Working on my ZZ4 Cam Install
 

Well I have the engine tore almost all the way down, still have to pull the Valve Covers, Rockers, Push Rods.

Thought I would share some of my discovery...….

Here is the thread that kicked this project off if anyone is interested in catching up!! https://www.corvetteforum.com/forums...-engine-2.html

010 is clearly written in white on the weight on the other side of the lower gear. There is also something written in black ink on the opposite side, but not sure what it is yet, might be a name...… EDIT: Yes it is a name..... Brian

Since the engine is fresh, of course it looks great inside!!

The crank has 12218 stamped into the end of it?? My research is turning up absolutely nothing!!

It also has a 3150 Cloyes Double Roller Timing set installed that is super tight.

More will come as I move forward.

Jared


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Well my neighbor decided right now was a great time to mow his dirt patch yard so I decided to shut the hood, close up the garage door, come inside, clean up and eat some lunch.

I did get the VC's off, and the applicable parts of the valve train disassembled and sorted by cylinder.

The gear on the distributor was obviously replaced when the engine was refreshed, kind of a golden color I haven't seen before.

The next thing to do which is going to suck a little bit is I have to get the Vette up on jackstands and pull the motor mount bolts so I can get the front of the engine high enough for the cam to clear the front cross bar.

More will follow of course!!

Jared

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Cloyes makes a very good chain. That looks like a bronze distributor gear. Not what you need with a zz4 or a stock cam. Makes me wonder what cam is in there.

I'm not sure, just has 049 stamped into the end of it......

I did get the ZZ4 Cam installed, getting the engine off of the mounts was a bit of a pain. When the engine was replaced they reinstalled the shoulder bolts for the mounts from the rear, and then they installed the exhaust manifolds. That made it impossible to get the bolts back out the rear so I cut them and pulled them out in 2 pieces. I went and grabbed new bolts to replace them and am in the process of getting them in.

Jared


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You say that motor is fresh?

Thats a lot of wear on that cam for a "fresh" motor.

I dont think my 71k mile LS7 cam looked like that when I took it out.

Hopefully you are putting new lifters in as well.

Engine has about 10k miles on it. I think the cam is damned clean. When I rebuilt the L98 I installed in my 91 S10, the cam I removed was black. If you're talking about the discoloration on the lobes, that's what they look like, the lobes are wider than the rollers. I'd really like to know what wear you are referring to.

And why in God's name would you buy new Roller lifters when they only have 10k on them. I know for a fact they were replaced with new. One of the things about roller lifters, if they aren't galled, and the rollers roll they can be used over and over again.

Jared

Yes the wear on the lobes...again, to me, in the pictures, it looks like more wear than I would expect for a motor with 10k miles on it...but that doesnt really matter since you are putting a new cam in.

As far as the lifters, I always put new lifters in with a new cam. That way the lifter rollers wear with the cam lobes. Ive also seen to many lifters fail within a few thousand miles of swapping to a new cam...now thats on cars that went from a stock cam to, usually, a decent bit bigger cam with much stronger springs, which I know both contribute to shit GM lifters failing. Ive just seen it happen to many times to not put new lifters in with a new cam. Again, my preference.

Must be the lighting in the pictures, the lobes are in great shape, no noticeable wear other than the shine that would be expected, Personally I'd be more worried if the lobes were dull. The lifters also looked fantastic and went right back in the same bores in the same orientation that they came out. When I rebuilt the 120k mile L98 I put in my S10, everything got replaced, cam, lifters, springs, retainers and the entire rotating assembly was refreshed. Every single thing inside of that engine was coked.

Jared

I'm don't know what valve springs were installed in this engine, but they allow more lift than the LT4 springs I purchased.

The LT4 Springs (which I don't have retainers for anyways) bind up before whatever springs are already installed.

Mystery spring on the left, LT4 spring on the right.

Just made a pot of coffee, gonna be a long night!!

Weird looking at the photos, they look bent but they aren't.

Jared

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049 iirc is a stock cam. Weaker springs will have more compression... thinner coil. Looking good. :cheers:

Thanks,

I bring up the spring compression because from what I understand the OEM springs would coil bind when used with a cam with this much lift.

I can't be positive but I doubt the springs that were installed when the heads were rebuilt were OEM Spec. I say this because they have more compression than the LT4 springs, the LT4 springs coil bind before the springs that were already installed.

I've got the valve train reassembled, rolled the engine over by hand with the plugs out 12or so times and everything felt really good.

I'll be heading back out to the shop here in a while...… coffee comes first.

Jared

just to be clear, did you install the LT4 springs or reuse the "mystery springs"? nice article by the way

Based on spring compression, I chose to use the springs that were already installed.

I will hang on to the LT4 springs just in case.

Jared

While probably fine, I would be slightly nervous with valve control. But again probably fine.

Alright, little bit of progress.

I hate this part of a rebuild, I'm taking my time and cleaning all of the gasket surfaces really good. The thing that bugs me is I really, really want to clean everything. I know there is no way to make all of this stuff look new again on a car with 122k on it though...… it just is what it is and it sure as shit ain't a show car.

Lower intake and some accessories are back on, now the tedious stuff starts. Looking pretty good so far though, figure 4-5hrs and it should be ready to start.

One thing I really did like about this Mahle gasket kit that I bought, it came with seals for the China walls so I didn't have to use an entire tube of RTV trying to seal them.

Jared

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Almost there!!


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It runs!!!

Unfortunately I have to pull the passenger side valve cover back off and find the rocker I didn't adjust properly. Very pronounced TICK from under the passenger valve cover, cylinder 4 I think.

Besides that, it fired right up which was great, made sure to mark the distributor when it came out so timing isn't too far out. I'll take care of all the fine tuning adjustments through the week.

Now I can't wait for the exhaust to be done..... I know it's going to sound great! Idle was nice and steady, I also replaced the fuel pressure regulator while it was apart and added an adjustable cap.

I'm going to grab a bite to eat while the motor cools off and then get back out there and pull the valve cover.

Jared


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Well it wasn't a loose rocker, they were all adjusted fine, It's the springs...…. which I guess is one of the reasons that the LT4 springs are needed. The LT4 springs are a taller, single coil. The springs I currently have installed are a shorter double spring. The inner spring is binding up with the outer spring...…. and it's a little noisy. Sounds just like a collapsed lifter/lifters. So even though they will ultimately collapse further than the LT4 springs.... they are not designed to do so.

Anyways..... since I already have the LT4 springs, I just had to order the retainers. Summit had them in stock so should be here in a few days. Also..... the reason the new retainers are needed is because the LT4 springs have a larger O.D.

At least all the hard work is done, just have to pull the drivers valve cover (passenger side is already off).

Live and learn!!

Jared

So...you decided to leave the same lifters and pushrods and rocker arms in place?? Just new springs?

Yes, I reused the lifters, pushrods, and rocker arms.

The LT4 retainers are shipping out today via 2nd day Air and I will replace the springs/retainers when the retainers arrive.

Jared