Distributor Springs Advice
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=47660
Printed Date: May-17-2024 at 5:30am
Topic: Distributor Springs Advice
Posted By: davidg
Subject: Distributor Springs Advice
Date Posted: June-30-2019 at 1:02pm
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Hi Guys! On my '87 Martinique w/ 351 Ford, I had an issue where it wouldn't run higher than 4000 RPM. After digging into it, I discovered that one of the distributor advance springs was broken, and the one remaining was very rusty. I am surprised the boat runs as well as it does even with the timing a bit screwy, but, I want to get it fixed right. The PO had set the idle timing at ~30 degrees BTDC. I knew I would find something interesting when I started digging in to it. Can these springs be purchased at Autozone or O'Reilly's, or do I need to go go Skidim or another specialty supplier? Also, is there a special number, or "strength" of spring to ask for? Are both springs identical or is one "lighter" than the other. Thanks! Dave |
Replies:
Posted By: MrMcD
Date Posted: June-30-2019 at 2:44pm
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I was able to purchase advance springs at a local Speed Shop but that was several years ago. The distributor mechanical advance should offer somewhere around 24 degrees advance. With an initial timing set at idle around 8-10 degrees this would give you a total of close to 34 degrees when fully advanced which should happen around 3,000 RPM with a very smooth introduction of timing as the RPM climbs from idle to 3,000. If the initial timing really is set at -30 to make this engine run the advance mechanism was most likely rusted in one position and not working at all. Free it up, get it clean and lubricated and the new springs should have you good as new. Mark ------------- |
Posted By: KENO
Date Posted: June-30-2019 at 3:22pm
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The quote below is from a post from a year or 2 ago It tells what's a good spring to replace the small lighter one, which is most likely the one that's broke. It works in the clip down and the screwdown cap distributors. The heavier one has oval shaped ends and was made that way and generally isn't the one that breaks
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KENO wrote:
Posted By: davidg
Date Posted: June-30-2019 at 3:24pm
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Thanks Mark! I think the PO had it set so there (~30 on initial timing) so it would run good at top end, but it still wouldn't go past 4000. I set the timing back down to 10, and when I got up to higher RPM's, the engine made a very strange noise, and it did not like what I had done to the timing. So, I just keep it to around 2000-3000, which is where I run most of the time anyway, and it runs fine. I did put the vacuum gauge on it, and the needle really jumps around quite a bit, and is not steady. Hopefully the with new springs, it will settle the vacuum reading down too. I did hit the weights with PB Blaster, and they are free. Hopefully all will be good with new springs. Appreciate the advice. Dave |
Posted By: davidg
Date Posted: June-30-2019 at 3:30pm
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[QUOTE=KENO] The quote below is from a post from a year or 2 ago It tells what's a good spring to replace the small lighter one, which is most likely the one that's broke. It works in the clip down and the screwdown cap distributors. The heavier one has oval shaped ends and was made that way and generally isn't the one that breaks [QUOTE=KENO] Hi John Thanks Ken! If we get up to the lake today, I will stop by Ace and pick one up. Should be a good solution until I can get the permanent ones. |
Posted By: KENO
Date Posted: June-30-2019 at 3:38pm
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When the little spring breaks, your timing which was probably properly set at about 10 degrees BTDC at idle, jumps up to about 30ish with the little spring having no ability to control the advance. Your total advance won't be much over that (maybe a few degrees) as the big spring starts to control the advance. On your Prestolite the big spring isn't in the picture till around 4000 rpm (because of those oval shaped ends) not the 3000 mentioned above. You won't find the original springs pretty much anywhere these days and you can't slap any old springs in there. In other words don't buy springs for an AC Delco distributor and expect good results. The Hillman I mentioned works good and pretty closely duplicates the stock curve. Fixing this really should have no effect on your top end rpms, it just gives you the stock curve with the same amount of total advance |
Posted By: KENO
Date Posted: June-30-2019 at 9:17pm
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Mark I moved this quote to here from the thread you had it in because this is where you meant it to be 
