20 replies to this topic

[wobblybob]

ive finished building my new engine , new pistons, rigns, shells, spark plugs etc.. but it cant get it to start, ive got a spark, i can smell petrol when i take a plug out, but dont think its flooded, its got oil, so why wont it start > ?? its not turning over as fast as my mates cars but still at a good speed so can anybody think of why it wont start??

Kev,

[Jimmyarm]

We are having the same problem with an engine we have just put the head back onto, it will turn over but not start, its getting fuel as it goes BANG out of the lcb (with no exhaust attached) every now and then.

Will be interested to see what people say !

Jimmy

[Tarks]

id say your timing gear is out of its tdc position! (behind dizzy that locateds on cam )

try removing your dizzy cap !
take cyl no 1 s-plug out find tdc! with a long screwdriver take care not to score piston head !
rotate engine till piston is at top of travel (tdc)

then see if your rotor arm is hitting position one ! on dizzy ! usually about 2 oclock postion !
check firing order its 1-3-4-2 anticlockwise !
replace leads in this fasion no 1 cylender near radiator/waterpump replace s-plug and try to start!
then come back to us here on tmf lol


(also did u time you crank with the cam correctly by the marks on the gears! )just an extra thought !

[wobblybob]

yep all cams timed rite and so is the dizzy, even with a full charge on a new battery it still wont turn over at normal speed, someone said it might be becasue the engine is tight because its all new and said tow it round the block a couple times, would this work any better?

[1984mini25]

We are having the same problem with an engine we have just put the head back onto, it will turn over but not start, its getting fuel as it goes BANG out of the lcb (with no exhaust attached) every now and then.

Mine did exactly the same thing and I found out it was because I had set the dissi up to be 180 out[attachment=14485:attachment]
As No 1 and 4 pistons are both at tdc at the same time but only one is on the power stroke,

Try stetting the crank to tdc with timing marks on pulley, taking out the dissi drive and turning the engine over by hand one revolution and reinstalling dissi.

[Mini Mad Rich]

This would tie in well with my I.V.A assignment, is it ok if I could keep an eye on this because this could be handy.
So you've got fuel, a spark, and its turning over but not as fast as it should
Being only in my second full year at college I dont know that much, but I would say because it's new it's 'teething' but thats only a guess.

Rich

[wobblybob]

well by teething u mean tight, then i have been told this and suggested to tow it round the block, so if it doesent start with a full bat then looks like im goin for a tow

[Mini Mad Rich]

I take it this is the engine thats in the Mini in your pic?

Rich

[wobblybob]

i wish, no its a 1293, mg metro head, HIF44 carb, 270 piper cam, all new pistons rings etc, blocks not be run since its ahd the work done either

[DANTOO]

well by teething u mean tight, then i have been told this and suggested to tow it round the block, so if it doesent start with a full bat then looks like im goin for a tow

Get a hair dryer on it and warm the head hahah!

umm.. if it were me I would say... you sure your HT leads are in the right order?? do you get huge backfires every so often?

youve got spark.. so u know thats right.. its not turning over fast... hmmm take the spark plugs out and try start the engine, see it is sounds any faster.... maybe it has ridiculous amount of compression and just wont start because of it, but that would have to be extreme and I dont even know if thats even possible.

youve got a full charged battery... has it got water if its not a sealed one? use a fluke.. check what you get.

I mean I to am doing my I.V.A lol so im no expert by any means, but its prob a very very simple solution.

[Sprocket]

Deffo an ignition timing issue.

Clean the plugs, dry them off with a clean rag and ensure the following before trying to start it again

Make sure that the dizzy is timed right and ensure the plug leads on the cap are 1,3,4,2 anticlockwise with #1 cylinder at top dead center with both the exhaust and inlet valves shut again on #1 cylinder and the rotor arm pointing to #1 plug lead. If you are getting a spark at the plug and it still does not start then its a fueling issue.

If you are still having problems by the weekend, I may be able to pop over and have a look though Jackman is on his way round then to get his engine ready for machining.

[Tarks]

as a thought ! you removed rods from crank have you replace all caps on to correct con-rods! as it could be holding the crank on an un matched rod ?

(very doutbful but poss)

Tarks.

[dklawson]

Since this is a rebuild the chances are that it is purely an ignition timing issue as you say the engine will turn over on the starter. This assumes you haven't done anything to the carbs while they were off the car.

There are a couple of points to be watched during re-assembly relative to the dizzy and cam timing. You say the cam was timed right so I'm guessing you set it up with a degree wheel and are confident that all the drive gear is on correctly. The cam drives the dizzy drive gear which can easily be placed in the block in the wrong position, specifically 180 degrees out. Confirm the valve timing corresponds to what the dizzy is doing.

To do this, take off the dizzy cap and valve cover and pull the spark plugs. Turn the engine over by hand watching the timing marks, rotor in the dizzy, and the rockers. When you see your timing marks lining up for #1 piston at TDC, look at the dizzy and confirm that the rotor is pointing in the general vicinity of where the #1 spark plug wire should be. Look at the valves and look through the spark plug hole at the piston. #1 piston should be at the top when you're sitting on the TDC mark. Grab rocker arms for # 1 & 2 valves (the ones above #1 piston). Both rocker arms should be up and loose. If all these conditions aren't as I describe, you need to go back and change something. Specifically, with #1 piston at top, the TDC mark lined up, AND both 1 & 2 rocker arms loose, you'll need to reset your dizzy position so the rotor is pointing toward the #1 plug wire connection on the cap.

[wobblybob]

cool, thanks for the help, just tryed it and when every revolution i think it back fires, as theres smoke or fuel vapour comin out the carb, is this right? inwhich case i dont think its hard to fix is it??

[wobblybob]

anyone???