Full Version: 1975 starter issues
Hello guys new to this forum, but have had multiple 914s,I'm working on a 75 with starter issues. Had a friend bring his 914 to me to work on carburation etc... When he got here I when to start it and nothing so checked wiring and it was fine. Tryed jumping starter it was locked up solid. He live about 3 miles from me and stated that he did here some grinding type noises . He just had a remanufactured replacement starter installed. I told him to get another so he did same thing Bosch reman. I installed it and it's doing the same thing once you turn the key to start it, it doesn't disengage. I've changed new ignition switch new starter relay(aftermarket). I'm at a total loss, and very frustrated doing this as a friend and am over it. Any suggestions? Also I pulled starter bolts out and grounded body to run starter in the open and running or bench testing it the solenoid doesn't push out. I thank it's possessed. One other thing is he had a shop swap his injection for China 40idf carbs. Of witch they don't have any vacuum ports in them or the manifolds, should it be ok to tap into the Manifold for distributor vacuum?
Ok a couple of confusing statements to clear up. You stated it was locked up and would not disengage. But on the bench the solenoid would not operate. It would seem that these two types of failure you describe are exact opposites. In order for it to lock up the solenoid has to operate at least once.
Did the motor run on the bench?
On the carbs need more info on engine and dizzy. But the vacuum advance may not be needed depending on the engine and dizzy.
Did the motor run on the bench?
On the carbs need more info on engine and dizzy. But the vacuum advance may not be needed depending on the engine and dizzy.
Wish I had the source for this to give proper credit but here is some info on vac advance.
Vacuum Advance 101
As many of you are aware, timing and vacuum advance is one of my favorite subjects, as I was involved in the development of some of those systems in my GM days and I understand it. Many people don't, as there has been very little written about it anywhere that makes sense, and as a result, a lot of folks are under the misunderstanding that vacuum advance somehow compromises performance. Nothing could be further from the truth. I finally sat down the other day and wrote up a primer on the subject, with the objective of helping more folks to understand vacuum advance and how it works together with initial timing and centrifugal advance to optimize all-around operation and performance. I have this as a Word document if anyone wants it sent to them - I've cut-and-pasted it here; it's long, but hopefully it's also informative.
TIMING AND VACUUM ADVANCE 101
The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency.
The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation.
At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).
When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean.
The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic.
Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.
If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.
What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone.
Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren't fully-deployed until they see about 15" Hg. Manifold vacuum, so those cans don"t work very well on a modified engine; with less than 15" Hg. at a rough idle, the stock can will 'dither' in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15" Hg. of vacuum at idle need a vacuum advance can that's fully-deployed at least 1", preferably 2" of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8" of vacuum, so there is no variation in idle timing even with a stout cam.
For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively.
Vacuum Advance 101
As many of you are aware, timing and vacuum advance is one of my favorite subjects, as I was involved in the development of some of those systems in my GM days and I understand it. Many people don't, as there has been very little written about it anywhere that makes sense, and as a result, a lot of folks are under the misunderstanding that vacuum advance somehow compromises performance. Nothing could be further from the truth. I finally sat down the other day and wrote up a primer on the subject, with the objective of helping more folks to understand vacuum advance and how it works together with initial timing and centrifugal advance to optimize all-around operation and performance. I have this as a Word document if anyone wants it sent to them - I've cut-and-pasted it here; it's long, but hopefully it's also informative.
TIMING AND VACUUM ADVANCE 101
The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency.
The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation.
At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).
When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean.
The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic.
Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.
If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.
What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone.
Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren't fully-deployed until they see about 15" Hg. Manifold vacuum, so those cans don"t work very well on a modified engine; with less than 15" Hg. at a rough idle, the stock can will 'dither' in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15" Hg. of vacuum at idle need a vacuum advance can that's fully-deployed at least 1", preferably 2" of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8" of vacuum, so there is no variation in idle timing even with a stout cam.
For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively.
