Need to get it running well before the wife gets angry!

[ScotcH]

Ok, the saga continues, but I hope to have some time to finally get this thing running right next week. In preparation for this work, I need a bit of info, and maybe some pointers on how to go about it.

Background: Car is a 1978 that's been "worked on" by previous owner. I think the engine is a stock 1.8, but all emissions have been removed, all coolant lines are gone, all vac lines are gone. It came to me with a dual DCNF40 setup, and was a PITA to drive on the street. Here is what I've done since:
- I have replaced the intake with a stock 1.8 single plane (new gasket)
- I have installed a stock DMSA, rebuilt (still waiting on a new accel pump diaphragm to complete rebuild)
- I have added a return line back to fuel tank (the DCNFs didn't need one)
- I have checked cam timing
- Spark has been converted to a pertonix in a stock mechanical advance distributor, advance is working (checked with timing light ... it advances)
- Idle timing set to 10BTDC (according to my mangled yellow cover piece still bolted to the bottom of the engine)
- Distributor arm is just past #4 when engine is at TDC

Some questions:
1. What is a reasonable compression for the stock 1.8? I'm going to start with the basisc: compression, fuel, spark
2. My electric fuel pump (aftermarket) puts out around 6-8psi ... is that too much for the DMSA carb?
3. The cams don't seem to align perfectly (I tried a few times) ... I do have a new timing belt, so I'll probably put that one and retime, but if they don't line up, should they be slightly advanced, or retarded? I do have some adjustable cam wheels but they are the kind that you need to remove and install in a different spot, just a sliding adjustment. I want to get it running well stock first.
4. Is there a TDC mark on the engine (not belt cover) somewhere? If so, where? I can' seem to find any info, and people talk about measuring the TDC at the piston (yes, I can do that ... but there has to be a mark, no??)
5. On the DMSA what are the absolute required connections? Fuel IN, Fuel OUT. Anything else, or can I plug all the rest of the ports? Seems when I plug the port that goes to the air cleaner (near the idle screw) the car wants to die. I will be using an aftermarket air cleaner since I no longer have a stock one (plus they look like shit), so where should this port go? Drill a small hole on the aftermarket filter housing?

My plan is to check compression first, then timing belt and cam timing, then work on the carb and tuning, and hopefully end up with a well running car.

Thanks in advance for any help you can provide!

[RoyBatty]

If you plug a vacuum fitting and the engine dies, it's probably because the mixture has been adjusted to compensate for that vacuum leak.
Might want to look into that.

[76was124]

Thread that may help http://www.fiatspider.com/f08/viewtopic ... nk#p198733

[ScotcH]

If you plug a vacuum fitting and the engine dies, it's probably because the mixture has been adjusted to compensate for that vacuum leak.
Might want to look into that.

Hey, that makes a lot of sense! So my question is: Can ALL the vac fittings on the carb be plugged, and I tune after that?

[vandor]

Don't plug the bowl vent, it will flood if you do.

>1. What is a reasonable compression for the stock 1.8?

150psi for a new rebuild, 120psi for a good used engine.

>2. My electric fuel pump (aftermarket) puts out around 6-8psi ... is that too much for the DMSA carb?

Yes, should be more like 2-4 psi.

>3. The cams don't seem to align perfectly (I tried a few times)

It's Ok to be half a tooth off. Just get it as close as possible within the limitations of the gear teeth spacing.

>4. Is there a TDC mark on the engine (not belt cover) somewhere? If so, where?

Not really. There is a mark behind the crank timing belt pulley, but you can't see it and it's very imprecise.

[RoyBatty]

Is that what he is plugging, the bowl vent?
Can you post a pic to let us see, scotch?

[ScotcH]

Is that what he is plugging, the bowl vent?
Can you post a pic to let us see, scotch?