And now I'll say that you haven't had much experience lately with a marine Prestolite as they came from the factory which is what I gave him the info for. Your 78 had the clip down cap Prestolite from the factory which had a better curve than the later Screw down cap did. It seems that Prestolite went the other direction and got more conservative in the mid to later 80's I'm telling him what he'll find with his distributor, not what may or may not be the preferred settings that take a lot of effort to achieve on the Prestolites Easy to say, hard to do
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Posted By: MrMcD
Date Posted: July-01-2019 at 6:55am
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Thanks Ken, I think the Marine guys stayed really conservative and your right it takes work to update it. ------------- |
Posted By: andrewmarani
Date Posted: July-01-2019 at 7:23pm
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Hopping in on this discussion. While I was working through some low idle stalling issues (see other post) I looked at the distributor springs. The small one was pretty badly rusted and still connected up, but I'm looking to replace it. Found the link below with what looks like a possible replacement. I'm ok spending $28 if it actually works. Anyone know if these are drop-in replacements? https://mcpartsdepot.com/products/springs-dist-351std-ho-elec There is a forum discussion about using a Hillman #`119 spring, which is available on Bay for $9 plus shipping. Search for Extension Spring #119. I would rather use ones designed for the distributor. Thanks Andrew ------------- Builder |
Posted By: davidg
Date Posted: July-01-2019 at 8:25pm
| Andrew......Interesting. My boat also was having low speed stalling and idling issues, and I was wondering if it was due to the timing issue. My marina guy ordered some springs from NAPA. It will be interesting to see if they are actually Prestolite springs. I can't believe these little buggers are such a PIA to source! |
Posted By: KENO
Date Posted: July-01-2019 at 9:37pm
Andrew As far as the Hillman #119 spring , I didn't look on Ebay to verify 9 bucks plus shipping, is that for one spring? If so, you're a lousy shopper Go back and read what the backyard hack who came up with that spring as a solution said.....................local hardware store and priced around a dollar and .........no shipping. The springs from MC parts depot might work in your Prestolite, hopefully the picture is a generic file photo 'cause I figure the heavy one doesn't resemble what's in your distributor right now at all. Take a look at what you have in there and compare to the picture. They'll give you an advance curve but will it be the same? You could call MC Parts Depot and see what they can tell you. Spend the 30 or so and then splurge for the extra dollar or so on the Hillman #119 and you can compare them and write up your findings here. What's your timing look like right now if you check it at every 500 rpm up to 4000 rpm? |
Posted By: andrewmarani
Date Posted: July-01-2019 at 10:08pm
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The ebay listing is for 10 springs, so not a horrible price, except I only need one... There is a local Ace hardware store that has a very large selection of small parts. They might have small springs but will one be labeled as a # 119? Maybe, maybe not. Total guessing game. Sure, I'll spend $30 for an experiment for the good of the forum, worth it for all the problems i've solved here. I did not check the timing up the acceleration range. I did check it Saturday at 1000 rpm and it's right on 10. I've checked the timing during previous seasons and it's alway been around 10. Is there a chart that tells me what is should be as I step up the RPMs? I'm wondering if there is a simple measurement to compare springs of the same wire size and length? maybe hanging a couple of different weights on them and measuring the extension. I will spend a few minutes on the Net and see what's been posted. ------------- Builder |
Posted By: andrewmarani
Date Posted: July-01-2019 at 10:21pm
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Nope, not spending $17 to ship two springs that I could mail for 75 cents. I will buy the #119 springs and see how they compare. ------------- Builder |
Posted By: KENO
Date Posted: July-01-2019 at 10:44pm
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Hillman provides the cabinet with drawers to the hardware store usually. The drawer that say 119 has the springs sometimes in a bag, sometimes loose. The dimensions are shown earlier in this thread in a picture. So.....not too much of a guessing game If you don't check your advance curve and total advance with the present springs, how will you know if the MC Parts Depot springs give the same curve and total advance if they're not an exact duplicate of what you have? You can have the same 10 degrees at 1000 and everything from there up could be different. I'd check it every 500 rpm starting at 600 or whatever your idle speed is, 1000,1500 and continuing up and write it down. You won't find any numbers or graphs from PCM showing the curve, but I might know a backyard hack who'd have some numbers to compare with yours |
Posted By: KENO
