67 Shovel Engine rings under load
-
- 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: 282 times
- Been thanked: 94 times
67 Shovel Engine rings under load
Hi,
I have a problem when accelerating under load. The engine rings. What can I do, someone an idea?
Regards
Markus
I have a problem when accelerating under load. The engine rings. What can I do, someone an idea?
Regards
Markus
-
- 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: 2159 times
Re: 67 Shovel Engine rings under load
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....
....RooDog....
-
- 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: 282 times
- Been thanked: 94 times
Re: 67 Shovel Engine rings under load
Engine runs well in every speed range. only when you accelerate quickly or uphill the engine detonates.
-
- Senior Member
- Posts: 1433
- 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: 997 times
- Been thanked: 711 times
-
- 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: 282 times
- Been thanked: 94 times
Re: 67 Shovel Engine rings under load
I assume that the bike have stock compression pistons, but not sure. I will first trie to retard the ignition timing, as RooDog mentioned.
-
- Senior Member
- Posts: 1433
- 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: 997 times
- Been thanked: 711 times
Re: 67 Shovel Engine rings under load
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.
-
- 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: 2159 times
Re: 67 Shovel Engine rings under load
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....
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....
-
- 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: 282 times
- Been thanked: 94 times
Re: 67 Shovel Engine rings under load
@RooDog , @Mongrel505558
…..I will first try the ignition timing method. Smoking up the neighborhood could get expensive, because someone could call the fire department
…..I will first try the ignition timing method. Smoking up the neighborhood could get expensive, because someone could call the fire department
-
- Senior Member
- Posts: 1433
- 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: 997 times
- Been thanked: 711 times
Re: 67 Shovel Engine rings under load
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
-
- 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: 2159 times
Re: 67 Shovel Engine rings under load
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....
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....
-
- 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: 282 times
- Been thanked: 94 times
Re: 67 Shovel Engine rings under load
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.
-
- Senior Member
- Posts: 1407
- Joined: Tue Feb 05, 2013 12:25 am
- Bikes: 1950 panhead, 1999 FLHTCI, 1987 FLHTC custom
- Location: Daytona Beach
- Has thanked: 446 times
- Been thanked: 651 times
Re: 67 Shovel Engine rings under load
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
Andygears