67 Shovel Engine rings under load

All Shovelhead topics
Post Reply
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

67 Shovel Engine rings under load

#1

Post by hdmarkus »

Hi,

I have a problem when accelerating under load. The engine rings. What can I do, someone an idea?

Regards
Markus
Larry
Senior Member
Posts: 522
Joined: Wed Mar 01, 2006 10:14 pm
Bikes: -
Has thanked: 33 times
Been thanked: 108 times

Re: 67 Shovel Engine rings under load

#2

Post by Larry »

Do you mean detonation?
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

Re: 67 Shovel Engine rings under load

#3

Post by hdmarkus »

Yes, knocking, pinging, detonation etc.
RooDog
Senior Member
Posts: 5327
Joined: Tue Oct 31, 2017 1:00 pm
Bikes: 1950 Panhead, Resto-Mod
1968 90", 5 Speed Shovelhead,
1984 Home Built Custom Evo 100" Bagger
Location: Knoxville, Tennessee
Has thanked: 2801 times
Been thanked: 2158 times

Re: 67 Shovel Engine rings under load

#4

Post by RooDog »

Too much ignition timing. Retard the timing, and be sure to use premium gas. Do this now before you break something internal like a piston, or some crank parts....
....RooDog....
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

Re: 67 Shovel Engine rings under load

#5

Post by hdmarkus »

Engine runs well in every speed range. only when you accelerate quickly or uphill the engine detonates.
Mongrel505558
Senior Member
Posts: 1418
Joined: Thu Mar 26, 2020 5:46 pm
Bikes: Rigid Panhead bobber, 68 Shovelhead, 2000 Road King Police bike, 2000 Dyna Wide Glide
Location: Rhode Island
Has thanked: 990 times
Been thanked: 701 times

Re: 67 Shovel Engine rings under load

#6

Post by Mongrel505558 »

Stock compression pistons?
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

Re: 67 Shovel Engine rings under load

#7

Post by hdmarkus »

I assume that the bike have stock compression pistons, but not sure. I will first trie to retard the ignition timing, as RooDog mentioned.
Mongrel505558
Senior Member
Posts: 1418
Joined: Thu Mar 26, 2020 5:46 pm
Bikes: Rigid Panhead bobber, 68 Shovelhead, 2000 Road King Police bike, 2000 Dyna Wide Glide
Location: Rhode Island
Has thanked: 990 times
Been thanked: 701 times

Re: 67 Shovel Engine rings under load

#8

Post by Mongrel505558 »

hdmarkus wrote: Sun Jul 18, 2021 7:58 am I assume that the bike have stock compression pistons, but not sure. I will first trie to retard the ignition timing, as RooDog mentioned.
Also, when was the last time the heads were off the motor? It might be time for what the Brits call "decoking" - removing built up carbon from the combustion chambers and piston tops. The carbon gets hot spots and can act like a glow plug in a diesel engine, causing pre-ignition or detonation. If you don't want to pull the heads there is a method I've tried before that can break up some of the carbon: take the air cleaner cover off and with the motor running spray a mist of water or Marvel Mystery Oil into the carb. Keep spraying and use the throttle to keep the motor running as long as possible until it quits. Have a fresh set of plugs ready and do this when the neighbors aren't around. It makes a racket and if you use MMO it makes quite a smoke show. I'm not sure of the exact science behind it, but I think it has to do with the cool non-combustible mist hitting the hot internal surfaces of the pistons, heads and valves that breaks up the built-up carbon deposits. Whatever it is, it worked for me.

As has been suggested, there are a lot of factors that contribute to pinging, and it seems Shovelheads are more susceptible than other motors, but too much advance is the easiest factor to adjust out. High octane fuel is also a must. Run the highest available and even try octane boost to see if that helps. I'm not a petrochemical engineer, but I believe the octane rating comes from testing fuels in a variable compression test motor, where the compression is raised until pre-ignition occurs. The higher the compression, the higher the octane rating.
RooDog
Senior Member
Posts: 5327
Joined: Tue Oct 31, 2017 1:00 pm
Bikes: 1950 Panhead, Resto-Mod
1968 90", 5 Speed Shovelhead,
1984 Home Built Custom Evo 100" Bagger
Location: Knoxville, Tennessee
Has thanked: 2801 times
Been thanked: 2158 times

Re: 67 Shovel Engine rings under load

#9

Post by RooDog »

