IH PARTS AMERICA
Click Here!

Go Back   IH PARTS AMERICA > Tech Forums > Ignition Tech
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read Photo Gallery IH Store Home

Reply
 
Thread Tools Display Modes
Old 06-21-2018, 12:14 PM   #1
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Can't stop from Pinging

Hello,

I am new to this forum but I have been trolling for some time. This pinging issue has got me stumped and I need some of your expertise. I have a lot of engine ping that I can only resolve by retarding the timing a lot (like 20 degrees ATDC).

1979 traveler
345/727
Stock ignition (I think)
Edelbrock 1406 carb (no idea on jets, rods, springs etc.), carb was on it when I got the scout
I “Rebuilt” the engine: New crank, mains, rod bearings (all std size), cylinders within spec, so light hone and new standard piston rings
Did not have the heads redone
NOS OEM gaskets – engine not decked
New 3332 plugs gapped to 0.035”
Compression is 140-150 on all cylinders
Vacuum at idle (~675) is 22”
Engine has about 180 miles since rebuild
Engine runs great except the pinging. It starts easily, runs good, no back firing, no hiccups, no stutter, no ticking, clicking, knocking, nothing, revs excellent, just pings under load or trying to maintain more than 55mph.

What I’ve tried:
Timed using “normal” procedure: No 8 cylinder, timed to 0-5 deg TDC with vacuum advance not hooked up, tighten distributor and hook up the vac advance – engine pings under load
Switched from port to manifold vacuum for advance – engine still pings under load
Disconnected vacuum advance entirely (and plugged open vacuum port so no vac leaks) – engine pings slightly less under load
Retarded the timing (to like 20 deg ATDC) and left vacuum advance disconnected – engine pings very little (but idle is very low, like the engine does not want to be there, but this actually gave it the most driveability of all the settings tried)

What I’ve verified:
Idle vacuum is great (21-22”)
Vacuum advance is working (advances the timing approx. 10 deg when engine is revved)
Mechanical advance is working (advances the timing approx. 15 deg when engine is revved) and the rotor rotates easily by hand, it doesn’t “snap back” though
When timing is set to 5 deg BTDC, total advance when revved is between 30 and 35
Tried timing by using vacuum gauge, pretty much nets me at 0-5 deg BTDC
Idle air screws adjusted 1.5 turns out (also netted the best idle vacuum)
Manually opening the EGR does cause the engine to stumble but stays running

Things I’m wondering (some are getting desperate):
Could I have the cam not aligned – pretty sure I triple checked this during assembly
Could the EGR system be contributing? (when I was assembling the engine I noticed the EGR was stuck open, so lubed it up and got it working. Now it seems as though the diaphragm is junk – I’ve hooked it to straight manifold vacuum and it doesn’t actuate) I do remember the truck not idling nearly as good before I tore it down for rebuild – probably because the EGR was open all the time.
Could having the electric choke hooked to the coil be causing some issues
Could the distributor “fail” in such a way to cause too advanced of timing (funny why not seeing this when revving with timing light – occasionally I did see the timing moving around but never too advanced)?
Are there differences in cranks (crank came out of another 345 I had), and this is causing the crank timing lobe and/or crank to camshaft to be not aligned
If I got some bad gas – I have not drained and tried premium yet

Thank you all so much.
Jrwittlin is offline   Reply With Quote
Old 06-21-2018, 01:48 PM   #2
1975IH200
Senior Member
 
1975IH200's Avatar
 
Join Date: Dec 2008
Member Number: 731
Location: 3rd to last cave on the right
Posts: 551
Default Re: Can't stop from Pinging

My comments in red.

Quote:
Originally Posted by Jrwittlin View Post
Hello,

I am new to this forum but I have been trolling for some time. This pinging issue has got me stumped and I need some of your expertise. I have a lot of engine ping that I can only resolve by retarding the timing a lot (like 20 degrees ATDC).

1979 traveler
345/727
Stock ignition (I think) Find out what you have please. There is a sticky thread on distributors to look thru to determine which unit / system you have.
Edelbrock 1406 carb (no idea on jets, rods, springs etc.), carb was on it when I got the Scout
I “Rebuilt” the engine: New crank, mains, rod bearings (all std size), cylinders within spec, so light hone and new standard piston rings
Did not have the heads redone
NOS OEM gaskets – engine not decked Is the head gasket composite or metal shim style?
New 3332 plugs gapped to 0.035”
Compression is 140-150 on all cylinders
Vacuum at idle (~675) is 22”
Engine has about 180 miles since rebuild
Engine runs great except the pinging. It starts easily, runs good, no back firing, no hiccups, no stutter, no ticking, clicking, knocking, nothing, revs excellent, just pings under load or trying to maintain more than 55mph.

