Hello everyone, and Tom and Karl/KED:

This weekend I will be working with a friend on his 1987 S10 Blazer and one of the things we plan on doing is replacing the timing chain on his 2.8 V6. Karl, I was wondering if you have any tips, trick, or general help in getting the job done. I know we've got to get everything out of the way: any engine accesories in the way, radiator, water pump, timing chain cover. We need to get the Crankshaft sproket removal and installation tools. As far as I know we need the following parts: timing chain, cam and crank shaft sprockets, timing chain gasket set, some blue RTV - anything else?. It would be handy to know ahead of time of any problems you have had or if you have a proven procedure.

Tom, Karl, and anyone else: I am also looking for information about timing chain replacement on V6 thirdgens. I have done some searches on the forum and read about problems with the balancer and the rubber between the core and outter ring. I've also read about the balancer snout sleeve. We will be checking these items and I will also check them on both of my 2.8 V6 Camaros this summer when I change the chains on them. I would appreciate any other tips.

Also, Tom, what procedure to you follow for adjusting valve lash? Karl, what procedure do you follow (from what I have read, something to do with a compression gauge and adjusting for max compression on each cylinder.) Any one else have suggestions?

Thanks for any help.


Edit: Whoops. I forgot to put "chain" in the subject! And I can't edit the titile displayed in the V6 forum list, oh well.

 

You can't use a regular puller on a harmonic balancer because a stock balancer is made of three parts; a center core, a rubber isolation ring, and an outer steel ring. Using a regular "jaw type" puller on the balancer will tear the outer ring off of the rubber isolation ring. This isolation ring is the "damper" part of the balancer.

Sometimes with age, the isolation ring deteriorates (it's only rubber, after all), and cracks, and "sneaks out" of it's position between the center core and outer ring. You can see this by looking at the side of the balancer. All three pieces (center, rubber ring, outer ring) should be in alignment. If any piece isn't, the balancer should be replaced.

The outer ring holds the timing mark for top dead center. There's no physical "Lock" between the center core and outer ring. So if the rubber isolation ring deteriorates, the outer ring can slip- and your timing mark will move.

They sell special pullers for balancers. They look like (and are nicknamed as) a duck's foot. One center bolt goes thru the ducksfoot. This touches the center of the crank, thru the harmonic balancer's center hole. You then thread 3 bolts thru the outer holes of the ducksfoot, into the center core of the harmonic balancer (remember, our engines = metric threads!). Then you tighten the center bolt, which draws the ducksfoot - and the balancer - towards the front of the motor.

DO NOT USE THE CENTER BOLT OF THE CRANKSHAFT TO DRAW THE BALANCER BACK ONTO THE CRANK!!! I did this. I overstressed the bolt and snapped it. So you know that big, metric 10.9 hardness (very hard!) bolt in the center of the crank pulley? Yeah well I don't have one. It's snapped flush with the crank. My mechanic welded my balancer to the crank; it's been that way since '98. (He knows his stuff!) So DON'T re-use the center crank pulley bolt to install the balancer! I actually put a ton of stress cracks into the bolt, AND messed up the threads of the crank snout.

Approved method? A balancer installer, they're a bit pricey and can be hard to find- remember that our cranks have a METRIC thread in the front of the snout. Here's one installer: http://www.eastwoodcompany.com/aspfi...05012&T1=46040 I believe our crank bolt is the 12x1.50 thread. And by looking at the installer, you probably figured out how to make one yourself. You need a length of threaded rod, same threads as the crank. Spin it into the front of the crank. Place the balancer in position, over the threaded rod, and onto the tip of the crank. (Coat the balancer flange, where it goes into the front cover seal, with engine assembly lube.) Make sure the balancer is not cocked sideways on the crank snout. Then, install a BIG washer over the threaded rod, one that's big enough so it fits against the outermost edge of the balancer. Now spin a nut onto the threaded rod. Tighten the nut to install the balancer, and as you do this, make sure that the balancer doesn't **** sideways.