I have done what Mongrel suggested on an old FORD engine, pouring about a pint, 1/2 liter, of water down the carburetor while jacking the throttle to keep the engine running, Followed with the same amount of kerosene, paraffin. And it did smoke up the neighborhood, but I found all sorts of black chunks of carbon blown out the exhaust behind the car, so it's safe to assume that the procedure must have been successful....
Regarding your spark timing, it should not require a lot of retard, just a little less than your current maximum advance, to cure your present problem.
I'm sure the engine runs great , otherwise, most engines like a lot of advance during normal operation, but one needs to tune for that high load situation causing the spark knock & pinging sounds of detonation. Remember, you don't always hear detonation, some times it is a silent killer, so if it is audible, it is too much.....
A good article explaining detonation:
https://www.comeanddriveit.com/engine/d ... -and-knock

....RooDog....
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

Re: 67 Shovel Engine rings under load

#10

Post by hdmarkus »

@RooDog , @Mongrel505558

…..I will first try the ignition timing method. Smoking up the neighborhood could get expensive, because someone could call the fire department :lol: :lol:
Mongrel505558
Senior Member
Posts: 1418
Joined: Thu Mar 26, 2020 5:46 pm
Bikes: Rigid Panhead bobber, 68 Shovelhead, 2000 Road King Police bike, 2000 Dyna Wide Glide
Location: Rhode Island
Has thanked: 990 times
Been thanked: 701 times

Re: 67 Shovel Engine rings under load

#11

Post by Mongrel505558 »

hdmarkus wrote: Mon Jul 19, 2021 6:25 am @RooDog , @Mongrel505558

…..I will first try the ignition timing method. Smoking up the neighborhood could get expensive, because someone could call the fire department :lol: :lol:
You have to break in your neighbors. I do most of my wrenching on my four bikes in my backyard, and on the other side of a fence lives an older retired guy who used to just give me dirty looks and never say much. One day I was putting together my 68 shovel bottom end on my picnic table and saw him looking over the fence. I invited him over and showed him what I was doing, putting the idler gears, breather, and cam in. I showed him how the marks all have to line up and the timing of everything, the oil feed in the pinion shaft bushing, etc. Since then he comes out whenever he sees me working out there and we talk over the fence. He's taken a keen interest in my bikes and we get along just fine now. I've actually come to like the guy.

Still, the smoke might be a bit much for them. There will be a lot of it.

Jim
RooDog
Senior Member
Posts: 5327
Joined: Tue Oct 31, 2017 1:00 pm
Bikes: 1950 Panhead, Resto-Mod
1968 90", 5 Speed Shovelhead,
1984 Home Built Custom Evo 100" Bagger
Location: Knoxville, Tennessee
Has thanked: 2801 times
Been thanked: 2158 times

Re: 67 Shovel Engine rings under load

#12

Post by RooDog »

Yep. I try to keep the neighbors pacified and on good terms....
The smoke generated from the water is generally steam and will quickly dissipate, no biggie.
The kerosene, on the other hand, is smelly, but it too will be quickly gone.
It cost nothing to retard the timing....
....RooDog....
Larry
Senior Member
Posts: 522
Joined: Wed Mar 01, 2006 10:14 pm
Bikes: -
Has thanked: 33 times
Been thanked: 108 times

Re: 67 Shovel Engine rings under load

#13

Post by Larry »

Have you told us what gasoline you're using?
hdmarkus
Site sponsor
Site sponsor
Member
Posts: 281
Joined: Sun May 07, 2017 10:32 pm
Bikes: 1955 FL
1967 FLH
2003 FLSTF Custom
Zuendapp Bella, Custom DKW etc.
Location: Germany
Has thanked: 281 times
Been thanked: 94 times

Re: 67 Shovel Engine rings under load

#14

Post by hdmarkus »

Now I’m using 95 octane. I will change to 98 octane, this is the highest I can get…. Maybe I try that before I retard the ignition timing.
Andygears
Senior Member
Posts: 1396
Joined: Tue Feb 05, 2013 12:25 am
Bikes: 1950 panhead, 1999 FLHTCI, 1987 FLHTC custom
Location: Daytona Beach
Has thanked: 438 times
Been thanked: 648 times

Re: 67 Shovel Engine rings under load

#15

Post by Andygears »

Great read RooDog, thanks. I have been chasing detonation in my ‘78 Dodge motor home with only a 318 pushing it around. In this hot Florida weather, poor cooling in a van motor setup, running cheap gas, and often high load/low RPM, I have reduced it, but still “I” can hear it faintly. Seems all the “bad” conditions, I have! Ugh!

Andygears
Post Reply

Return to “Shovelhead”