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

[forcefed86]

Think I'm floating valves with my current setup in sig. Around 28psi. Currently run 110# springs. Less than 50 miles on them. Car seems to break up at anything over 25 and get worse as boost rises. No knock. Really doubt it's plugs. I think I'm just runnign to much boost for my cam/boost levels.

I'd like to run the highest "safe" spring pressure on the factory componets. Suggestions?

Thanks!

 

[87chrisss]

are your grounds good? maybe to much spring pressure grinded down a lobe.., ive gone a bit over 30#'s by mistake on stock valve springs/cam no breaking up... from what i understand the stock cam really just limits your rpms and when you make the hp tq levels...dont think its limited to boost levels

 

[forcefed86]

are your grounds good? maybe to much spring pressure grinded down a lobe.., ive gone a bit over 30#'s by mistake on stock valve springs/cam no breaking up... from what i understand the stock cam really just limits your rpms and when you make the hp tq levels...dont think its limited to boost levels

I doubt it’s a ground issue? Isn’t the coil module/pack grounded through the mount directly to the motor? I have several large ground wires from frame to the motor. If the coil pack isn’t grounded through the case though I may have a poor ground I suppose? I’ll try a smaller gap and new plugs. Maybe different wires. I did go from a 90lb spring to a 110 last season. Floating valves around 6k for sure then. Switched to a 3.08 from a 3.27 gear though so I don’t need to rev that high. I run the zink addatives and VR1 20/50 oil so I shouldn’t have an issue. No evidence of metal in the filter. (last season anyway) I’ll have to check again. The only thing I found this winter was a few boost leaks which I sealed and a slightly larger 72mm turbo.

 

[87chrisss]

well hopefully it isnt the cam, but maybe you have a weak spark plug wire and or coil or bad plug, what are you gapping your plugs and what plugs are you running? .032? .030? 42's?

 

[bison]

What rpm are you at?

 

[forcefed3.8's]

What headgaskets are you running? There are alot of things that can cause breaking up.

 

[forcefed86]

well hopefully it isnt the cam, but maybe you have a weak spark plug wire and or coil or bad plug, what are you gapping your plugs and what plugs are you running? .032? .030? 42's?

Autolite race plugs AR132. (6 steps colder than stock, non-projected) With e85 You get no plug fouling so I see no point in running a warm plug. Gapped at .024 out of the box. Coil module is less than a year old (magnavox unit). High output coil less than a year old as well.

What rpm are you at?

Seems to be boost related. Since fixing all my boost leaks, and running open 3" DP I get quite a bit of creep. WG set to 25psi, holds steady until 5300 or so and creeps up to 30. Starts breaking up around 27-28psi.

What headgaskets are you running? There are alot of things that can cause breaking up.

RJC SS HG's. ARP studs.

 

[forcefed3.8's]

I had steel shim headgaskets leak and cause a pop. If everything else is ruled out, pull the heads and check for carbon tracing.

 

[forcefed86]

I had steel shim headgaskets leak and cause a pop. If everything else is ruled out, pull the heads and check for carbon tracing.

Arg... Maybe try a re-torque first... Pulling heads isn't in the time frame at the moment. Thanks for the tip though!

 

[87chrisss]

does your fuel climb when it starts to creep? have you ran those plugs before and had good results with this amount of boost? these motors seem to like basic plugs why dont you try some basice autolite 23's or ac delco's 42's gap'd tight? just for the hell of it i understand your point with e85 but these motor's always seem to like basic plugs, in my rx7 12a turbo on e85 i would eat up all my plugs the only ones that worked for me @ 35 psi were some ngks racing 115's they were priceyyyy, but they were the only one's that worked i think you should look into your plugs try some tight gap'd 42's cant go wrong trying them out they are cheap ass hell

 

