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damunk

engine struggling to turn

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damunk
 
Engine struggled to start third time round. After rebuild, with news cams, pistons, rings etc engine ran for ten minutes then there was a oil leak. 
 
two weeks later oil leak sorted, started engine and ran at 2000rpm for another ten minutes stopped engine but this time around tried to turn it over straight away and the battery could not turn the engine over. felt like a dead battery.
 
the mechanic said because the engine is now hot the compression will be higher and the battery is struggling. stopped the engine as while the radiator fan kicked in.
 
 i have converted the engine from 1.4 to a 1.6 afh conversion. Does this mean I now need a stronger battery? 
 
The battery for the 1.4 should be 440ca, 50ah.
The battery for the 1.6 should be 550ca, 60ah. but ive seen people using a 45ah in thier 1.6's infact some websites sell 40ah for the 1.6.
 
 i measured the battery with a multimeter and it read 12.2V when engine switched off. 
 
p.s new battery & new alternator
 
Edited by damunk

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dvderlm

starting takes a lot, I reckon on 15- 20 minutes driving to replace what is lost.

Charge it up overnight? Should be fine if you can turn it by hand with socket on crank pulley.

Loosen spark plugs and it won't compress air.

Make sure battery contacts are tight, and that you refitted all earths.

 

I know you disconnected a lot finding blowing fuse #4. Is it all re-connected?

.

Edited by dvderlm
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damunk

well i havnt put alot of the fuses back except for fuel, ignition and engine electronics. none of the others are related to a starter or battery.

 

ermm... i let the engine get cold,  took spark plugs out and cranked it on starter and it turned freely. so thank god nothing was seized.

it's as if when it was hot it struggled to re-start, it felt like a f****** dead battery 🙂

it's as if crank, new cam, new rings were really hot and tolerances must have been very tight and the battery couldn't pull.

 

there are 2 earths. on from battery to gearbox and the other from engine cover to engine bay wall.

 

and then theres a cable from starter motor that goes to battery positive

 

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dvderlm

Good.

 

Friction will be higher for a while. That's why it runs hot and is hard to start.

I aimed an electric fan at my rad for the first run-in. Was summer though.

 

It works, get driving it. You can put proper load on the rings to bed them in.

Vary the speed. Don't over do it.

 

Carry a spare battery? Or don't go so far you can't push it home!

 

 

 

Edited by dvderlm

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caretakerplus

Even a battery that is 'past its best' may well still show 12.2 volts without a load on it.

If you wish to test your battery when it is fully charged, connect your multimeter across the battery terminals and ask an assistant to turn the key to the 'start' position - a battery in good condition should maintain a voltage of at least 9.5 v whilst cranking.

 

You can also use your multimeter to check that those earth connections that you mention - and even the main cable from battery positive to the starter motor are in good condition:

(1) Connect or hold the RED meter probe onto the positive BATTERY terminal (NOT the terminal clamp)

(2) Connect the meter BLACK lead to the starter main terminal (NOT the lug on the cable)

(3) Ask your assistant to turn the key to the 'start' position.

(4) The meter should NOT read above 0.5 volts during this test.

A higher reading indicates a poor connection, so to locate the poor connection, remove the black meter lead from the starter terminal and clip it onto the cable lug, if the reading under load now remains below 0.5 v, the bad connection is between the cable lug and the battery terminal post.

Using the above method, you can work back towards the battery, finishing up with the red meter lead on the battery post and the black lead on the positive clamp.

 

Earth connections can be checked in the same way, but this time, the meter RED lead is connected to (for example) the engine block and the meter BLACK lead to the battery negative post.(You would still be looking at 0.5v as a MAXIMUM reading.)

 

What you are measuring here is something called voltage drop, in essence, this means that when you have higher readings, electricity, being lazy stuff, finds it easier to flow through the meter that through the intended route of the cable and its connections.

 

Regards

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damunk

I will do this caretaker. In the process of rebuilding engine it's only been run in the garage through camshaft break in procedure at 2000rpm so it's asking alot to keep battery charged.

I can deffo check battery like u said.

