MAF Tuning For Larger Cam - Roller 304 Engine

[Monarols71]

Hi All.
Manifold and ECU upgrades on hold after we had a lifter guide retainer plate break a couple of fingers which ruined the camshaft and some roller followers. For the moment, we have put a 230/230 @110LCA flat tappet cam and associated parts in place of the 220/220 @ 110LCA roller cam until we can get tie rod rollers lifters, new cam etc.

Obviously we now have tappet rattle under hi load low revs, because we are using the old tune as a starting point.
I have been taking some advance out of the "Main Spark Advance Vs. RPM Vs. mgc" table. Is this correct, or am I going down the wrong path.

Any guidance or advice hugely appreciated before we do more damage to the old girl or the new parts.
Kind Regards

[HQ355]

Did you change the pushrods as well ? I know the roller ones are shorter

[vlad01]

whats your AFR readings like around those areas?

[Monarols71]

You're correct HQ355, and pushrods sure are changed, and have correct 1/2 to 3/4 turn tension.
vlad01 - I don't know but I'll check the log if I can find the correct area.
Cheers

[vlad01]

Im guessing you dont have a wide band O2 then?

[Monarols71]

AFR Chart.PNG (39.52 KiB) Viewed 4436 times

No. Only what it left the factory with.

[Jayme]

thats your AFR target logs its what the pcm is aiming to do, not what is actually happening. post up the o2 sensor mv histogram.

Obviously we now have tappet rattle under hi load low revs, because we are using the old tune as a starting point.

im not really sure what you are getting at with this one.... its not really obvious as nothing you can do in the tune will make your tappets rattle..... and nothing you play with in the tune will stop tappets rattling. having too much spark advance might make it rattle from pinging.... is that what you were getting at??

generally a larger cam will like more timing, so unless it is pinging... start with a wideband and get your AFR's right. MAF based PCM will be measuring the grams of air going in, so the AFR's should be closish already.

[Monarols71]

AFR.PNG (54.55 KiB) Viewed 4425 times

Sorry every body. I meant "pinging" form too much throttle, under high load, 1 gear too high, if that makes sense.
Jayme, is this the chart you were after.
PS How the hell do I get the attachment to go to the end, not the start.

[Jayme]

PS How the hell do I get the attachment to go to the end, not the start.

you mean to scroll in the graph? using the scroll bar just below the graphs. engine RPM added to one of the graphs would also be helpful to read it. also you should see some knock retard from pinging in there somewhere.


on second thoughts. attach your XDL's and we can all look through the logs in tunerpro.
to answer your first question - yes removing spark advance is correct, but also be wary of really lean mixtures (which we should be able to identify int he log you post up)
need to be sure its actual pinging and not some other noise, as the pcm should be detecting knock and showing knock retard in the log and removing timing for you.

[HQ355]

Is the lift different on new cam ? What car is it in and is it auto or manual ?