Yeah, I didn't learn much about LS7 until after I got my LS7. It's the best and worst LS engine GM ever made. There's more issues than valve guides, I don't want to scare you. Bottom line is it just needs more maintenance than typical, stay on top of it and keep your oil temperature in check and you'll be fine. It's a powerhouse, LS7's run....

 

That's the Only major problem being the valvetrain and valve guides.
😉

 

Common Sense Says...

It has to be the geometry as this doesn't happen with other heads. Change valve material and guides same problem?

Geometry!

Great head porter can fix it with a few techniques.. longer valve guide being one.

it is The Best engine Ever made and sold in mass production.
limit quantity? Mercury DOHC sb based off of the ls7 and there dohc bb and tt.

 

Thank you for the comment about maintenance and oil temps. What extra maintenance would you suggest and what oil temp range?

 

Is there any shop that has done this type of work successfully on these engines?

 

I just hate bad valve guide issues! As I posted earlier, I've owned my 1980 Z28 since it was new. That car wasn't driven all that often and it often sat for 1-2 weeks at a time. Within 10,000 miles, it was blowing blue smoke out of the tailpipes from bad valve guides and/or seals. I've always been afraid of valve guides since then !

 

Just install and enjoy this LS7. That’s what I’d do regardless of issues.

If you are really, really concerned, sell your heads and buy aftermarket like BR7 or TFS.

Engine block and rotating assembly won’t have any issues with proper timing, a/f ratio and good oil-frequently changed.

If still not convinced, you won’t have a problem selling this engine. Few guys here would buy it without hesitation.

 

I'm going to run it as is until it gives me problems. Hopefully that won't be for a very long time. Thanks, Marcin!

 

Probably OK to do, and I wish you the best of luck. Sadly, many times, by the time you know you have an issue, it's too late. I have a built LS7 in my C5. By 20,000 miles, 7 of 8 intakes were losing their CrN coating, and all 16 guides were junk. Cam had only .010" more lift than stock. They were 'fixed' before they ever went on the block, with a Serdi valve job. Worst part is not knowing if, or when, you'll have trouble. Like many things, if you get a good one, they're great, if not, hopefully you'll see signs of trouble before anything happens. My take on it is this: Since most everyone loves the power of the LS7, why did GM stop making it? I think we all know why. Even they couldn't depend on the engines vendors doing the proper machining. My .02, and yes, mine is still running fine. Right now. This minute. Best of luck to you. Enjoy...

 

Roller tip rockers would help reduce guide wear.

 

Thank you for posting your experience, grinder. Just for clarification; were your LS7 heads "fixed" with the Serdi valve job and then within 20,000 miles the guides were junk? If so, what valve guide work did they do?

 

I did some research last night and it does appear that roller tip rockers would help. From my one evening of research, it seems like the OEM valve guides are too short. Having a competent machine shop install longer guides and then do a valve job seems to fix the problem. At least that's what I read.

 

Your on the correct road... if the guide is wearing out or killing coating on the valve....

🤔 must mean the angle of the valve once in and the valvetrain is set up is causing the rub. Wear comes from something touching not a up and down motion. Aka other heads don't have this problem. I also believe it is the Ls7 rocker length and pivot points as well as the guide itself.

 

Who to contact on a permanent fix? GPI. They looked into it and made there own head using Brodix. Ceasar developed the port they use on there Brodix ls7.

Me personally I wouldn't use a factory rocker with this particular head.
1 it's a small stud with a larger ratio at 1.8
roller tip wanted. Guys replace the guides and sometimes still have the same problem.

Eliminate the factoy rockers and any thoughts of using them.

side note rocker studs Flex reasons for a girdle or shaft mounted system
or a larger stud. ..

 

Old thread... but I just ordered and received a LS427/570HP engine and 4L75E trans from GM. Putting it in my '70 Chevelle. Very excited about the project and will post dyno numbers after we get it installed and running.

 

Very cool Old School. Start your own thread over in Conversions and Hybrids. Keep it updated. I’d like to follow along with you.

 

OldSchool3, congrats on getting your hands on an LS7. I would've thought that they'd be as scarce as hen's teeth now.

 

A++ OldSchool look forward to following along as well!

 

I was planning on ordering the LS3/525 connect and Cruise package, but there was a 4-5 month wait. Scoggin Dickey in Lubbock, TX had this one in stock, so I jumped on it and had it within a week!!

 

Just found this thread while looking for info on the cam.
I'll just leave this here.