You must be getting fed up of my idiotic questions now, apologies for that!

My new question is,

I've rebuilt the engine, 711m 1700 Xflow, weber 40's, high compression, big valved, ported/polished, 244 cammed little beastie. Before the engine came out the old starter was a bit sluggish but would always start it. Now though, I get about 5 or 6 revolutions out of it before it just can't cope any more. I have cleaned the earths and I'm sure they are all fine. I have a charger/starter which when connected it will start with no trouble at all.

What is the next step? Better battery or suck it up and buy a high torque starter motor? The battery is only a 45AH jobbie. Specs are 45AH 350A(gobbledegook to me) Fully charged just before trying to start the car. Ignition system is all good, coilpack running from an omex ecu. Still using the original Lucas(the name may be the problem ) inertia starter.

I may have raised the compression, it's hard to tell as the old HG was mincemeat when removed and the head has had a light skim. I had to guess at the thickness. Engine runs perfectly though and will be going on the rolling road to be set up before going on the road so that doesn't bother me.

I just want it to start!

Thanks in advance for any help.

Can you adjust the map on the omex ? When we used the X-flow, what made starting much better was retarding the timing under 1k rpm on the megajolt.

[Edited on 9/3/16 by UncleFista]

quote:

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Originally posted by UncleFista
Can you adjust the map on the omex ? When we used the X-flow, what made starting much better was retarding the timing under 1k rpm on the megajolt.

[Edited on 9/3/16 by UncleFista]

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How old is the battery.

If you have jump leads, then fit lead from battery earth to starter and see if any different.

Similar for positive be be prepared for large spark.

I would imagine the battery is quite old to be honest. Perhaps I'll borrow one and try that before forking out any money.

I will also try the jump lead trick. Shall I earth directly to the starter body?

I'm not a fan of large sparks after having a battery explode in my face many moons ago. I shall man up and wear a welding mask this time!

After you checked the usual leads battery etc maybe it's a tried starter motor ?

As UncleFista posted the ignition timing at cranking speed is the prime suspect, if the spark occurs more than a few degrees before tdc when the engine is turning on the starter results on the engine trying to run backwards against te starter.
One of the reasons modern tintops start easier in bad conditions is that the ignition timing map at cranking speed (ie below 500 rpm) is very conservative but quickly jumps up to 13 btdc once the engine fires and the rpm rises toward the aproximately 800 rpm idle.

Battery testing can be done in a limited way with simple equipment, disconnect the coil or fuel pump and measure the voltage accross the battery when cranking the engine. On good battery will crank the engine at 10+v, if the battery voltage drops below 9 volts there is some kind of problem if it drops almost instantly to 6 volts there is a dead cell in the battery.

This osicillscope trace is what happens to battery voltage starting an engine with a good starter and fully charged good battery.



[Edited on 9/3/16 by britishtrident]

This shows ignition advance at start up for a modern tintop.
For easy starting the engine initially the cranks with the spark at 5 deg btdc when the engine fires and the RPM exceeds about 500 rpm it rapidly advances the spark to 13 to 14 degrees bdtc.





[Edited on 9/3/16 by britishtrident]

[Edited on 9/3/16 by britishtrident]

@Britishtrident. Nice charts but what about this.

old starter was a bit sluggish but would always start it. Now though, I get about 5 or 6 revolutions out of it before it just can't cope any more.

The battery should be able to turn engine over at a healthy speed for a minute easily.

First call is to make sure battery has the oomf to do that..

You say it starts with a starter / charger attached. Is that just the type that is a battery with jump leads attached?

If so the problem is likely to be your car battery.

Easy way to check for over advanced ignition timing is to disconnect the live feed for the ignition, if the engine then cranks over easier it's too far advanced . Sounds like it might be a good idea to test the battery ? Inertia starters on a Xflow seem to have a hard life even when relatively new.

The OP has not said whether the engine is firing or not. If it is, then ignition needs looking at but if battery only turns engine only 6 times, that should be first place of call.

Incidentally remove 2 spark plugs. Engine will be easier to turn and will run, assuming it fires. I do this after mine is standing for long time without being used and battery is somewhat drained.

No crossflows were harmed during the making of this post.

quote:

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Originally posted by Adamirish
I have a charger/starter which when connected it will start with no trouble at all.

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Adamirish - 9/3/16 at 04:25 PM

Wow! Thanks for the response guys.

Just to give you a bit more info, I started it using a starter/charger. NOT a booster pack. It's a SIP one, was about £70. Highly recommended actually, bought from tool station.

If it is an ignition problem then I find that very strange. Nothing has changed bar a lot of new gaskets and seals. Beforehand it always started without issue. I may break out the laptop at the weekend and see what is going on. I shall update when I get chance to do that. This will most certainly be looked at when it goes to the rolling road, I'm not keen on playing with the ecu too much as I know very little about it and wouldn't want to cock it up!

When I try to start it with just the battery, it will spin over 5 or 6 times but not fire. The occasional cough as it tries to start but it sounds as though it just isn't spinning over quickly enough. Connect the starter/charger, first compression stroke and it will fire up. It will then settle down to tick over and run forever more.

I really get the feeling there just isn't enough go there to start it, in my mind(strange place, wouldn't recommend it) there is a simple power issue, whether that is the starter or the battery I'm not sure.

Genuinely, thankyou for your help, I really appreciate it! I will buy any one of you a pint shall our paths cross one day!