Then, there's the cheapest method, with a risk of damaging the balancer and the crank. You'd use a rubber mallet and a block of wood. Why the wood? Because if you smack the outer ring of the balancer, youll tear the rubber isolation ring, and wind up with a worthless balancer. (GM sells them new for $60, all 2.8/3.1/3.4 balances are "neutral balanced" which means you don't have to rebalance the crankshaft to use one. 82-86 externally balanced 2.8's are balanced on the flywheel.) So you'd put the wood against the balancer, and EVENLY tap the balancer on, trying to concentrate your blows in the center of the balancer. Again, try not to **** the balancer sideways, and remember your engine assembly lube on the balancer flange.

A balancer flange sleeve is used on a stock balancer when the old front cover seal has worn a ridge into the balancer flange. This ridge will cause a leak, and if you have one, you'll be able to feel it with your fingernail. My balancer had no ridge, but the isolation ring was falling apart. I got a balancer from an '86 2.8 Firebird for $30 from a junkyard, and amazingly, it had no ridge either, so I didn't need the balancer repair sleeve. It's a thin piece of metal that taps over your balancer's flange after you coat the flange with a special locking fluid, and creates a flat area for the front crank seal.

Hydraulic lifters are self adjusting. The manuals (Haynes AND GM's Service Manual from http://www.helminc.com) give a procedure to follow. I don't remember the order off hand, but you'll rotate the crank so certain valves close. Then you perform the adjustment on those closed valves. Then you rotate the engine again so other valves close, and you adjust those valves. I think it takes two rotations of the crank (4 cam rotations) to get to all the valves.

For each valve, you adjust lash as follows. "Jiggle" the push rod up and down as you slowly tighten the rocker arm nut. When the push rod won't wiggle up and down anymore, you've reached zero lash. Now, you tighten the nut an additional 180 degrees. By turning the nut an additional 90 degrees, you're pushing the pushrod down slightly. This extra "push" will seat the plunger in the hydraulic lifter at a mid-way point between fully-bottomed-out and not-pressed-down-at-all. And this is how the lifter self-adjusts.

There's some high-tech way to use a dial gauge and magnetic stand to verify how far the pushrod "sinks" into the lifter as you tighten the rocker arm nut. But, that's going overboard, it can be done, but if you don't have the tools, giving the rocker arm nut an extra 1/2 turn is just as accurate.

As to procedure for an '87 2.8, well, in '87, 2.8's got a one piece rubber oil pan gasket, which supposedly is re-useable. (And supposedly expensive, I looked it up, I don't really call $8 expensive!) 82-86 has a two piece gasket, rubber around the rear seal, and cork from the rear sides curving around to the front of the pan. The timing chain cover rests against the top of the front of the pan flange. On my '86, it has two bolts underneath the bottom of the timing chain cover. I don't think 87-up does. Also, when I did mine, obviously, the seal tore (it was cork). My gasket kit included a front pan segment, about 3 inches long. I was supposed to cut the torn original gasket at the joint between the oil pan and engine (visible with the timing chain cover removed). Then I was supposed to put this segment between the timing chain cover and pan. Then I was supposed to dab some of the included black rtv at the joint where the new segment met the engine/oil-pan joint, and install the front cover. Screw that. I cleaned the front of the pan flange with brake cleaner on a rag. Then I laid down a blob of blue RTV on the front of the pan flange. Then I put the front cover in place. No leaks. Now, if the fancy rubber gasket really IS reusable, it probably won't tear when you remove the timing chain cover, and you might be able to reuse it. But I don't know, reusing a used gasket is a little odd. BUT- you might have no choice, if the '87 does not have any front pan bolts that go into the timing chain cover....

Whew, this is long. Good luck, let me know if you need any more info. And don't use the center bolt of the crank to pull the balancer on!!

[edit] Found the question I had asked on the tech board a while ago. Vader explains the lifter preload bit at the very end. https://www.thirdgen.org/techbb2/sho...threadid=23615

 

Nice novel TomP

Just follow Tom's instructions and you will be ok, Auto Zone sells or rents which ever way you want to go, all the tools needed for this job. One helpfull hint though is remove the radiator or at least cover it with a sheet of plywood, its amazing how tools tend to poke holes in radiators that cost $150.

