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Volvo 140 B20B Electronic Ignition

C

CRatcliff

Member
Joined
Nov 21, 2016
Location
Seattle, Washington
Hey All!

First off: Yes, I have done an extensive search of the forums, and haven't had a clear answer as to the best option. :)

Volvo 144 1971 with a factory rebuilt engine (F head, bored out, K Cam), carb'd.

I'm hoping for a good way to get some more HP out of it without damaging the engine in any way, and I've heard that at low RPM driving the Weber Sidedraft carbs can thin out the oil and cause other problems. SO, my first safe step is to get a good electronic ignition.

I'm seeing a lot of options out there, namely:

123Ignition (will this work on the 144?)
Crane
Pertronix (this is the one my mechanic suggested)
Hot Spark

I'd love your advice as to which is going to provide the most improvement, and mainly keep the engine safe! I have put electronic ignitions into most of my motorcycles and familiar with the improvements. I'll say that I would love to remove the mechanical advance and condenser, but that my ignition on my CX500 has software to completely customize the curve, and I've never used it once (though it's nice to have if I want to!).

Thanks all!
 
CRatcliff said:
I'm hoping for a good way to get some more HP out of it without damaging the engine in any way, and I've heard that at low RPM driving the Weber Sidedraft carbs can thin out the oil and cause other problems. SO, my first safe step is to get a good electronic ignition.
Click to expand...

Whaaaaa?

Only if your carbs are super poorly jetted and dumping **** tons of fuel that is getting past the rings.

Step 1: jet properly, verify with WB02.

I'm working on my B20B-> F head and Dual DCOE45's right now.
I went the pertronix route, but will be supplementing with MSD 6AL box for multispark discharge below 3K rpm as well as a lower impedance coil for hot spark.

The 123 ignition dizzy is awesome from all accounts. Programmable curves to tune it...
 
I have a Mallroy electronic distributor for the b20s

$450

IMG_6251_zpsrxbptunk.jpg
 
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Yeah, I'm not sure about that whole Weber sidedrafts and thinned oil theory. I've never noticed any issues, although perhaps my *cough*cough* lack of low RPM"s might be why? Heh...

Probably lots of ways to skin this particular cat. I do know that my original bone stock ignition system (firewall mounted coil, points, and condensor) put out very thin frail looking sparks. this was perfectly fine on the stock 95 hp B18, but as I started to increase the HP levels on the motor through a variety of mods, eventually I noticed a sort of wavering weakness to higher RPM high throttle power output.

What I've done on mine (and this is just one of the ways to skin said cat) is:
- replaced the Bosch distributor with an old eBay-sourced Mallory dual point distributor body. This has better and adjustable (somewhat) advance curves, mechanical only, no vacuum advance or retard.
- Put an old eBay sourced Crane optical (so old it's actually called an Allison) box on it so no more messing around with points
- An old skool square Mallory coil

This produced big fat nasty sounding sparks and cured the upper RPM weakness. Ignition isn't quite graded on a pass/fail basis, there are differences in the quality of ignition even if it doesn't completely fail.

Later on, since I had the parts laying around (changed my turbo 245 to coil-on-plug) I put on an MSD box and a newer MSD Blaster coil. This makes significantly stronger and multiple sparks (under a certain RPM), and this makes a noticeable improvement in the way it starts and in lower RPM power (under 3000 - 3500 rpm or so). So far, though, it has burned holes in my rotor, it might actually be a bit of overkill.

I really like the Crane optical system, it's been rock solid for 15 years or so on the PV's motor, never need to adjust timing. It's never skipped a beat.
 
Awesome. Definitely sounds like Crane is the way to go. I really really want these side-draft carbs, so I appreciate y'all's votes of confidence.

Any other simple changes of that sort that you would recommend?

PO had installed a fuel pump, which baffled the mechanic - any thoughts on that?
 
My DCOE's were never happy with the mechanical fuel pump. The SU's never had an issue, but the DCOE's didn't seem to like it much. I think they require an even lower fuel pressure.