Is the bowl vent the 3rd nipple by where the fuel inlet is? I've played with various plugs, so quite possibly! I'll get pictures and more info once I start playing with it next week ... gotta finish the race cars for an event this weekend (I can completely disassemble and reassemble a modern BMW down to the frame ... but carbs are a mystery to me right now ... I can't tune it with a laptop, lol )

Thanks for the help and suggestions so far guys!

[ScotcH]

Running pretty well now, but has a few issues I'd like to sort out. Got some good advice from AndyS, but figured I'd post here as well in the interest of sharing. Here is the current situation:

- Idle is ok, but gets progressively worse … after a few minutes, it starts to be more lumpy and uneven. It starts out at 11:1 AFR, then gets richer when idling (I have an LM-1 hooked up), like below 9:1
- Mixture screw is around 1.5 turns, but it’s seems better more screwed in
- I think idle is all the way out (not touching the cam) … pulling air in from elsewhere?
- Idle at ~900 rpm, 10º BTDC
- Acceleration is decent, but I think it floods when I get on it from a stop … it bogs a bit, then picks up.
- Moderate accel (part throttle) it progressively leans out to around 14:1 all the way through revs.
- If I go WOT (second barrel open), it pulls to ~11.5:1 and stays there through the entire RPM range (to about 5.5k, don’t push it much more than that)
- Jetting is as follows: 50 main idle, 60 secondary, 145 mains. F7 tubes. 175 needle valve (as I got the carb)
- I have not checked float … what do I measure???
- Supply is electric Facet pump, low PSI (I don’t even see it on the gauge … maybe 2 psi?)
- All ports on the carb plugged except bowl vent … open to air. Fuel in, fuel out, that’s it.
- Should there be any check valves in the fuel system with the electric pump?

Andy suggested going down on the idle jet to 45 (both, or just primary??) and secondary main jet to lean it out a bit at WOT, and maybe increase the primary main jet to bring the part throttle to 12:1 or so. Thoughts?

[bradartigue]

You have to understand something - your wife is going to be angry after it runs. I have years and years of experience with Italian cars and wife. If all she is is angry then you're okay.

You can mail me your DCNFs and manifold...I can use them! I'll trade you for an unused 34ADF repo. Bolt it on and go!

1.5 turns is pretty far out there - so more in is a good thing. So long as the idle goes up and down when you adjust it you're okay. When it doesn't do anything but die you have an issue. Usually carbs get leaner when idling, not richer, so you're bringing in more fuel as things warm up...so I think you're idling off of your main jets somewhat. How much adjustment is your throttle set screw? More than a turn or two?

[ScotcH]

Ha ha, thanks for the advice on the wife, Brad Fortunately, we have a couple other cars, and this is just a fun (I say that hesitantly) project and sunday driver.

I'll PM you about the DCNFs see if we can make a deal.

As far as the mixture screw, I thought between 1 and 2 turns out is a good thing? Maybe I misunderstood your tuning guide. The car actually runs well all the way to fully closed, never dies when screwed in. The idle set screw I believe is completely unscrewed (ie, not touching the linkeage). I have the choke zip tied open ... maybe there is a fast idle that is still in play somehow keeping the throttle open a bit?

[toplessexpat]

In my experience ... "Happy Wife = Happy Life".... so I bought her a spider

[bradartigue]

I can always use more carbs and manifolds!

If you put the mix screw all the way IN and the car still idles then you are running off the throttle plate; the car needs to run (or nearly run) with the idle set screw all the way OUT and the mixture screw OUT about 1.5 turns. Then you touch the idle set screw to the linkage and turn it so that the throttle opens slightly. Then you start it and find the optimal place with the mixture screw (which will be between 1 and 2 turns, but usually 1.5 is around the limit....it depends on the carb). Finally you increase the idle to 850 using the idle speed screw.

Understand the goal here is to make the car idle off the mixture almost exclusively, the throttle plate open slightly just to let in enough air to keep it running.

IF the car has no adjustment range with the mixture screw...as in, it runs the same until the screw is seated (and then dies) then the primary idle jet may be a size too big.