2012 yukon denali hot idle engine tick/noise

[Chughart]

hey guys, ive got a question, i have an engine tick noise that only appears when the vehicle is at operating temperature. its coming from the passenger side of the engine. i bought this yukon 2 years ago with a jasper engine installed, i had to replace said engine (with another jasper engine as it was under warranty) last year due to low oil pressure causing lower end knock, just to give a back story. im afraid its either a lifter noise or rocker noise as ive checked the exhaust for leaks (plugged the pipe and laid under it to listen for any leaks) and i checked the manifold for broken/loose bolts and they are tight. i also used a stethoscope and the noise is the loudest on the exhaust side of cylinder 6 (2nd cylinder from the back). if anyone has any insight into what it could be that would be great.

thanks,
chris

link to short video of the noise:

 

[rdezs]

What's your idle oil pressure when the engine is completely warmed up, like after 15 minutes on the freeway? This could just be a symptom of lower oil pressure. (Oil pick up tube o-ring, AFM relief valve in the pan getting weak, oil pump oil relief valve gummed up, a leak in the VLOM plate, etc.)

If you're 100% sure there's no exhaust leak off the manifold, that pretty much sounds like either a lifter issue, or a trunion bearing. Both leave too much slack in the valve train, hence the sound.

If you confirm you have a rocker that is loose, you caught it early and it's a good time to delete the AFM. (More cost-effective than repairing the AFM.)

Still under warranty? I'm not even sure that matters considering it's a Jasper engine. That's like pondering how many times do you want to pull the motor. I'd be inclined to pull the heads and do a proper AFM delete, and forget about their warranty. But that's if you do your own work. It can be cost prohibitive for a lot of people if you have to pay a shop to do it. In that case pursue the warranty I suppose....

 

[Chughart]

I didn’t mention but it’s a deleted engine already. So no afm. And the oil pressure is slightly above 20psi on the gauge.

 

[rdezs]

Not oil pressure related then. Identify which lifter by looking for slack in a rocker arm.... Could very well end up being a trunion bearing as well. You'll notice that pretty quick if the rockers loose.

Did this come from Jasper with the AFM deleted, or is that something that was taken care of after delivery? If it came from Jasper already deleted, I would not expect them to use genuine Delphi LS7 lifters. And if it does turn out to be a lifter, it's less hassle to just replace all 16 with genuine Delphi LS7 lifters from Michigan Motorsports. That sure beats pulling the motor to exchange the engine under warranty, with who knows what parts they're using inside.

 

[Geotrash]

If you've ruled out an exhaust leak as it seems you have, and there isn't a chirping noise accompanying the tick, then I would wager that you have a lifter that will no longer pump up properly with oil pressure. I concur with rdezs's opinion of getting those lifters out of there and replacing them with LS7 lifters. Morel's are another good option. Whatever you do though, only use new genuine GM lifter trays when you install the new lifters, and source both the lifters and the trays from known-good suppliers like Summit, BTR, Michigan Motorsports, etc and not Amazon. Lots of counterfeit parts on there.

 

[j91z28d1]

sounds like exhaust leak me. being a jasper rebuild, I bet it doesn't have the oem style MLS gaskets, probably composite and blew out.


when you say you checked with a stethoscope did you use the metal end or open ended hose? if you pull off the end probe and use to open hose, run it along the top and bottom right where the exhaust manifold flange hits the head. you'll hear the puff puff of any exhaust leak.

best was I know to find leaks, even the smallest will show up. if not, time to. pull valve covers

 

[Chughart]

Ya it was deleted by jasper. I called and they said they use the non afm lifters to replace the afm lifters. So nothing upgraded just “stock” lifters.

I used the metal end of the stethoscope to pin point the noise and it’s coming from the 2nd cylinder from the back on the passengers side and all I did was plugged the pipe and listened and the ticking didn’t change and I tried tightening the bolts but they’re tight. I’ll use the hose on the stethoscope to see if it is an exhaust leak that’s easy enough.

My plan was to remove the valve cover and check the rockers. If they’re good then I’ll dig further into it. I’m tossing up the idea of getting a Texas speed cam kit with new lifters but we’ll cross that bridge when I get there lol

 

[kbuskill]

I have used a BBQ lighter to check for exhaust leaks on motorcycles.

