Hello All! Not wanting another year marred with breakdowns, I took the plunge last week and dropped the engine out of my 1973 camper. What I have decided: - Not much really. I have purchased a top end re-build kit so I will be replacing the barrels (1641), pistons, all seals and gaskets, cylinder heads and the push rod tubes. - I have also decided all tinwork needs replacing, because it is too far gone. - I have an electronic ignition system that did try previously but didn’t like, I want to give it another go. What I would really appreciate some advice on: - Crankshaft pulley. Mine is the original with just the dimples and grooves. Do I update with a sexy looking new one with all timing marks? I have heard bad things about the aluminium ones…? - Twin carbs. Are they worth the money, in terms of the performance they add? - If I go for twin carbs, do I need to change anything else other than the fan housing? - Clutch - I think if I’m in, I might as well…? - Is there anything else (other than a really good clean) anyone would advise doing? I am mainly in pursuit of less hassle and a bit more poke. All advice would be greatly appreciated.
As above, what "breakdowns" were you having? If you want to push the boat out, 1776 is a nice size. Does involve having the case/heads machined. 1641 doesn't add much to a stock (underpowered) 1600, only a moped's worth of cc-age. Electronic ignition is worth having. What didn't you like about your setup? Stick with the stock pulley - they're fine. If you want timing marks, the CSP pulley is good, if pricey. It won't explode like Chinese ally ones. Twin carbs are worth considering, but there's added expense in terms of manifolds, linkage, etc that you need to add to the cost of the carbs. The CSP centremount is an excellent, simple linkage. You don't need to change the fan housing. They will need work setting up.
Random waffle ... For a certain set of problems, a valve re-seating and a proper tune up of a stock 1600 may be all you actually need , as if they are well set up you cant tell the difference between that and a 1641.. not even an electronic distributor needed. Pulleys - if it was working OK, not throwing belts off , chewing alternator pulleys etc. leave it as is for later messing around. I have had run-out (radial and axial) issues with new Brazilian crank pulleys, and less with a machined aluminium pulley. Carburettors - if your setup has a working choke, hot air feed and heat risers that work and you like using it in cold weather, stick with the stock carburettor until after you have improved the engine. If its a filthy blob with poor compression, flickery oil light and chuffing noises ... then it needs TLC .. You can gain a noticeable amount just by changing the exhaust and fitting dual carburettors in the end, but do it in stages, fix the engine first . Or you may just be introducing more things that need setting up at the same time. Dependent on history - until you take it apart, you dont know its not already a 1641 or even a 1776 .. so save buying top end kits until 100% sure.. 1776 needs the case stripped down to do machining - so if you were having the full on align bore done, then its going to add less hassle to machine for the 1776 at the same time. But if you fried your 1600 by thrashing it, then a 1776 can just be a quicker way to fry the new engine. At least new tinware from your description... End float - is the crank banging backwards and forwards in the case when you haul back and forwards on the crank pulley , or is it moving so little you can hear it but not feel it .. Oil pressure : What was it like with any flickery oil light at idle ? If it did then it may need more than a top end kit to make it any better than what it is now, as you may need new bearings and an align bore to restore oil pressure. . Its possible by now its been worn out so many times that you actually need a new engine case as well. New cylinders and pistons may be different lengths to stock; introducing new parts means more measurement, checking valve ring gaps, cylinder head CCs for compression ratio and then maybe adding cylinder shims .. I have had 1641 CC engines for over 105000 miles - I am known for blowing them up, but they were 1) a junk one that came with the bus which wore out, then 2) one I built myself which dropped a valve , then 3) a JK Preservation Parts 1641 which overheated on a hill because of a duff timing light adding about 5-10 degrees advance (swapped distributor because a condenser failed.. but the timing light failed with the "new" distributor) .. now onto second top end on that engine. I have had so many hassles with points and basic electronic ignitions, that I think that things like the 123 distributor are the answer ( I made my own because I could.. )
Thanks for your replies, so far. So… The general theme of the breakdowns seemed to be timing problems. Lots of backfires and rough running. Nothing that ever left me stranded, just something I seemed to have to constantly sort. When I did get it “right” and running, it didn’t have a lot of power…I know none of them really do but, it was woefully bad! That is why I tried the electronic ignition. This actually improved the performance well, at higher speeds, but it was a dog to drive slowly. So, I went back to points. It blew a couple of coils (not sure why) and the spark plugs are very oily. I would certainly describe it as a filthy blob @mikedjames! I’m not sure anything was done to it before I got it. The inlet manifold has rusted through in two places. I didn’t notice a flickery oil light… The end flood seems fine. No noticeable movement or noises.
