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Bench testing an EA81 engine had it firing but after a few days tried again but won't fire . I have can verify the following

1) spark at the coil & coil lead
2) spark at the plugs
3) fuel in the carby
4)tdc, disty set correctly #1 cylinder
5)good compression
6)new coil
7)spark leads in correct firing order

still won't fire what am i missing here ?

The distributor is a Hitachi D4R82 with ignition module built in under the rotor.

Is it possible for a faulty module in the distributor ?would it still a throw a spark to the plugs ? or would it be a no spark situation at the plugs? I can't see what else it can be and its the only part that I have not replaced.

Need some ideas/feedback on this one .

Thanks . Tucker

If you have spark at the plugs then normally the module is working, have you checked the valve clearances? while you may have good compression, if the clearances are out you may not have a closed cylinder under spark conditions. As well the distributor could be 180 degrees out but appear to be set properly.

when the motor is cranking has anyone moved the distributor to the left then to the right to see if it can fire?

Check the dizzy cap if it isn't new (not sure if you replaced it) it could have a crack in it which is causing it to short.

TOONGA

I have'nt check the valve clearances. Can someone offer some step by step advice on checking the valve clearances on the cylinders ? or what I should look for ?
I have tried moving the distributor while cranking the engine but still won't fire.

it isn't overly difficult to check

this part of the gregorys I re uploaded has the steps

http://rapidshare.com/#!download|808l3| ... up.pdf|651

the rest of the book is here

showthread.php?t=16439

TOONGA

Before trying the valve clearances.. try to swap two of the spark plug leads over.. I know you said you have the engine on No1 at TDC but remember the engine crank has 2 x TDC (engine rotates twice and only fires once) but only 1 TDC is at the compression stroke. With the dizzy you have the firing order as 1-3-2-4 so try swapping over 3 and 4.. if the engine coughs and splutters like it wants to kinda run then you have the dizzy 180deg out.

IM confused, you say it wont fire, but u say it has spark at the plugs.
Is the issue that the engine wont run, or that you are getting no spark.
Valve clearances off, will make it run rough but if u got plenty of juice in the battery, it should still start.
Has it been running in the exact same configuration since the belt was last installed?
If so, consider fuel supply being the issue.(if you do indeed have spark)

rebuilder wrote: Has it been running in the exact same configuration since the belt was last installed?

the only belt an EA81 has is the fanbelt.

I didn't notice from your first post that it was bench testing... as in on a frame before it goes into the car... or in a car waiting to be used?

if it is in a frame check every earth strap you have and then add another.

TOONGA

Simple but check the ignition fuse. The hitachi carbs have a valve at the back of the carby which apparently does eff all. Mine burnt out and had no idea and it burnt the fuse. wouldnt start and i didnt even have a clue what to look for. Should be a post on the site about it. Might not be your problem but worth checking.

ah ok i was thinking it might have a chain but just made an assumption, my appoligies!
What i meant to ask, is has it been runnign since the last time it was assembled?
in other words, has it been running in its current cam-crankshaft lineup?
Simply tryign to ask if everything is lined up but i cant find the right words haha

a good way to test if it is spark or fuel that is lacking is the spray like aerostart, start ya bastard. If you got spark and no fuel it will kick on a lung full of this stuff.

Nothin' changed since you had it firing or did you say running ?

Thanks for all the replies.

The engine is on a stand and has been wired up correctly. I am using aero spray in the carb to get it to fire. I have bought a new coil thinking that the old coil was maybe giving a weak spark under compression.

I have ordered a new ignition module. Funny thing is I had the engine firing a week back but tried again and it cranks over fine. I have used HT test light on all the plugs and I know I have spark.

I can only think it can be 1) valve clearances 2) Timing or 3)ignition module. I will try changing the plug leads 3,4 as suggested.These are quite simple engines so there is not a lot to eliminate of replace.

I would like some more suggestions to maybe re-check I have the tdc right. The method I used was taking sparkplug out of #1 cylinder , turned over crank pulley until all pressure relieved and then set disty rotor #1 plug lead . I had to use this method as no markings on the pulley.

Thanks in advance.

the timing on an EA81 is done on the flywheel. there are marks on the fly wheel that correspond with a hole in the bell housing that is normally covered with a rubber bung.

Do you have a standard flywheel or an after-market one?

TOONGA

u can do the visual spark plug hole check and get away with it.
But dont forget having #1 at TDC is no good unless #1 valves are also in the correct spot. this correct spot is lining the timing marks on the camshaft and crankshaft with the timing mark on the chain and or block.
Saying this, i havent touched a chain engine before, but the procedure should be somethign like that.
Im sure you have some idea how to do this, so i dont think im telling you anythign new.

It is not a chain engine nor a belt engine but a cog to cog drive from crank to cam driven at the rear of the block, rebuilder!
Think , as my EA82 rotor goes in anti clock direction so does EA81 -Gregories simply says anti does not diff beteeen 81 and 82.

Maybe you can use my EA82 start up method. Use rocker vision to get it on #1 TDC, use flywheel to set at 8 or 10 DBTDC and set dizzy so the two bits inside that excite the module on shaft and fixed bits are 25 though from lining up about to 'touch'

I can start EA82 just nice by trying this is all is well.

Again thanks for all the replies. Some really useful input/advice. After reading the replies I think it is probably a timing issue. If I got spark at the plugs the ignition module must be working. I have not checked the flywheel markings.

I will check the inlet and exhaust valves at Cylinder 1 when I have set tdc, both exhaust and inlet valves should be closed on cylinder 1? any easy way of checking if they are closed ? what if they are not ?

I waiting for a replacement ignition module to arrive so I will try that first . If no start then I will re check if the disty is not 180 degrees off by swapping plug leads 3,4 to see if I get cough or splutter.

Also when I have tested the negative of the coil to ground with a test light while cranking the engine the test light blinks/pulses but the bulb in the test light is very weak and dim. is this correct ?

Thanks again

If you have spark then your ignition module is ok.. I would try (see below) before removing your rocker covers.

Take out #1 spark plug (sometimes it's easy to remove all to stop compression making it hard to crank).. using a ratchet and socket, turn your engine over (clockwise) and whilst turning over put your fnger over the top of #1 spark plug hole.. as you feel the pressure of air forcing it's way out then watch the flywheel for the timing marks.. when you get to 8deg BTDC then stop turning the engine and make sure your rotor button in your dizzy is pointing towards #1 spark plug lead.. if not undo you dizzy and lift up.. turn to the right position and drop back in and this should get you close enough to run the engine.

I would try this first before doing anything else

OOPS didnt know bout that one!
before i make a fool of myself anymore (never touched an EA 81), Ill ask, does the dizy have contact points?
If so, sometimes worn / incorectly set contact points can produce a spark, but a fraction too late which just ends up going nowhere.
If all efforts fail, while cranking the engine, turn the dizzy left n right a bit while cranking n see if it picks up, that is if u have it within 20 degrees of correct.
Then again i know nothing about this engine haha.

and i found this quote from some bloke with one in his plane..
What you do need to worry about in the distributor, is the little horseshoe shaped magnet next to the points. I have had them crack and separate into two effective magnets, which will cause your engine to stop pronto. I have had this occur in a Suburu EA81 powered car, and was probabily caused be heat.