engine rebuild trouble

[agnew1985]

amazing, I'll do that first thing tomorrow. Thanks so much for giving me so much of your time, I'm really grateful.

[agnew1985]

Thanks Boxy. I actually went round all the tappets again today to double check the settings. Each screw now has a 6 thou gap so is ever so slightly loose when the valve is closed. All tappets are the same and I can't think of a reason there would only be compression (and low at that!) on 3 and 4. Any more thoughts would be very gratefully received!

[123-jn]

something sounds jolly fishy to me, When you set up the crank and camshaft did you line up the marks on the drive cogs? Just a thought? with a rebuilt engine compression will be on the low side until the rings have bedded in for which their is a specific technique but you need it running first!!! From experience they will still fire with very little compression as mine did when all the old tappets drained down. You will know if you have hydraulic tappets because you will have narrower steel pushrods about 9/10 mm diameter. If they are solid the pushrods will be big fat aluminium ones. Did you have the liners glaze busted? otherwise your rings will not want to bed in. After my rebuild I set the dizzy to point at cylinder 1 on firing stroke and she fired straight up. Once warm I reset the timing.

[agnew1985]

Hi 123jn, i did line up the marks on the drive cogs but I have been wondering if one or both might have moved when i put the crankcase halves back together. is there any way of checking with the engine in the van?! Having said that, with compression on 3 and 4 this sounds less likely than if I had no compression at all? I can safely say I have solid tappets - I thought they looked solid before I knew that there were solid ones and the pushrods are aluminium. I honed the cylinders and did no more - hope that was right! Everything measured to the manual. I really wish mine fired up like yours - I'm literally banging my head against a wall!

[itchyfeet]

From experience they will still fire with very little compression as mine did when all the old tappets drained down.

With no electrics its not going to get the chance to fire up, i think you need to do some work on them next so that you can get it cranking with ignition.
keep that battery on charge regularly, an intellegent charger is best, what battery voltage do you have today before charging?

on the compression front did you grind the valves in and stagger rings? Sure pushrods are seated properly?
you could try a bigger tappet gap also

[ghost123uk]

Re lack of compression on 2 cylinders. Could it be that when the preload was applied to the solid tappets, the valves were held open enough for the piston to hit the valves (on cranking) and bend them I wonder.

[agnew1985]

Itchyfeet I did what you suggested and everything worked as it should in position 1. Stupidly I forgot to put the battery on charge last night but it still reads 12.83. Re compression - I did grind the valves in and I have been wondering if I did a good enough job? but then I reason that even a shoddy lap in would still give some compression? Rings were staggered and I'm pretty sure the pushrods are seated properly but I will double check! At the same time I will give a bigger gap. I've been wondering if there is anything apart from the tappets that could be holding the valves open? Colets not seated properly? Although my memory is that the head look all nice and tidy before it went back on.
Ghost - I suppose that is certainly possible, although would 2 turns of the screw extend them that far? I suppose there's no way of finding out without taking the head off?

Thanks again

[agnew1985]

just thought I'd add pics of the valves I'm having no compression on. These were taken just before I put the head back on after the rebuild.

[itchyfeet]

Ok
so you have dash lights with the link in place?
check you have 12v on the coil also

then make up a Y link same as before but with an extra connection, keep the fuse between red and black as before
the extra wire will come from the same red connection in the ignition switch but will temporarily be connected to the red black in the ignition switch connector, thus will trigger the starter, as happens in position 2 of the standard ignition switch

When not cranking make sure this extra terminal does not short to anything ( ie in the event it starts)

if that turns over and dash lights stay on then i can only assume both ignition switches are duff

[itchyfeet]

Re lack of compression on 2 cylinders. Could it be that when the preload was applied to the solid tappets, the valves were held open enough for the piston to hit the valves (on cranking) and bend them I wonder.

Ghost - I suppose that is certainly possible, although would 2 turns of the screw extend them that far? I suppose there's no way of finding out without taking the head off?

I have a head and a pison with liner and comp seal and i have as best i can got them aligned to measure how far the valves can open before they hit the piston and its 6.2mm ex and 5.7mm inlet, adjuster threads are 1mm pitch so 2 turns would be 2mm
so thats around 4mm or less between valve and piston, im pretty sure pistion goes to top of liner



one of the pistons i looked at has a valve shaped dink in it implying its possible so you could try lifting the plugs and shining a light inside to look for marks, pistons would need to be at the bottom for any hope of viewing them

[agnew1985]

Great, thanks so much. Unfortunately I don't think I'm going to get any time tomorrow but will let you know what I find ASAP!

[123-jn]

I dont think the valves will have hit the pistons and by taking off the rocker gear and putting a straight edge against the valve stem tops you will see that the valves are all roughly level give or take a few thou. Thus we are left with ignition which we can check for with the switch in running position with the dash lights on, if they are not on is there power to the coil? If this checks out set engine to number 1 at TDC using timing mark on pulley, pull dizzy cap off and loosen dizzy clamp. turn body until rotor points at or just before cylinder 1 lead on the cap. (that should be close enough) Now check that the choke is on and the cold idle cam is on at least the middle notch. If it doesnt start now there is obviously a more sinister issue. Sometimes a tow behind a car with the ignition on at about 15 mph and bring the clutch up in second gear can pursuade them into life. Are the vacuum lines connected to the carb? Do you have a spare carb to substitute? Just a thought It is easy to get confused as to which cylinder you are adjusting when setting valve gaps. I start at TDC number1 (front right) then turn the engine backwards half a rotation of the big pulley and set number 2 rear right, then backwards again half a rotation and set number 3 front left, and another half turn backwards to do rear left number 4 but have been known to get it wrong!!!!
without being there thats about as good as it gets!!! with these things it is often something really silly when you work it out. Sometimes its worth getting someone to crank it while you gently move the dizzy round 30 or so degrees just incase you re a bit out. I resorted to that on an allegro once. that really dint want to go after a rebuild but it did after a quick tow up the road!!! then a quick dizzy twiddle and she ran much better.

[Yetti85]

Hi I have just replaced water jacket seals on my 85 1.9 dg and found cylinders 3&4 had no compression and was only firing on 1&2 went through everything until I noticed the pushrods were not seated correctly and holding the valves open sorted them and she fired right up. Might be worth a look.

[agnew1985]

I'll split this into 2 to make it easier to follow!
ELECTRICS: With the red and black connected I get all my lights indicators, hazards, horn, (no wipers), and 11.97 volts at the coil. With the black and red/ black connected to the red the starter turned over. So I replaced the switch again but same thing as before happened - when in the start position the starter turned and the oil and battery warning lights came on but nothing in any other position except with the headlights switched on the starter turned when i operated the full beam switch. Only difference to the second switch is that with the headlights turned on the indicators didn't operate the starter! I've put a pic of the wires coming out of the starter switch just in case its useful.
ENGINE: I can't see how I can have the pushrods wrongly seated - they are in their cups on the rocker arm and the tappets have a concave seat so they have nowhere else to go! I've added a pic anyway. Unfortunately I don't have a spare carb and the vacuum hoses are attached. Pretty sure I have been adjusting the valve gaps on the right cylinders- I have been over it so many times! I have altered the valve gap on the 1 and 2 (no comp cylinders) to 0.015 to see if the makes a difference. Had a look throught the spark hole to see if any marks on top of piston. I couldn't see any but my view was very limited.
I took a fair bit of video during the rebuild so quite easy to add some pics of anything that may be useful. I think that's everything to follow but I may have missed something as my brain is beginning to crash! Thanks again

[agnew1985]

Here are the pics from above