Run it around the port and if it blows out you found your leak. Obviously on a car you need to do this when cold so the radiator fans don't blow it out.

 

[Chughart]

Hey guys so I used the stethoscope and put it around the exhaust manifold and did not hear anything. I took a smoke machine and stuck it into the exhaust pipe and it did not leak any smoke.

I got the engine hot and removed the valve cover and the rockers move side to side but not up and down (they all moved the same amount and same way) nothing felt off or loose.

I put the cover back on and changed the oil from 530 to 540 and let it run and the noise changed. It’s not as loud or “tingy”. Which I would assume means it’s something in the lifter/cam.

Let me know what else I can do to try and pin point this issue before I pull the heads off and replace the lifters

 

[Chughart]

Ok I’ve started spiraling but trying to piece together a “cam kit”. I’d buy the Texas speed cam kit but it comes with things that I don’t need (the dod delete stuff) and all the gaskets have like 7k miles so figured I was good to reuse those (except the head gaskets).

But my question lies in what cam should I do? I have the Texas speed stage 1 208/214 truck cam in the cart and the ls7 Delphi lifters with the gm trays. What head gaskets do I get? Do I do the Texas speed ones? The Michigan motors ones? Or ac Delco?

Another question too, can I reuse the head bolts as the engine is basically new? Just trying to get a list lol oh and I have an hp tuners tune for the dod delete so what tune should I get for the cam upgrade?

 

[rdezs]

LOL, I would slow down a bit. Pull the heads, the oil pump, timing set, lifters and the camshaft and see what you find. If you've already decided to upgrade the camshaft, you'll need the following:

Genuine Delphi LS7 lifters from Michigan Motorsports with genuine GM lifter trays.

Hold off on the pushrods until you get the heads installed and measure.

I would have the heads checked over by a machine shop. Have them skim the heads if they check out.

Felpro head gaskets

OEM MLS exhaust manifold gaskets. Pick up your manifold to pipe gaskets as well. Often the passenger side is a donut and the driver's side is a thin steel one.

ARP head bolts, much easier to torque the old-fashioned way instead of using the torque to yield plus applying the angle. So no, your current bolts are not reusable. One time use on the TTY.

You're dealing with a Jasper rebuild, so I think it's safe to assume they went low budget on the parts. I would go for a quality timing set with tensioner, and a Melling 10296 oil pump that comes with the +10 PSI spring installed.

You want to drop the oil pan and make sure they plugged the oil pressure relief valve that's in the pan. Several sources online where you can pick up a stainless steel Allen head plug with a copper washer for it. Amazon has them. The oil pump will come with the o-ring for the pickup tube.

You'll need the crankshaft locking tool that bolts in place of the starter.

And a new OEM harmonic balancer bolt. You can spend a little more and avoid the torque to yield of the OEM, and go for an ARP bolt that is reusable.

Camshaft. You'll have to decide what you want. You can use an oem L92 non AFM camshaft and retain the 400 plus horsepower in stock trim, keeping the VVT. Or lose the VVT and go with and aftermarket camshaft for more top end power. (You'll get a lot of recommendations on that)

Most likely you have a lifter that isn't pumping up all the way. In other words it's not collapsed, it's just not pumping up all the way. And that could be a very small amount, almost imperceptible by checking the rockers with the engine off.

It should probably be said that if you're just looking to fix the problem, you can always just pull the heads and replace the lifters with new GM lifter trays. All depends on what you want to do.

 

[rdezs]

Note: if you stick with a VVT cam, you'll need to replace the camshaft actuator that threads into the end of the camshaft and retains the sprocket. It's also a one-time use torque to yield.

 

[Chughart]

My thoughts were since it’s basically a new engine I was just going to do the lifters and cam. If I do all the things you listed, would it be easier to pull the engine out and do it all on a stand or just do it in the car?

 

[Chughart]

Also if I’m removing the lifters to “check” them I’m just going to replace them. No point in removing all of the stuff to just check them. And since I’m there figured now would be a good time to replace the cam and tune it.

