Pinging

[Pvmt-Pndr]

I have a 69 C60 with a 427TD, HEI distributor, block huggers and a custom 2-1/2" exhaust with an H-pipe I built .I just swapped the worn out governed Holley to a brand new edelbrock AVS2 650 cfm and took it for a quick 1 mile drive. It's pinging, I have the inital timing set at 8 degrees and currently not using vacuum advance though the HEI and new carb has provisions for it (I do plan to utilize it). At higher rpms she pings like crazy. It starts, idles, runs and shuts down perfectly. She seems low on power. The fastest I was able to get her up to was 42 mph. My gearing says I can go 59 mph in 5H at 3200 rpm. I'm confident my tach is not correct because it said I was at 3200 rpm at 42 mph. I've done a lot of googling but not too much specific comes to the tall deck. Any ideas?

It was pinging before I swapped the carb something terrible at high rpms and I haven't tuned the carb yet. It has a 2 speed rear end and I thought maybe my 42 mph was because I was stuck in low, not the case, it's definitely in high gear.

[C10 - C90 Bill]

Is it running worse since that day you drove it home?

Generally speaking pinging means your timing is too far advanced, octane too low or both.

[Pvmt-Pndr]

It has pinged since the day I drove it home at high rpms. I was able to hit the 59 going down hill and 55 on the flats with no problems, it took a long time to get there but it did. On the slightest hills I would loose speed, an over pass if I recall correctly was 5-8 mph. On a long grade "hill" here in Michigan I would loose 20 mph or so and that was empty and the truck weighs in just over 8k pounds. Now I hit a top speed of 42 and it takes me a legitimate mile to get it to that speed.

The timing was set so high I have no idea where it was at when I originally got it. I dropped it down to 2,4 and 8 it didn't improve it at all. Currently it's set at 8.

It has great power down low, nothing to brag about mid rpm and falls flat on its face with pinging or knocking possibly at high rpm.

[C10 - C90 Bill]

Did you install the HEI yourself or was it in there when you bought it?

Either way, I feel the Distributor, especially not being original, could have been installed wrong. Unless you feel very confident about it, I would check the installation. It would be a good place to start. Also important is to connect any necessary Vacuum Lines.

[Pvmt-Pndr]

The truck had the HEI on it when I bought it. What I have done with it is pulled the cap (seemed to be in good working order), replaced the weights and springs, new wires, new plugs gapped .045. I'm not sure what could be wrong with the install aside from everything I've already look into. I did find that it was only getting 9 volts, I ran a new 12v wire with no difference.

I also did run a tank of premium gas through it too with no difference either.

[C10 - C90 Bill]

I would re-check the position of the Distributor as mentioned to make sure it got installed correctly. I'm not familiar with an HEI, as I'm an old Points fan and never had or wanted one, but I would guess they install the same way. You need to bring the No #1 piston up on the power stroke and complete the accuracy by lining up the mark on the balancer to zero. Then check to see how the Distributor lines up. With Points, it's the Rotor to the #1 Plug Wire on the Cap.

[Pvmt-Pndr]

I edited my previous post for more detailed info.

I have checked that too... see why I'm scratching my head here? Something isn't making any sense to me. I'm wondering if I have a worn hard part somewhere. When I pulled the old plugs I was hoping they would tell me something but they didn't. They looked like it was burning slightly rich but one of the cleanest set of plugs I've ever pulled.

My secondaries on the stock Holley were frozen and it was leaking. I was hoping that it was running lean and causing the pinging at the higher rpms and the new carb would fix that. The biggest difference I noticed when I swapped the carb was how quiet the engine was vs the old carb. It should rev faster then the old Holley and throttle response should be vastly improved but also not much difference in that either.

When I get home today I'll adjust the secondaries to kick in sooner and see if that could be the problem. Maybe they're not kicking in soon enough and letting her lean out too much.

[C10 - C90 Bill]

Also, some engines cannot be timed by the marks. After you get everything else straightened out and if it still pings, try timing it by ear.

[Airdirect]

I am with Bill, retard the timing until the pinging stops. I have seen harmonic dampers replaced with new ones that have incorrect marks. Don't continue to allow it to ping, bad things happen!

[Pvmt-Pndr]

I plan to retard it again tonight if I have time. When I experimented with the timing last I had to pull start it.