What I’ve tried:
Timed using “normal” procedure: No 8 cylinder, timed to 0-5 deg TDC with vacuum advance not hooked up, tighten distributor and hook up the vac advance – engine pings under load
Switched from port to manifold vacuum for advance – engine still pings under load
Disconnected vacuum advance entirely (and plugged open vacuum port so no vac leaks) – engine pings slightly less under load
Retarded the timing (to like 20 deg ATDC) and left vacuum advance disconnected – engine pings very little (but idle is very low, like the engine does not want to be there, but this actually gave it the most driveability of all the settings tried)

What I’ve verified:
Idle vacuum is great (21-22”)
Vacuum advance is working (advances the timing approx. 10 deg when engine is revved) -This is actually indicating centrifugal advance, not vacuum advance.
Mechanical advance is working (advances the timing approx. 15 deg when engine is revved) and the rotor rotates easily by hand, it doesn’t “snap back” though -Rotor should snap back, clean the advance weight mechanism and lube them.
When timing is set to 5 deg BTDC, total advance when revved is between 30 and 35
Tried timing by using vacuum gauge, pretty much nets me at 0-5 deg BTDC
Idle air screws adjusted 1.5 turns out (also netted the best idle vacuum)
Manually opening the EGR does cause the engine to stumble but stays running

Things I’m wondering (some are getting desperate):
Could I have the cam not aligned – pretty sure I triple checked this during assembly
Could the EGR system be contributing? -Yes. (when I was assembling the engine I noticed the EGR was stuck open, so lubed it up and got it working. Now it seems as though the diaphragm is junk – I’ve hooked it to straight manifold vacuum and it doesn’t actuate) I do remember the truck not idling nearly as good before I tore it down for rebuild – probably because the EGR was open all the time. -Sounds as if the EGR valve is bad, a torn/leaking diaphragm will give you a vacuum leak.
Could having the electric choke hooked to the coil be causing some issues - Yes, definitely incorrect, choke should have it's own power source when the key is in the "ON" position.
Could the distributor “fail” in such a way to cause too advanced of timing (funny why not seeing this when revving with timing light – occasionally I did see the timing moving around but never too advanced)?
Are there differences in cranks (crank came out of another 345 I had), and this is causing the crank timing lobe and/or crank to camshaft to be not aligned -No.
If I got some bad gas – I have not drained and tried premium yet

Thank you all so much.
Correct the above items and report back.
__________________

My Junk --> 1975 "200HD" AWD Truck
My Cave location --> Western North Carolina
1975IH200 is offline   Reply With Quote
Old 06-22-2018, 04:23 AM   #3
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Thank you for the reply.

I have verified that my ignition is a prestolite with pertronix module. I disassembled last night and cleaned and lubed the weights for the mechanical advance, the rotor now snaps back fully. I also ran a separate wire for the electric choke.

I forgot to mention, that when I discovered the EGR was not opening, I disconnected the vacuum (and plugged the line - so I do not have any vacuum leaks - but obviously I don't have a functioning EGR). I will work on sourcing a new EGR valve....

I said my vacuum advance was working because it is advancing during revving and I've sucked on the hose and verified it moves all the way (I also cleaned and lubed the mechanism last night). I have my vacuum advanced hooked to port vacuum so that would advance the timing as the engine rpms are raised. As stated in my original post, I've switched to manifold vacuum with no better result - still pings.

I timed again and took it for a drive - still heavy pings. To stop the pinging I again netted out at about 20 degrees ATDC - so no change.

Please continue to help me....
Jrwittlin is offline   Reply With Quote
Old 06-22-2018, 10:19 AM   #4
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Update, I misspoke I have a prestolite distributor with the oem electronic module not a pertronix unit.
Attached Images
File Type: jpg 20180621_191432.jpg (57.2 KB, 42 views)
File Type: jpg 20180621_201058.jpg (58.9 KB, 39 views)
File Type: jpg 20180621_191424.jpg (57.3 KB, 36 views)
Jrwittlin is offline   Reply With Quote
Old 06-22-2018, 03:29 PM   #5
1975IH200
Senior Member
 
1975IH200's Avatar
 
Join Date: Dec 2008
Member Number: 731
Location: 3rd to last cave on the right
Posts: 551
Default Re: Can't stop from Pinging

Thanks for the distributor photos to verify identification. Photos are always helpful.

How about a photo of the cap & rotor?
Photos of the engine might be helpful as well.

Is the dust cover intact? It is needed for the Prestolite cap to fit on the distributor body properly, without being a sloppy fit.

Install the distributor and time the engine to about 5° to 10° BTDC.

