Strange rpm limit

[dank GN]

I'm replacing my springs today with some fresh 980. My question is can I up the seat pressure by shimming them to somewhere around 100-105lbs?

 

[bison]

You could but you better be sure you're not in bind

 

[dank GN]

So I'm going to shim them till I get within .60" of coil bind right or get closer to 100lbs

 

[Chuck Leeper]

So I'm going to shim them till I get within .60" of coil bind right or get closer to 100lbs

Why not use a set of springs that will do the job, w/o the shims??

 

[RmvBfrFlght]

I would snap the throttle open and it would not want to go past 51-5200 but if I went through the rpm rang slow it would rev to 6k clean what would cause that to happen ? Springs ? I just ordered some but now I'm thinking it's ignition issues . With load it doesn't like to go past 5200

Check the fuel pressure/delivery. When the throttle is snapped open, and when under load, the engine requires more fuel.

Only a small amount of fuel is required when the RPM is brought up slowly.

RemoveBeforeFlight

 

[dank GN]

I have a transducer hooked up fuel is good just installed 430 LPh with SS fuel lines

 

[RmvBfrFlght]

I have a transducer hooked up fuel is good just installed 430 LPh with SS fuel lines

I'd say that you are good to go there.

RemoveBeforeFlight

 

[dank GN]

Cylinder 1 spring pressures
Should I go with the 981s?
Cam is broken in with 980s

 

[dank GN]

Tested a brand new set at 1.7 and 1.250

 

[Eticket]

Maybe I missed this - do you have an RPM problem under power?

 

[dank GN]

Yes right at 51-5200

 

[notacarlo]

What plugs and gap.

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[dank GN]

AC42 Gapped at .25

 

[Eticket]

Have you considered plug wires?

 

[dank GN]

Yes I ohmed out coil pack and wires and they checked out

 

[Eticket]

I know guys like to "ohm out" wires and coil packs, but unfortunately my experience is that tells you nothing. They need to "at least" be put through caspers tester. Sometimes, EVEN IF THAT CHECKS OUT, they sometimes need to replaced by a completely spare setup to pinpoint a problem.

I had a brand new set of known brand plug wires that were bad from brand new, I found out inadvertently that spark would randomly jump from the wire to the trans dipstick or firewall - I found out "for real" through my hand. I had already "ohmed" them out and also checked with caspers checker and didn't find the problem until the misc spark jump. This is why it is good to have a complete spare coil pack and module and even wires to make sure things are kosher. put a brand new set of "other brand" plug wires on and problem solved.

My car wouldn't pull past 5500 at the time (different symptom than yours). after the change, 7500rpm was no problem.

I ask all this because you don't have a big cam and I've never seen a small cam that didn't require much spring to begin with actually have issues with weak springs. Guys like to point to that as a problem and like to change valve springs, but I've actually never seen anyone with aftermarket springs and a small cam actually fix a problem with new springs. This is only my experience - that is all.

 

[dank GN]

My old springs seat pressure was down around 70 :-(

 

[dank GN]

Good point I have also had bad coils right out the box I will triple check