Cylinder Head Replacement (Now Total Engine Replacement)

[therealsethallen]

As I mentioned in a recent post in my build thread my 97x has been suffering from hard starts when warm, a pretty rough idle and a minor but existent lack of power. One of the intake valves on the #6 is bad, which is causing low compression. I had my mechanic check compression, and 6 was pretty low which has lead us to conclude bad or worn valves. It's okay enough that I can daily drive it still, but I'm getting so sick of the ticking.

There's several threads on this subject but I figure it's worth a new one since I've yet to see one on the 9-7x.

So, for starters he's a video of the 9-7x idling like a diesel.

Anyways. I found a 2004 head used with 90k miles for $100. I'm going to clean it up and flatout reinstall. Due to money for one, and secondly to the fact this is a daily driver, It's just a gonna be straight up head swap. Only thing I'm buying is the new head, head bolts and head set. That's it.

This thread will take some time, and it'll be a work in progress. I'll make sure to take plenty of pictures, because it's rare that I see them.

 

[Bill Reid]

If you haven't seen it yet search for Trailblazer Valve Job on You Tube and you'll find a 2 part video on a guy that pulled/reinstalled an I6 head...

 

[gmcman]

I don't know if this would aid in removing the head bolts, but I thought about if I had to remove mine that with the cooling system drained, I would try to fill the block with boiling water or close to boiling before I tried to remove any head bolts.

The expanding aluminum may release tension on the head bolts. The head bolts are TTY and have been know to break when removing. Probably a long shot but I think it's worth a try.

 

[therealsethallen]

I don't know if this would aid in removing the head bolts, but I thought about if I had to remove mine that with the cooling system drained, I would try to fill the block with boiling water or close to boiling before I tried to remove any head bolts.

The expanding aluminum may release tension on the head bolts. The head bolts are TTY and have been know to break when removing. Probably a long shot but I think it's worth a try.

I've never heard about that and with TTY bolts I'm totally willing to try it.

 

[Mooseman]

Is the 2004 head compatible with the 2005 engine? Wasn't there a change in 05? I think at the very least was a change in coils and the valve cover.

You should check the new head surface for flatness. Being aluminum, it doesn't take much to warp them.

Expect broken head bolts. That's all I can say. Getting them out will be a bitch. Just check out The $85,000.00 GM 4.2L Engine Repair
and

http://gmtnation.com/forums/threads/4-2l-i6-head-removal-engine-restoration.4373/

 

[therealsethallen]

@Mooseman AFAIK the 2004 and 05 Heads are identical. The GM part numbers for the 02-05 are the same. The "new for 2006" heads got a different valve cover and coil design. 2005s have no FPR.

The complete head comes with all the related components. Valve cover included so I'm covered if that's the case. I'm going to buy the head, paint the valve cover either General Motors Blue or Chevy Red/Orange

I'm going to send them off to a machine shop to be inspected, but this is going to be a "super duper on the cheap-ish" install.

 

[therealsethallen]

Update for the day. I re-watched my own video several times over. For some reason I feel like there's some hidden lower end noise like a light rod knock. Engine oil is clean, and topped off. I also took the chance to clean the CPAS (VVT Solenoid) too, there were some very minute metal traces in one screen leading me to THINK there's a bad rod bearing. I believe there's going to be a missing rocker arm or lash adjuster when I finally pull the valve cover.

Here's my question, what's the possibility that a missing rocker arm or lash adjuster hasn't just destroyed my entire motor? I plan to change the oil this week weather permitting and I'm interested to see weather or not there's any kind of metal shavings in the oil.

Guess now it's time for prayer.

 

[Mooseman]

If a rocker was out of commission, you'd have hell under the hood like poor running engine, codes and lotsa noise.

 

[therealsethallen]

That was my thought. It runs, well fine for the moment. It's a little low on power but that's pretty much par for the course with low compression. It skips like a mother, and hard starts when it's warm.

But the metal shavings do have me a bit worried.

 

[Mooseman]

Might be worth it to pull the oil filter and check there too for metal. Might also be worth it to get oil analyzed for metal content, especially the type bearings are made of.

 

[therealsethallen]

Blackstone Labs is sending me the kit. I'm going to change the oil this week, I'm gonna chop open the filter and see if there's any particles. If there aren't, I'll assume it's something top end. If not, I may look into a replacement engine.