[forcefed86]

does your fuel climb when it starts to creep? have you ran those plugs before and had good results with this amount of boost? these motors seem to like basic plugs why dont you try some basice autolite 23's or ac delco's 42's gap'd tight? just for the hell of it i understand your point with e85 but these motor's always seem to like basic plugs, in my rx7 12a turbo on e85 i would eat up all my plugs the only ones that worked for me @ 35 psi were some ngks racing 115's they were priceyyyy, but they were the only one's that worked i think you should look into your plugs try some tight gap'd 42's cant go wrong trying them out they are cheap ass hell

Already got a set on the bench... I'll try anything at this point. Fuel rises AFR's in check. I used these plugs all last season. Boost didn't creep up as much though with the old turbo and boost leaks. Usually creep to 27 or so if set at by redline. Now it creeps slightly over 30. But the motor just powers down and breaks up. It's a light missing sensation with loss of power. Not an abrupt sputter/pop.

 

[87chrisss]

hope it works out please keep us posted, watsup with that 1st gen damn i loved my little 12a bugger zipping around town @ 13k rpm... good luck hopefully those plugs will be it..

 

[Blazer406]

Close the gap down to 0.018"

 

[forcefed86]

hope it works out please keep us posted, watsup with that 1st gen damn i loved my little 12a bugger zipping around town @ 13k rpm... good luck hopefully those plugs will be it..

Sold the daily driver 1st gen. Bought a tubbed 79 1st gen. Working on a ls1 turbo setup for it. It doesn't weigh much so it should scoot around 600hp levels and last awhile. Hope to finish it up this winter.

Close the gap down to 0.018"

Will do. I hope it's spark. I'm dumping a ton of fuel in this thing now with e85. May just have a difficult time lighting it all off.

 

[87chrisss]

damn that 1st gen looks mean@!! i can see your not a fan of rotary, i was a huge fan they run HARD.. check it out

 

[87chrisss]

now your making me want to go buy one and throw in my spare lc2 motor in it!!

my buddy's still run the rotary's they have world record's my good friend run's the car named Time Machines Racing its a second gen fastest irs suspension 8's my other buddy runs low 8's toyota corolla with a 13b called most wanted they are all over youtube impressive what the little motors can do

 

[forcefed86]

Nothing against rotaries. Played with them alot in highschool. IMHO I can make more power for less money with cheapo LSX series junkyard SBC's. Been picking them up for less than $300 for a semi complete long block. When I blow one I won't even trouble shoot it. I'll just pull it and drop in another. Should last a long time around the 600hp mark. Local here just set the stock shortblock record with an FB chassis. 8.65 @ 167.9. 140k junkyard 5.3 motor, shortblock is oem right down to the rod bolts. This car was driven to wichita from kansas city as well (3hrs).

 

[bison]

Sold the daily driver 1st gen. Bought a tubbed 79 1st gen. Working on a ls1 turbo setup for it. It doesn't weigh much so it should scoot around 600hp levels and last awhile. Hope to finish it up this winter.

Will do. I hope it's spark. I'm dumping a ton of fuel in this thing now with e85. May just have a difficult time lighting it all off.

Richer mixtures fire easier than lean ones. Why don't you pull the wires one at a time and observe the spark?

 

[forcefed86]

Richer mixtures fire easier than lean ones. Why don't you pull the wires one at a time and observe the spark?

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.

 

[forcefed86]

So one reason the car was running horribly was the alternator stopped charging and I just noticed last night. Replaced the alternator, new wires, new plugs gapped at .020. Runs and drives normal. Found a hole in the WG diaphram. Half-ass fixed it with a small dab of JB quik weld and went to the track. No more creep. But still has the same symptoms. Tried 18-26 psi. Anything above 5500 any boost range the power drops off and I can feel a very slight missing. I go roughly 90mph in 1st gear. I can short shift 1st at 5k avoiding the break up and it pulls clean up until the top of second around 5500 again. No Knock. Managed many 10.50 passes around 132mph. AFR in the 10.7 range timing at 21*. Can't figure it out... same exact setup with the 3.27 gears would rev to 6300 rpm at 30 psi last year.