Holley Sniper adjustments (1 Viewer)

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I did the desmog and added the Holley Sniper. I made some minor adjustments but haven't gotten in detail yet with the programming so it's pretty much out of the box as far as set up. I am getting pre detonation with whatever fuel type I run when I lug the motor. I have the stock dizzy, wires and ignition coil. So I am considering upgrading these things before I go any further however I really don't want to if I don't have to.

I haven't checked the timing yet either that is on the bucket list. Do you think that a timing adjustment and adjustment to the Sniper can fix these problems or will I just be beating my head off the wall without the other upgrades. ?

Thank you !
 
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I suspect you need to recurve your dizzy to account for the lack of EGR, but I'm not sure how much impact that would have on an EFI conversion.

I actually need to ship my dizzy off to Jim to be recurved for my EFI build.
 
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If your ignition is completely stock and you did a full desmog and you are getting pinging:

1: verify your base timing is set to to 7 deg btdc
2: try swapping the two vacuum on the vacuum advance.
3: because you removed the EGR you will likely need to have the dizzy recurved.
 
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I suspect you need to recurve your dizzy to account for the lack of EGR, but I'm not sure how much impact that would have on an EFI conversion.

I actually need to ship my dizzy off to Jim to be recurved for my EFI build.

efi cannot compensate for ignition problems.
 

MoaByte

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For now, put in 91 octane and retard your timing a couple degrees at a time until it stops. If I remember right, you want to use the inner port on the distributor.
 
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For now, put in 91 octane and retard your timing a couple degrees at a time until it stops. If I remember right, you want to use the inner port on the distributor.
Yes inner port . I’ll check timing later today . I’ve been using 92 it helps a little . Also tried ethanol free that didn’t help
 

MoaByte

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It feels good to free yourself from all the excess plumbing. How is your start up and idle? The turn around on a recurve is a couple months unless you DIY. You might want to get a DUI HEI, or non-smog dizzy for the meantime.
 
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It feels good to free yourself from all the excess plumbing. How is your start up and idle? The turn around on a recurve is a couple months unless you DIY. You might want to get a DUI HEI, or non-smog dizzy for the meantime.
It starts right up and idles fine . It’s in the high side 850rpm but I think that’s a minor adjustment
 

MoaByte

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It starts right up and idles fine . It’s in the high side 850rpm but I think that’s a minor adjustment
I settled for 750rpm. I had it at 650 but had stalling issues when engine braking before a stop. It still stumbles in that situation until it's coolant temp is about 180°. I need more tuning but have a valve or compression issue I need to get sorted first.
I'd be curious to see everyone's tuning numbers.
 
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Setting time on these seems a little different than I'm used to and I haven't used a timing light in 20 years... lol Is there a good guide on here start to finish ??
 

MoaByte

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It's on the flywheel, passenger side. There should be a shutter held on by a single bolt.
On the flywheel, there is a line for TDC and a divot (called a beebee). The beebee is 7° before TDC. It should be on the money. Mark it with some white paint. Your new timing mark will likely be somewhere between TDC and the beebee.
 

MoaByte

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Oh! Disconnect the vacuum hose. You need need to set your idle down to 700 or less so the centrifugal advance isn't giving you a false reading.

(Something you should know: the advance limiter in your dissy had a plastic cap that likely disintegrated allowing you to get too much advance, hence the pinging)
 
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7416D08F-A448-4755-AD7D-BD8DEF22C3C4.jpeg

Just painted mine actually, so if you need a photo reference, here is timing mark and bb.
 

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