Toyspeed.org.nz Message Board

*My KE70* · by **solberg Fan** » Mon Jul 17, 2006 12:22 am

Hey,
Ive got a 4k and im trying to set the ignition timing. In sure your suposed to advance it take it for a run and if theres no knocking do it again untill it starts to knock, then take it back a few degrees. Im using 95 octane (its a race motor) and its curentky at 50deg BTDC at around full revs and that sounds like its way to much to me!!

Ive had it up to 8000rpm (rev limit) but still cant here any pinking..... and i dont want to take it any further. Its at 20deg at idle (vacume advace is disconected also) The mechanical advance reaches its max advance at 4000 rpm. IE it dosnt advance any more from 4k to 8k. Is that normal?

Im not to keen on damaging the motor at all. Its running standard compression ratio with lumpy cam if that matters. Its a new head that hasnt been skimed yet as i wanted to see what the standard C/R would be like. It loses power from 7000 onwards. im gessing the exhaust cant be helping as its not the best and im going to try running with out the air filter/pipe to see if that is causing any problems, altho it shouldnt.

Let me know what you think...

Details of car here · by **AE85coupe** » Mon Jul 17, 2006 10:12 pm

advance the shit out of it, i've come across numerous 4k's that seem to happily go way past the factory specs and run much better

by **Crucible** » Mon Jul 17, 2006 10:34 pm

Just set up the dwell to specs or approx .45 - .5 using feelers, advance until it begins to pink and then back it off untill it stops. Because its not factory the specs go out the door, this is the next best way apart from on a dyno of course...

OMG so shiny! · by **Dell'Orto** » Mon Jul 17, 2006 10:36 pm

Yeah, 4K's seem to be able handle lots of timing, I guess due to the lowish compression they run. With a bigger cam too, you're probably running even less than stock compression, depending on how much overlap it has.

by **matt dunn** » Mon Jul 17, 2006 11:51 pm

Really?

Most race non turbo motors i've had anything to do with max out at about 36deg on WOT.

You can run more at cruise etc

*My KE70* · by **solberg Fan** » Mon Jul 17, 2006 11:59 pm

So just keep on going untill it starts to knock then back it off a few degrees? 50 deg just seemed like heeps to me but i will keep going. Altho im not to sure about the lower compression ratio due to the overlap in the cam. At high revs it should raise the compression (comared to static). Over lap should help with scavenging and not lower the compression ratio. Well that was my understanding anyway.

And yep, i will check the dwell also. If you have any other coments or advice, please add!

by **matt dunn** » Tue Jul 18, 2006 12:02 am

Advance it too far and it will run a bearing.

*My KE70* · by **solberg Fan** » Tue Jul 18, 2006 12:02 am

matt dunn wrote:Really?

Most race non turbo motors i've had anything to do with max out at about 36deg on WOT.

You can run more at cruise etc

I thought 36 deg was about normal too! Have you ever set the timing doing it the way i am? Or in other words how do you set it? I dont want to run into preignition...

by **matt dunn** » Tue Jul 18, 2006 12:22 am

No. Never done it that way, as you will not always hear detonation.

With N/A engine we either set up the dist in a distributograph and then just set base timing,
or run electronic advance via an ECU.

Different 4K distrubitors have different advance limits too.
some of them are printed on the weights.
Others we modify in then tester.

I have just ordered some new knock detection equipment this week too so will get to play around with it when I get my 4K corolla going again.

Matt

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Ignition Timing on 4k. Is it too much??

Ignition Timing on 4k. Is it too much??

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