sh*t! i just replaced the heads/cam, ran it not even100 miles and spun several rod bearing in my 130000 mile lt1. guess it happened to me........

 

How can this possibly be unique to an LT1?

 

All I can say is that 200 miles after I had my heads ported (with only 7900 miles on the clock) I wound up buying a new short block.

 

I drive the hell outta my car each and every day. Did heads/cam at 83k and now have like 89k on it with no problems. Plus, I'm TRYING to break mine before winter so I can throw an all-forged 355 in there.

 

This makes absolutly no sense. Because lets say that you rebuild your engine. Hot tank it, rebore the cyls and then put it together with new parts. Then if what they are saying is true you would still have misalligned bearing bores.
So this means the only reason to fix this problem is to get a new block? That is a whole lot of crap.
Maybe a machinisnt can comment but I am pretty sure it wouldnt matter if you replaced the bearings or not.

 

:werd:

It makes perfect sense from the business standpoint. 1. you get the extra work/money of rebuilding the block and 2. since MTI puts the entire motor together they don't face the bad publicity after someone spun a bearing in there stock block and them running around telling everyone on the internet. 3. I'm pretty sure Jayson got tired of customers b!tchin at him for ruining thier motors and sueing him and blaming it on poor workmanship.

I believe a healthy cam/head swap comes down to these things.

1. An aftermarket oilpump to keep up with the addtional RPMs and bearing loads(I use the Moroso 22122)
2. Cleanliness
3. Break in
4. How the owner drives the car.

my $.02

 

you guys also have to remember that if this is "frequent" it means over 1% of the time.

 

I believe there are numerous (obvious) causes for bearing failure as well as causes that one will never know unless a painstaking analysis is conducted following the event.

I doubt that many perform this analysis, but just go with the flow (throw in a new block).

You can only really trust yourself when it comes to building an engine. If it goes bad after a mechanic works on it, it is highly unlikely that they will fess up if they screwed up (no matter how good their rep is.)

And, of course, the engineers who spec out the engines for production certainly build in a margin for some abuse, but not for excessive abuse or use.

You pay to play.JMHO

 

I have said it before and I will say it again. Failure of an otherwise sound engine after a cam install is from sloppy technican work about 99.89% of the time. This "thermal stress" and misalignment stuff is a smokescreen - If that were the case it wouldn't just affect the LT1, it would affect all SBCs and other engines as well.
I wouldn't probably install a cam in an engine that had over 100,000 miles on it unless it looked extremely well cared for. I wouldn't hesitate to turn someone down who had a car that looked like it was under-maintained at lower mileage, even 20,000 miles.

I don't do this for a living anymore so I don't have to take every job that comes my way. If MTI gets a car in their shop and takes off the valve cover and is greeted with a burnt up sludge pit, they should consult thoroughly with the owner that there is absolutely no guarantee on the bottom end of the engine after the work is performed. Or, if it is truly nasty and filled with crap, it might behoove them to just turn it down without a complete rebuild.

The biggest enemy is dirt and dirt in all forms. Sand, grit, abrasive material, (Scotchbrite and Roloc discs are as good as putting pumice in your oil) lint, and oil that hasn't been changed after a major surgery are all hallmarks of bad techs. Another enemy is the tech with no use for a torque wrench. You have to torque fasteners and those fasteners have to be treated properly before installation - cleaned, lubed, replaced if necessary etc.

 

dave: How's everything in Webberville. Born and raised in Dewitt.

 

Quiet, just like I like it. Of course, I don't work in Webberville, - most people don't. Number of murders last year = 0, Number of rapes reported last year =0, Number of registered child molesters in the village limits = 2 (father and son).

 

I think if you maintain your car well and let it warm up before you drive it like you stole it than you shouldn't have a problem. I just use good oil and change it around 3k and I have not had a problem yet.

 

anyone remember my letter to superchevy?

I have a feeling this might follow along the same lines.

 

Hmmm, you guys got some good points i guess technically its rite and WOULD twist the block, but at the same time, it would do it on EVERY rebuilt top end block out there too so its kinda stupid thing to post in a majorly read GM magazine ... ... I was jsut stating thats what the magazine said. I dont take everything they say as gospel lol ... They also had a "Street Machine" shootout with modded LT and LS cars in it and on the Fuel rating, the LOWEST was 94 octane( I think ) with most having like a 100 ... How much of a street machine is it if you have to run 5$ a gallon worth of fuel in it ! ... then again they might have jsut run that for the track, but still youd think since its a street shoutout theyd explain at least what they normally run or sumthing ...

 

Im a believer now.. Heads came off at 94K, Block is useless now with 117k