Rebuilt 4k won't turn over

[DANK-KAGE]

Hey all,

I just put my rebuilt 4k back into my ke30, but when I turn the key it won't turn over.

When I try, it makes a clunking sound and I can see the fan and distributer rotor attempt to rotate but stop.

I've tested the starter (which is new), and I can see that it spins with power to it.

I've tried without the spark plugs in to make sure it's not that my compression is too high, its definitely in neutral, the rotating assembly is torqued as per the yellow book and I know power and ground is where it should be.

Has anyone else experienced this? I am inclined to think that something is acting as a blockage, but am loth to disassemble without consultation.

Any help would be appreciated as I have no idea what I'm doing.

Thanks.

[kickn5k]

Did you paint the back of the block, when it was rebuilt?

If yes, then chuck an earth strap from starter bolt to body and you should be peachy. The starter usually earths to the back of the block, can't if paint won't let it. Happened to me many, many years ago. 

 

[7000rpm]

Can you rotate the engine with a ratchet and socket on the crank pulley bolt freely?

[rebuilder86]

Haha I just had the same problem last month and posted about it on here.

I had rebuilt it and installed the big end caps the same way they came off, which incidently happened to be backwards! And with the nice new bearings, it locked up.

Check that the 3 lumps on the connecting rod big end caps are facing the front of the engine, and that the conrod is also facing forward.

There should be some marks on the side of the caps which indicate the cap is aligned correctly with the conrod.

So..

Piston one has one mark stamped on both the cap and rod on the same side.

Piston 2 has 2 marks 

And so on

Edited February 2, 2018 by rebuilder86

[DANK-KAGE]

58 minutes ago, kickn5k said:

Did you paint the back of the block, when it was rebuilt?

If yes, then chuck an earth strap from starter bolt to body and you should be peachy. The starter usually earths to the back of the block, can't if paint won't let it. Happened to me many, many years ago. 

 

I'm quite certain the starter is getting is earth properly from the block.

40 minutes ago, 7000rpm said:

Can you rotate the engine with a ratchet and socket on the crank pulley bolt freely?

I've been able to rotate the engine off the crank bolt a few times which has resulted in the starter doing its job. But for some reason now it has completely locked so I can't even do that.

16 minutes ago, rebuilder86 said:

Haha I just had the same problem last month and posted about it on here.

I had rebuilt it and installed the big end caps the same way they came off, which incidently happened to be backwards! And with the nice new bearings, it locked up.

Check that the 3 lumps on the connecting rod big end caps are facing the front of the engine, and that the conrod is also facing forward.

There should be some marks on the side of the caps which indicate the cap is aligned correctly with the conrod.

So..

Piston one has one mark stamped on both the cap and rod on the same side.

Piston 2 has 2 marks 

And so on

I'll give this a go. Hopefully this will be the answer.

 

Thanks for your help. I'll let you guys know how it goes.

[Banjo]

Wow, that's a bummer !

Did you rebuild the 4K yourself, or did someone do it for you ?   What was involved in the rebuild ?    Was it bored or honed ?  Was there new pistons or rings ?  New big end and/or main bearings ?  Crankshaft reground ?  New crankshaft oils seals back &/or front ?

Was the head rebuilt also ?  Was the camshaft, & camshaft sprocket removed ?

If you tell us what was done to it, it will narrow down where the issue may lie.

With all four (4) spark plugs out, with the dizzy out, with the fan belt off, gearbox in neutral,  the engine should spin freely on the starter motor, or be relatively easy to turn over using a socket & ratchet on the crankshaft pulley retaining nut.

If it won't turn, easily, then don't try to force it, as you run the risk of damaging something.

Strange.  Normally an engine assembler spins the crankshaft by hand, then adds pistons & conrods, one at a time, spinning it at each addition. Finally camshaft & sprocket & chain.  when they are happy, everything is free to spin, then, & only then, does the sump get replaced & sealed.

Any chance of you recording the attempt to turn it over, with audio,so we can hear the clunk ?

Cheers Banjo

[LittleRedSpirit]

Hit starter with hammer and try again.

[rebuilder86]

15 hours ago, DANK-KAGE said:

the rotating assembly is torqued as per the yellow book

OP sais that which makes me think it's a home job, which will be fine, so long as the bearings and caps are all correct size and orientation.

When I had the issue, I was doing one big end at a time, underneath the car,  rotating the Assembly after each change, and noticed it was getting progressively more difficult to turn, and with all 4 don't the thing was completely jammed. Leaving me screaming in anger, dirty, tired fuxking frustrated and angry at myself for being a shit mechanic. But it was just all because I copied someone else's mistake.

The big end caps were backwards all along, which was incresibly surprising, seeings as the wear in the bearings that came out, was visually perfectly even and it was previously perfectly easy to turn. That goes to show just how finely machined they are. They're almost perfectly symmetrical, but just not quite symmetrical enough to go on either any way. I have no idea how the engine builder managed to build mine with the caps backwards and have it apinning so freely, enough for it to last the 3 years minimum that I've had it with next to no wear, but replacing bearinga caused it to lock up. they would've had to run it loose and slowly tighten the caps as the bearings were worn haha.

