2450 (78mm x 100mm) engine build

[Bruce.m]

Not sure about dells, but with webers you have to buy the vacuum ports as a separate piece…. Or make them by soldering a bit of tube to a spare jet that fits in the blanked off thread.

[Tony Z]

Pffff
finally got the carbs sorted out..
Looks to run ok enough to go to the Rolling road.
I have a small question, I would like to run the cb black box, do some of you run the vacuum directly off the dellorto vacuum connection
Don t want to use the cb plates, the gaps are 48mm instead of the 45.

Thanks in advance
Eddie

OOh and question nr 2 what spark plugs do you use with the black box **Resistor Spark Plugs are required** says it on there website.

Use the same spark plugs that you would have anyway, just make sure they have the prefix "R" in them.
For example - beetle uses NGK BP6HS. The resistor equivalent is BPR6HS

[Piledriver]

Based on the manual you hook it to manifold vacuum.
I don't know itf the vacuum port you are looking at is manifold vacuum...
...ported vacuum for distributor vac advance has to turn off at idle, you don't want that.

What plugs are you running? It's usually easy to look up the resistor equivalent.
AFAIK, to avoid ignition noise issues, you can usually run resistor plugs, resistor wires or a rotor with a built in resistor (pick one)


I still prefer cable pull linkage setups, you can usually find a decent splitter at a motorcycle junkyard.
Of course Synclink is still an option.

[Eddie010]

Thanks Guys,

Very helpful
Going to look for those plugs.

Piledriver, linkage issues solved, was carb related.

Regards

[Bruce.m]

The plugs mentioned above are for stock type1. So if you want stock type 4, that would be different (bpr6es I think).

[Bruce.m]

This is the vacuum port part for Weber & also, it appears, dells.

https://www.dellorto.co.uk/shop/dellort ... off-union/

Although you can make them, as mentioned above.

Interestingly the same company sells a pulley for a cable linkage. Nice part and that’s the hardest piece to make if you change your mind & want a synclink style linkage.

[Eddie010]

This is the vacuum port part for Weber & also, it appears, dells.

https://www.dellorto.co.uk/shop/dellort ... off-union/

Although you can make them, as mentioned above.

Interestingly the same company sells a pulley for a cable linkage. Nice part and that’s the hardest piece to make if you change your mind & want a synclink style linkage.

Correct Bruce those are the ones,
You have to turn them a half turn to open them to work for vacuum, so normally they are closed, you only use (open) them to sync the carbs.
But I want to use them for the black box, but this means they are open the whole time (half turn open), don t know if this works.
Or if someone tried this.

Thanks

[Bruce.m]

The you-tube bloke I mentioned earlier certainly uses this approach with his CB black box. Although he made his vac ports by drilling out the blanking screw (or using an old jet, I forget) and soldering on a stub of tube. 4mm OD stock brake pipe tube would probably do the job?

He made them because buying from the UK with shipping & tax was silly price for the genuine part.

The genuine part probably seals on the tapered tip when bottomed out. You could cut that off or go with a home made part instead?

[Piledriver]

You can also install vacuum ports in the intake manifolds, the fittings are inexpensive.

[Eddie010]

The you-tube bloke I mentioned earlier certainly uses this approach with his CB black box. Although he made his vac ports by drilling out the blanking screw (or using an old jet, I forget) and soldering on a stub of tube. 4mm OD stock brake pipe tube would probably do the job?

He made them because buying from the UK with shipping & tax was silly price for the genuine part.

The genuine part probably seals on the tapered tip when bottomed out. You could cut that off or go with a home made part instead?

Thanks Bruce, I have the genuine part in my carbs, so will give it a go.

[Eddie010]

You can also install vacuum ports in the intake manifolds, the fittings are inexpensive.

Pile I use thick heat risers between the manifold and carb, to get the carbs a bit higher, so I think by using vacuum in my manifolds,
it would be to far off from the throttle plate. Not a strong vacuum..
This is what I think, I did not test this.

Regards Eddie

[Piledriver]

If you have the parts to do it just under the carbs, it will work as long as it's not ported vacuum. but you still need to run all 4 lines to a common reservoir and connect the MAP sensor to that signal... ported vacuum goes to a drilling in the carbs just a tiny bit below the butterfly on the side that moves down, so its "off" with closed butterfly at idle.

Technically the vacuum gets stronger nearer the source (intake valves), but it effectively doesn't matter where in the manifold you get manifold vacuum. Folks frequently use a cheap fuel filter for a damper for the combined vac signal.

[Bruce.m]

Did a bit of research (carbs not on my radar these days). Typically the left carb on a set of dells (supplied for a VW as a kit) would have had a single brass tube on one barrel that was for a distributor vac advance. That drilling exits on the edge of the butterfly so at idle gets no vac signal until the throttle is cracked open.
The other four ports which are normally blocked, were designed for balancing via a 4 channel vac gauge. These have a vac signal from below the butterfly. So they should be adaptable for your purpose, I believe . The original vac port adapter seems to be available in three versions. The one linked above which has an o-ring and a tapered end (which is sealed unless cracked open). The are also 2 more versions which have the M5 thread but a short end without the taper and no o-ring. One has a 3mm bore and the other has a 0.8mm bore. I guess those are for a permanent vac connection and don’t seal when nipped up.

I’d imagine the 0.8mm version will damp fluctuations in the vac signal, even without a manifold?

[Eddie010]

Did a bit of research (carbs not on my radar these days). Typically the left carb on a set of dells (supplied for a VW as a kit) would have had a single brass tube on one barrel that was for a distributor vac advance. That drilling exits on the edge of the butterfly so at idle gets no vac signal until the throttle is cracked open.
The other four ports which are normally blocked, were designed for balancing via a 4 channel vac gauge. These have a vac signal from below the butterfly. So they should be adaptable for your purpose, I believe . The original vac port adapter seems to be available in three versions. The one linked above which has an o-ring and a tapered end (which is sealed unless cracked open). The are also 2 more versions which have the M5 thread but a short end without the taper and no o-ring. One has a 3mm bore and the other has a 0.8mm bore. I guess those are for a permanent vac connection and don’t seal when nipped up.

I’d imagine the 0.8mm version will damp fluctuations in the vac signal, even without a manifold?

Your correct Bruce, I got the carb you described.
The brass one for the distributer is blocked by me they are on the 'inside' when set up on a beetle.
I got the version that you have to turn open with the o ring.
Yes I will give it a go and see if it will fire up with Black Box.

Regards eddie

[Eddie010]

For some reason I got not get a break with this engine.
Engine still needs to get on a rolling road, but appointment is due in august.
But the car needed it s last MOT (APK).
It is a 20 min drive, but on they way over I saw the oil temp rising above 100dgr C, I am not used to this because it is always in the 90-95C region
even on a warm day driving for hours on the freeway. Well got at the mot station, temp rose to 120C oooh poop I thought. case was bloody hot.
But could not find the reason I did not change anything to timing or carbs. Car got the MOT with out problems.
So drove back, same thing... temp rose to 120 again.
Came home after 20min. No freeway driving, just local roads. Only driving 50km/h roads.
Started looking for the cause.. looked at my plugs, they did not looked white from heat.
Thought maybe the fan was loose or something, although I did not hear that, feel the fan to find out there was a peace of paper stuck
in the fan... So engine has become hot because of not sufficient cooling, explaining the rise in oil temp and hot case.

Would this be a problem for my engine, becoming too hot.
I am afraid for cracked heads or falling out valve seats or cylinders turning oval from the heat.
Any thoughts?

Regards