I love this thing too much to give up on it.

 

[mrrsm]

Seth... I was watching your Saab Engine Video and FWIW...

Your Engine sits at idle as "Steady as a Country Parson..." implying that if you DID have a Bad or Excessively Worn Set of Connecting Rod Bearings on the Crankshaft...the vibration from this would soon become evident if you raised the RPM gradually... and then let off the gas pedal suddenly. After a few cycles of raising and letting off...if you hear the distinctive "Knock-Knock" sound of the rod banging against the Crankshaft Journal ...then this would be an obvious and quite unmistakable indication that your Connecting Rod to Crankshaft Bearings were bad on at least one Connecting Rod. However at present... If you listen to some other GM 4.2L Engines in a few other Trailblazer Youtube videos... I think you will find that yours sounds very much the same as they do.... mine included...when it was running with 240,000 miles on the engine

I'm not saying that it is completely out of the realm of possibility... but based upon what I have seen in your video... I'm very dubious that your engine has a Bad Rod. Of course, I too am hoping that this is not just wishful thinking on my part... but presently... My Confidence is quite High.

One other diagnostic thing to observe is that ...once you have the #1 Piston at the TDC (Top Dead Center) Position...with the Camshaft Flats facing up and evenly Horizontal with each other.... after you pull the Engine Head... you will notice that the #6 Piston is also at TDC and this gives you a chance to observe that both are essentially even with the top of the block (with just a very small space left there for "compression quench")...and if not...and the #6 Piston is sitting lower...then you might suspect something is wrong in the Bottom End.

Look for scoring, scraping and burned cylinder walls down inside #s 2,3,4,5 at their staggered positions in each of the cylinders as they will afford different levels of viewing access within each cylinder. You should NOT rotate the engine to inspect each Piston/Cylinder relationship... unless you know EXACTLY how rotate the engine ONLY in a Clockwise Direction when standing at the front of the Saab to eventually bring the engine back in sync with the #1 Piston perfectly positioned at TDC on its Compression Stroke with the White Painted Mark on the Crankshaft Serpentine Pulley at the 12:00 High Noon position.

Frankly... because you would have the almost impossible task of controlling the Loose Timing Chain from SLIPPING OFF OF THE CRANKSHAFT during each rotation from where it would have to be statically held in place with a Special Aluminum Wedge Tool... I would not risk doing this myself. Knowing what I know so far about your engine... I don't think such a drastic measure is necessary... but likewise... if there is any question about Bad Crankshaft or Connecting Rod Bearings... I would NOT reassemble the engine knowing that it might be doomed without getting a clarification of the integrity of The Bottom End.

If you get any second thoughts about why ANYBODY would go through ALL of this trouble... this link will edify the matter very well:

http://gmtnation.com/forums/threads/cylinder-head-repair.2501/

 

[therealsethallen]

UPDATE: THIS IS NOW A FULL-ON MOTOR SWAP

I found a 2005 Engine, with 90k Miles on it. It is missing an Oil Pressure Switch and a My truck is at 140k, so it's not bad. I'm now trying to compile a list of things that a 100k mile engine that's been sitting in a warehouse since 2014 should have.

ACDelco 41-103 Plugs
ACDelco D1843A Oil Pressure Switch...and that's it.

 

[mrrsm]

This is a contemporary related post that covers some additional things to take care of... before the swap...while accessibility to every external area of the 90K Swap Engine is still possible...and easy to do:

http://gmtnation.com/forums/threads/used-4-2l-engine-replacement.15185/#post-495333

EDIT:

Ooops... I see you have already visited this one... I think your choice to do it this way is the wisest of all choices... as long as the "90K Engine" does not wind up costing you $90,000.00 (*wink*)

 

[therealsethallen]

It's $500 for the motor. I'm going to buy it, put it on a pallet and wait until I have the money to install.

 

[mrrsm]

Great Idea... and in the mean time... if you can gradually accumulate as many Brand New OEM Parts and Pieces (Thermostat Unit, Alternator, Starter, Water Pump) as possible that can be so difficult to install if any of them happen to fail soon after the engine in its "New Home"... the prevention of their possible or potential failures would give you some very nice "Peace of Mind".

