TheSamba.com :: View topic

Wed Mar 03, 2004 6:16 pm

I've got the freshly de-GEXED engine running great since Sunday, but have found some conflicting info regarding timing - and little about the type 4 especially. I want to protect my investment - and wouldn't hear detonation over the exhaust and carbs - so I'm paranoid.

Checked the archives here - not much on type IV. *sniff!*

Here's the stats:
72, ugly, lots of heart.
little or no hesitation, smooth, much more torquey than before. (yayyy!)
stock compression, 1700cc pancake
using 92 or 93 octane only
Webers (40IDF)
009 distributor (looks new, appears to function smoothly when timing light used)
currently set around 4 deg. BTDC at idle and full advance about 26 (?), but not sure where I SHOULD be at FULL advance. I've tweaked it a bit more advanced since starting up the thing, but only by ear, so the above is my best guess, since ATDC settings didn't cut it at all.

28? 32? more? less for a type 4 at full adv?

The shop manuals would be great if the motor had stock dizzy, but show timing AFTER TDC for most applications, with other distributors.

Thanks for any help !

Zwrench

Wed Mar 03, 2004 7:42 pm

I am not a 009 guy but perhaps this will help. I am not convinced they are an asset to a type 4 in a bus, but that is just my opinion.

http://www.bostonengine.com/articles/009.html

Unless you are pinging from pre-ignition, I would not think you would need the premium fuel. Stock compression. Regular should be OK.

Wed Mar 03, 2004 11:27 pm

I think you can advance it some more. I thinks as much a 12 degrees advanced at idle if it does not ping under load/ and or overheat.
take the light/tools with you and time it on the road is what I personally would do.

I found a real old thread.... read through the whole thing

http://www.thesamba.com/vw/forum/viewtopic.php?t=27506&highlight=maximum+advance

appears "aufever" is now "Karl" he had some good advice and corrected me on an assumtion I had about how much advance a type2/4 engine can handle.

or you may want to try a stock distrib, but I think the 009 should work well with those webers

Wed Mar 03, 2004 11:48 pm

Each engine combination is different! Chamber shape, deck height, piston design (dished or flat top etc) will play key roles in the equation.

The best thing to do is try different settings and keep a log of your results and seat of the pants feel. Log gas mileage, log temperatures going up the same grade at the same speed at wide open throttle. To do it right you need a CHT gauge and run the fuel that you plan on running.

Before I had a dyno I did this for my first time combos and then kept the settings for my engines that we shipped out as a known standard..

Alot of people trick themselves with running 32 degrees of advance because the engine feels faster there! Thats simply because you most feel acceleration in first and second gear and you feel THE RESULT OF HIGHER INITIAL ADVANCE that comes along with the HIGHER FULL ADVANCE! With a 009 you don't have the capability to up the initial advance while limiting full advance.

Long story short timing that is as little as 2 degrees from being optimized (either higheror lower) can cost you 10HP or 50 degrees of cylinder head temp, or as much as 5 MPG..... There is ONLY ONE correct timing setting for each engine, it can also be effected by enrichment.

There is no substitute for a dyno tuned engine, and no substitute for A Mallory....

To be safe keep your full timing at 28-30 for a Bus.