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02GF74 - 9/3/16 at 07:46 PM

Tyre shops will have battery tester. Chances are the meter they use will tell you the battery is knackered. so they can try to sell you a new one LOL.

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britishtrident - 9/3/16 at 08:54 PM

These days there are two methods used to test batteries the old school way was to put an enormous current load on the battery and observe what happened to the voltage. This type of test has its risks but is still in use and testers like this Silverline can be bought for less than £20. I bought one about 3 years back to replace one that had been in use since my grandfathers days.


Description


The more modern test is a microprocessor controled device that estimates the condition of the battery by measuring the AC impedance, this type of tester can estimate the remaining life in the battery, the remaing effective cold cranking amps.
I bought one last year a Ring RBA50 it cost less than £50 and works a treat if but buying now I would probaly buy a Foxwell BT100 as it is less than £40 and has a better display.


Description

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Adamirish - 12/3/16 at 01:13 AM

I did a couple of videos to show you good people what the car is doing.

Trying to start the car with a fully charged battery alone.

http://youtu.be/VKHv-O_tCuI

And starting the car using the charger/starter.

http://youtu.be/5SrIwrXfZ30

Just to add, the music is not my choice!

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02GF74 - 12/3/16 at 04:46 AM

I did wonder it it were the case, the few turns before stopping is engine firing which disengages the starter, mine does that too.


Car battery alone does sound a little bit sluggish but i,ve started with much worse. Once running, it sounds 100% fine.


How does it go if you try to start only off the jump battery (i.e. disconnect the car's own battery)

You have cleaned up and tightened battery contact points?
Have you tried a starter battery lead from - terminal direct to starter motor?

Spark plugs in good cond, gapped correctly? same for ignition leads?

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britishtrident - 12/3/16 at 08:17 AM

Unless you do the simple tests you will be playing parts swap lottery.
A cheap multimeter measuring battery voltage will tell you a lot.
The simplest test is to measure the cranking voltage with the ignition disconnected, if it when cranking drops to immediately from 12.5 to 6v (even if slowly rises) the battery is goosed -- end of story, The normal cranking battery voltage is over 10v below 9.2 volts points to a some kind of battery issue.
If the engine cranking speed is ok with the ignition disconnect then it is an ignition timing issue.
I suspect however you have a combination of a battery well past its best and over-adanced cranking ignition timing.

see https://www.youtube.com/watch?v=tsJUuLu1cw0


[Edited on 12/3/16 by britishtrident]

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Adamirish - 12/3/16 at 08:20 PM

A bit of an update.

After measuring the voltage at the battery while cranking it was dropping down to around 7.5v. I thought, sod it and went and bought another battery. This one is a bit more powerful. 430a up from 350a.

Fitted the battery and while still cranking slowly, just the same as before, it did actually fire up. A bit reluctant but it did at least. I didn't charge the battery, just stuck it on and hoped for the best. It was showing 12.4v with no load and up to about 9v while cranking. It's still not right but it's progress at least.

So I thought sod it again and got the laptop out, couldn't get it to connect to the ecu though. Saying online but couldn't find the port or some such nonsense. That's for another thread though!

After running for approx 30 secs I switched it off. Tried again and it fired straight up, spinning over quickly, just as it should. I did this 4 or 5 times and it was perfect.

I shall charge the battery properly and try again tomorrow when it's stone cold again. I will also steal some jump leads tomorrow and see if earthing the starter body makes any difference.

I hate cars!

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britishtrident - 15/3/16 at 06:35 PM

The old battery is showing classic symptoms of a dead cell sometimes called a gassing or boiling cell.
The new battery is showing the signs of being stored without a recent top-up charge. If a battery has discharged slowly over an extended time period it should be charged a low amp rate over and extended time period ie 12 to 24 hours.

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Adamirish - 15/3/16 at 06:48 PM

To be honest, I have no idea how long it had been sat on a shelf for. I have since put it on charge to full capacity. I will play again at the weekend.

Just out of interest, as it started absolutely fine after it had been running for 30secs or so, if I heated up the coolant temp sensor prior to starting, would that trick the ecu into thinking the engine is warmer than it actually is? It just seemed weird that with a touch of warmth in the engine, everything worked perfectly. It span over just as it should.

I have come round to your way of thinking though. I'm sure it must be the ign timing. It's the only thing it can be now really.

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britishtrident - 16/3/16 at 05:20 PM

Batteries are a bit of a black art.

Even short period of charging either from running or connecting to a battery charger puts a surface charge on the plates of the battery. After a brief charge the measured voltage across the termminals of the battery will rise to for example 12.6 volts but this is only short lived and will disapated fairly quickly. After a couple of hours this would drop to 12.4 volts or so.

For the charge to last the charge energy has to permeate the full thicknes of the plates of the batteryl and that takes time. The rough and ready guide for charging time and rate is if battery has been discharged quickly (as is a single cold start) it can be recharged fairly quickly but if it has been discharged slowy (as in leaving a tintop parked up while on holiday) it should be recharged slowly.
After a cold start a modern tintop will replace the charge energy used to start the car within 5 minutes in days gone bye with old style charging systems and batteries it would at least 20 minutes running.
If the battery has been discharged slowly the amps setting on the charger should to be lower but normally 24 hours is the maximum time required for a full recharge.

New car batteries are normally at their best after 2 weeks normal use has conditioned the battery.

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