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I searched all over the forums and haven't found anything close. Just had my 98 LS1 bottom end rebuilt with forged pistons and rods, all new Clevite bearings, and i did all the top end work. It only had 53K on it before but basically EVERYTHING but the block and crank are new and i even had the block honed and the crank balanced and polished. Most of my mods are in my sig. Here's what happened.
Finished putting the engine together and in the car. With the plugs out and injectors unplugged i cranked the engine in 15 second bursts till i got oil pressure. No funny sounds and the engine spun very smoothly and oil pressure was great. I hooked everything back up and fired it up. Right away the engine wouldn't idle (I had Speed Inc. do a mail order tune so i could do the initial break in) something seemed to be dragging. Initially i didn't notice and thought maybe the PCM just needed to get used to the engine so i gave it a little throttle just to keep the rpms between 1,500 and 2k just like my break in manual suggested. As soon as i let off the engine would die. The first round of starting lasted about 45 seconds. I thought maybe i needed to adjust the idle screw. After a slight adjustment i tried again. Same problem but it almost idled for a half a second. Then as i tried to let it idle again i heard a short and barely audible screech and the engine seized. This second round of attempt to run didn't last longer than 20 seconds. I had my builder come over and he tried to turn the crank and it was VERY hard to turn. The crank would rotate back and forth in the little slack of the timing chain so he thinks the crank and pistons are fine. As soon as the timing chain got tension the crank wouldn't rotate without a lot of force with a torque bar. He said there must be something causing the cam to not spin. He checked over my valvetrain and said I had done an excellent job getting proper PR length and preload. What could cause my cam or something other than the crank to seize in a little over a minute with solid oil pressure??? Obviously the engine didn't even have a chance to get hot.
I have a brand new melling HP oil pump and a double roller timing chain. He installed and shimmed the pump and said everything had clearance. I pulled the front cover off and there wasn't anything obviously messed up. Attached are pics of the cover off maybe there's something i don't see. Any help is appreciated because I am freaking out.
if u do that you might have valves hanging down and hit the pistons. would need to pull the pushrods first.
with the pushrods out you could see if the cam turns easily too
if u do that you might have valves hanging down and hit the pistons. would need to pull the pushrods first.
with the pushrods out you could see if the cam turns easily too
Good idea, thanks. I should be home in an hour and will post results.
Okay finally got home and pulled rocker arms. After I took the cam gear off I found the cam like the first pic and it seemed stuck. I put the WP bolts in it and tried to spin it. At first it didn't spin and it sounded like it was rubbing on the cam retainer plate once it did. I pushed the cam back like the second pic so the face of the cam was flush with the retainer plate and it spun with hardly any resistance. When I pulled the cam forward how it originally was it became more difficult to turn and it sounded like there was sand between the cam and the retainer plate. Was the cam binding on the retainer plate? How is it supposed to sit? I kinda tried to rotate the crank but I didn't wanna mess up the timing unless I have to. Thanks for all the quick replys so far!
Engine has all new cam, crank, and rod bearings. After having more time to look at it, it seems the crank gear may be too forward. This is pulling the cam gear forward which is pulling the cam into the retainer plate. My builder is a local guy who does everything from dirt track cars to diesel trucks. Obviously more of a all around builder than an LS specialist. So far his work has been great, up to this point, and he definitely had a great price which included a warranty on the bottom end (thank god)
Just to clarify, cam plate off is spins OK all the time or only when set way back in the block? With the cam plate on and no gear installed, does it spin OK?
If yes, I would measure the undercut on the front of the cam and compare it to the old cam to see if it is shorter.
Just to clarify, cam plate off is spins OK all the time or only when set way back in the block? With the cam plate on and no gear installed, does it spin OK?
If yes, I would measure the undercut on the front of the cam and compare it to the old cam to see if it is shorter.
I haven't taken the cam plate off yet, but it spins fine if i push the cam back into the engine.
Was there a torrington bearing? Do you have a pic on the back of the sprocket? If it was supposed to have a bearing and didn't then your cam and lifters were probably in a bind.
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Was there a torrington bearing? Do you have a pic on the back of the sprocket? If it was supposed to have a bearing and didn't then your cam and lifters were probably in a bind.
The cam gear does have a torrington bearing. I also noticed very tiny metal flakes around that area. I assume this came off the back of the retainer plate. Being that the car didn't run longer than 1.5 mins do i need to worry about the flakes getting into the oil passages? It's still the first round of break in oil and it will be changed as soon as the car warms up all the way.
10-13-2016, 12:56 PM
PLEASE HELP!! Brand new forged LS1 seized. 