Date Posted: July-01-2019 at 10:50pm
Probably a good move I'd been using one of the Hillmans for about 300 hours before I decided it was time to post here about it. Kinda like acceptance testing to be sure I was happy with it. |
Posted By: andrewmarani
Date Posted: July-01-2019 at 11:22pm
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I did see the specs on the #119 and found the same info on-line. It has a weight rating of 10.18 lbs. Which might be the same spec as something called the "working load" or it might be the " initial tension". If my current spring is still giving me the originally specified advance curb then I don't need to replace it. The problem is I don't know if it is. it's pretty rusted and I would expect that to change it's properties and by extension, the advance curve. i'm probably diving too deep in the weeds, but. If someone with a small distributor spring in good shape can give me the following information I might be able to use a fairly complicated online spring calculator to figure out all the properties and see if they have a similar spring in stock. I would try it with mine, but it's all rusted up. Need the following: Wire diameter, overall spring length including the hooks, outside diameter of the spring, number of full coils (not counting the half coils at the ends), And the amount of weight you have to hang from the spring to cause light to just start showing between the coils, in other words just when the spring starts to extend. I played around with the calculator some and I'm guessing that weight is between 5 and 10 lbs. A picture would be great as well. Meanwhile I will pick up a #119 and install it to see what happens. Probably be a few weeks till I do, we've got plenty of skiing planned and I don't want to take the boat out of service. ------------- Builder |
Posted By: MrMcD
Date Posted: July-01-2019 at 11:35pm
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If the springs are weak you will bring the timing in early which can cause performance issues, pinging and maybe detonation. If the spring is rusted it is weak and your timing will come in early. If you have a Speed Shop locally they usually have a selection of springs to choose from. Summit Racing shows many available on line or check the hardware store selection. If the new spring is too strong it will delay your advance and make the engine sluggish. ------------- |
Posted By: KENO
Date Posted: July-02-2019 at 8:52am
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[QUOTE=MrMcD] If the spring is rusted it is weak and your timing will come in early. /QUOTE] In that case every distributor spring out there is weak, since they all get rusty And for Andrew, I really don't think the distributor has anything to do with your idle issue right now. You still have the same 1000 rpm timing you've had in other years. I tend to think you're on the right track with carburetor idle adjustment and checking for vacuum leaks like mentioned in the other thread.. |
Posted By: KENO
Date Posted: July-02-2019 at 9:04am
I've been in those same weeds and that's how I eventually found the Hillman #119 I have quite a collection of springs for other brand distributors and none of those really came close to the original. |
Posted By: fanofccfan
Date Posted: July-02-2019 at 10:29am
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Ken knows his springs! He also knows a thing or two about the curves as he helped me get things back to normal on my 78 commander about a year ago. Thanks again btw! ------------- 2004 196 LE Ski 1969 Marauder 19 1978 Ski |
Posted By: KENO
Date Posted: July-02-2019 at 10:25pm
Speaking of numbers, for whoever cares, here's what I came up with for the PCM heavy spring and a Hillman #119 installed in a clip down cap distributor. RPM advance 500 0 plus initial 1000 4 plus initial 1500 12 plus initial 2000 16 plus initial 2500 18 plus initial 3000 22 plus initial 3500 24 plus initial 4000 24 plus initial won't go any higher because of the slot length in the advance plate (also referred to as the stop plate at times) limiting the advance. Now these were with my tach which may read different than your tach and my eyeballs which aren't your eyeballs but they give you an idea of the timing curve with the springs mentioned above. Some people may like it, some may not, but I think it's pretty good keeping in mind that with the heavy spring you don't reach full advance till about 3500 to 4000 rpm as it originally came from the factory. The engine runs good with this setup With the screw down cap the advance plate is different (shorter slots) and the max advance will be less if you start with the same initial timing. |
Posted By: davidg
Date Posted: July-03-2019 at 5:33pm
