Lq4 excessive crank end play.
Lq4 excessive crank end play. I purchased a used Lq4 engine for my truck this weekend. It was supposed to be a 150k mile stock engine. When I took the pan and windage tray off to inspect things, I found that this was a lie. The rods have been marked and numbered, telling me that it’s been apart before. I checked the crank end play, and I measured it at .045”. That’s 9 times what the recommended end play should be, if I’m correct.
A cam bearing walked out on my original engine, and took out my bottom end. I purchased this hoping to save a few bucks, and just use the short block with my top end. At this point what would be my best option to get back up and running? This is my personal vehicle, and I’m on a budget.
I’ve got my original short block that had a cam bearing walk out, and a rod bearing failure.
I’ve also got this new short block that has excessive crank end play.
what to do what to do?? 🤷♂️
A cam bearing walked out on my original engine, and took out my bottom end. I purchased this hoping to save a few bucks, and just use the short block with my top end. At this point what would be my best option to get back up and running? This is my personal vehicle, and I’m on a budget.
I’ve got my original short block that had a cam bearing walk out, and a rod bearing failure.
I’ve also got this new short block that has excessive crank end play.
what to do what to do?? 🤷♂️
I pulled it apart just now. Thrust bear was definitely worn. The rest of the bearings looked acceptable. But at this point I’m just going to have the crank polished and throw new bearings at it. I miced the rod journals and it looks like it’s already been turned down .010”.
Good lort that’s some crazy movement there. You can see where the reluctor wheel…or a counterweight… got into a main cap, it’s moving around so far. Your bearings will all be stamped on the back as to what size they are, ie std, .001, etc. I’d clean it all up, throw another set of bearings at it, ball hone it and new rings, and send it, if your on a tight budget.
Good lort that’s some crazy movement there. You can see where the reluctor wheel…or a counterweight… got into a main cap, it’s moving around so far. Your bearings will all be stamped on the back as to what size they are, ie std, .001, etc. I’d clean it all up, throw another set of bearings at it, ball hone it and new rings, and send it, if your on a tight budget.
There ya go. I’d go back with the same. Clevite is a great bearing. I measure everything out to the .0001, and Clevite never disappoints. I was a King fan for a little while, but they got sloppy.
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I’m going to take the crank, rods, and block to a machine shop. Just to be 100% certain. I’m hoping they can just polish the crank, and I can send it with new bearings, a quick hone, and some new rings. 🤞
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Teching In
Joined: May 2025
Posts: 20
Likes: 6
anytime i see your post abt recommendations hasn't done me wrong now have an lq4 bored and stroked pushing close to 1k crank
Well it just keeps getting worse. I polished the crank tonight and everything cleaned up really well! I started measuring everything, and the measurements were great too. Then I got to the crank main journal that rides in the thrust bearing. That’s when I noticed it. The portion of the crank that rides against the thrust bearing is fubared. I just can’t win.
I will 100% have it checked out. I’m still just on the fence of having the rotating assembly balanced. I have an old machinist here locally who can measure everything. I just don’t have access to a machine shop locally. I’d have to drive 4.5 hours to one. That’s the part I’m really struggling with.
TECH Addict
Joined: Dec 2017
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Have your old machinist check the bob weights on the old crank and the new one. If they're close enough, and the old one was close enough, it's already ... close enough. There's no such thing as "perfect" for that anyway, since the "balance" of each cylinder's parts changes according to the position of the crank in its rotation. Close enough is close enough.
Well I got another crank, and it’s in great condition. No nicks, no scrapes, and everything measured out 100% standard. Got the cylinders honed lightly. Got bearings and rings ordered. Should start putting it back together on Tuesday.
Well things are looking up! I got the crank polished, and all my measurements came out great! I ordered a set of standard mahle Clevite bearings. I took all my readings, and came out perfect on my rod bearing clearances. I’m getting .0029-.0030” on my rod clearances. However my main bearing clearances were .0015-.0018”, which is too tight for my liking. I ordered another set of X .001” bearings, and got them in today. My new main bearing clearances are .0026-.0028”. I think that should be just about perfect. I cleaned everything twice, and got the crank lubed, and installed the crank and bearings. With everything torqued down, the crank spins like butter with no tight spots. Tomorrow I’ll install piston rings, and get the rods in the block. Things are starting to look good. 😊