 

But is there a a way to charge alternator? if i measure across battery while car is running should it be 14.7V to prove alternator is fine.

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caretakerplus

When you connect your meter across the battery with the engine running (fast idle speed), you are measuring the charging voltage from the alternator.

14.7 v is a little on the high side, but if the battery is less than fully charged, 14.7 is fine - it should, however taper off as the battery becomes charged.

The problem with a charging voltage that is constantly too high, is that it will eventually cook the battery and could shorten the life of bulbs.

 

I wouldn't worry too much at this stage about 14.7 being high, in any case, depending upon the quality of your multimeter and its calibration, it could be that the meter is reading a little on the high side. In some cases, re-calibration of a meter can cost more than the meter did in the first place and the very cheap meters can't be re-calibrated.

 

There is no way of adjusting the alternator output voltage, other than fitting a new voltage regulator in the back of the unit - much cheaper than buying a new alternator.

 

Regards

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damunk

as soon as i switched engine on battery voltage shot up straight away up to 14.7v ish

 

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damunk

all i did was re-tighten a earth strap. alternator works.

 

surely a new battery can't be dead. bought it November 2018 and been part of the rebuilding process for 3 months.

 

wonder because i got uprated cams, 1.6 piston n crank n a fresh build it n when it was hot it couldn;t get going again.

 

i will run the engine again for 5 minutes at 2000rpm. 

 

what battery would you suggest for a 1.6 afh conversion setup?

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dvderlm

New starter motor?

The clubshop sells high torque slim starter motors.

 

 

Battery:

One with highest cold cranking amps that will fit.

 

I chose a Duracell car battery - was on special offer.

Edited by dvderlm

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damunk

Yeah , im using brand new starter motor; bosch one. it said 6N 1.4 on the listing ,i messaged them to ask if it will work on 16v, i gave registration , and they said it is the right one. think its 1.1KW

 

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=281756439257&_sacat=0

 

 

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caretakerplus

Just because a battery comes with a higher Amp Hour capacity (To put this in very crude terms, this means a larger bucket full of electricity!) it doesn't necessarily follow that it can provide a high cranking current (again very crudely - a larger tap to allow the electricity out)

 

Let's have a look at the meaning of some of these terms:

Volts = electrical pressure

Current (measured in Amperes or Amps for short) = electrical flow

Ohms = resistance to flow

Watts = unit of electrical power

 

Amp Hours can not be taken literally, as you might imagine that a 38 Amp Hour (a/h) battery might provide one Amp for thirty eight hours or alternately, 38 Amps for one hour  as its title suggests BUT we have to take into consideration something called the 'rate of discharge', which simply put, means that, as current is drawn from the battery, so the voltage becomes less.

 

You can do a lot worse than use the old analogy of thinking of electricity as 'water': The higher the pressure (volts) the faster it will push it along; The larger diameter of the pipe (cable) the easier water (electricity) can flow through it; any restriction in the pipe will offer resistance - if the cable is too 'thin' this will offer electrical resistance (Ohms), causing less current (Amps) to flow (and overheat as it does so).

Jokingly, it has been said that electricity is like invisible water flowing along a solid pipe! Joke it might be, but it does help people in grasping the principle.

 

As your new engine appears to be a little tight - no bad thing, providing that (1) it isn't too tight and (2) the tightness is between the pistons and cylinder walls - the starter motor will draw more current to overcome this tightness, this is where Watts comes in - So, if we take the battery voltage as 12 and the starter draws an INITIAL 400 Amps (for the sake of argument) 12 x 400 = 4,800 Watts (not bad when you consider that a one bar electric fire is a 'mere' 1,000 Watts!) (This 4,800 Watts is equivalent to nearly six-and-a- half Horse Power! - 746 Watts = I HP)

 

From the above, you can see why dvderlm recommends that you have a battery with the highest cold cranking output that you can get into your battery box.

You can also see why it is vitally important that ALL connections are clean and tight and that cables are of adequate cross sectional area (pipe size)

 

I hope that the above is not too simplistic.