 

Here's what I've done twice & will have to do again (to the Firebird as I didn't know better).
Removal.
I used a Harmonic Balancer removal tool I got from (my instance) Autozone.
In process of balancer removal, I destroyed the tool.
I returned it & wasn't charged (it's a throwaway tool).
As Tom mentioned, One can HARM the crank.
The THREE times, I've done this, I "got lucky".
Tom's time, had bad luck & THAT CAN HAPPEN, too.
Suggestion, find an old hydrualic lifter, insert into the crank and tighten away on the H balancer tool.
EVENTUALLY, the balancer gives up & part of mission done.
NOW SIMPLE for the CRANK SNOUT GEAR REMOVAL.
ONE QUICK HARD WACK OF A HAMMER (don't be afraid!) ONTO A SHARP SHARP METAL CHISEL, the crank gear splits!
It was fun & magical. Most fun of the project!!
I PLACED CHISEL onto the WEAKEST part of that bottom gear.
Guess where, common sense the key area of the gear.
NOW DON'T REMOVE A THING.
MAKE SURE YOU ALWAYS LEAVE THE GEARS POINTED DOT TO DOT.
ALWAYS
Replace one gear at a time.
Top, make sure it's at the DOT TO DOT point.
Bottom gear, here's my trick.
I used a large socket, over the gear & crank snout, STRONG FIRM GENTLE TAPS to place bottom gear in position. NOT POUNDING, firm gentle strong.
HOW DO YOU KNOW WHEN IT's "IN POSITION?"
Easy.
Take a FLAT STRAIGHT EDGE, SHORT IN LENGTH, make sure the GEARS ARE LEVEL, not one infront or behind. (ex. -------, NOT --___--, make sense?)
LEVEL, FLAT IN LINE.
This reduces EXTRA WEAR ON CHAIN.
You've kept everything "DOT TO DOT".
Bottom gear can't loosen to attach chain, but ya can to the TOP GEAR.
Loosen top gear, place chain in positon, KEEPING DOT TO DOT positioning.
install bolts
USING RTV RED LOCTITE ON THE BOLT THREADS!
NEXT
TENSIONER.
YOU NEED NEW ONE.
YES YOU DO!
I have to go back into my 3.4 swapped Firebird engine to install a new tensioner. AND BALNACER SNOUT SLEEVE!
WHY?
I neglected to understand how important this detail is.
The tensioner helps keep chain in proper positon for longer life
PLUS an OLD tensioner will BREAK APART, plastic falls to the oil pan which clogs the oil pump screen & you can imagine rest.
YOU LOOSE FULL OIL PRESSURE DUE TO CLOGGED OIL PUMP SCREEN.
Really
This happened on my 1974 Corvette original timing chain gears.
I found the plastic parts in the oil pump screen.

Balancer, yes install a balancer crank snout sleeve for the $4 it costs.
HOW
Also easy.
Get GASKET-SINCH (Yellow gasket sealer, very liquidy), CLEANER The snout of the balancer (sand paper, steel wool , just "clean").
Apply gasket-sinch on the balancer snout, TAP THE SNOUT SLEEVE OVER BALANCER til seated well. I used a block of wood to absorb "blows" (not hard, again firm strong hammer taps). Hammer handle is good tool, too!
Installing balancer,
I use a hammer & a block of wood and some oil on the crank.
I tap on balancer, install bolt, tighten bolt, TAP ON BALANCER, tighten bolt, repeat until seated.