I will attach a .pdf file that you can use to check your distributor, plus an article on engine timing.
Attached Images
File Type: pdf Distributor Tests - Rev 4.pdf (44.5 KB, 32 views)
File Type: pdf Timing101.pdf (108.7 KB, 41 views)
__________________

My Junk --> 1975 "200HD" AWD Truck
My Cave location --> Western North Carolina

Last edited by 1975IH200; 06-22-2018 at 03:45 PM..
1975IH200 is offline   Reply With Quote
Old 07-02-2018, 06:14 PM   #6
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Sorry for not getting back to you, I was in vacation with the family. Anyway, I took some pictures of the engine and the distributor. The dust cap is in place and not cracked. The dist cap is also newer and not cracked and fits reasonably tight. Thank you for those manuals, I will do the mechanical and vacuum advance checks tomorrow night. I am honestly leaning toward a faulty timing gun. Mine is a hand-me-down that has had a hard life and been dropped more than once. The scout now starts very easy when warm with the timing retarded (as my light tells me anyway). I am getting a new light tomorrow and will verify and do the tests you sent me.
Attached Images
File Type: jpg 20180702_200634.jpg (70.5 KB, 31 views)
File Type: jpg 20180702_200618.jpg (68.7 KB, 29 views)
File Type: jpg 20180702_200601.jpg (69.6 KB, 35 views)
File Type: jpg 20180702_200610.jpg (58.3 KB, 27 views)
Jrwittlin is offline   Reply With Quote
Old 07-02-2018, 06:17 PM   #7
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Pictures of the engine
Attached Images
File Type: jpg 20180702_200521.jpg (87.1 KB, 33 views)
File Type: jpg 20180702_200511.jpg (58.5 KB, 36 views)
File Type: jpg 20180702_200438.jpg (76.8 KB, 32 views)
File Type: jpg 20180702_200406.jpg (78.6 KB, 31 views)
Jrwittlin is offline   Reply With Quote
Old 07-03-2018, 06:43 AM   #8
Hondo
Senior Member
 
Hondo's Avatar
 
Join Date: May 2012
Member Number: 4714
Location: Fremont
Posts: 487
Default Re: Can't stop from Pinging

Might have missed it, but what octane fuel are you running, and have you tried any octane booster? If you look in one of the owners manuals, they recommend "regular gasoline of 92 octane or better".
__________________
1975 Scout II healthy 258, Wide T19 , 4:1 D300 3:54s,
1972 Real clean stock Scout II P/S, P/B, 345, T18, 3:73s
1969 Mach I. Balanced ported 351W, 650 double pumper, Super T10, Detroit locker with 4.11s. Lowered with racing springs, bars, Konis etc.
(Don't worry about getting arrested when I drive the Scouts).
Hondo is offline   Reply With Quote
Old 07-03-2018, 07:21 AM   #9
Scoutboy74
Moderator
 
Scoutboy74's Avatar
 
Join Date: Apr 2008
Member Number: 453
Location: Daze Crick, Jefferson
Posts: 4,057
Default Re: Can't stop from Pinging

These are low compression engines. High test is meant for high compression engines. Unless the compression ratio was dramatically increased via machining, it should be able to run just fine on regular, if not mid grade.
__________________
Favorite hobby...Driving Salma Hayek in my Scout

Coal Trickle - '99 Dodge Ram SLT 2500 Q-Cab SWB 4x4 - 5.9L 24V CTD/NV4500/8800# GVWR/12K# winch
Hooty - '74 SII 4x4 - 392/TF727/D20/3.73 D44's/Spartan FA/Krac-lok RA/RC 4" SUA/34x11.5 TSLs/33g Fuel/8K# winch
Lemuel - '72 1210 LWB 4x4 CS - 304/TF727/NP205/RA D60 4.10 - "Pull Lemuel, pull!"
Mongo - '71 1210 LWB 2WD - 345/TF727/RA17 D60 4.10 Krac-lok - "Mongo love candy! Duh, huh, huh!"
Scoutboy74 is offline   Reply With Quote
Old 07-03-2018, 06:30 PM   #10
Hondo
Senior Member
 
Hondo's Avatar
 
Join Date: May 2012
Member Number: 4714
Location: Fremont
Posts: 487
Default Re: Can't stop from Pinging