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Ken....I appreciate you posting those numbers, and your help on this situation. I stopped by a NAPA today just to see what the response would be when I asked for these springs. Pretty much the same as AZ or OR....ie....what year, what make, what model, what engine, etc, etc. Stopped at ACE on the way home. Took me 30 seconds to locate the Hillman bin. There was good ole #119 just waiting for me (three actually), so I grabbed 'em @ $1.69/ea. My marina guy said he got me some springs too from NAPA. It will be interesting to see what those are since NAPA had no clue when I asked. Well, it's nice to have options anyway. I may throw the timing light on it to see what kind of numbers I get. |
Posted By: andrewmarani
Date Posted: July-03-2019 at 5:45pm
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Compare the Napa springs to the # 119. Tell us how they compare in length (overall), number of full coils and diameter. If you have a spring fish weighing scale, pull just hard enough to cause the coils to open up slightly and tell us the weight for each spring. ------------- Builder |
Posted By: KENO
Date Posted: July-03-2019 at 10:53pm
Umm..........you should do that yourself at least for the Hillman, you'll go bug eyed trying to count the full coils on the Hillman. and the scale should be for miniature goldfish or something like that
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Posted By: davidg
Date Posted: July-04-2019 at 7:54pm
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Initial Field Report: Mixed Results! The Good: The NAPA spring for "my distributor" my marine guy got me did help the timing to work. The timing was advancing at higher RPM's like it was supposed to. Got close to the 25ish BTDC mark when revving at mid throttle, based on what I could guesstimate under bad conditions. The Bad: Got everything buttoned up. Idle seemed fine. Gave it some gas to get underway, and it was running real rough (seemed like it was missing). Made sure all the plug wires were attached, and tried again. Same thing. The Ugly: Trying to work on a boat in 90 deg. heat, 110% humidity, blistering sun, and 2'-3' swells. The Springs: Top is the NAPA. Bottom is the Hillman #119. Only tried the NAPA today. Anyone know why the boat would suddenly start to run very rough with a new spring in and the distributor advance "working"? I may have inadvertently changed the point gap, but, I think I had it very close. Maybe the condenser is bad?? But the distributor is "fixed" and it now runs rough. Go figure!?! I'll need to keep tinkering with it to figure it out. May throw the Hillman spring on, and/or go back to no small spring at all and see what happens. It ran perfect with no spring. 
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Posted By: KENO
Date Posted: July-04-2019 at 10:02pm
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I think you may be right on the gap changing when you put things back together. I also think at least from looking at the picture that the NAPA spring is longer and a lot beefier and will give a slow curve and won't let you get to full advance very easily Could be that I'm still bug eyed from trying to count the number of coils in the Hillman spring
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Posted By: TRBenj
Date Posted: July-04-2019 at 10:09pm
| I’m sure you realize this can all be done on the trailer? |
Posted By: davidg
Date Posted: July-04-2019 at 11:46pm
I do realize that, but, I wanted to use it today and also see how it did on the water. Nothing like an in-water trial once "fixed". But, today's conditions were less than ideal for doing what I was doing, plus the wife was helping me. Next time.....the trailer! 
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Posted By: davidg
Date Posted: July-05-2019 at 1:25am
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I was just reading my original CC manual that came with my boat. It say that the idle should be 600 rpm in gear. I have been setting my timing with the boat in neutral, and the rpms are probably closer to 900/1000. Should I be setting the timing with the boat in gear at 600 rpm? Also, point gap spec is .018" (I had been using .017"....probably not a big deal), and the dwell spec is 29-32. The timing spec is 6 degrees, but, it seems like everyone is using 10, as am I. |
Posted By: KENO
Date Posted: July-05-2019 at 8:59am
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If you look at page 9 of the manual in the link from the reference section here on CCF you'll find the timing spec for the screw down cap as 10 degrees and the clip down cap as 6 degrees. Reading the notes, they limit you to 30 degrees total advance with those numbers. They're different because the slots in the timing plate are different lengths. The screw down distributors have a white nylon type plate with shorter slots. That's probably what you have. being an 87 You'll also see a note on page 9 referring you to page 6 of the manual for timing instructions on 87 octane that say to reduce your settings by 4 degrees. Everybody will start yelling now that those are ultra conservative numbers..............yell at PCM and Ford, not me, they came up with them It probably was to cut down on warranty claims while still getting OK ish performanceMyself, I'd set it at 10 and check total timing.to be about 30 with the Hillman spring and the heavy spring installed.and tweak things from there if you want to. Note that they say 30 degrees max at 4400 rpm. Depending on your prop, you may never see 4400 rpm As far as your timing question, setting timing in neutral is perfectly fine but the idle could be lower like around 650 to 700 rpm , which when you put things in gear will drop the idle down to 600 or so if the carburetor is adjusted right. http://correctcraftfan.com/Downloads/PCM%20Owners%20Manual_New.pdf" rel="nofollow - link |