NOT SLAMMING ON THE BALNCER
Again firm strong wacks, using buffer/absorbing the blows, the wood.
I TAPPED ON THE TOP, then THE BOTTOM (distribute the force, firm gentle taps)

NOW YOUR OLD BALANCER....
YOU MAY GET LUCKY YOU MAY NOT.
It MAY be good IT MAY NOT.
You will find out while it's removed.
IF YOU SEE OLD CRACK HARD RUBBER in the balancer CHUCK IT FIND NEW ONE OR DECENT USED ONE.
WHY?
It's a grenade waiting to go "ZOOM" at a high RPM.
One person told me it went thru his radiator and disappeared.
This was a Small Block Chevy example, yet, same is true w/you.
My 211,500 mile S-10 Blazer fell apart in my hands.
Parts & Numbers
Balancer snout sleeve
Fel Pro # (I misplaced box-ask for a 2.8/3.1 application) $4
Pioneer # 14908/HB-4127-S (same application I used on the 3.4 balancers) $4
Gasket set, I asked for a FEL PRO TIMING CHAIN GASKET SET, cost was about $20.
CHAIN....
$30
DYNA GEAR #73042.
WORKS PERFECT
Ya can spend/waste $90 for a double roller this & that.
My bill for parts totaled $90 or less.
ALSO NEW WATER PUMP (it's in your hands just get one, cheap insurance). $20
Tensionser was about $10-15

BOLTS ARE SIZED
8mm (The TWO under the timing chain cover, FINE MACHINED THREAD BE CAREFUL UPON THOSE BOLTS INSTALLATION!!)
10mm
I had a few at 11mm
13mm
15 mm
& balancer crank bolt was 17mm or 19mm.
WORTH IT SCALE
100% WORTH IT!
SUCH A RETURN TO SMOOTH POWER AND SMOOTH IDLE AND LOWER OPERATING TEMPS AND SLIGHTLY BETTER GAS MILAGE.
NOW
ONE DETAIL.
IF THE CURRENT ENGINE IS STRONG AND REALISTIC MILAGE (about 75K to 150K miles) THIS PROJECT IS WORTH IT
ANYTHING OVER ENGINE MILAGE 150K THINK ALOT ABOUT DOING THIS!
Why age & lots of milage, MAY make this project a moot point.
IT MAYBE WISER TO JUST LET IT BE & keep driving UNTIL THE ENGINE DIES!
EASY BAND AID IS TO JUST LOOSEN THE DISTRIBUTOR AND TWIST TIL IT HITS THE FIREWALL & TIGHTEN!

ONLY YOU
KNOW if the project will be worth the effort.
IT'S ALOT
Took me 4-6 hours, first time.
Second & third, the two 3.4 mills outta car so it was easier.
This fourth time (the 3.4 swap engine in the Firebird), I'll assume the 4-6 hour job.
YET I have a 55K mile 3.4 mill & that's worth the investment for the LONGEVITY & peace of mind.
I'M PISSED AT MYSELF I DIDN'T know better before, oh well!

How to tell to do this
EASY
socket on the crank, distributor cap off.
Twist crank to left or right by about 2-4 inches.
IF ROTOR MOVES INSTANTLY, chain is good.
IF ROTOR MOVES LAZY, replace chain.
Again ENGINE milage & condition of the engine will help your decision.
IF NEVER DONE THIS BEFORE plan two days!
I also refill with straight water.
WHY Checks for leaks & then refill with proper coolant.
Oh, new hoses help too. Cheap insurance again.

I hope I hit upon all points for your secure feeling effort.
Glad to contribute
PS as you think about this, You could be doing this project to a V-8 mill under the hood.
Look how much room you already have due to a V-6!!

 

Timing chain on s10, and timing chain on camaro is same thing. Everything goes together same exact way.

 

Thanks for the replies everyone!

Lots of helpful info there Tom! I think we will use the bolt, washer, and nut method to put the balancer back on. Thanks alot for the section on adjusting the valve lash. One question on that: You said in your post "Now, you tighten the nut an additional 180 degrees. By turning the nut an additional 90 degrees, you're pushing the pushrod down slightly." - So should it be tightened an additional 90 or 180 degrees? I am assuming 180 since a later in the post you said "giving the rocker arm nut an extra 1/2 turn is just as accurate."

SSC: Thanks for the advice - we were planning on removing the radiator and replacing the hoses.

