Hey guys,

looking for ideas as to the culprit of my issue.
if you see (just replaced) the date of that being done is 7/24/21
fresh rebuilt 6.0 Gen 3 engine bored 40 over. (6.1)
milled 862 heads (.020)
Melling M295 oil pump
Comp trunion upgrade (captured needle bearings)
Elgin E1839P camshaft
Comp 7.400 3/8 diameter pushrods 7162-16
7 layer MLS head gaskets (just replaced)
ls7 lifters (just replaced)

I replaced head gaskets and lifters because of an intermittent EXTREMELY LOUD lifter tick that would occur.
Oil pressure is fine at 30+ pounds, higher when cruising.

Even with just having replaced the lifters and head gaskets, it is still doing the same thing.
Fresh Synthetic 10W-30 oil, and brand new PF48E filter (muscle car swap pan).

Is it possible that the pushrods at 7.400 are now too long and possibly not allowing the lifters a chance to fill up?

If anyone has any ideas or solutions, I am all ears.

My brain is hurting worse than my wallet at trying to figure this out.
We did find one of the removed lifters was crunchy and sticking a little when inspecting them earlier this evening.
I did not have the power wire hooked to the starter when the heads were off, so I was unable to spin the motor over to inspect the camshaft.

I have a suspicion that the engine being run for a while with the bad lifter and the tick may have damaged the camshaft in the motor.
I did not find anything in the drained oil for metal flakes, but the oil had recently been changed.

Thanks to those who offer suggestions.
Unfortunately a new engine is not in the cards or budget.

 

You need to measure for the correct pushrod length, That's the only way you will know for sure. The lifter should fill up regardless of pushrod length, If the pushrods are to long they may bottom out in the lifter bore but that usually means it's also going to hang a valve open. I would measure length and go from there, Until you know if they are the correct length...the source of the noise will be a guess at best.

 

According to another thread I read where the guy milled .015 off, he needed 7.385, but was told 7.400 would be fine.

my biggest fear is it has already damaged the camshaft.

 

OK, Lets put it this way, You changed cams and changed head thickness and have an aftermarket head gasket all effect pushrod length. Your lifter has a operating range that makes everything happy, Go beyond that range and you can have problems. Why not check it before removing the cam? It doesn't take that long and it doesn't really cost anything and is easy to do compared to tearing it down and looking at a camshaft that may or may not be damaged.

 

Not all LS7 lifters are created equal. many are LS7 spec, but not factory LS7 lifters. the copies are known to be hit or miss.

 

Are you sure it's a lifter?

 

it comes and goes like lifter tick does. Everything was new inside except the crank and rods. All new bearings, all new lifters and trays, new pistons, new oil pump, new timing chain set…

 

how much preload do I need when doing a pushrod length?

 

I usually shoot for 0.050-inch. If you're not familiar with the procedure I would watch a couple videos on the correct procedure.

 

Yeah, the owner started doing reading and has sent me half a dozen different things about it.

this is a $400 set of lifters that are supposed to also be for a CTSV and several other high revving engines. I have to pull the valve covers tomorrow and see what the measured pre-load is at right now between zero lash and the 22 ft lb torque spec for the rockers. Gonna have to break out the cam degree kit micrometer to see how far it goes down and if that jives with what I was told. Something about 1/4 turn being .020

 

Best way to do it is with an adjustable pushrod and checker spring, There are other methods that work and a few that don't lol

 

I think the Caddy lifters have a different cup position than the LS7 lifters.

 

engine is in the Jeep and completely together.

 

they apparently do. Which is why we have to figure out the pushrod length issue.

 

You can measure with the engine in the vehicle, There are plenty of how to articles and videos. And you won't need a check spring as I stated above, I usually do pushrod length and PTV measurements not just pushrod so that what's came to mind. You just need a COMP Cams 7702-1 pushrod length checking tool and some instructions, It's not difficult/costly or time consuming.

 

EOIC method to get on the base circle of the cam for the cylinder being measured. Install the PR checking tool onto the lifter and run the rocker arm down hand tight making sure your not putting any load on the PR tool. If your hands are small enough to get your fingers on the tool then you can turn the adjuster out until you've taken up all the slack and that will be zero lash. Mine aren't so its on and off with the rocker arm until I find it. I'd measure several of them to see if your getting some consistency in your measurements but once you figure out the length at zero lash just add your suggested preload and that's your PR length.

 

I don't think your going to change rocker geometry with these fixed rockers - all your changing is preload with these different pushrod lengths.

I have genuine LS7 lifters and measured plunger travel with an indicator and .230. I ended up using 7.425 pushrods which gave me .115 preload, confirmed with indicator. Right or wrong we'll see what happens.

Curious how much spring pressure the OP's heads are setup with. Could also be the rockers making noise.

 

I have BTR 660’s on the heads, and comp trunion upgraded rockers. I do have a couple sets of stock rocker arms and bolts. But if it was the rocker arms, wouldn’t it be loose once the center bolt was tightened?

 

Who knows but if you have another set to try go for it. Sometimes non of this stuff makes sense so my philosophy is to try "all of the above" until its fixed. You already tried new lifters and it does the same so you can rule that out at least. Have to ask though - did you check piston/valve clearance, retainer to seal clearance, coil bind, rocker to retainer etc.? Probably all OK but these need to be verified.

Sometimes I think these OE lifters just don't like all this spring pressure. Having said that I'm also running the BTR springs and STG2 BTR cam. Praying for no noise!!!!

 

It’s been together and in the Jeep for 6 months or more.

none of the pistons had any damage or signs of contact when I changed out the lifters. All rockers and valves move up and down freely, no issues with any of the springs being higher or lower than the others.

I have run this cam on the same head casting and no issues. Even ran 7.50’s in the 1/8th with the S10 I had. And I weighed 480 at the time.

I dont really want to tear back into it. I honestly just want to put the drivers fender on it and call it good enough to survive for a while.

When whatever fails, it’s gonna go and we can find it then.

someone suggested it may be a broken piston skirt.