 

Regards

Edited by caretakerplus
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damunk

 I took my car out after two years of building it. I was nervous has heck but went allright . Ran it for 5 minutes but the problem with the hot start was still there but won't let that ruin my day.

thanks for the help you guys have been giving me


loc1.jpg
loc2.jpg
loc3.jpg

 

Okay so I can repeat this fault as follows;

 

1) The car is fully charged with trickle charge to 13.5V

2) Start cold engine: shows 14V on gauge to prove alternator is working

3) While driving around it is 13.7V, when fan kicks in, it's 13.6V.

4) Get engine to operating temperature, which happens pretty quick , so im assuming it's a "tight'" engine.

5) After 5 minutes drive (I know it's not enough but shouldn't be that drained  from full to not start a car twice) stop car and try to re-start. Struggling to turn crank, can't start.

6) Put trickle charger back, shows 12V on charger gauge. Charge it up to 13V on trickle charger. 
7) Time to try to start HOT engine, and turns crank n starts.

 

 

The modifications that have taken place that can affect the start;

1.4L to 1.6L displacement.
Race/Road cam installed with new springs n lifters.
New bearings, pistons, rings etc

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dvderlm

Hooray for on the road.

 

Everything expands as it gets hot. Rings, piston walls, cam lobes .. 

Needs about 20mins to recharge to prestart levels.

It will loosen up, but only if driven at varying loads.

Deceleration is good as the vacuum sucks oil up and acceleration is good because it forces the rings against piston walls.

Don't thrash it.

 

New plugs I assume?

 

 

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damunk

yep new plugs . reason im doing small run is because makeing sure no leaks

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damunk

pretty sure i got wrong battery

 

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caretakerplus

I would think that your engine being tight is probably causing this starting difficulty.

 

Suggest that you try the volt-drop check that I mentioned earlier. If that results in much more than the 0.5 Volts MAXIMUM, then you could do worse than install 'heavier' battery cable and earth connections between battery and starter motor. www.vehicleproducts.co.uk would supply cable and fittings.

 

Remember that if you do fit a larger battery, as well as taking longer to discharge, it will also take longer to charge on your charger.

 

Regards

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damunk

okay. looks like  the higher profile camshaft need to push the springs down a little bit more and the springs are oem so that alone makes it a bit tighter than stock.

i did buy a new earth cable from engine to chasis.

 

https://www.ebay.co.uk/itm/18-450mm-Insulated-Ring-Ring-Black-Motorbike-Battery-to-Earth-Strap-Lead/323028775738?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

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damunk

ordered a bosch S5 520cca, 53A. so pretty high percentage increase on cold crank. 

Dimensions 207 x 175 x 175 as opposed to the one I have in which is 207 x 175 x 790

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damunk

same problem with stronger battery. noticed the alternator/battery voltage drops as the car gets warm.

so starts off at 14.3-14.7 volts to show alternator is working , gradually drops to 13.3v as car gets hot so i think the battery not being charged. drops in 5-6 minutes.

when i put engine in , i did use a wet cloths to clean all cables.

alternator is new(refurb) bosch.

 

 

 

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damunk

batterycables.jpg.a270bb4b5db4eeed6ec13fc0fbdefee7.jpg

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damunk

will be doing voltage drop test as in video below;

 

https://www.youtube.com/watch?v=fd5LeTdxIzg

 

p..s cheers caretakerplus. needed a vid to understand it better

 

Edited by damunk

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damunk

so did voltage drop test on cables when engine running cold.

from alternator to battery positive = 0.01v 

from negative battery to gearbox bolt = 0.01v

from startmotor  to battery positive - 0.01v

theres no earth connection on starter motor. dont think there ever was one to start with as im using the original leads.

 

alternator seems to kick out 14.4v

been measuring at battery this time around

 

going to move this thread to electrical section now.

Edited by damunk

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vwfan3
25 minutes ago, damunk said:

.....theres no earth connection on starter motor. dont think there ever was one to start with as im using the original leads.

The body of the starter motor is connected to the engine block with big bolts. That provides the earth.

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damunk

and i assume same with alternator

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