Need help with timing
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- G-Sergeant
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Need help with timing
My 43 GPW has no timing marks on the flywheel, the engine is GPW. Nothing on the front cover like later jeeps. I pulled the starter to get a good look at the flywheel and had the engine turned slowly by hand numerous times and nothing. The motor runs OK. How can I check the timing? I heard you can use a vacumn gauge but where would you hook up etc.?
- artificer
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Re: Need help with timing
Does your engine plate have a window?
See if you have timing marks on the flywheel when 2 or 3 are @ top dead centre.
No window, of course it can be done with a vacuum gauge: If the window is there, pull all spark plugs & get 2 or 3 @ IGN on the flywheel, if nothing is showing when 1 & 4 are there.
With ANY cylinder @ TDC compression, no matter what else is happening move the loosened distributor clockwise, with the ignition on, until the points can be heard opening or use your voltmeter to see the break in continuity, then you are very close.
There are 3 vacuum points on the inlet manifold including the middle one with the PCV valve....
So go for one of the other 2 to & plug in your vacuum gauge....
Your vacuum gauge reading should be up to 21# of mercury @ idle or just above, depending on altitude &/or engines internal condition, it may be down to about 17#....
When the engine is running ADVANCE the ignition timing by turning the distributor housing slowly clockwise until you get the best vacuum reading....then turn the outside of the distributor housing CCW about 1/8-1/4" maintaining the same or about 1" less reading .
Tighten the distributor & test drive ....make sure there is no pinging or pinking. If there is RETARD [CCW] a little further until the noise is gone.
https://en.wikipedia.org/wiki/Engine_knocking
See if you have timing marks on the flywheel when 2 or 3 are @ top dead centre.
No window, of course it can be done with a vacuum gauge: If the window is there, pull all spark plugs & get 2 or 3 @ IGN on the flywheel, if nothing is showing when 1 & 4 are there.
With ANY cylinder @ TDC compression, no matter what else is happening move the loosened distributor clockwise, with the ignition on, until the points can be heard opening or use your voltmeter to see the break in continuity, then you are very close.
There are 3 vacuum points on the inlet manifold including the middle one with the PCV valve....
So go for one of the other 2 to & plug in your vacuum gauge....
Your vacuum gauge reading should be up to 21# of mercury @ idle or just above, depending on altitude &/or engines internal condition, it may be down to about 17#....
When the engine is running ADVANCE the ignition timing by turning the distributor housing slowly clockwise until you get the best vacuum reading....then turn the outside of the distributor housing CCW about 1/8-1/4" maintaining the same or about 1" less reading .
Tighten the distributor & test drive ....make sure there is no pinging or pinking. If there is RETARD [CCW] a little further until the noise is gone.
https://en.wikipedia.org/wiki/Engine_knocking
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
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- Jeep Heaven
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Re: Need help with timing
After 70 years, small differences due to factory changes, original Jeep timing mark locations may no longer be useable to set timing due to mixing of parts to create a good Jeep engine. The MB/GPW and 40's CJ 2A flywheel timing marks may become unuseable because of changes in the timing procedure due to physical changes in starters and block castings.
A later Pulley with timing notch can be used to overlay and accurately locate a notch on an older pulley having no notch.
What I have done for years for my customers is to install a later pulley of the same type originally installed that has the timing notch and a CJ Timing pointer if the Timing Cover is unmarked, or just file a notch on the original unmarked pulley A CJ Timing Pointer fits on the Timing Cover studs of all 4 Cyl engines. I bought a quantity of late CJ Timing Pointers in order to correct the timing mark issue. Am now out of the CJ pointers tho.
The trusty timing light makes timing fool proof and eliminates the guesswork of trial and error vacuum methods.
Check with your Jeep parts dealers to see if they have the timing pointer that attaches to the timing cover. As for purists, very few persons will notice the CJ pointer.
A later Pulley with timing notch can be used to overlay and accurately locate a notch on an older pulley having no notch.