Posted By: davidg
Date Posted: July-05-2019 at 11:23am
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Thanks Ken! I may go back up today and continue working on it to try and dial it in. My manual on page 9 looks completely different than the reference guide from this site. It does not have all the info regarding the different distributors, and timing difference. As it relates to my idle, when I drop it in to gear, it seems like it drops down quite a bit. I will try to get specifics numbers, but, it seems like around 300-400 rpm. Gonna take the dwell meter with me today to put that in the mix to see how close I am using .018 as the gap on the points. |
Posted By: MrMcD
Date Posted: July-05-2019 at 4:25pm
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Sounds like you are almost dialed in. When working with points try and carry an old fashioned paper business card, white without the new style plastic face. The thick white paper works really well to swipe through your points. Open the points install the card, release the points so pressure is now on the card and it is between the points. Drag the paper through the points. Ususlly you can only get about a 1/2" drag due to space limitations. Now with the card removed look at it. The white paper will drag out any dirt or grease that landed in your points. Even on new points install I have seen this trick pull out dirt or grease and fix points issues. It will not fix glazed over points. If the points are good and clean you will see a clean drag mark on the card. This is a 15 second check and lets you know the points are clean. An old mechanic showed me this trick 40 years ago and it still works today if you have the old style paper business card on hand. I suspect many points issues are caused by less than clean feeler gauges when setting the gaps. ------------- |
Posted By: davidg
Date Posted: July-05-2019 at 8:03pm
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Field Report #2......Success! Points Cleaning: Not wanting to make too many changes at one time so I could tell what actually fixed things, I left the NAPA spring in the dizzy. As Mark suggested above, I dragged a piece of an ACE Hardware brown paper bag through the points to clean them. I learned this trick late in life (as in last week) when the boat wouldn't start. I had sprayed PB Blaster on the timing advance weights. Apparently some got on the points and it wouldn't start. My marina guy grabs a piece of an ACE paper bag, drags it through the points a couple of time, and wallah......it fired right up. The PB Blaster and points apparently don't work and play well together. Points Gap: Yesterday, I inadvertently took the points off the dizzy plate, and screwed up the adjustment. Re-gapped them today to .018". Timing: I confirmed I was at 10 BTC. Also watched the timing mark go up toward 25ish or so at 3,000 rpm. So, the advance is working properly. Result: Headed out from the dock to open waters, and brought the rpm's up to 2500 or so. No stumbling, no missing. Ran like a pup! Dwell: I checked the dwell once everything else was pretty much dialed in. The spec calls for 29-33. I was at 25. I assume the only way to change the dwell is to change the points gap, correct? If so, to increase the dwell, do you decrease or increase the point gap? Hillman #119 Spring: I wanted to see if the boat would even run with the NAPA spring, and it did. I am not sure it's optimal, but, I feel a lot better today, than I did yesterday at this time. Next time up, I would like to throw the #119 in to see if I can feel a difference. I will say that with the NAPA spring, the acceleration is okay. It certainly wasn't a rocket sled. Hopefully the lighter spring will put a little hitch in the giddy-up. Overall, I am pretty satisfied with how its running now. I sure do appreciate all the input and advice you guys gave. However, I am still a little concerned with the quality of the idle. Tends to range from 600 in gear at idle, to 1100 in neutral.. So, I am going to research the finer points of tuning the 4160 carb. Other than the idle screw, the only other way to adjust it I could see was two very small screws (one on each side of the carb metering plate). I assume one, or both, or to adjust the idle circuit. |
Posted By: MrMcD
Date Posted: July-06-2019 at 5:03am
