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Pinging 505 help

PeteyDaMan

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Location
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Hi all,
I’ve been racking my brain and trying everything I can think of but my 505 build pings pretty good under load. The motor only has 1500 or so miles on it but the issue seems to be getting worse as it gets driven more. Here’s the list of things I’ve tried:

- I have a Wide Band O2 gauge that shows 10-11.5 under load and the plugs also show no lean conditions. Rejetted the carb every way to Sunday.
- Tried 110 VP race fuel. This did quiet it down a lot but it was still there under heavy load. Normally I run 93 with a mix of 100LL AvGas
- I backed the timing off considerably and limited the overall advance to 18 total (starts at 10 goes to 28) with the heaviest springs. It has an MSD ProBillet distributor and a 6AL box
- Took the PCV system off and replaced with a couple breathers on each valve cover
- Checked for vacuum leaks with a smoke machine. Capped off everything. No heater controls, not power brakes, no PCV.
- Pulled the heads and had them checked. No issues found
- Lowered the compression from 10.5:1 to 10:1 with thicker Cometic MLS head gaskets.
- Reset the cam timing to straight up.
- check and rechecked valve preload.
- tried colder spark plugs

Details of the engine build are as follows:
  • 77 440 RV block bored, clearanced and checked by LRB performance in Franklin, NJ
  • Edlebrock RPM heads (60185) w/ 88cc chambers
  • Eagle Competition Rotating Assy (B21202030) stroker crank, rods and pistons
  • Mahle BBM475350F08 pistons (part of the Eagle kit)
  • Comp Cams 23-712-9 hyd roller cam and lifters (Duration 286/294, Lift .544/.541)
  • Hughes 1.5 roller rockers
  • Edlebrock RPM air gap intake manifold
  • AED 950 carb
  • TTI 1 ⅞ headers
  • Edelbrock Performer RPM Street Fuel Pumps 1723
  • All ARP hardware

Some other symptoms I’m seeing that may or may not be contributing factors

  • Coolant keeps getting dirty/muddy. I flushed the block several times but it keeps coming back. Tested for combustion gasses in coolant but it showed none. No water/coolant in the oil.
  • Blow-by over 3k rpm. This is tested under no load. I don’t have a dyno so it’s really hard to test this under load at any higher rpm
  • Scoring on the lower cylinder walls at the 12 and 6 o'clock positions. It’s not very deep although I can feel them with my fingernails but not catch on them.

I have a complete handwritten list of all the assembly measurements I checked as I built it along with the cam card that I’ll try to attach here somehow.

Any advice would be appreciated.
 
Here's a link to the build specs


Here's a link to the cam card:
 
I couldn't get 10:1 to run on pump gas with 88cc open chamber heads and a stock 440. I'd do a compression check and see where the cylinder pressure is. Bet your getting some contaminates in the combustion chamber. Intake valve is probably closing too early for the cubes and compression. Going to thicker head gaskets can make detonation worse. A lot of stuff to check. those heads are for quench dome pistons.
 
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Compression check was at 160lbs pretty much across the board. Leak down was 5% and under for all as well
Heads are aluminum so 10:1 shouldn't be an issue with 93 octane fuel (or so I always thought)
 
Maybe a video? With that list I’m not seeing how this could be pinging. Might be another sound.
 
Long shot guess…..the “ping” is something slightly loose in your valve gear?
 
Lock the distributor and set it at 32 and see what it does.
 
I would lock distributor at 28 total to determine if sound is ping. Also run 50/50 race gas to disqualify as ping. do you have a infrared heat gun thermometer so you can check each cylinder exhaust port area for exhaust temps??
 
Going to thicker head gaskets can make detonation worse. A lot of stuff to check.

I was told this back in 2012-2013 by a few members here when I was having detonation with my 440/493. I went ahead and swapped in .075 Cometics dropping my static ratio from 10.9 to 10.17. It worked fine. I was able to run 91 octane gas and 34 degrees of timing and it ran without knocking.

Compression check was at 160lbs pretty much across the board. Leak down was 5% and under for all as well
Heads are aluminum so 10:1 shouldn't be an issue with 93 octane fuel (or so I always thought)

There is/was a common belief that aluminum heads are a magic fix for detonation. I've heard many instances where it didn't help matters.
I was at 180 psi before and low 160s after the head gasket swap. You might not be detonating at all but something else is going on.
 
I can’t imagine you would have pinging with 110 octane.
Are you sure that’s what you’re hearing?
 
I can’t imagine you would have pinging with 110 octane.
Are you sure that’s what you’re hearing?
I agree.
When mine was knocking, 110 totally stopped it, 104 knocked out most of it.
 
Thanks all for the input, greatly appreciated.

The only reason I keep going back to pinging as opposed to something else is that reducing the timing and using race gas reduced the severity of the "pinging" noise.

One of my concerns is maybe the block is cracked somewhere allowing coolant into the combustion chamber but I tested the cooling system and it held 15psi for 15 minutes with no leak down.

I can't really do much real world testing at the moment as I live in NY, it's 30 degrees out and the roads are covered in salt so "The Beast" isn't going out.

I think I'm going to pull the engine this weekend and see if I can't get it to an engine shop with a dyno to see if they hear pinging and give it a real tuning

There's a engine shop in Oak Ridge, NJ (Tester Motorsports) that I think I'm going to call and see if they can help me out.
 
Pull the engine?
You can't find someone with a chassis dyno to test it under a load?
 
I had an issue similar to this several years ago, although 110 octane stopped the pinging on mine. Turned out to be the MSD distributor shaft was riding up starting at about 1500 rpm and adding 15 degrees of timing. A $3.00 collar on the distributor shaft cured it.
 
Pull the engine?
You can't find someone with a chassis dyno to test it under a load?
Pulling the engine takes a couple hours, salted roads means the car stays home... Get it on a dyno...

With the compression ratio where it is pinging shouldn't be an issue... Yet here we are... 110 octane should easily support 11.5-1... Cam is a little mild but should be fine, especially with 110 octane...

I tend to agree the rattle isn't pinging...
 
I'm lucky in that I have a nice garage with a lift so pulling the engine is literally an afternoon.
I have looked for chassis dyno's around and all of them are for tuners. If they can't tap keys they can't tune.
 
I had an issue similar to this several years ago, although 110 octane stopped the pinging on mine. Turned out to be the MSD distributor shaft was riding up starting at about 1500 rpm and adding 15 degrees of timing. A $3.00 collar on the distributor shaft cured it.
Years ago, a friend had a 440 that was a dog. He arranged to ship the engine to a well-known Nascar shop (associated with the name, The King) that would "blueprint" it. Before he shipped it a committee of 4 of us took it apart. We wanted to find out what the Kings shop changed. When it came back, we found a piece of rubber fuel line on the distributer shaft to be the only change. It ran better and was an expensive lesson.
 
If you have ping, then you have one or more pieces of information/data that is/are incorrect.
 
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