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revolve40

2.3L Stroker Dyno Results and Power Discussion

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So I pulled the plugs today and I've got some evidence of pinging on cylinder #2 only. The other three look fine... any thoughts?

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If this is a new build, it wouldn't be carbon buildup in that cylinder. The other possibilities are intake valve adjusted too tight, an intake leak or other cause of lean mixture in that cylinder (think idle mixture). 

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15 minutes ago, Chris_B said:

If this is a new build, it wouldn't be carbon buildup in that cylinder. The other possibilities are intake valve adjusted too tight, an intake leak or other cause of lean mixture in that cylinder (think idle mixture). 

 

Thanks Chris - appreciate all of your input. The head is new, but the short block is not. However, when apart, there was no excessive build up. I have soft mounts currently - I suppose it could be those?

 

The mixture screws are all pretty evenly adjusted to 2.75 turns out from seated. Air bypass screws are tight/closed. Come to think of it, my AFR at idle jumps around quite a bit. Not sure how much of that is normal (e.g. 12.0 - 12.5 - spike to 13 - back to 12, etc.). Should it be pretty solid? Idle is solid at 1000 rpm / 15* advance.

 

A vacuum leak could also explain the excessive shaking.

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Excessive shaking or high, unadjustable idle is a typical symptom of unbalanced carbs. My AF meter jumps all over the place at idle, but usually within  a range indicating (AFAIK) the approx. mixture (say, from 12.5 to 13.5, with occasional jumps above or below these levels).. I try to average these in my brain (not always easy) when adjusting my idle/transition mixture. There are so many factors involved between the carbs any your O2 sensor that I would be really surprise to see any installation with a rock solid AFR at idle. Maybe there is a perfect FI system out there somewhere...

 

Soft mounts are notorious for leaking. I gave up on them the last time I remounted my carbs and haven't looks back. AFAIK, I have had no negative effects from nuking those babies.

 

Most sources (always questionable) I have seen suggest that advance at 1K RPMs s/b ± 10° advance. I have no objective or even subjective evidence to prove this is right. It is what I am running now and seems to be OK. 

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38 minutes ago, Chris_B said:

Excessive shaking or high, unadjustable idle is a typical symptom of unbalanced carbs. My AF meter jumps all over the place at idle, but usually within  a range indicating (AFAIK) the approx. mixture (say, from 12.5 to 13.5, with occasional jumps above or below these levels).. I try to average these in my brain (not always easy) when adjusting my idle/transition mixture. There are so many factors involved between the carbs any your O2 sensor that I would be really surprise to see any installation with a rock solid AFR at idle. Maybe there is a perfect FI system out there somewhere...

 

Soft mounts are notorious for leaking. I gave up on them the last time I remounted my carbs and haven't looks back. AFAIK, I have had no negative effects from nuking those babies.

 

Most sources (always questionable) I have seen suggest that advance at 1K RPMs s/b ± 10° advance. I have no objective or even subjective evidence to prove this is right. It is what I am running now and seems to be OK. 

 

Thanks - carbs are in sync according to my flow meter. I'll bump back down a few degrees at idle to see how things go from there. I've also ordered a set of hard mounts from Pierce, so will add that as a to-do.

 

In retrospect, I wish I had bought 152G's with the fourth progression hole vs. the standard 3-hole 152's, but such is life. I've got a dyno appointment in the morning with the main objective being to confirm where my all-in timing should be. 

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Just curious   what kind of flow meter are you using?

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Looks just like mine. Are you testing only at idle, or at max motor shake?

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(edited)

At idle, which is max shake. Once it revs above 1500 or so it smooths out significantly.

 

Showed up for the runs and the dyno was out of commission. Rescheduling.

Edited by revolve40

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Well, I'm stumped. When was the last time you checked it. Sync has a way of going out of, when you make other adjustments in and around the intake system.

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1 hour ago, Chris_B said:

Well, I'm stumped. When was the last time you checked it. Sync has a way of going out of, when you make other adjustments in and around the intake system.

 

This morning haha. Might be par for the course with the 304, just not sure.

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