 

[rdezs]

Yes, always replace them.

With the engine in the car.

Since it is a Jasper engine and you're pulling the cam, I would definitely replace the timing set with a good quality one so you know what you have.

Oil pump? Do you trust that Jasper didn't just reuse a pump that tested out okay? Piece of mind. Build it like you want to keep it forever.

Same for your rocker arm trunions. Brian tooley has an upgrade kit with caged roller bearings, easy to swap them out on the bench. Same thinking as the oil pump.... You kind of want to know what's in the engine.

When you have the oil pan off to make sure that AFM relief valve is plugged.... Again for peace of mind, put a torque wrench on the crank and rod bolts just to verify.

Pick up an oil pump pick up tube girdle. Several different manufacturers online, pay attention to the reviews. Your current pickup tube is only held on by one bolt, although the oil pumps have a second threaded hole. The girl goes around the pickup tube and secures it with two bolts.

Felpro oil pan gasket and front timing cover kit. A dab of RTV on the corners of the oil pan gasket where it overlaps the joints between the front and rear cover and the block.

Push rods. It's not uncommon for inexpensive engine builders to reuse pushrods. Since you're in it, and looking at a cam, I would go with some thicker world push rods like Melling or Brian tooley racing offers. But you'll need to wait till you reinstall the heads and measure.

 

[Chughart]

ok so every cam "kit" ive looked at doesnt say anything about replacing the pushrods. given its all "stock" and the ls7 lifters are the same size, are the pushrods an issue? and id like to have some faith in this engine but given this is now the 2nd jasper engine, i dont know how much "faith" i want to give it. regarding the oil pump, with my oil pressure being good am i just "wasting" money on a new oil pump? just trying to do this the right way but not spending a fortune if i dont need to. and the cam kit i was looking at comes with the cam, ls7 lifters, vvt delete and all the associated gaskets/bolts/parts. i was trying to piece a kit together but its cheaper to buy the already assembled kit then buying everything out right.

as for the tune, im assuming i would need to contact hp tuners and tell them what im doing and they have a base tune i can use and then tune it further from there? ive never tuned a vehicle before this one (i had to tune out the afm stuff when i got the deleted jasper engine which they supplied the hp tuner device (HPtuner rtd dongle).

 

[rdezs]

PS.... What I meant by taking apart and see what you have didn't mean to inspect the lifters and reuse them..... It meant to see what you have, and get a clear picture of what you're dealing with. Inspect everything closely as you go. I.E: when you get the rockers off, check each valve spring very closely.... It's quite possible you have a broken valve spring on the offending cylinder. After you remove the timing cover, the first thing to look at is the tensioner, make sure it's not broken. That will also give you a ticking noise usually. If you don't have a dial indicator gauge, pick one up that you can clamp to the block to measure camshaft end play. .001 would be a new camshaft with a new retainer plate. .003 and more would suggest they reused a camshaft/VVT timing gear.

You'll need a new camshaft retainer plate as well..... Add that to your list.

 

[rdezs]

The LS7 lifters are slightly different in height of the plunger. Well it's pretty common that stock 7.4 inch push rods measure out fine, it's not unusual to need 7.35 or similar.

If you're getting the kit, make sure you're getting genuine Delphi LS7 lifters and not cheap made in China ones. There's a lot out there that are described as LS7 lifters that are junk. Look for the gold retaining clip in the end of the lifter to verify their Delphi. You also want to make sure you're getting genuine GM lifter trays. If the kit has that, by all means go for it.

 

[rdezs]

And HP tuners, yes, they can give you guidance on a recommended base tune to get started with.

 

[Chughart]

Here’s the kit that I was looking at.

GEN 4 07-13 GM Truck DOD Delete Kit w/ Texas Speed (TSP) Truck Cam Kit

GEN IV 2007-2013 GM Truck DOD Delete Kit w/ Texas Speed (TSP) Truck Cam KitTSP's Complete AFM/DOD delete kit includes the necessary components to delete your problematic DOD system as well as the standard VVT (Variable Valve Timing) delete kit w/ 3 bolt timing gear upgrade. This package also...

www.glennsautoperformance.com