Sorry the starter being locked up was the first starter. The one I'm dealing with not disengaging is the second starter. I am also thoroughly confused about the whole thing. When I got it. I installed the new starter and new ignition switch, the owner had already installed a aftermarket starter relay, of which after some reading is not the best idea. So after installing these two things when I turned the ignition key to start there was nothing. So I traced the big yellow wire from ignition switch back to starter solenoid and wasn't getting any power to solenoid when switch was activated. So I traced wire and there is a break in the yellow wire somewhere. I tore the interior out of car to get to wire harnes. The yellow wire goes into a box under the passenger seat. So I ran a new wire from the yellow wire back to the ignition terminal on the solenoid . It starts but like I said the starter doesn't disengage, so it just sits there grinding away until you turn ignition off. So here's were it gets weird when the starter is bolted up, the solenoid ingages, but doesn't disengage. If I unbolt the starter and energize it it spins but solenoid doesn't push out.(ingage) what is the black box under the passenger seat? Also most all the plugs under the seats are unplugged or ends ripped off. I'm assuming seatbelt lock,start system?
The engine started out a 1.8 but has been rebuilt into a 2.0 so I've been told, stock distributor, has vacuum port on each side of diaphram I know when I'm building vw turbo motors I lock the distributor out at 32 to 34 dagrees but not sure about naturally aspirated. From what I get outah the article you posted yes I need vacuum, and from manifold should be fine. Correct me if I'm wrong
Big box under passenger seat. Two yellow wires. Disconnect them from the box and connect them together.
So one solid yellow and one yellow with red stripes? And what is it I'm bypassing?
you are bypassing the passenger seatbelt safety mechanism thing-a-magig.
if i remember it correctly, if it fails or it thinks there is a passenger seating, it wont start until the seatbelt is inserted. hence bypassing.
if i remember it correctly, if it fails or it thinks there is a passenger seating, it wont start until the seatbelt is inserted. hence bypassing.
Hello guys ok I figured out the wiring aspect hopefully . But this thing is still chewing up starters. The owner keeps buying the rebuilt Bosch started from pelican parts, has anybody had any issues with these? Is there any possibility that it needs to be shimmed out or something? I'm dieting here just want get this thing outah my yard
Why not just admit defeat and have him come get it? Or have a little patience and we can help you work it out.
I have heard of certain (aftermarket?) starters binding up like you describe if the starter body is not shimmed away from the trans case.
Does anyone recall that?
I bought an ebay high torque starter and it came with a shim.
IIRC I put it in and have zero problems.
Does anyone recall that?
I bought an ebay high torque starter and it came with a shim.
IIRC I put it in and have zero problems.
QUOTE(stugray @ May 19 2016, 10:19 AM) 
I have heard of certain (aftermarket?) starters binding up like you describe if the starter body is not shimmed away from the trans case.
Does anyone recall that?
I bought an ebay high torque starter and it came with a shim.
IIRC I put it in and have zero problems.
I also have the Hi-Torque starter, and am using a 3/16ths aluminum shim between it and the gearbox. Works perfectly. When I first read the post, I wondered it the starter was jamming the bendix into the ring gear, but with ign. key released, the solenoid should try to retract, and starter motor should be un-energized.
Unscrew the solenoid clean it as they gum up and the piston sticks in the bore.
Make sure the engagement arm is free to move after the solenoid is removed,you could have a broken Bendix spring for example.
You say it didn't bench so I can only assume the solenoid is gummed up or faulty.
Whats the condition of the flywheel ring-gear ?,I have seen these pretty chewed up in the past.
Make sure the engagement arm is free to move after the solenoid is removed,you could have a broken Bendix spring for example.
You say it didn't bench so I can only assume the solenoid is gummed up or faulty.
Whats the condition of the flywheel ring-gear ?,I have seen these pretty chewed up in the past.
Thanks guys, wow to the cabinetmaker. Very random answer I wouldn't take the time to write a post if I wasn't asking for help. And I have lots of patience it's been with me for 2 months. I've fixed just about 15 issues the car had when I got it so now I'm down to the starter issue. I guess I will suggest a high torque starter and try the shim to see what happens
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