I had never worked on any motor bigger than a single cylinder lawn mower engine until I swapped cams in my 96 Z last spring (2003).

I was **** about protecting the motor from debris.

I did not use "cam lube"; instead I used straight 30w. I read that hydraulic rollers need no break-in lube.

I replaced the OPTI & the water pump while I was in there (It had about 60K on the motor).

Before starting the motor after the swap, I put in brand new valvoline 5-30 and Purolator filter. I replaced oil & filter after running the engine for 20 minutes, all the while maintaining between 1500 & 2000 RPM. I drove the car easy for about 100 miles, and again, replaced oil & filter.

I've driven and pushed the car very aggressively since, and it is still going strong, more than a year later. I am VERY happy I swapped in a more agressive cam and would do it all over again.

I don't believe it can be stessed more, how important it is to keep the internal engine components absolutely free from debris, when tearing into a motor.

If your engine is on its way out anyway, then you're poked, but if its healthy before you start, and you pay special attention to cleanliness and proper lubrication, I think the chances of success are outstanding.

Oh, and BTW... this site (and it's sponsors) has been INSTRUMENTAL in allowing me to work on my car myself. A valuable resource!

 

You CAN run 5w30 oil in the summer in Texas, but you have to use a high end synthetic like Amsoil. Anything that isn't of that quality will fall apart real quick. Still better to use 10wXX though.

 

M1 5w30 and 10w30 are really closer to 20wt. oils and actually become 20wt. after a few miles, M1 is a quality oil but they chose to run their 30wts at the bottom of the 30wt range, this is fine for some motors not great for the LT1. Amsoil while many tout as the best oil is a good oil and in this case it's 30wts. are better suited to the LT1 because they tend to the thick end of 30wt., but it is not the golden ultimate oil they claim. Amsoils marketing while some swallow hook line and sinker, is actually missleading and a bit over the top in claims it is a shame a good product is being marketed in such a manner a real turnoff.

as far as the "You CAN run 5w30 oil in the summer in Texas, but you have to use a high end synthetic like Amsoil. Anything that isn't of that quality will fall apart real quick. Still better to use 10wXX though."
M1 is a quality oil just the 0w40 or 5w40 are better choices for the LT1, one of the best choices seems to be German made Castrol Syntec 0w30, your 10wXX doesn't mean much since it is the hot wt. that is more important since the oil will spend more time protecting the motor while hot, what you need is a high 30 to low 40 wt. and the cold rating can be 0, 5 or 10 that is of less importance unless an extremely cold climate in which case you want a 0w or 5w, and of course depends on it being a good oil in the first place.

 

That's a very good question I've been pondering lately. After many hours on the racetrack and oil analysis with both M1 and Redline 5W-30, I've come to the conclusion that this weight is simply inadequate for my use (which is likely much harder than most here).

How many of you who got at least 1000 miles after your cam swap (to eliminate most obvious install errors) but have spun bearings since were using a synthetic oil thicker than 5W-30?

 

What he said someone should do a poll.

 

Sorry to hear,but i went through the same thing,now i have a nice new 383...I dont care what anyone says head and or cam change equals spun bearing,their might be a few lucky ones but the odds are against you.Good luck

 

Maybe there is something here regarding the lube?? Seems that the guys who just used oil didnt have a spun bearing issue??

 

LMAO! okay

I think there's a lot more people that have had no spun bearings than is realized. People as a whole don't really post up successes, only failures. Just like the news .

Hmm.. I must have really *good luck* considering I've had different 5 cams in my engine

 

well, on my head/cam install, I used oil on the bearing journals, and assembly lube on the lobes. I used alot of the assembly lube on the lobes, so its poss. it restricted oil to the main.s for a brief period. BTW, mine went heads off, cam out/in, heads on and lasted 300 mi.s. I did spin the cam, it was fine. didnt think to look at the bearings inside the eng, but the #1 bearing looked fine. it was kept very clean, and rinsed w/fresh oil before filling the eng. w/oil. as in the plug was taken out, and a few qrts or fresh oil were poured over the new valvetrain/timing chain and drained right out. changed the oil after 1/2 hour of running, didnt get a chance to change it again before the rod knock. I reused my stock w/p. I used GM assembly lube which is like 30wt oil and did prelube the oil pump/eng till there was oil coming out of all rockers before putting on the intake. I wish I had looked at the cam bearings to see if they had turned in there holes. that is a good poss. of why my #4 main bearing was worn, but the others seemed fine. damn it wish I had thought of that to look.
anyways now I have a csi pump and all good bearings now. we'll see.
chris

 

i have personally done over 15 cam swaps on LT1s and never once had a spun bearing. you guys are either nicking/scraping the cam bearings while pulling or installing the cam without realizing it, or else improperly lubing the bearing journals on the new cam. you need 100% coverage of the surface with a good assembly lube, not motor oil. motor oil will wipe off of the journals much easier when pushing the cam through the bearings than a good assembly lube will.

take a minute and think about it... why would replacing one cam with another with identical bearing journals cause a bearing to go on its own.

 

well i was begining to think the problem lay in the overall design. my question is what was done different??

maybe it's just people getting dirt in there or just not prelubed well??? or maybe gm tolerance is a hair tight here. if gm machines the hole for the bearing .0005 smaller it can trash that bearing.

i pulled apart a rebuilt engine with roughly 20K on it and the front bearing was shot. it's at the shop getting them changed and the 230/236 cam installed. once home, i'll pop in the pistons, timing set and get this puppy together! it'll be ready for that winter vacation drive to florida! lol

 

if you put a big cam in on a high mileage engine you better put in a high volume oil pump or your bearings won't have enough oil to cool them. Also the teeth on a stock oil drive gear tend to sheer off or bind then your sol!

 

Here's another data point:

Prior to 59115 miles completely stock.
59115 miles -> Install LPE 74211 Cam,Meziere H2O Pump, LT4 heads and intake
80920 miles -> Remove LPE cam and install GM 847 cam

I do my own mechanic work and have had no problems with either install. I photographed the bearings during both installs and upon review of the photos there is no significant cam bearing wear between cam changes. I am very clean and meticulous when doing this type of work and use a generous amount of engine oil on the cam, lifters, galley and etc. I only use a moderate amount of assembly lube on the cam lobes because the stuff is so thick.

Oh, i also used assembly lube on the cam bearing surfaces. Wen i say i used oil on the cam, I mean the surfaces that don't contact other surfaces. I used asembly lube on all the load-bearing surfaces. I also installed 4" long bolts in the end of the cam where the timing gear mounts. I used these long bolts for grip and leverage while installing the cam taking care not to scuff the bearing surfaces. Also, the LT4 heads i installed had double valve springs. I agree more lift and stronger springs increase cam bearing stress, however i am not convinced this additional stress is detrimental to bearing life because I have had no issues with either of my hi-lift cams...a couple more cents worth
FWIW,

Loren

 

Horse sh(t.
I've stabbed many cams and all have been a success.......... except for one I did on my own car about a year ago... Thank Christ it wasn't someone else's car.
However my reasoning is that I was a dumba$$. I felt hurried, I did not use the right or enough lube on the cam, got a bit overzealous when stabbing it and ended up seizing a bearing on the journal. 944 has hit it right on the head. You MUST pay attention to detail. If you hurry through anything related to motor work then you run the high risk of paying the consequences.

 

my vote is cleanliness.

could be as simple as using greasy hands while holding the cam. i know a few builders who are fond of medical gloves for stuff like this.