Slow crank when hot on 3.2 Stroker

[Sada]

I've just completed my 328i to 3.2Ltr stroker Conversion.
I have picked up this problem that the car refuses to start when hot.
The starter cranks very slowly , as if the battery is dead or starter dragging.
I've tried 3 diff starters and replaced the battery with a new one.
Initially the car wouldnt start after just idling it for a few minutes , but now it the engine has to be really hot for the problem to occur.
Anyone with some help to this problem ?

We rebuilt the engine completely, to USM3 spec(s52b32), M54 330i crank , larger JE pistons with 11.5 compression , new bearings , shrick cams etc..

Problem is driving me crazy :eyecrazy.

[MShareef]

I cannot offer any help with your problem, but it sounds like a nice build you got there. Any links/pics to build and car?

And where about in CT you from?

[CGramme]

does the engine actually turn over when you have this problem? any dark smoke coming from the exhaust when it wont start, if it does turn over? do you have any aftermarket software? I'm guessing the engine runs fine except for the no start, right? maybe replace the starter relay. look in your exhaust pipe for little blue men aka smurfs. if there are, well, you have a problem...

[Sada]

If the car is cold she starts fine. she even runs quite well, considering she's not tuned up.
But once the engine is hot, no dice. Engine turns but very slowly, havent noticed any smoke or smurfs.
Wherabout is the starter relay located ?

[pinkerton]

With higher compression, you'll need more starting power. This is old school hot rod basics. You might want to search a bit on some such forums for more detail. I assume you have a stock starter and battery and may need to upgrade both - Or possibly just renew them if they're old/weak. When they get hot, you effectively lose torque at the flywheel.

BTW, how does it run otherwise? It sounds like a great set up.

[jfmjr442]

With higher compression, you'll need more starting power. This is old school hot rod basics. When they get hot, you effectively lose torque at the flywheel.

BTW, how does it run otherwise? It sounds like a great set up.

Heat soaked. You need either a high torque starter or relocate the solenoid away from the heat (Remote solenoid, i don't know if it is possible)
here's a link http://www.oldengine.org/unfaq/solenoid.htm

You could also wrap the wires in something like header wrap or spark plug wraps that are used between headers on old amnerican muscle V-8's
HTH

John

[baseball]

It sounds like what you are experiencing is called heat soak (Do a search for how to solve it) Good Luck

[pinkerton]

A larger gauge starter cable is also worth considering.

[Sada]

I've ruled out most electrical issues.
New starter and battery and have tested voltage at the starter when hot. all ok.

Seems as if the engine is getting tight when hot. I think it's a clearance issue with the crank/bearings or some internal component.
I've done a simple test that leads me to this conclusion, when hot the engine doesnt turn with a spanner on the front crank bolt.
When cold it does.

Looks like engine needs to come out. :redspot

Ruled out heat soak , a quick drive at low ambient air temperatures also gives the same problem.
also tried hosing the starter down to rule out heat soak.

[pinkerton]

Fascinating!

How about getting it hot, pulling the plugs, and see if it turns freely?

[CGramme]

Fascinating!

How about getting it hot, pulling the plugs, and see if it turns freely?

from what the op has explained this should be the next step for sure. If it doesn't turn when the plugs are out there is a big problem with the way it was put together. the build sounds pretty sweet though. did you notice alot more power after the rebuild?

[baseball]

Seems as if the engine is getting tight when hot. I think it's a clearance issue with the crank/bearings or some internal component. I've done a simple test that leads me to this conclusion, when hot the engine doesnt turn with a spanner on the front crank bolt.
When cold it does.
Ruled out heat soak , a quick drive at low ambient air temperatures also gives the same problem.
also tried hosing the starter down to rule out heat soak.

That is exactly what heat soak is, whether it's the starter or the engine itself. The heat is causing the problem thus it's called heat soak. I had a 1941 Cadillac that had the same problem after a rebuild it turns out the clearance on the main bearings were insufficient.

[Sada]

That is exactly what heat soak is, whether it's the starter or the engine itself. The heat is causing the problem thus it's called heat soak. I had a 1941 Cadillac that had the same problem after a rebuild it turns out the clearance on the main bearings were insufficient.

I get what u saying now, i was thinking heat soak regarding the starter.

Anyway the problem is easing up after i've done some miles on the new setup, she startsup when hot now and is not really a problem. :buttrock
Still turns a tad slower then when the car is cold but the engine starts up.

My mechanic was in no mood to pull the engine so he suggested putting some milage on the car , and guess what , engine seems to have loosened up;


going to run her in and get a good tune now.

[Shadetree930]

With higher compression, you'll need more starting power. This is old school hot rod basics. You might want to search a bit on some such forums for more detail. I assume you have a stock starter and battery and may need to upgrade both - Or possibly just renew them if they're old/weak. When they get hot, you effectively lose torque at the flywheel.



Agree with this

[mistermac]

Nice work on the 3.2 L conversion! I'm thinking of doing this myself. Did you use the original 328 conrods? Because I notice they're different part numbers on OEM between 328 and M3 S52. Do you have anymore details of these JE pistons? Cheers.

[DJCarbine]

Its funny how engines work like girls... just put some miles on them to loosen those tolerances up :devillook

[Cy101]

E36 M3 slow to crank, weak battery light on dash.

PROBLEM SOLVED - my E36 M3 had same issue. It always seem to not want to start, like a weak battery. The battery light on the dash comes on when I crank, and it felt very weak to crank. Battery is new and starter Replaced with brand new but issue continues. Especially when it’s hot, I turned the key to on position, and I had to hold it for like 3 seconds before it starts cranking slowly crank, like a bad starter.

The problem is because of a slowly dying EWS, that is causing the car to have a hard time to turn over, causing the battery light to come on when it’s cranking like a weak battery. What you need to do is remove the glove box and get to the EWS module. Then jump or connect the two big wires together. It’s pin 1 & 3. The car fires right up normally and no more weak battery cranking.

[Eric93se]

Cy101, welcome to the forum.

The battery light is on before the engine starts because its energizing the field in the alternator, the light goes out when the car starts, this is normal. It has nothing to do with your ews.

You should test your crank sensor one of the most common issues. Second thing is to remove and clean your main ground strap.