[jimmyjimny]

hey all!!

I'm doing a head gasket on my sierra and just put the timing belt back on after doing the headbolts all nice and perfect, I go to turn it by hand to test everything is all good and it turns 2 full rotations with ease and I think beautiful.
Well after putting the timing case back on I went to turn it again and the motor had seized.. Now form this point I can't remember exactly what I did but I took the timing cover back off and the markers were all in the right place and it wasn't budging (I didn't force it to hard), I thought it was a valve or something and freaked out but thought it couldn't be locking up due to the plugs being removed?? I took the belt off and spun the cam in fear of stuffed valves and they were all good so I tried spinning the crank and it was frozen solid.
So I freaked and thought it was due to no oil in the block and poured oil down the plug holes and that may have been how I freed the bottom end.. I also backed off the lifters at some point between all this and could be how I got the crank free. With the belt and cover back together I turned it and it felt a bit rough at first but came around after a few spins and surprisingly felt normal again. I thought I'd dodged a bullet. Next thing to put on was the crank pulley, I decided to spin it again for another random test and behold it' had seized again. I backed off the lifters completely and got it free, it's spinning fine and hasn't seized again but feels like it has more compression/harder to turn (could be wrong).

By this point it's amazing it still spins and I'm afraid to tighten the lifters back down onto the valves as I think that's what is seizing the crank. I was told with the plugs are out pressure can't build up to bend any valves so I don't get why this is happening but have a feeling it's to do with lifters. I've only done headgaskets on cars with hydraulic lifters and these look like they can be adjusted and I just screwed them back down to what they were before, could this be why it keeps seezing? I dunno what else it could be I just want to get it back together and fire it up to make sure it's all good at this point. Any help would be greatly appreciated!

[jimmyjimny]

I tried it today with the tappets backed off and it's fine, I think I must've hit a valve with the piston, pretty peeved I'm not sure why this has happened the valve clearances are the exact same as they were before I backed off the tappets they shouldn't need any new settings I believe. The cam timing mark is also correct so I'm not sure why ir would be locking up like this, the timing must be out somewhere.

[Marko_SJ]

Mate I ummed and ahh'ed about responding to this because I'm not the most knowledgeable person on here by a long shot.

But.... I have a 1.6 never ending project that i'm stripping down and that is relatively stiff to turn, with the head on but plugs removed mine had oil in it though.

Is it siezed solid and you can't turn it or is it a heavy drag? It might help the people whom actually know what they are talking about.

[tanshi]

arent the 1.3 motors non interferance? i.e the valves wont foul in the pistions.

[droverdave]

jimmyjimny wrote:

I took the belt off and spun the cam in fear of stuffed valves and they were all good so I tried spinning the crank and it was frozen solid.

So the crank was "frozen" when the cam was spinning freely with the belt removed? So no interaction between cam and crank (so no compression) and the crank was stuck.

All i can think of is the crank is bent.... :S

Cranks do bend....and often you get them trued up during a bottom end rebuild.

Not sure how a crank gets bent in the first place though.

[jimmyjimny]

Cheers guys!! Yeah it was seized frozen solid and not even close to budging (even lifted the motor up to discover a dodgy engine mount!) I can't remember if it was putting oil in the plug holes or spinning the cam is what got it free but I've just gone out to see if it's seized again and it hasn't. I think it seizes after I spin it with the tappets screwed down but that doesn't sound right?? I dunno I'm a bit weary to tighten them down again and give it another spin haha

[want33s]

tanshi wrote:

arent the 1.3 motors non interferance? i.e the valves wont foul in the pistions.

YES





but.....







if the OP seriously wound the adjusters down then I believe it would be possible.

[Mickc]

Did you scrape the carbon of top of pistons or cylinder wall or
drop any hard bits that can wedge between piston from old gasket?

[fordem]

Seized in the normal context of the word - without starting & running it - is unlikely to happen. It's sounds more like you have something where it shouldn't be.

Oh - FWIW - the 1.3 8v motors are normally non interference, if you're running flat topped high compression pistons, it may not be, if you're running a 16v 1.3, I would be very careful - I know the OP asked about a G13a so 8v, but don't assume that they all are.

[jimmyjimny]

hey guys turns out I had the cam sprocket back a tooth or two somehow how I managed that I do not know it was all lined up beforehand! I've got it back together and it sort've runs although not so well haha. I tried fiddling with the dizzy roughly (my previous timing mark not working) and got it going rather smooth but I have to keep the revs up otherwise it dies below like 800rpm, it's blowing out a shiteload of petrol too and when I rev it the motor hangs and doesn't respond to the accelerator properly? The timing could be better but that shouldn't make it cut out like this, maybe one of the hoses on the manifold? I'm not really sure what to think but it's running!! sort've!