472 sputters at WOT?? Help!

[DanE]

My uncle's 73 454 SS came from the factory running 240*. While on a trip running around Florda we desmoged it,recurved the distributor. jeted the carb, and installed a 180* thermostat. It ran noticeably better.

[White Lightning]

Originally Posted by DanE

My uncle's 73 454 SS came from the factory running 240*. While on a trip running around Florda we desmoged it,recurved the distributor. jeted the carb, and installed a 180* thermostat. It ran noticeably better.

Back in the early 70's engine temps were raised in order to bring down emissions (unburned hydrocarbons) because of not-so-efficent combustion chamber designs that were left over from years before.
Rob

[bigblok86ranger]

Originally Posted by 92stango

thanks rob for the advice i will start with the jets you and A70 recomended as well as the advance in timing ill check the power valve as well! and big block ranger i have noticed the car running hot, with a huge 3 core alum rad and 160 tstat , markviii fan its touching 210+ cruising in 80 degree temps, not enough advance will cause it to run hott?

I ran my 86 gt with factory for cylinder radiator and cheepie electric fan and factory water pump in 110 weather and sitting in a traffic jam for over an hour never went over 195. So yes timing plays a very big role in engine temps.

[92stango]

i picked up a holley jet kit today and hopefully ill get the carb back on the car tonight and make all the recomended adjustments! ill let you guys know how she runs!

[CarsByCarl]

Originally Posted by 92stango

i have a msd billit dizzy and 6Al box, base is set at 0 and it locks out about 20. as i rev up to 4k. also it has silver advance springs

Are you still only running 20 degrees total timing? It's never going to run right till you get the timing right. Set it at 30 total, with 76/84 jets, 4.5 primary power valve, plugged secondary power valve, and go from there.

[92stango]

Originally Posted by CarsByCarl

Are you still only running 20 degrees total timing? It's never going to run right till you get the timing right. Set it at 30 total, with 76/84 jets, 4.5 primary power valve, plugged secondary power valve, and go from there.

i havent adjusted it yet, i pulled the carb to change the jets and i will have it back on tonight and then i will adjust the timing as recomended. once i get it running ill take it out and she how she responds, and check the plugs as mentioned before , ill let you guys know how it goes!

[BBFmavrick]

Before you even attempt to set timing.make sure you find TDC with that adjustable timing pointer.If you don't,you will never know the correct timing. If you don't know how to find correct TDC,just ask and we will guide you through it. The correct timing will wake it up for sure.

[92stango]

ok everyone , i installed 78s and 84s set base timing at 12 and total was right around 30-31, it runs alot better and cooler to mention but im still having some sputter and i take my foot out of it beause right around the same time the secondaries open and it starts to sputter my oil pressure drop almost to zero! and it is consistant with rpm starts around 3200 and just drops. because of this i havent really been able to see how the motor runs above 3500- 4k. i am using a autometer electric gauge and sender on the back of the block 10-40 royal purple 6qts in a FMS swap pan. new oil pump w/ arp drive. the gauge is smooth and brand new when crusing under 3200 its ok, but even slowly depressing the accel pedal past that i see oil press flutter and drop???? any ideas??

oil pressure reads 75 cold , 30 warmed up and will raise up to 60-75 when accel up to 3200 and start to fall above that or drop to zero with a WOT

[White Lightning]

Originally Posted by 92stango

ok everyone , i installed 78s and 84s set base timing at 12 and total was right around 30-31, it runs alot better and cooler to mention but im still having some sputter and i take my foot out of it beause right around the same time the secondaries open and it starts to sputter my oil pressure drop almost to zero! and it is consistant with rpm starts around 3200 and just drops. because of this i havent really been able to see how the motor runs above 3500- 4k. i am using a autometer electric gauge and sender on the back of the block 10-40 royal purple 6qts in a FMS swap pan. new oil pump w/ arp drive. the gauge is smooth and brand new when crusing under 3200 its ok, but even slowly depressing the accel pedal past that i see oil press flutter and drop???? any ideas??

oil pressure reads 75 cold , 30 warmed up and will raise up to 60-75 when accel up to 3200 and start to fall above that or drop to zero with a WOT

Ok. You probably have an electrical connection problem I'm guessing. Ground on the engine? Throttle linkage hitting the wiring harness? Alternator going haywire at a certain engine RPM? Wiring harness loose at the firewall connection? Broken wire that's moving? Have you got a rev limiter somewhere in the system? The fluctuating oil pressure indicates that you have a wiring problem with that, at least.
Check it out.
Rob

[92stango]

Originally Posted by White Lightning

Ok. You probably have an electrical connection problem I'm guessing. Ground on the engine? Throttle linkage hitting the wiring harness? Alternator going haywire at a certain engine RPM? Wiring harness loose at the firewall connection? Broken wire that's moving? Have you got a rev limiter somewhere in the system? The fluctuating oil pressure indicates that you have a wiring problem with that, at least.
Check it out.
Rob

Hey Rob i did indeed find that my oil pressure wire was loose ! also i added a ground to the sending unit. i revved the motor up a few times past 3500 and the gauge seemed to operate properly! i would like to go test drive it to make sure that was the problem but after all the beer i drank i dont think its a good idea! i will take it out tomarrow and run WOT a few times and let you guys know what happens, i would also like to thank everyone for the great advise and help with project

[bigblok86ranger]

Hope that cures the problem, I had a similar oil pressure once and turned out my buddy has dropped my engine down a little to fast and caved the oil pan in. It sure didn't look like enough to do any harm but the oil pickup was to close the pan so I had to pound out the spot on the oil pan while it was off I welded some 1/4" feet on the pickup to prevent any further issues.