I'm wondering if I should throw a new timing chain in it just if there isn't any changes. The odometer reads just over 80k but I know it's not the original engine either. Is there anything special with the timing chains on these engines? Double roller or just a cheap single?

[C10 - C90 Bill]

Good idea to change the Timing Chain and Gear. Not sure about which one, but you could always check with your real parts store. I would also buy a good brand name.

[Pvmt-Pndr]

Whelp... It's all my fault or it jumped a tooth. I'm pretty confident it's my fault though. When I fired her up today and checked the timing it was at 0* BTDC.

I thought the points were 2* and I didn't clean the rust off previously. I had a feeling to do it today so after a pain saking time trying to reach in there I found each point was 4* and not 2.

I reved her up to 3500 according to a gauge I don't trust and no pinging just popping out of the carb. Now I'm on to adjusting the valves and tuning the carb. Thanks guys! Anyone know the gap specs on the valves?

[C10 - C90 Bill]

I would say they should be Hydraulic. Therefore you won't need to set a "Gap" just tighten them to the correct specs. I always figured you had the original engine in there, but do you know what you have for sure?

[Pvmt-Pndr]

It's still a 427TD from 1972 instead of 1969.

[Captainfab]

I would suggest verifying your timing marks on the riming pointer to balancer mark to make sure Zero on the timing tab is actually #1 piston at TDC.

[Pvmt-Pndr]

I'm right back at it again. Timing I thought changed something but turns out it didn't. I got her out on the road after I did a compression check on it and she was popping under load at the same rpms.

Compression shows:
1-165
3-156
5-162
7-139/141, I checked it twice.
2-165
4-170
6-172
8-180

Where should I be looking from here? I'm not new to engines but deal with diesels and newer cars most of the time.

[Pvmt-Pndr]

Maybe someone else's ears are tuned to know exactly what this is. Here's a video I recorded yesterday
Watch "Not right" on YouTube
https://youtu.be/wHgW4VsdapY

[truck-kid]

Sounds like camshaft has worn lobes not opening valves far enough. Will cause steady popping thru carb and low power. Remove the valve covers and crank the engine over watching all valves to see if they are all opening the same amount .

[cadillac_al]

I'd say not even close to pinging, more like a bad cam. Pull the valve covers and see if all the rockers are moving the same.

[Captainfab]

I agree that, that is not pinging.

[Pvmt-Pndr]

When I started this thread it was pinging bad too. I got the pinging taking care of and now onto this problem.

If time permits tomorrow I'll pull the valve covers and see what I'm working with.

Is there anything special with the tall deck vs standard deck as far as cam/ timing gear/lifters go? I know push rods are longer but need to know if there's anything specific to the TD when I order parts. I'll probably go with a stock cam or RV and call it good if I have to replace it. Does anyone see a red flag with cylinder #7?

[Pvmt-Pndr]

It's worse case scenario...
The cam is gone in it. I only pulled the driver side valve cover and that was enough cylinders 3,5 and 7 are moving roughly 3/32 while cylinder 1 is moving 2-3x as far. A stock rebuild seems to be in order. If there's something I can upgrade that isn't a compromise I'd like to know about it. Thanks guys

[Captainfab]

Yes, unfortunately you are looking at a complete rebuild of your 427. With todays oils a roller cam is the best way to go, but that cost alone is close to $1000.00. If you go with another flat tapped cam, I would suggest a name brand over a generic cam. Since this engine is in a C60 you will have to stay conservative in cam selection, but you can still upgrade some from stock. I would suggest calling or emailing a few cam companies and ask for their recommendation. If you do stay with a flat tappet cam, proper break in is of the utmost importance. If not followed to the letter, you will be right back where you are now plus a bunch of money down the drain.

[Pvmt-Pndr]

Thanks for the suggestions! I'm still torn between rebuilding this engine or finding a different engine, an 8.1 vortec is sounding better and better. If I had access to another 427 in a similar truck that would make or break my 427. It has never been right since I've owned it and I'm not exactly sure what to expect power wise out if it. By the time the truck is said and done I plan to haul upwards of 20k pounds with it

[cadillac_al]

There are a lot of peanut port 454's on craigslist that may be a cheap alternative. Sometimes I still see 366's for sale.