140 Won’t start

I had the original fibre timing gear go a little while back and, after getting new steel kit, bearings etc., i proceeded to replace the gears.While i had the engine out, I also did rear oil seal, new clutch/pressure plate, gaskets etc after dropping the sump and cleaning all of the collapsed timing gear garbage.

Fitted the new timing gear, making sure the timing marks lined up and all seemed correct.

Refitted the engine, static set the timing gear and have been trying to get the volvo to start.

I checked the following:

spark - both from coil and at plugs

Fuel - electric fuel pump and wet plugs after trying to start

Checked static timing several times - according to manual, set at 5’BTDC on compression.

Checked valve clearances and re adjusted just in case.

Trying to start, it turns over with compression, seems to nearly try and fire but no real ignition, more a quick speed up as though about to fire.

I have rebuilt various engines of my cars (datsun240z rally car- sons Vauxhall, daughters mzda 323) without issue.

Have checked all known areas, gaps, timing, etc but am at a loss.

If anyone has anything extra to add,/suggest something to check, it would be appreciated.



  • 1971_144GL1971_144GL @1971_144GL Launceston, Tasmania

    My first guess is that the engine is 180 degrees out on ignition. I would try setting to TDC, loosening and lifting the distributor, rotating the engine one turn and then drop the distributor back into engagement. Hopefully then you have spark at the right time.

  • Angus242164Angus @Angus242164 Western Victoria

    Is it possible that the ignition timing is somehow out? If you haven't already done so, it might be worth verifying that the rotor button is pointing in the general direction of the #1 post on the cap when cylinder #1 is at top dead centre, using a screwdriver in the #1 plug hole to make sure that's where it is.

    This way you can check that the distributor is definitely where it needs to be, relative to the pistons.

  • Thanks for both comments - i checked the rotor button position and alignment to number 1 lead and alls ems to be in the correct position. I am going to re set the timing Azan and double check valance clearances again too as a google of specs showed an old copy of b20 specs on a volvo uk site that seems to have a different valve clearance setting than the Haynes manual i have. To that end, if anyone has their accurate spec on the clearance in thou’ would be appreciated to check my manual.

    Re advice 1971_144GL, I wasn’t sure that the distributor locating leg could fit more than one position. Will double check that too, thanks

  • What sort of fuel pressure is the electric pump delivering? 3 or 4 PSI max for carbs, more for D-Jet, lots more for K-Jet.

    Clearances on B20s are 16 to 18 thou (0.40 to 0.45 mm) on everything except the B20B, which is set to 18 to 22 thou (0.50 to 0.55 mm). Hot and cold, inlet and exhaust.

    Source for above is the 1973 model 140 Greenbook, page 0-5 (which is in the trusty Oz Volvo Archive).

  • Fuel pressure was checked at 4-5psi running single stromberg. It was fine fuel delivery last year or two before the timing gear blew up.

    Thanks for clarifying the valve clearances, will note that to check against my manual for another go at it this coming weekend if I don’t get out to the ga=rage before. The motor is a B20A.

    Much appreciated

  • Angus242164Angus @Angus242164 Western Victoria

    I would have thought that the drive lugs on the distributor were offset from the centre, meaning that it can only be fitted in one position, but I don't know for sure.

    In any case, that can't be relied upon as the distributor drive gear can be installed in a number of positions relative to the gear on the cam.

    If the distributor is timed correctly to the pistons, everything in between is going to be ok.

    If valve clearances are way out it may not start due to a lack of compression, but if they're close it shouldn't cause too much of a problem. You can do a compression test to verify that you have enough compression.

    Another possibility is that you may have already fixed whatever the issue is, but the cylinders and plugs are too wet with fuel to allow combustion, ie: it's flooded.

  • Angus242164Angus @Angus242164 Western Victoria

    I guess there's an outside chance that the new timing gears could be marked incorrectly. A compression test and checking the valve clearances will help to rule this out.

  • Thanks Angus for booth comments. Certainly fuel was dried out between several different attempts to start it.

    Re the distributor, I also thought the Lo=ug was offset as I had tried dropping the distributor in loosely and then rotating the shaft to check location of the lug dropping in.

    In checking the position of the rotor, it is pointing to the front top of the engine and aligning pretty well to no 1 lead on the cap, so i suspect that is in the right position.

    I bought the timing gear from IPD so hopefully the markings aren’t an issue - but who knows.

    Will check compression etc next weekend as well.


  • Oh yeah - BTW, you know the B20 dizzy spins anti-clockwise, right?

    It's 1-3-4-2 like most 4 pots, but they spin the opposite way to B21s and the OHC stuff.

