First Car! Motor sometimes doesn't start

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Brett 1970
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First Car! Motor sometimes doesn't start

Post by Brett 1970 » Mon Feb 27, 2017 10:02 pm

Hello, I am a 17 year old and about two years ago I bought a 70 bug for my fist car. I have redone the entire interior, installed a new wiring harness and done some basic modifications to it, such as a big stereo and some little custom leds inside. I've also done some maintenance to the engine, a 1641 single carb 34-PICT. The issue I am currently having is it doesn't start. Now I've been driving it for over a year now, and i've replaced the starter with a rebuilt bosch, replaced the points and condenser, along with a new coil a few months ago. I have previously sand down the points, multiple times when it didn't start, ultimately ending up getting it to work. I would take off the distributor cap, wiggle the rotor, wipe off the contact points on the cap and the rotor, put a piece of fine grit sandpaper in between the points a few times. This seemed to work on about 10 different times, then the most recent time I tapped on the solenoid with a wrench and grounded out the starter which ended up working. I am dropping the engine and thinking of going with a pertronix electronic ignition and possibly rebuilding it. I would like a little more balls on it, but I'm not really sure where to start and what to do. Any help or suggestions would be greatly appreciated.

-Brett

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Marc
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Re: First Car! Motor sometimes doesn't start

Post by Marc » Mon Feb 27, 2017 10:25 pm

There are two kinds of "won't start" - cranks over fine but doesn't fire up, and does not crank over.
You've conflated the two making it impossible to try to diagnose effectively at a distance (that's hard enough anyway).

Fiddling with the points would be something one would do if the engine's cranking and not firing, if they're not making good contact when closed that can cause a lack of spark. See "Kettering troubleshooting 101" here: shoptalkforums.com/viewtopic.php?f=11&t=146793

When they're properly maintained, points are all you need...if you'd rather spend $75 on an electronic pickup, it's your money - but many have been smoked by being hooked up backwards so be sure not to do that! Black is ignition positive supply (Term 15) in the DIN standard used by VW, but on electronic pickups RED is positive and black goes to the negative side of the coil (Term 1).

If assaulting the solenoid or bridging the terminals is needed to get it to crank sometimes, but other times it cranks fine with the key, there are a multitude of possible problems which could create an intermittent symptom - and it's not necessarily just one thing, two or more borderline conditions may be "stacking up" now & then. Start with the basics, the battery condition and making sure that all of the cables are clean & tight at both ends. There's a braided ground strap that goes around the front transmission mount that could be loose or broken, too.

The 87mm pistons and cylinders that you have now are the biggest sensible size requiring zero machine work. They make slip-in 88s (1679cc) but the cylinders are like tin cans with fins on them - DO NOT go there. If you plan to go through the whole engine so it'll be possible to have the case machined, I would recommend going no further than a mild 1775 for your first build...that's a subject that we can talk about for hours when the time comes. Be aware that the 1970 "B6" case, while better than the horrid `68/`69 H5 & B5 cases, isn't quite up to being the foundation of a high-performance motor - I wouldn't even build a 1600 dualport out of one personally - so if you intend to get at all serious about a hopped-up motor the first thing you should be looking for is a `71-`74 dualport to start with, and leave your `70 alone until the new one's built.

Brett 1970
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Joined: Mon Feb 27, 2017 9:17 pm

Re: First Car! Motor sometimes doesn't start

Post by Brett 1970 » Mon Feb 27, 2017 10:48 pm

Sorry Marc, forgot to mention that. Thanks for the reply. It doesn't even crank. I don't know a whole lot about engines, no where near the amount I would like to learn, but I have a general understanding of my vw engine. And also I was looking where to buy an engine gasket kit that has everything I will need. The engine leaks oil like crazy, I know they're going to always leak regardless of what you do, but I have a few vw mechanics tell me that it leaks a lot more than normal. Any suggestions?

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Marc
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Re: First Car! Motor sometimes doesn't start

Post by Marc » Tue Feb 28, 2017 6:04 am

I meant to mention that you'll find an inline connector under the back seat in the red wire that goes to the starter solenoid. That's a good place to "insert" +12V using a fat wire from the + battery post to see if that'll make it crank without you having to crawl underneath. If it cranks from there but not from the key, it may indicate a problem with the ignition switch itself but it's not conclusive (this is one of those things where there may be a couple of "borderline" components or connections, and by jumping it right off the battery you're giving it a little extra current that's overcoming another problem).

Most of the gaskets that can be replaced without major surgery are seldom responsible for "big" leaks. The most economical way to purchase them if you need more than a few is to buy a complete overhaul gasket set, available for ~$20 from any place that sells VW parts... VW P/N 111 198 007AF.
There are sets that include the flywheel seal for a bit more, but normally you purchase that separately: 113 105 245F.
The pushrod tubes are sometimes reusable but they're inexpensive enough that most folks just buy 8 new ones: 311 109 335.
As a rule, your F.L.A.P.S. isn't the best place to buy parts for an ACVW - usually you're better off going to a VW specialty store, or at least a general foreign auto parts store.

Some of the more common leaks are at the oil cooler seals (look for oil dripping off the bottom of the fan shroud right along the bottom edge, ahead of the fuel pump & distributor), the pushrod tubes between the heads and case, and the flywheel seal. The oil cooler seals can be replaced with the engine still in the car, it's not all that hard on an engine with the pre`71 fan shroud and cooler although if you still have a functional thermostat system there are some things you need to know to adjust it properly upon reassembly.

The flywheel seal is conventional but the means of affixing the flywheel to the crank is not, some special tools are required and there are pitfalls for the novice. If it's dripping where the engine meets the transmission, right at bottom center, you'll need to remove the engine. Details to come, if you have to go there. But DO check that the crankshaft does not have excessive endplay - you can do that in the car, just grab the pulley and push/pull on it. There should only be barely perceptible movement, just enough to see, feel, and make a light clunking noise (it should be .006" or less). If you have significantly more and what appears to be a flywheel seal leak, your problems are much more serious - it takes a complete engine teardown to repair by machining the case for an oversized thrust bearing so you may as well just keep putting oil in it until you're ready for the big job.

The pushrod tube seals can only be replaced by removing the cylinder heads (again with the engine out). They do make a couple of types of expandable "repair" tubes that can be used to postpone the job. They nearly always leak a little bit but can be an improvement if you've got a big leakage problem.

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