New member here ... in need of advice(seized engine?)

hey guys , I am new . I hope to bug you with many questions in the future. lol
I will start by saying that I have a red 89 st165. I have been rebuilding it over the past year...till now.
I put the bare engine back in the car a couple months ago and everything was fine,but due to my work I didn't work onb it for several weeks and about 3-4 weeks ago i started working on it and it will no longer turn at all.
I was able to very slowly turn it with a breaker bar for about a third of a turn and then it ceased moving at all . I tried wd 40 in the cylinders for 10 days to no effect. I am on day 5 with marvel mystery oil and a little pb blaster still no movement other than a few mm back and forth at the flywheel,which was discovered during the wd40 stage.
SO seeking any advice or insight anyone might have as too my perdicament??????

p.s. I checked a rod bearing and a crank bearing and both still looked like i just put them on.
I guess tomorrow I will start making way for the head to come back off and start a more systematic check of the bearings.

Can you turn the engine backwards at all? Or is it now completely stuck in that spot?

it won't turn at all from the front with a socket and breaker bar(or i cant tell if it does)... but when i wedge a big screw driver in the teeth on the flywheel and pry i can see a few millimeters movement at the flywheel teeth.
and on the two pistons that are down in the block can see slight movement and penetrant seeping through. I have not been able to get a good view of the two up pistons, but what i can see of the bore appears to be smooth.

I'd drop the oil pan and pull off the valve cover and see if anything looks off before pulling the head, maybe remove the timing belt from the cam gears as well and see if that makes a difference.

well today I pulled the ,valve cover, cam gears, oil pan. great minds think alike ...
nothing helped... I was checking the side to side clearance on the connecting rods and one is suspiciously tighter than the other three... hopefully tomorrow i can investigate further...
the more i think about it, I am starting to think it is a bearing problem. I would think that two weeks of soaking would at least loosen it a little were the rings the cause...but I have never had a problem with an engine like this.(unless you count hydro-locking a 5s-fe)...
if i cant find a problem on the bottom end the head is coming off.
I have another head with 264 cams in it... :twisted:

I pulled all the bearing caps and found no problems...I then re-installed the caps hand tight and found the engine would turn... so the bearings are too tight or my torque wrench is trash...I am leaning toward bearings. I am going to plastiguage them when I can make time this week.

well I finally got around to respec all the bearings and I found the number 2 rod journal bearing is tight all the other bearings check out fine.looking for advice on whether I should try to sand down the back of the bearing polish the crank or buy a new bearings...

Any chance the cap was installed on the rod backwards? A simple mistake, but it happens.

Cap was on correctly I have since found a couple small problems on the journal that was tight... that journal was about half a thou bigger than the others so I polished it to correct size...The other problem was the rod cap was between 1 -2 thou narrow...apparently the machine shop forgot to true it ...but it appears to only be on the cap side so I have hand honed the sides down about 1 and a half thou and ordered new rod bearing...waiting for the weather to warm up so I can test fit everything to see if I got the cap right...

It it's funny that you say cap backwards since that is the reason I got the car...proud owner thought it needed to be rebuilt since it started smoking around 100k (leaky turbo)so whoever rebuilt it put the number 2 rod cap on backwards...a couple thousand miles later it doin the bearing and stretched the rod cap and scored the crank, oil pump...I have been dealing with the aftermath for a coupe years now...but it's not over until I win!

Well after being depressed and demotivated all winter ...I have decided to finish this cluster frak of a st165 for my own birthday...I figured out all the issues over the winter but my lack of a garage has made everything harder than it should be....I am pulling the head off and pulling the pistons out and taking then to a machinist ...this course of action still allow me to put my other head with 9'2 cams in....I am motivating myself but this car has been nothing but trouble ...wish me luck guys