When it arrives... after Air Nozzle blowing all the transport and storage junk off of the outside of the Engine... pulling the plugs to see if they are all "Fried Chicken Brown" should give you confidence that the engine was literally "Firing on All Six Cylinders" at the last running. If the engine has been in storage...with all the plugs pulled... putting a drop or two of 3&1 Oil in each hole and slowly turning the engine over clockwise when looking from the front to the back... may reveal anything that sounds fishy or sketchy on the inside and gradually distribute the lubrication around the cylinder walls and rings... but only a drop or two.

If you noticed any "Cooked Oil" thickened and collecting down inside the Spark Plug Wells... then pulling the Valve Cover and Replacing those Gaskets- "O" Rings ahead of time would not hurt a thing. You would also then be able to get a pretty good idea of how it was maintained from looking over the Valve-Train for nasty collections of any nested black gunk. Cleaning that out before hand means that your Top End would be less likely to drop any of that garbage down inside the Oil Pan after sitting for so long and getting "gummy". Likewise, with such uncommon access that a H-F Engine Stand would afford you ... pulling off the Intake Manifold and washing it out and cleaning out all the black "Mung" inside the Intake Ports on the Head and then putting in new gasket "O" Rings there would be helpful as well to eliminate vacuum leaks. It goes without saying that the Throttle Body would benefit from a nice cleaning as well..

I would bet a Brace of Gutenberg Bibles that there are people within your social sphere who own GMT360s that would be very curious to observe any work you do to the engine... especially before it gets installed in the Vehicle. It would not hurt to cultivate their interest in your project early on... and see if some of them could be on hand to help to speed things along on 'Swap Day". A cooler full of Cold Drinks and a Stack of Hot Pizzas has a tendency to "Magnetize the Hands of Young Mechanics" and hypnotize them into wanting to work on such vehicles.

But notice I said Cold Drinks and not Booze or Too Much Beer. The only thing worse than being around someone being Drunk AND Stupid... is when they are Drunk AND Stupid AND have Wrenches in their hands when being around your vehicle. Only the ones you KNOW are competent should actually be working with you.... "Hands On..."

The Condition of the center Bolt Pattern of the Flex-Plate will speak volumes about any Hard Use it has undergone... if you notice any Hexagonal Crack-Lines at the perimeter of the Flex-Plate Bolt Holes. Changing the inexpensive Flex-Plate also gives you the chance to replace the Rear Crankshaft Seal, too.

Anything and Everything you can think of that is reasonable to do before "The Swap" should be done and you would be wise not to wait until the engine has been bolted under the hood to get it all done. This Engine is nor very forgiving during almost every single situation that involves repairs.... So a Minor Repair now while the engine begs to be fixed "On The Stand" ...will become a Major Headache later on if left undone... Especially on 4WD vehicles... Such as those Front Axle Carrier Bearings in the Base of the Oil Pan for example... You get the Big Picture, I'm sure.

 

[therealsethallen]

@MRRSM my Amazon cart is full of everything I'll need. As it so happens, I know the vehicle that motor came from and I know the owner took VERY good care of it. I'll compile a list of everything, and paste it here. It's got a 2014 stock number at that yard, plus I'm getting it at wholesale price. I do a lot of business with them. Lucky ole' Seth.

 

[mrrsm]

Due to the fact that my Trailblazer is from the inaugural "Year 2002" flavor of the TBs... I am Blind, Deaf and Dumb on any significant Engine Modifications that happened afterwards as the decade moved on and the changes cycled ahead. And so... consulting other more seasoned and astute members about the GM 4.2L Engine Idiosyncrasies will be an important preliminary step. The PCM variance between your present TB set-up and the one that should come bolted to the Intake manifold with the "New Swap" is a significant example to investigate prior to the R&R of the two Engines.

 

[therealsethallen]

Here's my parts list, so far. Only part of this engine I plan to open up is the camshaft cover, to remove and paint Detroit Diesel Green.

