Wiped a couple cam lobes

[Weston19]

Was driving the hybrid home the other day, and somethin wierd happened. It started ticking really loud, which turned into random clanking. I knew what had happened, so i parked it and tore into on my lunch break. An exaust rocker had jambed up next to the valvespring, it bent the pushrod, and sheared the guideplate in the opposite direction. I brought it home for further teardown as i had figured there had to be somthing more that was wrong with it. All the lifters looked ok, didnt really look at them too hard but they wernt collapsed or anything. Dumbfounded and trying to find a cause, i started to blame the timing chain. I figured it maybe jumped timing or had tons of slack so i took that off. The chain had taken out a peice of the tensioner due to exxcessive slack, but it didnt jump timing. At this point i figured i might as well cam it, so i dropped the motor down to yank the cam. (BTW its not nearly as bad as most make it out to be. But all the motor mount need to go, and the subframe on the passenger side needs to drop.) As i was pulling the cam out i notice a couple lifters that wernt lifting worth a shit. As i got the cam out, i notice the intake lobe on number one was completly wiped, and the exaust on number 4 was well on its way. So, out comes the cam. And in goes a 260H comp that im still waiting for, however the cam bearings are into the copper. I want to know if its at all possible to change the bearings with the motor in the car. Altough i highly doubt it. Ive got about 3-4 thou clearence from the cam journal to the bearing, measuring with a dial indicator and those ID spring loaded gauges that you measure after you lock. Now i ordered a new set of bearings, and if neccesarry i will change them, but pulling the motor is gonna be a whore and i dont really want to. So, can they be changed with he motor in the car or will those bearings and the cam survive 10-15k more of mostly easy driving with some dragstrip jaunts? Cause i really cant toss a cam in and not see what it can do, considering it went pretty good with a stock cam down 2 lobes.....

[ForcedFirebird]

Motor has to come out. The installation tool for the bearings is actually longer than the cam, and you have to drive the rear two bearing in from the back of the engine, and the front two from the front. It's a difficult job to do properly, nevermind trying to accomplish it with the motor in the car.

[Weston19]

I have an engine builder that will do it for me, im just going to drop the motor on the ground and have him do it in my driveway. I just dont want this to happen again or ruin a brand new cam.......And i have until tuesday to get new bearings in there. AND i have a machine shop down the street.....The builder has been doing it for years, so im sure he could accomplish the job. Are the inner 2 bearings a smaller OD or are the OD's all the same?

[ForcedFirebird]

I have an engine builder that will do it for me, im just going to drop the motor on the ground and have him do it in my driveway. I just dont want this to happen again or ruin a brand new cam.......And i have until tuesday to get new bearings in there. AND i have a machine shop down the street.....The builder has been doing it for years, so im sure he could accomplish the job. Are the inner 2 bearings a smaller OD or are the OD's all the same?

They come labeled. I recently did mine, it's not that bad with proper tools. The cam bearings are the same size as a SBC, and in fact you can swap to them seeing the SBC's are wider to give more bearing surface. The same SBC tool works on 60*'s.

I didn't measure them to be sure, but I remeber the inner two bearings kind of sliped pased the outer two races fairly easily, whereas the outer bearings were a tight fit in the outer races.

Make sure you have the little "channel" facing the front of the block on the front bearing. This slot is what guides the oil into the timing cover to lube the timing set. You'll see what I mean when looking at the front bearing.

[Weston19]

They come labeled. I recently did mine, it's not that bad with proper tools. The cam bearings are the same size as a SBC, and in fact you can swap to them seeing the SBC's are wider to give more bearing surface. The same SBC tool works on 60*'s.

I didn't measure them to be sure, but I remeber the inner two bearings kind of sliped pased the outer two races fairly easily, whereas the outer bearings were a tight fit in the outer races.

Make sure you have the little "channel" facing the front of the block on the front bearing. This slot is what guides the oil into the timing cover to lube the timing set. You'll see what I mean when looking at the front bearing.

Looking at my stock bearing i cant even see that lol. The front bearing has 2 oil holes and thats it. No slot......Well better yank the motor tommorow.....And if what you say is correct then the inner 2 bearings must have a smaller od......So what exactly do i need to do to make the 350 bearings work? i may actually have them in stock at the store, ill check tommorow. Gotta get a cherry picker too. Whats the best way to prep lifters? And what exactly would the break in procedure be for that cam?

[ForcedFirebird]

What cam? Flat tappets break in the same as any other, 2000RPM for 20 mins seems to be the consensus.

Nothing is needed to make the SBC bearings work, they are a direct fit - just wider. The 60* bearings are narrower than the journal, the SBC bearings fill it up.

[Weston19]

Comp 260H. Im gonna grab the 60* set and the 350 set and see how they match up. Gotta call my engine guy tommorow and get him over here so he can change em out for me. Worn bearings+new cam......im sure bad things will happen. Are 60*'s bad for wiping lobes or what? I dont know how this happened

[1988GTU]

The 2.8 and 3.1 mpfi's are known to take out lobes due to poor oiling at high rpm's. The sfi engines most likely snap cams due to material and design + limg failures leaking coolant onto the cam bearings.

[SappySE107]

make sure you use an oil with the additives still in them to break in flat tappet cams. Comp makes break in additive as well but I beleive its a diesel oil that you want. Otherwise, they will be wiped again.

[Weston19]

Anything specific you can recomend?? We carry rotella 15-40, and a couple other diesel oils, i really dont want to do this twice........What should i be soaking the lifters in? Im getting some assembly lube for the cam, and i got a couple filters to swap around with.

[1988GTU]

GM makes an ZDDP formula. I think one container is more than enough for break in purposes. IIRC it's about 10.00 or so for it. I dont know the pn off hand. Or you could try using that rotella.

[Weston19]

i believe that formula is called EOS. its apperently been discontinued and reformulated and is no good. Ive been reading up and most people either say valvoline racing oil or rotella but theres an entire discussion about how diesel has too much detergent and will end up causing other issues that take away from the high zzdp. Anybody here have any insight? What are you non-roller guys using?

[SappySE107]

first I have heard of the rotella having too much detergent in it. What issues did they say? The engine builder mag and some other shop related magazines had articles with the different oils and I remember rotella being one to use. Maybe extended use is bad?

[1988GTU]

I know you can buy straight ZDDP from some online sources.

http://www.zddplus.com/purchase.htm

ebay.com
Performance shops locally near you should be able to get it or have it readily available for you.

[Weston19]

Im thinking im goign to use the rotella for the break in witht he comp additive and lots of assembly lube, and it seems amsoil is pretty good for zzdp content and its readily availabe to me, so i will more than likley go with that.