How did you set the ignition timing (which sounds like a poss cause of your problems)? How did you determine that the coil was "blown" (they're virtually impossible to damage)?
I set the timing with a strobe light. In terms of the coil - I came to that conclusion because when I replaced it, everything worked... I'm on my third! What am I doing wrong?
Instead of changing LOTS at once a better approach would be to spend your money on the problem areas and not waste time on changing barrels / pistons if they're not needed , have you even done a compression test ??. You say your main issues are ignition related , sort out the ignition issues first which judging by your replies would be a foolproof 123 , not cheap but fit and forget . Reliability is all about elimination not replacing good items with potential crap . I've had the same coil fitted for 30+ years (came with the van) nothing special but it works . I do carry a spare which to me is as good as preventative maintenance gets .... Sent from my SM-G960F using Tapatalk
Electronic ignitions need a higher amperage coil although the manufacturers rarely tell you this so try a good known make and should read over 3 amps across the terminals . Sent from my SM-G960F using Tapatalk
What they said^. Bolt your bits to a new/rebuilt engine and it will probably be no better. However - do a compression test. If you have good cranking pressure already, rebuilding the top end won't make any difference but until you know...
The total disassembly and reassembly of the engine to facilitate machine work is potentially a DIY way of saving several days of garage bills. I once saved £400 on a job just by handing the guy a VW engine delivered in the back of my estate car.. But the machining is a specialised job you pay for - the garage would farm out that job anyway. But seriously if its rough running electrically speaking it could be loose wires and general messiness rather than a rebuild time. Do a compression test first. Put up a picture looking in the engine bay- another source of rough running is people stripping off pipework because " it looks better " without it, or just leaving pipes open when they should be connected properly or at least blocked off.
Begging to differ there squire... Investigation into the different coils available for the lumenition revealed many of the older coils can be as low 1.5 ohms and fine with points but not quick enough to keep up with electronic , just what I gleaned but I'm an electronics oaf .... Sent from my SM-G960F using Tapatalk
I beg to differ with your beg to differ, Sir Any coil with a, say, 1.5 - 3ohm primary will be fine with most electronic ignition systems. You'll get better HT with electronic, even with the same coil, because the coil current is switched more cleanly and much quicker than than manky contact breakers (Mr Faraday promises us this is so). The higher HT may spell death to a coil that's not in good shape, but otherwise everything's much the same.
I bow to your superior electrickery knowledge...however ... Lumenition states categorically the coil MUST read over 3 ohms and I did actually look at lots of sheeeite on t'internet saying go for a higher ohm-page coil which must be true coz it was on t'internet. I was most surprised , nay , amused to find the old Bosch blue thats been fitted for decades read at 3.2 .... Sent from my SM-G960F using Tapatalk
Just looked on the 123 website they recommended a coil of at least 1 omh https://123ignition.com/support/
Yep, our Bosch coils tend to have primaries of about 3ohms. What's recommended will depend on what the switching transistor in the unit can handle without getting too hot. Obvs Lumenition want something higher, other units can handle coils with a lower primary resistance. Horses for courses!
The problem with electronic ignitions is that the switching device used for robustness (IGBT) has a saturation voltage of about 1 volt when its turned on. So a 3 ohm coil off 15 volts gives about 5 amps of current or 5 watts of heating.. A 1 ohm coil is going to draw 15 amps, producing 15 watts of heating. The 123 gets away with it by switching off as soon as the magnetic field has built to 100%, then next pulse delaying the switchoff to produce the spark at the right time , constantly adapting its "dwell" as the ignition supply voltage changes. A Lumenition is a simple switch, with an optical pickup. No "intelligence" , like a Pertronix Ignitor 1 its just a transistor used instead of points, so it gets hotter the lower resistance coil you fit. The Ignitor II and modern clones may be better but it still doesnt like being hot .. Points dont care so much about the current and the heating as they are either a short or open.. My EDIS uses two 0.6 ohm coils, fiddles with the dwell angle, and like the Lumenition, has a huge heatsink area away from the distributor or coil to keep cool. View attachment 130974 distributor used as a bung..
That's good news Chris,thanks as my 123 has a thirty year old blue bosch blue coil fitted as well . It's steady without any wavering. It doesn't hunt either, tick over a bit fast by about 150rpm. I am not worried about that much.
