B212 + B204 cyl. head -- cam problem?

[hansUS2]

Hello,

Got a problem with my engine; I'm all out of ideas...

I run a B212 + B204 head, turbocharged. At .2-.3 bar, the engine pings; however, at max boost (.8 bar) it's fine. The harder I hit the gas, the worse the pinging is (really bad!). If I am very gentle with the gas and don't build any boost until after about 4000 RPMs, I don't get pinging. So, the pinging is only with a heavy foot, starting at lower revs, and really bad if I slam the gas.

Some details:

I run highest octane gasoline available.

Timing is 1986 EZK (Hall sensor in dist) AND a Turbo distributor that I "fixed" so it retards but does not advance under vacuum; Base timing is at 15* BTDC. I installed a Turbo ignition control module and removed EZK from timing control -- pinging persisted.

Plugs are NGK 7.

The Hall sensor was kind of sticky (didn't move back & forth easily) but I oiled it and it moves freely/easily now; it didn't solve the problem anyway.

Fuel is Volvo LH2.2. I have tried two different air mass meters; problem persists. Injectors were professsionally cleaned/tested.

Exhaust cam is from the B204 head but intake cam is from 89 900 Turbo. I saw an internet post that the B204 head is thinner and therefore the timing is advanced 10 degrees but don't have specs to confirm.

Sooo...before I go hunting for another intake cam, does it sound like the problem is the intake cam? Or, could it be that I need to go hunting for yet another air mass meter?

I know of an 11:1 compression ratio B202 running 1 bar, plus a number of 10:1 B202 cars running 1 bar or more, so this shouldn't be a problem, yes?! I'm running less than 10:1...

Thanks!

-Hans

[mågis]

I think that you should go hunting down another setting for the fuelinjection and probably another timing of your spark. I did not belive at first that the enginge would be able to ping (or as we say, SPIKA...) at such low boost as 0.2-0.3 bar of overcharging (at least that's how i read your figures .2-.3, but maybe i missunderstod that, let's hope...) Otherwise, i don't know what your problem might be...

[V4]

Maybe the volvo LH is to lean. You should try to run your engine with a lambda so you can see if its to lean.

Where do you live?

[hansUS2]

Maybe the volvo LH is to lean. You should try to run your engine with a lambda so you can see if its to lean.

Where do you live?

Seattle USA

I have a wideband oxygen sensor on the car and have ruled out fueling -- the Volvo stuff does a great job, even on the smaller engine than it was designed for.

Last week, I took out the 89 900T intake cam and put in a B204 intake cam, so now both intake and exhaust are the original cams from the B204 head I'm using. Then, I took some runs and listened for the "spika." Each time I heard it, I retarded the timing some more. I did this until, finally, at *four* degrees before top dead center, the spika stopped. The thing I don't understand is that the car drives *really* well now, especially at the low revs, yet the timing is completely off!

This is my first engine build, and I didn't pay too much attention to cam information. Apparently, the newer heads are thinner than B2x2 heads, which throws off cam timing by 10-degrees, so you're supposed to use B2x4 cams to keep the timing proper?? But the low end boost/response is so good that I wonder if the cams aren't too advanced now?? And what about the timing??

I am probably going to have to remove the crank pulley to "degree in" the cams to see where everything is lining up...

[ahlis]

Ive tried to rebuild a distributor from an B202T to a B202i (Bosch ignition) which was VERY unsuccessful .. the engine pinged all the time except unloaded .. and when the ignition where set completely wrong the engine run sort of properly ( didnt ping but it ran very bad below 3 000 rpm with standard cams)

I tried to find the error for about a year until I gave up ..

My tip is try to find a complete ignition set( I believe its Bosch to your engine) wich are made for the saab engine you use.

(Note: this was an engine without turbocharger )

Good luck

kind regards ahlis


( one more thing .. when you check ignition timing I hope you remembered to remove the vacuum hose (and plugged it) )

[hansUS2]

ahlis -- That is interesting that the B202T distributor did not work with the Bosch ignition; I think I'll try the original, '86 distributor at low boost only to see how it works. If it does, then I guess I'll take the EZK system out completely and run a Turbo system.

Thanks,

-Hans

[Fredrik1765]

Hi!

I think the best solution would be to do a DI convertion.

Described here in english: http://www.900aero.com/main/diy_main_di.htm

No ignition triggering is done via the intake cam so you'll get rid of that problem. + You'll get a lot more energy to the spark plugs

Downside might be that if You want to change your ignition map you'll need an EPROM burner and use some beta software developed by Ragnar here at the forum.
Don't know if anyone have tried creating a map and used it on a running engine yet??

Also, the parts needed might be hard to find in the US.

/Fredrik

[hansUS2]

Hi Fredrik,

I have looked into DI in the past for my other car, an '89 900T, but the U.S. market only got DI/APC, never the DI system separate from APC, as was sold in Europe for a year or two. So, you're right, parts would be a problem.

I may just end up going straight to Megasquirt or MSII; there is a guy here in the States who has machined the back of his flywheel with grooves and is using a c900 ABS sensor as a pick-up for a crank trigger -- he is going to EDIS. It looks like he still has some tweaking to do, but this would be a nice, elegant solution to feeding MS crank position info.

http://msefi.com/viewtopic.php?t=8052

[Fredrik1765]

Hi Fredrik,

I have looked into DI in the past for my other car, an '89 900T, but the U.S. market only got DI/APC, never the DI system separate from APC, as was sold in Europe for a year or two. So, you're right, parts would be a problem.

I may just end up going straight to Megasquirt or MSII; there is a guy here in the States who has machined the back of his flywheel with grooves and is using a c900 ABS sensor as a pick-up for a crank trigger -- he is going to EDIS. It looks like he still has some tweaking to do, but this would be a nice, elegant solution to feeding MS crank position info.

http://msefi.com/viewtopic.php?t=8052

http://msefi.com/files/flywheel_128.jpg

Guess whos driving MSnS-E controlling a Saab DI cassette then

My car was originally equippe with DI APC and the crank-signal is shaped to a 4-1 pattern using a slightly modifyed DI-Trigger disc. Same mod could also be done with an EZK trigger at crank, in fact it would be easier.

Just make a third opening between the two others (at 180*), same size. Then you'll need a couple of 1k resistors for modification of the MS harware.

If you're intrested just send me a mail/PM, and I'll give you a more comprehensive instruction.

/Fredrik