Yeah I know, but running higher octane wont hurt anything but your pocket book. The pinging/detonation on the other hand can do extensive damage if allowed to continue. Adding a bottle of octane booster, or adding some premium is a quick, not too expensive sanity check. Don't know about his different crank question, but getting #8 piston at TDC on the compression stroke and pulling the distributor cap to make sure rotor is pointed directly at # 8 plug wire location wouldn't be a bad idea. I've seen dampers slip on the crank hubs before.
__________________
1975 Scout II healthy 258, Wide T19 , 4:1 D300 3:54s,
1972 Real clean stock Scout II P/S, P/B, 345, T18, 3:73s
1969 Mach I. Balanced ported 351W, 650 double pumper, Super T10, Detroit locker with 4.11s. Lowered with racing springs, bars, Konis etc.
(Don't worry about getting arrested when I drive the Scouts).
Hondo is offline   Reply With Quote
Old 07-04-2018, 04:41 AM   #11
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Hi Guys. Thanks for sticking with me on this. Hondo, I am running premium ethanol free 91 octane. Between me retarding the timing and the high octane it is no longer pinging but obviously is still not right.

Last night I tried a new timing light and got the same reading so that theory is busted. I conducted the tests to check the mechanical and vacuum advances. To start I set the timing from my retarded setting to 0 degrees (to make the tests "cleaner" (no math involved when starting from 0). Timing was set to 0 with vacuum advance disconnected.

Immediately the idle picked up (as expected) but the engine idled less smooth. It wasn't shaking or studdering, just not humming along smoothly like it does at retarded timing. It had a sort of small occasional miss. Non the less, I set the idle to 680 and proceeded with the checks.

Mechanical advance check:
At 680 timing = 0 deg, manifold vac = 21"
At 1000 timing = 3 deg, manifold vac = 21.5"
At 1500 timing =10 deg, manifold vac = 22"
At 2000 timing = 15 deg, manifold vac = 21"
At 2500 timing = 19 deg, manifold vac = 21"
At 3000 timing = 25 deg, manifold vac = 20"
At 3500 timing = 28 deg, manifold vac = 19"

Vacuum advance checks: idling at 690
At 0" timing = 0 deg
At 5" timing = 5 deg
At 7" timing = 7 deg
At 12" timing = 7 deg
Jrwittlin is offline   Reply With Quote
Old 07-04-2018, 05:03 AM   #12
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

Also I forgot to mention that the Scout started very hard when warm when set to 0. It turmed over very slow (like classic too advanced timing). It starts very easily warm and cold with the timing retarded.
Jrwittlin is offline   Reply With Quote
Old 07-04-2018, 07:24 AM   #13
Scoutboy74
Moderator
 
Scoutboy74's Avatar
 
Join Date: Apr 2008
Member Number: 453
Location: Daze Crick, Jefferson
Posts: 4,057
Default Re: Can't stop from Pinging

That doesn't make any sense. Timing measurements were taken from wire #8? I think like Hondo suggested, you need to re-examine your distributor stab and plug wire routing.
__________________
Favorite hobby...Driving Salma Hayek in my Scout

Coal Trickle - '99 Dodge Ram SLT 2500 Q-Cab SWB 4x4 - 5.9L 24V CTD/NV4500/8800# GVWR/12K# winch
Hooty - '74 SII 4x4 - 392/TF727/D20/3.73 D44's/Spartan FA/Krac-lok RA/RC 4" SUA/34x11.5 TSLs/33g Fuel/8K# winch
Lemuel - '72 1210 LWB 4x4 CS - 304/TF727/NP205/RA D60 4.10 - "Pull Lemuel, pull!"
Mongo - '71 1210 LWB 2WD - 345/TF727/RA17 D60 4.10 Krac-lok - "Mongo love candy! Duh, huh, huh!"
Scoutboy74 is offline   Reply With Quote
Old 07-04-2018, 07:37 AM   #14
Jrwittlin
Junior Member
 
Join Date: Jun 2018
Member Number: 9290
Posts: 9
Default Re: Can't stop from Pinging

I've already verified the order of my plugs on the cap and that the wires go to the right cylinders. Yep, timing on #8.
I will triple ck the distributor. I am able to achieve the correct timing off #8 it just doesn't like to run there. If I am able to obtain the correct timing does that not mean that my distributor is stabbed correctly? I will verify that it is at tdc on #8 and that it is pointing to #8 on the cap tonight. Thanks for the suggestions, keep them coming.
Jrwittlin is offline   Reply With Quote
Old 07-04-2018, 11:39 AM   #15
FDChappie
Senior Member
 
FDChappie's Avatar
 
Join Date: Aug 2011
Member Number: 3742
Location: Northern New California
Posts: 1,577
Default Re: Can't stop from Pinging

It might be time to remove the spark plugs, set #8 on TDC compression stroke and see if the timing mark aligns with 0.
__________________
1974 Scout II 345 T-19
1971 Travelette 392 T-36
1972 Loadstar 1700 dump truck 345 T-35
FDChappie is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 01:49 AM.