I took that off (used a B20E fuel pump blanking plate) and put an electric carburettor Holley pump back by the tank (filter between it and the tank since it's a nasty old rusty tank) and another finer filter up in the engine bay before a fuel pressure regulator set to 2.5 psi.

Setting up a set of Webers is tricky. Everything is changeable, but very little is adjustable. Almost all the tuning is accomplished by swapping parts around. In sets of 4, usually not returnable. So unless you have a nice set of jets to swap out and try, you might have a spendy time getting them set up right.

Also, if you're used to a fuel injected car, using a WB02 to help tune snorty old carbs (which I did) can be a little alarming. Because they're always going lean or rich, swings back and forth, going over bumps, going around corners, heh. It's not hard to see why the catalytic converters killed off carbs, they're not very accurate.

They make great noises and go like stink though. Love them on my PV.
 
JohnMc said:
My DCOE's were never happy with the mechanical fuel pump. The SU's never had an issue, but the DCOE's didn't seem to like it much. I think they require an even lower fuel pressure.

I took that off (used a B20E fuel pump blanking plate) and put an electric carburettor Holley pump back by the tank (filter between it and the tank since it's a nasty old rusty tank) and another finer filter up in the engine bay before a fuel pressure regulator set to 2.5 psi.

Setting up a set of Webers is tricky. Everything is changeable, but very little is adjustable. Almost all the tuning is accomplished by swapping parts around. In sets of 4, usually not returnable. So unless you have a nice set of jets to swap out and try, you might have a spendy time getting them set up right.

Also, if you're used to a fuel injected car, using a WB02 to help tune snorty old carbs (which I did) can be a little alarming. Because they're always going lean or rich, swings back and forth, going over bumps, going around corners, heh. It's not hard to see why the catalytic converters killed off carbs, they're not very accurate.

They make great noises and go like stink though. Love them on my PV.
Click to expand...

Makes sense and good to know on the Webers. I love my carb'd engines, though. They're a ton of fun and I'm doing my best to keep as much in life maintainable as possible (mind you this is on a thread about me seeking electronic ignition!)

SO, I have a set of those DCOE's (came with the car). If I were to put them on, before-hand, what do I need to hunt down? Jet sets and needles?

I'll be the first to admit I hate jetting carbs. SO much trial and error. I'm guessing a WB02 would make it a lot simpler. I'm still just dreaming about a set of those Mikuni slide carbs.
 
Are they already jetted for a Volvo engine? Google around and see what people have used on Volvo motors, they're probably close enough*.

No needles on DCOE's. The main tuning pieces you'd change are:
- venturis/chokes
- idle jets
- main jets
- emulsion tubes
- air corrector jets
- accelerator pump jets

What size DCOE's are they? I have a set of 40's on mine, which are almost certainly too small. they were just cheap, and far better than the SU's were, so it's a case of the good being the enemy of the better.

* - Tuning on carbs ranges from 'it runs' to 'it runs perfectly in all situations'. You have to be a real guru to get anywhere close to the latter, but the good news is that it's not that hard to get to 'pretty good'. Catalytic converters are far more picky than a motor itself is.

Mine tend to run a bit rich, but aren't happy when leaned out much. They snort and sneeze in cool weather. The mileage is not as good, from mid 20's with the SU's to high teens with the Weber's. But then the Webers make putting the pedal down so much more fun that I do it more.
 
JohnMc said:
Are they already jetted for a Volvo engine? Google around and see what people have used on Volvo motors, they're probably close enough*.

No needles on DCOE's. The main tuning pieces you'd change are:
- venturis/chokes
- idle jets
- main jets
- emulsion tubes
- air corrector jets
- accelerator pump jets

What size DCOE's are they? I have a set of 40's on mine, which are almost certainly too small. they were just cheap, and far better than the SU's were, so it's a case of the good being the enemy of the better.

* - Tuning on carbs ranges from 'it runs' to 'it runs perfectly in all situations'. You have to be a real guru to get anywhere close to the latter, but the good news is that it's not that hard to get to 'pretty good'. Catalytic converters are far more picky than a motor itself is.