ACDelco 41-103 Iridium Spark Plugs (6)
ACDelco 15-11006 Thermostat with Gasket and Housing
ACDelco 213-963 Engine Coolant Temperature Sensor
ACDelco 36101 Idler Pulley
Fel-Pro VS50584R Valve Cover Gasket
Fel-Pro BS40678 Crankshaft Rear Main Seal
ACDelco 213-1557 Engine Camshaft Position Sensor
Delphi SL10064 Variable Valve Timing Solenoid
ACDelco 252-822 Water Pump (Gasket 251-2029)
ACDelco 6K915 Serpentine Belt
ACDelco D1843A Oil Pressure Switch
ACDelco 12573024 Belt Tensioner
Dupli-Color DE1618 Detroit Alpine Green Paint

OPTIONAL
Flowmaster 2.50" 40 Series Delta Flow Center In/Offset Out
Vibrant 1792 Bottle-Style Resonator

@MRRSM The PCM from my truck will work fine with the new motor, but I believe I have to put my engine's crankshaft position sensor on it to avoid having to pay to have a CASE relearn done. I'm actually going to have it sent out for a tune while the motor is out since the turnaround is about the time my mechanic presumes the truck will be down.

 

[Mounce]

You do not want the dorman vvt solenoid (aka CPAS). GM or ACDelco only. It's one of the parts these engines are picky about, some people have had bad experiences with dorman's cpas.

 

[Mooseman]

You do not want the dorman vvt solenoid (aka CPAS). GM or ACDelco only.

Definitely. Dorman are known for poor quality electrical parts.

What about the rear main seal?

 

[therealsethallen]

I couldn't find the original GM Solenoid, until now. Rear main seal never crossed my mind.

 

[mrrsm]

I'm in absolute agreement with @Mooseman:

"What about the rear main seal?"

Because when you think of the size of the Outside Diameter of the GM Atlas 4.2L Engine Crankshaft Tail Journal... it is quite simply Gigantic! And that translates into remembering the common experience we have all had when our 10 Speed Bicycles were inverted with the tires spinning around... we could follow visually the individual spokes at their connection point to the Axle area with ease... but the further out from that center of the Axis of Rotation... the faster things moved!... So the logic here is that this thing is really being subjected to rapid increases and decreases in high speeds at the OD of the Crankshaft and risking wear and tear over tens of thousands of "Miles X RPM" as a result. Even though it is made of PTFE (Poly-Tetra-Flouro-Ethylene)..."Teflon"... why tempt the fates with a relatively Inexpensive Replacement Part that will install in a matter minutes ..before the engine swap...and virtually guarantee no oil leaks happening for years to come?

Short of the installing the OEM GM Part... Felpro's reputation with making these things is unsurpassed for their endurance and complete reliability...as long as it is thoughtfully installed back there. Cleaning the rear block circular cavity and seat area as well as the back and sides of the rotation point around the crankshaft with either Lacquer Thinner or Acetone is a must and taking your time when easing the seal on will pay dividends later. The important thing about the design of these seals is that they have an inner and an outer sealing area pointing in opposite directions from each other and their orientation must be cautiously maintained as the thing is being installed. This is the Make and Part Number for your Saab:

Fel-Pro Part# BS 40678
(The White Plastic Carrier MUST remain on the Seal until it is completely flush with the back of the Engine Block...)

 

[therealsethallen]

Added to the list are GM's Delphi CPAS and the Fel-Pro Rear Main Seal. I've yet to decide if I want to yank the front cover and do a timing set.

 

[Mooseman]

Which would mean pulling the oil pan. I think the timing set is about $100 or so. Or you could just replace the timing chain tensioner. Mine failed and have seen a couple on the Internet but nobody else has come here talking about it. At 100k, I think it's good and seems to usually last the life of the engine along with the timing chain itself. You'll have to decide between the money or the peace of mind.

 

[therealsethallen]

I think I'll let it go. I've see so many of these engines with over 250k without ever being cracked open.

 

[Bill Reid]

Can I quote you? Its all good You should be fine if you are into odds. It is definitely a "since yer in there" item.

Seriously though... you do have to take into consideration the amount of time you plan to continue to own this vehicle. Gonna flip it? Na . Gonna drive it into the ground?... maybe

 

[therealsethallen]

Gonna drive it into the ground?... maybe

I'm most certainly driving it into the ground. It's a solid truck, tows my camper like a champ and the frame and body are really really clean.

 

[mrrsm]

If you decide not to tempt the fates and do the Timing Set... Check out Rockauto for the Parts and Pieces and the whole Kit as @Mooseman suggested and focus on the ACDelco stuff before opting to go cheap on this thing. I just ordered and received a full set from Evergreen via eBay for around $80.00 ...just to be able to analyze the Tensioner portion of the kit and have replacement Chain Guides to work into my repair. I took some interesting images that will clearly show the sketchy quality of the castings and the likewise unfinished machine work done.