What I have done for years for my customers is to install a later pulley of the same type originally installed that has the timing notch and a CJ Timing pointer if the Timing Cover is unmarked, or just file a notch on the original unmarked pulley A CJ Timing Pointer fits on the Timing Cover studs of all 4 Cyl engines. I bought a quantity of late CJ Timing Pointers in order to correct the timing mark issue. Am now out of the CJ pointers tho.
The trusty timing light makes timing fool proof and eliminates the guesswork of trial and error vacuum methods.
Check with your Jeep parts dealers to see if they have the timing pointer that attaches to the timing cover. As for purists, very few persons will notice the CJ pointer.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
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- G-Sergeant
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Re: Need help with timing
Yes my engine plate has the small inspection hole and no there are no marks anywhere no matter what cylinder is on compression stroke. The intake manifold only has the PVC valve. I like the idea of lining up a later pulley with a notch , Can the vacuum gauge method be used off the PVC inlet? Thanks for the replies
- artificer
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Re: Need help with timing
Yes.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
- Chuck Lutz
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Re: Need help with timing
If you wish to use a self-installed timing mark on the pulley, use artificer's method to get the timing set correctly to begin with...and THEN file a mark for future use. Be sure you have also gotten the points set to 0.20" and they are in good condition....
Don't try using the cover of a matchbook to set the points....they are much thinner card stock than they were when that was first offered as a road-side option to a feeler guage.
Don't try using the cover of a matchbook to set the points....they are much thinner card stock than they were when that was first offered as a road-side option to a feeler guage.
Chuck Lutz
GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
Bantam T3-C 1947
GPW 17963 4/24/42 Chester, PA. USA 20113473 (USA est./Tom W.)
Bantam T3-C 1947
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- Jeep Heaven
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Re: Need help with timing
Chuck, it is more accurate to establish the timing mark on an unmarked pulley using an original marked pulley for reference. marking the pulley according to readings from a vacuum gauge is arbitrary at best.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
- Tony W
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Re: Need help with timing
Hey Ben
Can you go to the HOSS,S MOUTH manual and give us the vacume adjustments again please.
The manual is so specific about vacume tuning , I would like to know the correct procedure, from the hoss,s mouth
Thanks
Tony
Can you go to the HOSS,S MOUTH manual and give us the vacume adjustments again please.
The manual is so specific about vacume tuning , I would like to know the correct procedure, from the hoss,s mouth
Thanks
Tony
GPW Feb, 45,
chassis 259112
body 214625
engine MB131277 Overstamped XXX4B1945
ARN 153851
chassis 259112
body 214625
engine MB131277 Overstamped XXX4B1945
ARN 153851
- artificer
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Re: Need help with timing
PM sent.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
- Sean Collins
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Re: Need help with timing
There is a fairly accurate method of establishing timing marks by purely mechanical means.John Peeff wrote:My 43 GPW has no timing marks on the flywheel, the engine is GPW. Nothing on the front cover like later jeeps. I pulled the starter to get a good look at the flywheel and had the engine turned slowly by hand numerous times and nothing. The motor runs OK. How can I check the timing?
It relies on the published Willys specification for "checking" valve timing.
With #1 tappet adjusted to .020" clearance, put a dial-indicator in #1 spark plug hole against the intake valve face, and zero it.
Turn the crank until the dial indicator JUST BARELY MOVES. This is 9º Before TDC.
Put a matching pair of marks on pulley & timing cover.
Measure the pulley diameter, multiply by pi (3.14159), divide by 360 = inches of arc per degree.
Multiple by 4, put another mark on pulley that far CCW from first mark, that would be 5º before TDC.
Multiple by 9, put another mark on pulley that far CCW from first mark, that would be TDC.
Or do the opposite, with 3 marks on the timing cover, and only one on the pulley.
I made a DIY timing pointer, with 3 pips corresponding to calculated distances, mounted with timing cover bolts, then marked the pulley.
- artificer
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Re: Need help with timing
Really good practical info from Sean!
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.
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- Jeep Heaven
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Re: Need help with timing
M-38 And M-38A1 Indicator can be used also. I'll check to see if I can get pics of the Indicators.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO
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