Logo
FULL SITE MENU

Timing Advance Troubleshooting

P

philme

New member
"About a 1977 140 4 cyl. I am

"About a 1977 140 4 cyl. I am only getting about 8 degrees of mechanical advance @ 2K rpm, service manual indicates should be about 24 degrees. Distributor is a rebuilt that was on boat when I bought it and bushing etc are in good shape, advance assy. is clean and seems to work properly. Numbers on case match manual so pretty sure it is correct one. My thought is that springs may be too weak causing most of advance to be "used up" at idle OR too strong and not getting enough advance. Qustions are - How could I tell which one might be happenig, could there be any other incorrect parts inside distributor that would cause this and what problems would this cause. Thanks - Phil"
 
"try popping the cap and note

"try popping the cap and note where the rotor is pointing. Then move it in the Retard direction - it shouldn't move. If it does, springs aren't tight or the weights/pivots are worn.

Then move it to the Advance direction. When you release it, it should move back to the original position. The total motion should be ~ half of the total mechanical advance.

You can also use a timing light with the advance feature. A 'jumpy' timing strobe anywhere in the advanced portion of the curve indicates the advance mechanism has issues.

Could there be wrong parts - absolutely. Wrongs parts usually means wrong timing curve. that means poor fuel economy and lousy performance. Not enough advance will keep you from making WOT.

You may be stuck with alternative parts if its a Presolite...they were sold and the new owner doesn't support it.

If all else fails, see if there's a 'speed shop' in your area. Call them and ask if they can hook you up with somebody with a distributor machine. If they have one of those, they can find suitable springs and weights and make the timing curve just what you wnat it to be."
 
"Thank you for your informatio

"Thank you for your information and advice. It is a Delco Remy distributor. Already tried the "Turn" test and there is no play turning backwards and goes forward about 10 degrees (On the distributor) and then snaps back. Will try to find a different timing light and someone with a distributor machine. Asumming I find a distributor machine would I be best off with the stock (as per service manual) curve or would there be a better setup in light of different fuel, etc. I am not looking for speed boat performance but am going for a balance of reliability and performance with decent economy. Thanks - Phil"
 
No need to play with the advan

No need to play with the advance curve on a 4 cylinder........no gains to be had. IF IT IS THE STOCK PARTS.
 
Agree w/ Kghost - not enough C

Agree w/ Kghost - not enough CID to make it worth the effort.

You can always scribe the balancer if you don't have an advance light. Another option is a Timing tape - you just need to get the diameter of the balancer to get the properly marked tape.
 
"After a bit more pondering, i

"After a bit more pondering, it is possible that it was rebuilt with too 'stiff' of a set of springs.

A distributor machine may be quicker but, if you want, you can experimment by cutting off one coil, at a time, from each spring and seeing what the advance curve changes too. If total advance doesn't increase after the second coil is cut, you may need heavier weights."
 
"Thanks for all your help, wil

"Thanks for all your help, will set up for stock curve if needed. Still tying to find some one with dist. machine so far no luck (small city - next biggest place 500km (300 miles) away) plus no time for boat at moment - work getting in the way. Will update when I have more information. Once again, thanks for all your help - Phil"
 
Go to napa or good/high peform

Go to napa or good/high peformance auto store and get a set of advance springs. They are sold in kits with instructions. That is a gm type distributor and I would bet most gm type springs would work.

Or check summitracing.com they have spring kits for GM hei (auto dist) some for as cheap as $10.
 
"Still no luck finding distrib

"Still no luck finding distributor machine but had some time to experiment. Set timing to 4 degrees BTDC at 800 RPM. Tied advance system solid, reassembled dist. and ran at 800 RPM, checked timing - now at 1 degree BTDC (difference may of been reassembly of dist. not quite the same as before - was marked carefully before taking apart but?? OR factory timing curve can have as much as 4 degrees advance max at 800 RPM- has pertronix ignition installed already so should be fairly close on reassembly)and at 1500 RPM was still 1 degree BTDC. This tells me that problem is not that the springs are too weak. Next I removed the tie wires AND the springs and then ran the engine at 800 rpm and checked timing - it was now at aprox. 26 degrees BTDC. This tells me that the dist. is likely capable of reaching max factory advance of 28 degrees. Next I put the springs back in and ran at 800 RPM again and checked timing - was at 1 degree BTDC. I realize that this is not a very accurate test but should be close enough to get me going in the right direction. I remember right after purchasing boat I checked timing and it was at about 14 degrees BTDC, this may of been previous owners attempt to make up for advance system problems. I am going to try and get a selection of lighter springs for dist. and see what I can do with total advance. If I can not get the distributor right what would be better (in regards to reliability/engine life - not performance) right advance @ idle with less total advance or more advance @ idle with close to correct total advance? Thanks - Phil"
 
"Forgot - makomark - am not ig

"Forgot - makomark - am not ignoring your advice - am just afraid that if i cut the springs and its worse I may not easily get it to run again - as it is it is usable. Kghost, local NAPA store not very helpfull but local autoparts store going to get me a "kit" with a few different sets of springs, I will post results when I get the parts. - Thanks again - Phil"
 
"Sounds like the advance mecha

"Sounds like the advance mechanism has close to the right amount of adjustment....now you have to get it to occur at the correct RPM.

You seem to have a handle on the process; now you have to get some springs and go thru the trial and error.

the difference could be due to the parts (manufacturing) or some wear. If you need more total advance, you can open the slots where the pins go (pins thru the weights). Go easy and keep it equal on both sides. and don't be surprised if the slots and pins already have some wear.

You may be able to get some new springs from a good auto parts store. worst case, you may be able to get themm at a junkyard, if they'll let you pick."
 
Back
Top