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Glad you made progress, it is amazing how much help a quick swipe of paper through the points can offer. As far as your swing in RPM in gear and at idle in neutral, 600 in gear to 1100 in neutral. That indicates a weak idle to me. It can be very lean and do this or too much timing at idle. With my old 78 351W with a Holley I found if I opened the two side fuel meter screws a half turn more each side it improved my idle quality in gear, made it stronger. If you go too far it will start to smell rich at idle. This also seemed to help with starting the engine without needing to give it throttle. This advice assumes the rest is working well already. Did you verify all 8 plugs are still firing? ------------- |
Posted By: KENO
Date Posted: July-06-2019 at 8:27am
Reducing the gap will increase the dwell The 2 screws each feed the idle circuit for their associated primary venturis. They both get adjusted together Shoot for best vacuum idling in gear 1 1/2 turns out is the "usual" starting point and turning out richens the idle mix on your marine 4160 The idle circuits could also need cleaning. Best way is to remove the primary metering block and then soaking and blowing out the passages with air. An ultrasonic cleaner works good for the soaking if you happen to have one
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Posted By: samudj01
Date Posted: July-06-2019 at 10:23am
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While you all are in this topic of metering blocks. Can I take off just the metering block and leave the carb on the boat? I want to clean and blow out. Just developed a rough idle but she runs great otherwise! Will I ruin stuff in the metering block (ie need to rebuild anyway)? ------------- 78 Ski Tique, 72 Skier w/302's, 93 SN w/351 & 17 GS22 w/zr409 Previous - 99 Sport Nautique w/GT40 and 87 Martinique w/351 |
Posted By: KENO
Date Posted: July-06-2019 at 12:19pm
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It might be less trouble overall to just take the carburetor off then do things on the workbench especially if you have a metal fuel line. Getting that sprung to get it off and back on can be "not a lot of fun" especially if you cross thread the fittings. If you have the non stick reusable gaskets in there now, it should come apart easily. You have to watch out for the O rings on the accelerator pump transfer tube that goes between the metering block and the body and also the O rings on the transfer tube between the primary and secondary bowls. (Older carburetors don't have the accelerator pump transfer tube, their body and metering block and the gasket between them are different with a drilled passage instead of the tube) Having a carburetor kit on hand is always a good thing in case you run into problems. Also if it's on the bench, getting the accelerator pump linkage together right is easier. But..............it can be done on the boat. Something I learned from a chef who also worked on carburetors, if you spray the gaskets with some PAM or whatever your favorite cooking spray is before assembly, they.ll come off easier the next time. Even the non stick gaskets like a shot of PAM
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Posted By: davidg
Date Posted: July-06-2019 at 12:54pm
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Ken.....Does it matter where you take a vacuum reading from? I already have a port on the back of the manifold. I also got one of those Dorman kits to get to right size hose(s) and fittings to get it to work with my gauge. I saw in one of your posts that you measure the vacuum from the PCV hose with a T set up. I assume either locations works!? By the way, the needle on my gauge is very "twitchy". It stays in one area, but, very "fluttery". What is that a sign of? The face of my gauge didn't have anything for that.  
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Posted By: davidg
Date Posted: July-06-2019 at 1:00pm
By the way, speaking of my manifold, while I was looking around under the hood, I noticed something interesting, or concerning actually. On one of the runners of the manifold directly under the carb, I noticed that there appeared to be a crack on a sharp edge. I am not sure if its just paint separating, or if its actually a crack, and possibly a vacuum leak. You guys ever seen anything like this on your engines? If it is a crack, it looks like a little epoxy mix (I forget the name of the famous stuff) may plug it up. I couldn't feel any suction when I put my finger over it with engine running. 
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Posted By: KENO
Date Posted: July-06-2019 at 1:22pm
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What you show for getting your vacuum readings works Dave. I'd vote for peeling paint but if you scrape it a little, it might tell you more. Spray a little carb cleaner or even just some soapy water there while the engine is running and see if anything changes Oh, almost forgot, that famous stuff must be Pete's favorite epoxy, JB Weld Nice skinned knuckle by the way
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Posted By: KENO
Date Posted: July-06-2019 at 1:28pm
| I'd look at one of the vacuum reading charts on line to see if you find a description of your twitch and what the variation is between the high and low readings. |