LT1 rebuild
 

For those of you that have rebuilt an LT1, I have a couple of questions.

I'm going with stock compression and stroke, either a stock crank and drop ins or a fully forged rotating assembly. Any suggestions on where to buy? How's the stuff from Texas speed?

Also what's the deal with the thrust bearing on these engines? Are they really welded to the block? (Think I read this somewhere) Is it pretty straightforward to replace? I've seen 180 degree thrust bearings and 360, does this depend on stock vs aftermarket crank?

I'm not looking to add power via a stroker kit, I don't want to sink the money into an upgraded fuel system. I will however be getting rid of the current jannetty cam which has never really ran correctly and looking for a different one. Probably katech from what I've been reading but if you have suggestions I'm open to them. It's a track only car, looking to keep near the 550-560 whp I have now with E85. Reliability is the main goal.


If you have some advice I'm open to it, I've rebuilt engines before, I'm confident in my ability to do that, but I've never opened up the bottom end of an LT1.

Hope you dont mind me tagging along in this thread but can anyone tell me who has experience in machining the LT1 block to accept a full face thrust bearing?

If youre not boosting and staying NA then theres no need for forged internals unless youre trying to spin them to more than 7400rpm.
Id avoid texas speed like the plague, GPI or BTR are the most trustworthy in the game currently. For cams on an engine with stock Piston To Valve clearance you can go with a GPI LT SS3 cam, the GPI LT NFC cam(not a fan of this one) or a BTR 225 cam. Anything bigger will require flycutting, and obviously you need .660 springs in the heads for these cams.

IMO GPI and tsp are closer to each other than to btr. Then you have BTR being closer to Katech.

If you go with the stock pistons it will limit you in the future if you ever want to go supercharged. But if your keeping it NA then your fine. Never had a problem with Texas Speed but Weapon X their thermostat failed pretty quick on me. Katech has been pretty good to me.

GPI drop in kit holding up fine at 1059 WHP, FWIW. Pretty good testament to their kit’s quality IMO.

If staying around 550wheel you shouldn't have to touch your rotating assembly.

I personally went with GPI, Customer service is great over there. IF you reach out to them and let them know your goals they will get you the right cam. Can even get a custom spec cam for 25-50$ more.

For what it's worth- I'm stock bottom end and closer to the 600whp range on my track car build. Revving over 7k.

Thanks for the responses. Without first hand knowledge it's tough to gauge who to buy from.

Definitely leaving it NA, at least until the mid life crisis fully kicks in. I'd like to build it to be ready for more power, but right now I don't want to add weight. I definitely want to put a forged rotating assembly in. After something failing (haven't disassembled yet, not sure exactly what) with the stock stuff I don't want to rinse and repeat.

Anyone have experience with the thrust bearing? I guess I may just have to figure it out for myself when I do the tear down in a couple weeks.

You may find a few answers to your questions in our LT1 build found here:

Supercharged LT1 Build

Thanks for the link! Good read.

I didn't see much on the thrust bearing though. I'm curious about aftermarket cranks and bearings vs OEM. Say, if I was to opt for a stroker, is that just a simple swap or is it more complicated than that, with regards to the thrust bearing? It's very interesting that they only use a 180 degree thrust bearing. Also that you can buy a 360, but is the #3 main cap even machined for that? Also if it's not used for a thrust bearing there's likely no alignment dowels and thus the possibility of the cap walking would increase. I'd say it'd likely be rare but technically possible.

I guess not being able to find the answer I'll try to get technical help from the vendor I decide to buy the rotating assembly from. I'd assume that they'd have the answers.

Baddawg53 - Reference the thrust bearing: I thought the images were pretty clear LT1 uses a 360 degree thrust from the factory and the Mahle/Clevite bearing still required removing the tang to properly seat. Believe they were set of LS bearings...*

Our engine is a 416 so there are challenges we ran into - piston hitting crank position wheel and the oil squirters crammed between piston skirt and rods...

Good luck on the build!

Man ... Not sure how I glossed over that part about grinding off the tang on the bearing. Need a bit better attention to detail there. Thanks for following up with that.

I've seen where guys have had piston cooler clearance issues as well as the relucter wheel, good info, it'll be coming apart Hopefully next week.

I believe my oil pump went bad and then I started getting some valvetrain noise, not running very good. It still starts and has oil pressure, but it dropped off and the oil temp climbed, as you can see in the picture ...

https://www.youtube.com/watch?v=paizumY5Ygs

IMO, a mild cam remove the AFM lifters, a good mild spring and you are golden to 7000 or so RPM,

Aftermarket cranks are going to run into fillet problems, but if you have a commitment engine builder you should be OK.

Thanks for sharing that video, really good stuff in there. Definitely subscribed to that channel.

I'm going to build the engine myself, I've built enough to have the confidence to do it, just not the LT1 engine.