Thanks for all the info Karl! I will be printing out both your post and Tom's. I understand the idea that this should not be done on an engine with more than 150K, but unfortunately the engine has 185K. At this time it is very gutless and has a hard time maintaining speed in 5th gear (and can not accelerate AT ALL in 5th even when floored). My friend has to drive this vehicle until late summer (and maybe beyond that) and we decided we would invest the time and dollars to change the timing chain amongst other things. Thanks for all the help once again.

 

Let me offer this.
ADJUSTING VALVES, I use a screw in to spark plug hole compresson gauge.
I adjust valves while engine is turned over (NOT IGNITING) till I see highest presure reading.
This method is 100% Idiot proof & I'M THE BIGGEST IDIOT HERE!
Chain.
SIMPLE SIMPLE SIMPLE.
FIRST
see how stretched the chain is.
Again, breaker bar on crank, distributor cap off & move the engine 2-4 inches one way or the other.
IF ROTOR MOVES INSTANTLY chain good.
IF NOT IT MOVES LAZY, you do need chain.
MY BAND AID IS TO JUST START ENGINE, loosen distributor bolt, twist distributor toward the firewall.
THE ENGINE WILL NOW SOUND SMOOTHER & YOU'LL HAVE MORE PEP.
Follow by New cap/rotor, plugs & plug wires.
MONEY LEFT OVER, add new HiPo coil for about $30-40.
This is a ChEAPER EASIER BAND-AID then breaking open AN OLD TIRED ENGINE.
Why this,
Honest, you MAY BE DOING MORE DAMAGE TO THE LIFE LEFT OVER MILL than trying to fix this older engine.
WHY,
These little things have a "life span" and it's life lived underpowered.
Open air flow to carb, and decent exhaust pipe or new CC.
Swap find as many cheap deals as ya can.
IF the vehicle HAS NO POWER IN OVEDRIVE, guess what,
Downshift.

AND
AND
AND
I'd START
This project BY FINDING THE CONDITION OF THE ENGINE.
MEANING,
my 211,500 Bazer 2.8 from 1985 to 2002 had a final compression of only
FIFTY POUNDS COMPRESSION per cylinder.
It was dead.
No new chain was gonna overcome that aged bottom end problem.
I'm offering COMMON SENSE observations after playing with these 60* mills from 1989 to present.
See what ya have to start with, try band-aiding it and keep going til it's finally dead.
Serious your real solutoon MAY BE JUST FIND/BUY/SWAP to a better vehicle for this drive, for the CHEAPER MONEY & BETTER RETURN ON YOUR EFFORT.
Some things ya can't overcome, especialy too low compression in an old engine.

Start from base findings of compression & then go forward.
UPON FINDING YOUR REAL WORLD ENGINE CONDITION ANSWERS only then,
SHOULD YOU
figure out the BEST solution for your effort.

Hope it all works well to your solution, glad I could offer tips.
Again, best solution may be to just toss this truck & find another vehicle.
Meaning a timing chain job is about $100 in total parts cost, plus your hours of "hope this does work" & labor.
Best thoughts....

 

Yeah, my bad, an additional 180 degrees of turn (half a turn). I did my timing chain at 180,000 miles, too. I put the Cloyes true dual roller on, and it requires that the chain tensioner/damper be removed. The new sprockets, with their bigger "teeth", hit the damper. The box said to remove the damper, I did, no ill effects, currently nearing 250,000 miles.

And also, check below the front of the timing chain cover. Karl said you'll have two 8mm bolts there; bolting the front of the oil pan flange to the bottom front of the timing cover. I had said in my first message that I thought this was done away with in '87. Let me know what you find!

Here's the ducksfoot puller I used on mine, didn't have a problem pulling the balancer off, and it didn't ruin the tool. Mine was made by Performance Tool, it's similar to the Lisle #45500 on this page: http://www.handsontools.com/store/li...tegory_id=8201 Just make sure some of the bolts it comes with have 10.9 stamped on 'em, that means they're metric. Hopefully three of them (the bolts in the bag come 3 each of same size) will fit your balancer.

