got an engine issue while away on holiday and need some advice. Did a long 8 hour run yesterday in the van and ran well although noticed a slight stutter perhaps twice. Today did about 4 hours including porlock hill in Devon and have picked up a few more issues. So: 1970 b code 1600 single port engine on single carb. Just changed 009 dizzy to a new vacuum advance dizzy with accucrap ignition. Timed at 7.5 degrees. So it seemed to run better on the vacuum advance dizzy. Symptoms which have got progressively worse: Slight hesitation or minor splutter on occasions and seemed to be just when starting up hill perhaps on load. This got more regular until I noticed further things such as backfiring when coming down steep hills say in second and high revs. This only happened a few times but formed part of the getting worse phase. A few times would be driving and it would lose all power for a bit only to come back, would still run but wouldnt rev when pushing accelerator, strange! Then after a long decent into lynmouth and after near brake fade and a bit of backfiring it did the same where it would lose power and cut out only for me to be able to start it again. Parked up let it cool a bit and was away again. Like this all the way to woolacomb!!! Early on with the spluttering I thought it was they accuspark, then considered maybe a problem with the newish fuel pump. Now considering it to be a timing issue? Seems to be an issue when it gets hot and also when high revving downs hill will cause backfiring. Wondered if the heat was effecting the accuspark and when it cooled down it would be ok. Looking at the John muir book it says the 1970 b code engine should be timed at 0 degrees at idle, I had done 7.5. I must say when I timed it at idle with hoses all attached I would rev it and it wouldn't always return to the same spot. I have points(although no grease) and I also have the 009 on points with me. Was considering timing it to 0 degrees. Do I have to remove pipes to do this properly?. I have a timing strobe with me. Any help appreciated I may be delayed responding due to no 3G. Thanks.
I would first try swapping that accucrap for points if you have any. But this is from personal experience on how unreliable accuspark stuff has been. Sent from my Pixel XL using Tapatalk
That was my first thought. Never fitted points before and I thought I need to grease them and have a swell meter to install?
i may be reading this wrong............ you timed it to 7.5 degrees.................... that should be the static timing to get the timing somewhere near, and then should be done with a strobe to 28 - 32 degrees with the engine upto 3500 rpm surely....
Using a timing gun whilst at idle I timed it to the one and only mark on the pulley at 7.5 degrees. To be honest it ran and reved well at this point.
The new dizzy is it acuspark ? cause there are Marmitee ....you need a genuine Bosch /vw dizzy .... timing is 7.5 degrees BTDC at idle ....Max 32 at speed
I think you may find your timing is slightly out when running at revs.. it may be getting hot which your accuspark won't like as its been said they have failed if they overheat.
Back firing on the over run is a symptom of timing being out. If it goes again after cooling down, that usully is an electrical issue. Classic condenser failure behaviour for isntance.
Timing is best done at max advance, but to be honest, 7.5 at idle is fine for now. Ignore the 0 degrees, that was for the original dissy that would have been on the single port. If it ran ok to start with the timing wont have a moved unless the clamp is loose. My first try would be points mate, iv had a few accuspark causing mis / backfiring of late.
http://www.hot-spark.com/hot-spark-009-vw-type-i-pulley-degree-template.pdf this is a template for the crank pulley so you could mark it out. the keyway on the crank pulley is 90 degrees anti clockwise to tdc so you can line it up correctly.
Hesitation like that is often electrical. I have had one Accuspark which would emulate closed up points by just not providing spark at start up sometimes and then working perfectly every time I looked at it and clipped on test gear. In the end it failed big time, it basically cut the ignition at high RPM like changing down for a hill or pulling away. This produced a brrm brrm Bang Bang effect. I drove it like that about four miles as I couldnt be arsed to break down in busy stop start traffic and the bit where the engine was running it sounded OK no rattles etc. I thought my current one was going dodgy when I got missing and bucking on the A43 en route to Techenders where I was constantly slowing down from 60-70mph for roundabouts then going hard on the gas again. But it fixed itself and then when I got to Techenders I tightened up some loose spade connectors and it has been ok since. I think my earlier troubles were caused by previously testing for a spark by leaving a lead about an inch from metal making for massive voltages on the primary side of the coil. Which cause permanent progressive damage to the switching transistor e.g. Pertronix or Accuspark. In a condensor it blows a hole but they are designed to self heal many times before losing capacitance and weakening the spark. If you look at the specs of the smart devices used in production cars these days they are light years away from the garage hacker bodges in the Pertronix and Accuspark. Its one of my projects to put together a crank fire system made with a proper ST microelecronics coil driver. I would try the points and condensor. Timing to 7.5. Hose off and blocked to carb but shouldnt make any difference as the throttle plate should be blocking the diztributor vacuum tube in the carb. If you can get points into the Accuspark SVDA try that it will help with hills better than an 009. Then when you get back try to get a recon Bosch SVDA that takes either points or a module. I am finally happy after buying two scrap Bosch units and making a good one then fitting an Accuspark module as its cheapest.
Got free wifi for a bit. Been an interesting week, Couldn't get points dizzy to work for some reason, could of been the old spare condensor. Long story short ordered a petronix dizzy vacuum advance!deleiveres to campsite reception, and she runs sweet again!!! Thanks for help.
I think I may have an idea why. Following the petronix installation guide the dizzy drive shaft thing should be perpendicular to the pulley wheel when in tdc. Mine was out by perhaps 30 degrees. When I got the petrnoix dizzy to fire and times the vacuum advance part of the dizzy was right round to the alternator stand and not how they normally sit. Obviously it runs and should get me home but perhaps the old vacuum advance with points couldn't be timed to start up because it couldn't be rotated enough. I will have to straighten it when I get home and test it!!!! Wonder if the previous owner/ engine builder bloke set it at an angle like that as it was running a 009 and didn't matter?
If you're referring to the dissy drive dog in the case, it may look slightly squiffy even when it's in the "proper" place. Might be installed one gear tooth out by the engine builder. Anyhoo...it doesn't matter. Use TDC on your crank pulley as the reference for timing.
What snotty says.. some dissy are orientated differently.. just line your plug leads up to match the new number 1 tdc.