This is a big end bearing, from the cap side, from my motor which had all the caps backwards for 3 years or more...

Looks relitively fine.

Edited February 3, 2018 by rebuilder86

[rebuilder86]

Oh another one is socket interference. See pic below. But ud have to be pretty unlucky and careless to suffer that. Personally I've never been a victim of it, and I'm just a backyard engine rebuild with many rebuilds under my belt.

[DANK-KAGE]

13 hours ago, Banjo said:

Wow, that's a bummer !

Did you rebuild the 4K yourself, or did someone do it for you ?   What was involved in the rebuild ?    Was it bored or honed ?  Was there new pistons or rings ?  New big end and/or main bearings ?  Crankshaft reground ?  New crankshaft oils seals back &/or front ?

Was the head rebuilt also ?  Was the camshaft, & camshaft sprocket removed ?

If you tell us what was done to it, it will narrow down where the issue may lie.

With all four (4) spark plugs out, with the dizzy out, with the fan belt off, gearbox in neutral,  the engine should spin freely on the starter motor, or be relatively easy to turn over using a socket & ratchet on the crankshaft pulley retaining nut.

First of all. Thankyou everyone for replying so promptly with solid advice and thought.

Second, it's a ground up rebuild. Every piece was removed and cleaned from top to bottom.

Mainly top end modification. I got a cam grind, head shaved, new carb, springs, electronic ignition, etc.

I've done all the assembly myself, making it slightly more irksome as it ran well before I rebuilt it.

 

3 hours ago, rebuilder86 said:

OP sais that which makes me think it's a home job, which will be fine, so long as the bearings and caps are all correct size and orientation.

When I had the issue, I was doing one big end at a time, underneath the car,  rotating the Assembly after each change, and noticed it was getting progressively more difficult to turn, and with all 4 don't the thing was completely jammed. Leaving me screaming in anger, dirty, tired fuxking frustrated and angry at myself for being a shit mechanic. But it was just all because I copied someone else's mistake.

The big end caps were backwards all along, which was incresibly surprising, seeings as the wear in the bearings that came out, was visually perfectly even and it was previously perfectly easy to turn. That goes to show just how finely machined they are. They're almost perfectly symmetrical, but just not quite symmetrical enough to go on either any way. I have no idea how the engine builder managed to build mine with the caps backwards and have it apinning so freely, enough for it to last the 3 years minimum that I've had it with next to no wear, but replacing bearinga caused it to lock up. they would've had to run it loose and slowly tighten the caps as the bearings were worn haha.

This is a big end bearing, from the cap side, from my motor which had all the caps backwards for 3 years or more...

After a painful night of taking the engine back out of the car and quick disassembly, culminating in giving up at 2am and restarting this morning, it seems that it was indeed the conrod caps being replaced in the wrong orientation. Similarly, I also put them on in exactly the same way I took them off, evidently the wrong way! The engine has shown signs of prior rebuild being done poorly, but I didn't think extended this far.

Unusually, the piston are obviously not original as they lack any of the marking described here or in the yellow book. Just some numbers and letters which don't seem to correlate. SO I just changed them in faith that would be the solution knowing that bearings were in good condition, and the camshaft was properly installed, so it wasn't valves or anything similar causing interference.

When I built it the first time I could turn it over via the crank bolt, but with effort. Now upon cap reorientation, the whole assembly rotates much more freely.

I've reinstalled the engine and the starter seems to be doing its job well without the spark plugs in, until the battery went flat anyway.

However, I am optimistic this was the solution. And on the bright side, I know I won't let it happen again.

 

[rebuilder86]

So wholly shit, someone else experiencing my exact scenario. I honestly thought to myself that the stupid local filipino engine builders couldnt possibly be matched in stupidity in a First world country. And certainly didnt expect anyone to come across the same issue in the next month haha.

Perhaps your engine comes from here haha.

 

[rebuilder86]

And do u think that like myaelf, before ur rebuild, it was turning fine, even with the caps on in the backwards orientation?

If so have a look at the old big end bearings for us. I'm interested to see just how even the wear is. It blows my mind that somehow the engine ran nice n tight with the caps backwards for me.

[DANK-KAGE]

Yeah, I drove it for about 3 weeks and it ran and started fine. Even when I pulled it out originally it seemed to turn fine.

Unfortunately I haven't taken any photos for you, but the bearings seemed OK, only one showed any wear, but even that was marginal.

 

[rebuilder86]

That's all I needed to hear to confirm what I thought. The caps must be so so close to perfectly symmetrical that they can be installed backwards and still somehow be turned untill a fraction of a barometer is worn off the bearings during it's first few hard starts.

Good thing u didnt just loosen it a bit and say she'll be right haha.

[DANK-KAGE]

Indeed, the thought had occurred.