Max Valve spring pressure on OEM Valve train? (low rpm 5800)

[bison]

I was thinking the volume of fluid in the chamber would be excessive with all the e85. E85 also doesn’t burn as well as standard petrol. This is why you get hard starting in colder weather. I assumed this was due to the volume, maybe it’s just the octane rating and slower burn.

Tried some r42s gapped at .020 last night. Car ran terrible and sputtered like mad. Didn't have time to pull them again. I did pull each wire individually to see if one cyl or lead was to blame. All appeared to be firing, definite change could be heard as each was pulled and replaced. Very visible strong spark jumping. #6 lead spark jumped up and bit me. I'll be replacing wires today. I either damaged an electrode or .020 is just to close. I have more time tonight. I’ll pull them all and try again.

With the heat and pressure in the cylinder under power it will fire very easy if the ignition is up to par. If throw another set of plugs in and make sure voltages and grounds are gtg.

 

[forcefed86]

With the heat and pressure in the cylinder under power it will fire very easy if the ignition is up to par. If throw another set of plugs in and make sure voltages and grounds are gtg.

Used a spare set of r42ts plugs I had the first time around (wed) Thursday I bought a new set with new wires and alternator. Are the IGN module/coils grounded through the case? I assumed they were, ground all the paint off and have some huge ground straps on the bolts securing the module. If not I suppose I could fortify/add another good ground to the harness going to the coil module. Also could jump power straight from the bus to the module and try it out. It's very close. Could also give the old iridium plugs a go...

Thanks!

 

[forcefed86]

Well nothing made a difference. I was able to turn the boost down to 25-27 without it spiking like it was, no change in symptoms. Several 10.40 runs. New plugs/wires/coil pack/module. Tried gapping at 22-19 with no difference. Really leaning towards the valve springs at this point. As it seems not boost, but RPM related. Anyone think 125# springs are overkill? As long as I kept the RPM down under 6k do you think the cam would survive? I hear of much higher spring pressured being used on factory valvetrains that this. Why do buicks seem to munch cams with very moderate pressure springs? (I use high zinc oil and additives)

I Could try another coil pack, but as I said this is a new high output pack. Wish these cars were a bit more common! Then I could swap parts with poeple. Guess i need to start looking into mustangs and hondas.

 

[we4Mateo]

Well nothing made a difference. I was able to turn the boost down to 25-27 without it spiking like it was, no change in symptoms. Several 10.40 runs. New plugs/wires/coil pack/module. Tried gapping at 22-19 with no difference. Really leaning towards the valve springs at this point. As it seems not boost, but RPM related. Anyone think 125# springs are overkill? As long as I kept the RPM down under 6k do you think the cam would survive? I hear of much higher spring pressured being used on factory valvetrains that this. Why do buicks seem to munch cams with very moderate pressure springs? (I use high zinc oil and additives)

I Could try another coil pack, but as I said this is a new high output pack. Wish these cars were a bit more common! Then I could swap parts with poeple. Guess i need to start looking into mustangs and hondas.

Haven't seen a wiped lobe yet from someone using a good amount of ZDDP in their oil so I think you'll be fine. These engines just developed a reputation, but everyone that tries to steer me towards roller b/c of a wiped lobe wasn't using ZDDP or a good oil with it already in it. Most new grinds have a reverese tapored #3 exhaust lobe to promote spin which was an issue in the past too that has been resolved. I have 15k miles and 50 passes or so on my flat tappet engine with 100lb springs and everything is good to go.

 

[forcefed86]

Haven't seen a wiped lobe yet from someone using a good amount of ZDDP in their oil so I think you'll be fine. These engines just developed a reputation, but everyone that tries to steer me towards roller b/c of a wiped lobe wasn't using ZDDP or a good oil with it already in it. Most new grinds have a reverese tapored #3 exhaust lobe to promote spin which was an issue in the past too that has been resolved. I have 15k miles and 50 passes or so on my flat tappet engine with 100lb springs and everything is good to go.

Thanks for the input. Running the 110# springs at the moment. I also run more boost pressure than most since my engine doesn't exactly flow well. Springs may not be the issue but I sure wish I knew a way to eliminate the possibility....

 

[SHADOWII]

What about the waste-gate? Is it possible there is a problem w/the spring or diaphram?

 

[GARY HARVEY]

Check the coil pack and follow up insuring that all of the ground locations are clean & secure.