    (I have a confession: I was caught by that...)

    In the event the dizzy is fitted 180 deg out, just put the dizzy cap on 180 deg out (well, not really, since the dizzy cap only goes on one way, hey). You just have to bear in mind then where #1 is going to connect on the cap.

    Timing for the B20A according to the book is 14 deg BTDC, presuming 97 RON fuel.

  • Actually, according to the 1971 green book, B20A ignition timing is 21-23° BTDC @1500rpm, dwell @ 59-65° and vac advance of 13°. 5°advance @750-950rpm and 10° @1210-1750 rpm. Advance is finished @2400 rpm.

    Try setting the static timing out to 10-12° to start with and go from there. Also check that you havent sandwiched the condenser wire under something.

  • Thanks Ian - my manual suggested static timing start at 5'BTDC so will try starting the set up at 10-12' as suggested, thanks

  • So checked all valve clearances, static timing at 12’BTDC, checked distributor alignment (only one position) and all seems OK. Tried starting yet no joy.

    One thought - when I blew the timing gear, I dismantled the old timing gear and reassembled with new gear kit. I lined up crankshaft and camshaft to the timing marks. I didn’t take out the distributor drive gear but wondered whether there was any opportunity for the camshaft/distributor gear could have got out of alignment somehow?

    In rotating the crankshaft, i can see the timing marks on the crankshaft pulley coming up while the rotor button is aligning pretty well to the no 1 plug lead so that does seem to be correct.

    I did see however that no 1 valve seem to be pretty late closing on the compression stroke. Would this be as expected?

    Am running out of ideas as to what may be stopping the thing from starting.

    From the sound of the engine kicking over, it does feel as though the timing seems off somehow still.

    Any wild ideas, left field suggestions etc etc appreciated/welcome


  • Just ren reading the Haynes Volvo manual, there is the following:

    Just in case your re not sure as to the position of the rotor, we mention here that when the timing marks are coincident, cylinder no 4 is at the top of its compression stroke. Hence the rotor should be selecting the plug on no 4 cylinder and the points just have opened. “

    Am a tad confused by the above. Am I correct to assume these are the marks on the timing gear? If that is the case, I would need to take the timing cover off again - with the resultant hassle of disabled/refit while the engine is in the car still.

    Any thoughts on the above appreciated


  • So just to confirm, you have done the following:

    * taken the rocker cover off and checked that when the valves are rocking for #4, #1 is on TDC, the timing marks align on the pulley and you have the dizzy @ #1.

    * you have pulled a plug, earthed the thread and have spark when cranking.

    * if have spark, connected the timing light and confirmed spark is aligning during cranking.

    * got compression and fuel.

  • Hi

    havent checked 1 completely with rocker cover off - will dot hat tomorrow

    have spark at Coli to distributor lead

    have spark at plugs checked on cranking

    plenty of compression and fuel confirmed both in pressure and seeing damp plugs when removed after cranking


  • I did see however that no 1 valve seem to be pretty late closing on the compression stroke. Would this be as expected?

    On a B20A, yes. 10 deg ATDC.

  • So i have checked gre positions on 1 at tic and dist pointing to 1 plug and also #4valves rocking and all seems ok.

    trying to start sounds very ,ugh like timing is severely out

    further searching found the following and before i pull the timing cover off to check all again, I wanted to see iof any comments o the detail here taken from the uk volvo forum

    If the garage doing the job doesn't have a good understanding of the B18 then they need to know at TDC No1 on compression stroke the pips on the gears are not together but 180 degrees apart.

    I think setting TDC on #4 pot solves that? My suggestion would be to get the marks lined up before pulling the gear. The new one can then go back in the same position.

    Any thoughts or has anyone set the timing gear this way?

  • Never heard of that being done, sorry.

    This very good Noridicar video makes timing gear replacement look easy - only thing wrong with it IMO is they fit the crappy fibre camshaft gear, instead of the Volvo Penta steel gears which last forever.


  • jamesincJames @jamesinc Oz Volvo Ice Fortress

    I'm not so knowledgeable on the OHV redblocks, but both the cam and crank timing gear have keyways correct? So you install them with the timing marks touching each other, and then you know that the cam and crank are properly oriented with respect to one another. All that's left is to turn the crank to #1 TDC and check the rockers to see that both valves are closed, and that if you turn the engine past TDC the exhaust valve starts to open. At that moment the distributor should be pointing at #1 ignition contact.

    As Angus says, as long as your clearances are vaguely correct the motor should run.

  • I've had similar issues with my B20 dizzy when I reinstated it before. I replaced it with a different one and the problem went away. I haven't pulled the faulty dizzy apart to find the fault.

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