Mine tend to run a bit rich, but aren't happy when leaned out much. They snort and sneeze in cool weather. The mileage is not as good, from mid 20's with the SU's to high teens with the Weber's. But then the Webers make putting the pedal down so much more fun that I do it more.
Click to expand...

I'll have to check when I get home tonight, but I believe they're 45s. I figured that they'd be running rich, which is where the mechanic's fears that they can unseat rings and flood the engine with gas probably comes from. Considering that since I already have everything to install the DCOEs I'll get them on there, and if it ends up upsetting me then I'll go back to my Weber downdraft.

Biggest thing is that I don't want to hurt the engine. The car isn't an everyday driver though - collector's plates and a garage a few blocks away from my house means it's more of a road-tripper / canyon carver / weekend driver.

SO, starter point:
-Crane or 123Ignition
-New fuel filter (or 2!)
-Get the DCOEs on there and reconnect the aftermarket fuel pump (mechanic moved me back to the mechanical one)


From what I understand the PO had the mechanical pump going to the aftermarket pump. Is that a bizarre move?
 
45's can be set up for much smaller engines than a Volvo B18/B20. It's not a case of it being too much carb for the engine, it's all just up to how the carbs are set up. Carbs that are too big for a motor tend to run a bit lean anyhow? Well, depending, of course, on how they are set up.

The tuning/setup starts off by picking the venturi size, and then going on from there. You can certainly go too big with the venturis, where the motor can't pull enough air through a larger hole to make enough vacuum to properly pull gas into the airstream.

40's are just adjustable to a smaller range, 42's are an oddball size that has limited range of available parts, and 45's have a very wide range.
 
PCH said:
Found old thread about B18-B20 ignition options: http://forums.turbobricks.com/showthread.php?t=277517&page=2
Click to expand...

Nice! Looks like the Compufire is the way to go, after all. Breaking into the ignition power might be a bit of a thing (no clue what that's gonna involve).

The one thing I wasn't sure about though was whether a points-replacement like Compufire or Pertronix would add as much power as the 123Ignition or Crane.
 
Any input on that? I'm guessing hiperfauto would have the best advice considering he's had all of them at one point.

Also, I've had a lot of experience with condensers going out on motorcycles and being tough to figure out if that's the problem - any thoughts on whether that's an issue for 140s?
 
Can't comment on the Compufire thing. The Crane models that I have seen, definitely the Pertronix (and the clone that looks just like the Pertronix) and I believe the 123 are primarily points replacement systems (with the 123 providing the option for a user defined timing map). They use an opto or Hall sensor to replace the mechanical switching of the points and they switch the ignition coil current with a power transistor. Some of them appear to use power darlington pairs for the coil current switching because the voltage across the switching module is very high when it is in its conducting state (about 2 volts). That high VCEsat voltage eats into the voltage available to energize the coil, reducing the coil primary current and potential spark energy. If your electrical system is good and runs around 13.8 volts all the time, then that reduction may not be material unless you start pushing the RPMs or you have a weak battery and a car that is hard to start already.

The points replacements systems eliminate the points and the wear issues associated with points. Except for the 123 system, they don't eliminate the wear issues associated with the advance mechanisms. The pure transistor switched systems (with the exception of the multi spark systems) generally result in a weaker spark because the high switching voltage on the modules reduces the maximum coil charging current. You can fix this to a certain extent by putting in a different coil with a lower internal resistance; however, some of those ignition systems are very explicit about not using low resistance coils because they are not rated for the increased coil current.

Keep in mind that if you are not suffering from ignition related misfires, a hot ignition system is not going to do anything for you. If you install an electronically switched system and retain the original coil, you have likely reduced the peak spark energy that the coil can generate and may induce misfires at high RPM.

