time to diagnose where. Had the manifold off two times to check gaskets, rechecked manifold bolts etc. No obvious leaks found. Since this is EFI, there are really no other sites for vacuum leak.

Carb spray around cyl three: Sound disappears and idle goes up.

Well after some head scratching I've found the problem: Vacuum leak on cyl three injector! These are brand new Holley 42lb Injectors. Tried to take them off, place them a little better, even tried Curil T on the O-ring, but no help. Injector seat is fine. It's driving me mad I tell you. It's the very last bit before the car hits the road.

So, I guess it should be pretty straight forward; replace the injector and if that doesn't help, bigger O-ring I suppose?

So close!

Is the o-ring damaged? The seating hole in the manifold clean and smooth?

Using a little oil or grease to allow the o-ring to seat easily?


Keep at it! Keen to hear how it goes on the dyno!

Everything looks fine, which is even more annoying. Going to change the injectors and see whats happens.

I hope 250hp is within reach with this build. We will see!

The injector pocket on the 3.2 manifold may be overlapping the edge of the 3.0 port causing a vacuum leak.

Compare a 3.0 and 3.2 intake gasket.

You are correct sir. Thats why I've cut the gaskets my self to at perfect fit. And I've triple checked those. Did also try with 3.0 gaskets and even with Locktite 574. No change. I'm faily sure it's the injectors.

If I cover the intake gaskets and spray directly at the injector, idle rises and the Sound disappears. You can even see the fluid getting sucked in.

Good then, carry on!

Curious why you went with the expensive and not particularly flexible twin plug distributor when the mcrosquirt could run dual COPs in a wasted spark configuration at the cost of a flywheel mod, crank position sensor, and plug for the distributor hole.

Seems like that would have been ticked all three boxes: Better, Faster, Cheaper. How often do you get to do that?

:)

I absolutely agree. But I'm building this for a friend and he specifically wanted the twin plug dizzy look. I tried......but no :)

3d print one :D

I went custom twin-plug distributor exactly for this reason, to have retro look. It is locked and has Hall sensor for cam sync, coils are fired directly from VEMS :)

http://forums.pelicanparts.com/uploa...1552933152.jpg

Nice!!!

Resolution!
 

After many many attempts with the 3.2 manifold, new gaskets, new injectors, different o-rings etc - well I gave up. After I'd pulled the manifold for the fith time I tossed it in the trash and fitted these:

http://forums.pelicanparts.com/uploa...1553512255.jpg

ohh bliss!!! No odd vacuum leaks, no bouncing AFR, no strange noises other than the lovely symphony from 6 airhorns

Now - tuning! I'm hoping this thing will put out about 250hp at 7000rpm. We'll see.

After a few setbacks (again) with a bad coil and a defect voltage regulator - it's back to business with tuning. This thing pulls like a train now!

I'm using 30LB injectors and I'm seeing close to 100% duty cycle at 7000rpm. Need to get on a dyno next!

First dyno session
 

First dyno session today. We didn't have long and were just beginning to dialing the fuel and ignition in.

Had maybe 10 runs in total. I'm was still correcting fuel efter a changed the ignition from 5BTDC to 0 to see what happened. What do you guys set a twin plug to?

Anyway, good thing and bad things. Nice flat torque curve with max at 295. HP was 242 at the engine, but I'm pretty sure I can get that up to 250+. I didn't even have time to run a log. That has to be next time.

http://forums.pelicanparts.com/uploa...1557849550.jpg

Now, the bad thing. I'm could see quite fast, that the AFR couldn't really stay at 12.5 isch, but was creeping up to around 13-13.5 just before 6000rpm. I know the old injectors were running 100% duty cycle at WOT at 3 bar pressure. And I didn't watch the new ones (42LB) this time, but I'm wondering if the old fuel pump is up for the job? The injectors should be more than fine.

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