Pep Boys actually tried to accuse me of stealing. The cashier told me "you just can't put those bolts in the bag" and started taking them out. I asked her what she was doing and she sneered at me and said "you have to pay for these, sir." I demanded a manager- who said the same thing. I told him to go find the tool in the aisle, you'll see they're all the same. He disappered for 10 minutes in the aisle. Meanwhile, the lady pushes me to the side and starts taking care of the very (very!) long line that had formed behind me. So I wait a bit more, then say loudly "this place is full of morons" and go stamp over to the manager. He's at the complete wrong end of the aisle. I ask him if he's found it yet. He says "that must've been our last one". I go "what!" I pick up one of 'em and go "what does this look like?" He comes over and goes "oh". Then I go "or the rest of these"? I started throwing all the other balancer pullers- even the Lisle ones (which cost a bit more, but they came in a plastic container, mine came in one of those resealable bags which I liked)- into his arms. I asked him if he wanted to open them and compare the number and size of the bolts to the one in my bag, because I've got all night. He stammered out a "no, that's not necessary". So I went off on him on how could you be a manager if you don't know what your store carries? Then I had him come over (he still had the other pullers in his hand) to tell the cashier that it was okay to sell the tool to me. He did. Some of the people that were waiting behind me were still in line, with shocked looks on their faces. I think they all thought that Pep Boys had caught a theif. BS! So then I went off on her asking her how she could be a cashier in a parts store and not know what tools looked like. Now I only go to that store if no other Pep Boys in the area has what I need.

 

ttt
Got any good feedback, good results for us?
Hope your mission went well!

 

It's going fairly well so far. We've never done this before, so naturally we are talking it a little easy.

Saturday we got our selves organized and took all the engine accessories off. Then we took off the TBI and tore it down, cleaned it and rebuilt it with new gaskets and filters.

Sunday we had to go get a harmonic balancer puller, and grabbed a timing chain tensioner and speedie-sleeve (crankshaft snout sleeve) so that we had those items on hand. Had to take care of some other items in town (and lunch) as well. We got back to the garage and started work trying to get the water pump off. We took out all the pump bolts (and this we are sure of, both of us have looked all OVER that thing for 5 minutes or more, both with eye and hand - all the bolts are out) - but could not get the pump off. We noticed the bolt that goes through the PS pump mount and into the water pump was broken off by some owner in the past, and figured that that bolt must go into the block or the timing cover. We decided to go talk to my Grandfather (machinist) to see how difficult it is to remove the bolt. At one point where we were trying to describe something to him I thought, "Wait a minute, my engine uses the same pump..." - so we looked at the pump in one of my Camaros. At that point, my friend had the bright idea of taking that particular bolt out of my pump and seeing how far it goes in (why did we not think of that EARLIER!?!?) - after doing this we found that that bolt goes through the water pump only. So, we went back to the garage and decided that since the pump would not budge, we would try to remove the rest of the timing chain cover bolts and remove the cover with the pump on it. I hope that there are not any bolts hidden behind the pump that hold the cover to the engine block...

So, tonight we will get the balancer off (already remove the pulley and bolt in the center of the crank) and proceed. Some would say things are going a little slow, but that is fine with us, we are just taking our time, and taking it easy (and having fun too).

I'll keep you guys updated! Thanks for all the help again.

 

You do have new water pump right?
Take a metal hack saw to the waterpump and break it off at the "stubborn" point. One way to see what the problem is.
Are your plugs "clean" or oily?
That is quick inspection to determine condition of the engine block
Good to hear you are not rushed, as this is not a job for the timid.
Have access to a compression tester?
PS Alot of the parts you are replacing, can be used on a upgraded (rebuilt) mill, too.
So meaning, you are not really "wasting" money, just investing for present & future usage and that's good.

ALSO be aware of the condition of the timing chain cover.
Notice the amount of aluminum left over in the water passages.
I had bad habit of just using water (for cooling) and the corossion had eaten thru the original timing cover & I had to replace it. FYI.

 

We have not purchased a new pump yet, but I think we are going to.

The spark plugs were changed in fall of 2002 and looked good. The Blazer has had very few miles put on it since then.

Yes, I've got a compression tester.

We will be sure to check out the condition of the timing chain cover.

Thanks again.