B&G provide an interesting little calculator which allows you to estimate the reduction in spark energy with a change in coil voltage (or other parameters).


http://www.bgsoflex.com/igncoil.html
 
142 guy said:
Can't comment on the Compufire thing. The Crane models that I have seen, definitely the Pertronix (and the clone that looks just like the Pertronix) and I believe the 123 are primarily points replacement systems (with the 123 providing the option for a user defined timing map). They use an opto or Hall sensor to replace the mechanical switching of the points and they switch the ignition coil current with a power transistor. Some of them appear to use power darlington pairs for the coil current switching because the voltage across the switching module is very high when it is in its conducting state (about 2 volts). That high VCEsat voltage eats into the voltage available to energize the coil, reducing the coil primary current and potential spark energy. If your electrical system is good and runs around 13.8 volts all the time, then that reduction may not be material unless you start pushing the RPMs or you have a weak battery and a car that is hard to start already.

The points replacements systems eliminate the points and the wear issues associated with points. Except for the 123 system, they don't eliminate the wear issues associated with the advance mechanisms. The pure transistor switched systems (with the exception of the multi spark systems) generally result in a weaker spark because the high switching voltage on the modules reduces the maximum coil charging current. You can fix this to a certain extent by putting in a different coil with a lower internal resistance; however, some of those ignition systems are very explicit about not using low resistance coils because they are not rated for the increased coil current.

Keep in mind that if you are not suffering from ignition related misfires, a hot ignition system is not going to do anything for you. If you install an electronically switched system and retain the original coil, you have likely reduced the peak spark energy that the coil can generate and may induce misfires at high RPM.

B&G provide an interesting little calculator which allows you to estimate the reduction in spark energy with a change in coil voltage (or other parameters).


http://www.bgsoflex.com/igncoil.html
Click to expand...

Wow, thank you! That is completely contrary to what I've heard before (that electronic ignition can improve fuel efficiency and power by providing a more powerful spark).

I will say that my experience in motorcycles (again, I know that's not 100% translatable) is that there's a marked improvement when electronic ignition is installed.
 
The 'easiest' ignition improvement you can do is if you can find some fine wire spark plugs like the NGK G Power or Iridiums (about the most expensive), Champion or Bosch equivalents. Just a plug with a single fine wire center electrode in platinum or iridium. None of that silly multi gap stuff.

Fine wire plugs take less voltage to fire the gap than a conventional electrode arrangement (like the NGK copper) and are more resistant to fouling. Unfortunately, I think the biggest problem may be finding a suitable heat range. A couple of years ago when I checked the only thing that came close were some NGK iridiums in the 6 heat range. 6 might be OK with your F head (if it has original CR) and your cooler climate. I think that 7 seems to be the more commonly preferred heat range for NGKs in B20s.

The biggest improvement in ignition performance / starting that I got in my old Honda CB750F (which had transistor switched ignition - wasted spark coils) was installing NGK Iridiums.
 
I'd vote for a 75 240 Bosch breakerless and a good blue coil. Or, if the budget allows, ms, crane opto pickup and a Bosch blue coil... ms1 box... $300 with a small harness, crane opto... $45, Bosch blue...$50. A 123 dizzy is about that much, and when you figure out that the carbs are a tiny bit short of your goal, you have fuel injection for just a few dollars more.
 
142 guy said:
The 'easiest' ignition improvement you can do is if you can find some fine wire spark plugs like the NGK G Power or Iridiums (about the most expensive), Champion or Bosch equivalents. Just a plug with a single fine wire center electrode in platinum or iridium. None of that silly multi gap stuff.

Fine wire plugs take less voltage to fire the gap than a conventional electrode arrangement (like the NGK copper) and are more resistant to fouling. Unfortunately, I think the biggest problem may be finding a suitable heat range. A couple of years ago when I checked the only thing that came close were some NGK iridiums in the 6 heat range. 6 might be OK with your F head (if it has original CR) and your cooler climate. I think that 7 seems to be the more commonly preferred heat range for NGKs in B20s.

The biggest improvement in ignition performance / starting that I got in my old Honda CB750F (which had transistor switched ignition - wasted spark coils) was installing NGK Iridiums.
Click to expand...

Oh man, yeah, I have iridium plugs in my CX500 and they're way better. CB350 is still stuck with the stock ngk's and I'm takin them out every couple of months to clean (mikuni carbs run pretty rich!)
 
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