Also...when trying to figure out which way to maneuver the Lock Release with the "Hole in the Handle"... it did NOT work to release the mechanism consistently as the internals were sloppy and the release action was hit and miss. This compels me to get the AC-Delco flavor from Rockauto as a separate item for around $40 or so; which by the way... is just about how much they charge for the "Junk Version" of this component! So I am willing to do this because I really need to know precisely how the OEM one installed down there NOW is designed and how it functions and is going to respond to being manipulated when I continue to re-set the plunger and do this repair in a few days. Ergo.. .I cannot recommend anything here other than an OEM Quality Timing Set... But First... Pound for Pound...Here is the Best Set of Instructions with Images on How to Do This Repair:

http://ww2.justanswer.com/uploads/GMGreatWrench/2011-01-08_023933_tblazer_t-chain_part_12.pdf

You can clearly see how rough, unfinished and incomplete the Machine Work is here...

 

[therealsethallen]

I'm probably just going to leave it. As Mooseman said, it's supposed to be a "life of the motor" thing. I'm a genuinely lazy person, I mean I could totally do the swap, but I'm having my mechanic do it because I don't own an engine crane and my building's management company HATES it when I do any kind of mechanical work in my parking lot.

 

[mrrsm]

Seth... I was thinking about your plan to paint the Valve Cover "Detroit Diesel Green" and it gave me pause. This is because the thing is made out of Fibre Impregnated Nylon that may not take to the painting material. My concern is also because it is an eventuality that the "O"Rings will leak oil again out of plain sight and also perhaps interfere with the COP Seals. The oil and cycles of engine heating and cooling might attack that paint to either cause it to chip and dissolve down and inside each Spark Plug Well, This chipped off stuff might then drop inside the engine block during the installation and removal of the Spark Plugs and Coil On Plugs Harness...and you'd never notice it.

 

[Mooseman]

This is because the thing is made out of Fibre Impregnated Nylon that may not take to the painting material.

Nylon? I thought they were just fiberglass but I have found this tech article explaining the following:

About three pounds were shaved from the cover by using sheet molding compound (SMC) vinyl
ester material in place of aluminum. In addition to the mass benefit, SMC offers excellent strength
and high temperature resistance.

I have seen others paint theirs here and there. I think @eutechnyx is one of them.

 

[therealsethallen]

I've seen plenty of these motors with painted valve covers.

My plan is to use the valve cover off my 2005 engine as a testbed for this. I'm going to carefully mask off everything, then paint what I feel competent painting.

 

[mrrsm]

Yeah... I stand corrected... I was confusing the information on Page 17 about the Glass Impregnated Nylon Intake Manifold with information on Page 12 about the Valve Cover being made of the exotic, weight-saving SMC material... all found in the exact same White Paper:

http://vortec4200.com/index_htm_files/vortec4200.pdf

I guess I'm just being conservative and hyper-vigilant in my thinking... because everything about my own LL8 Project has created one problem to surmount after another. And speaking of Projects...Is there any chance that you can take an extensive series of Step-By-Step Images covering your R&R? It is very likely that if you did so...those will be the first of their kind anywhere on the Internet to memorialise your work with this as an Epic Atlas Engine Swap and be quite a coup for GMT Nation Members to have them as the "Sterling Standard" to refer to in the future.

 

[therealsethallen]

Today, I parked the Saab. I won't have the money to fix it for awhile. Unfortunately, my school bills are bankrupting me. So, I'll have to wait. It's going to be awhile, too. Projected finished date unless something miraculous happens, is June 1st.

 

[Mooseman]

What you driving meanwhile?

 

[therealsethallen]

My chevro-legs. My parents don't drive and it's my only vehicle. Fortunately, I've got many friends with vehicles. While I do live in a small town, we have an excellent public transport system.

 

[therealsethallen]

UPDATE! I've found the money to do this way sooner. I'm ecstatic to say the least. I got my motor today, from a 2005 TB with 83k miles on it complete for $500 with a six month guarantee. I'm dropping it off at my mechanic on Monday and if all goes well I'll have it on Friday.

 

[mrrsm]

Wow...


"So Shines a Good Deed... Upon a Weary World..."

 

[Mooseman]