rebuilder86

4k timing chain broke, great fun replacing.

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So I am back in the jungle, havent got round to sorting out my missmatch of 4ku and flat top 4k engine parts yet..

Yesterday, we drove to a wedding in a farm in the middle of nowhere. The last time i saw the bride and groom, we were driving my inlaws multicab up a steep hill and the timing belt broke. I trust my jeepy's mechanicals because i had always assumed that timing chains are invincible.

Either thats horseshite, or these friends of ours are a curse, because as we pulled into their farm, the jeep went silent, and when i tried to start it, it span freely. 

So after a tricycle and motor ride back to town, i get a new chain for 500 pesos (about 12 dollars) and head back with no idea how to do it or what tools are needed. Ive only ever done timing belts; with big easy access tensioners.

So reaching down between the battery, fan blades, coolant hoses, radiator, steering components, laying around in the cow poo infested grass, i learned the process for doing this with the engine in place.

1. Loosen all sump bolts so the sump can hang down about 1 cm at the front.

2. Set cyl 1 to top dead centre and make sure cyl one valves are closed, by making sure dizzy rotor is pointing at cylinder 1 terminal.

3. Undo no 1 spark plug and stuff cylinder with rope or strong wire (i had some cat 5 network cable handy) to lock up engine, and then remove crank pulley bolt with short sharp blows.

4. Remove pulley and timing cover, needs a bit of persuation to break the gasket free.

5. Pull out broken chain. Say goodbye to the broken link which is now safely located in the bottom of the sump :p.

6. Ziptie tensioner to fully compressed position.

7. Visualy confirm through spark plug 1 hole that 1 is at absolute TDC. 

8. Remove camshaft gear and align the lug on shaft face to the dot on the block just below the shaft seal.

9. Drop chain in around crank shaft and then wrap around camshaft gear such that when pulles tight upwards, the gear and its lug hole line up with the camshaft lug and is perfectly centred.

10. Install camshaft gear bolt

11. Cut ziptie and remove with pliers.

12. Before complete reassembly, put spark plyus back, turn engine over by hand to check no interference, then start engine and confirm it works.

13. Happy dance.

14. Put timing cover back on, from underneath engine making sure to get the round part of the sump seal to sit in the groove properly, then tighten sump back up.

15. Reassemble and rinse off cow poo from arms, back, and neck.

It was a mission but relitively simple and straight forward, and i believe if it was designed by any other car manufacturer, it would have been impossible.

Edited by rebuilder86

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So who can tell me, why when i started the engine with the timing cover off, why did oil not spew out, is there no squirter for the timing chain? Or have i diacovered why it broke in the firat place? Blocked squirter?

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Hi Jeremy,

                   Great description !    I could also smell & feel the cow poo !   Been there, & done that, but not for a broken chain, but to replace the front crankshaft seal in the timing chain cover.

Were the very front two (2) sump bolts, actually bolts, or threaded studs with nuts ?  I can remember, mine being nuts & threaded studs.  The studs were too long to allow the cover to clear & come off.  There was just enough room on mine, to put two (2) nuts back to back, on the stud very tightly, to allow me to extract the whole threaded studs.  Needless to say, they were replaced with bolts.

Probably a reasonable amount of room in your "jeep" from pics you have posted in the past, of that area.  Not much room in a Rolla, although, after removing the radiator & sump stone guard, it is possible, but you finish up with a kinked neck, for a day or so.

Regarding the the oil squirter feed for the timing chain.  Yes there is one. It is a small hole drilled into one side of the timing chain tensioner, which works off engine oil pressure.

It is directly in line with the chain.

Tensioner.JPG.705d258bd0ae1834fb477fb5bc171c9a.JPG

It doesn't have a "squirter tube or spout"  fitted, like some older car engines. It is just a little hole.  They can block up. I've always dissembled the tensioner, soaked in in kero overnight, & run a straightened paper clip wire through it, until it was clear.  Don't be tempted to drill it out, as it's size is critical, as you don't want to bleed tensioner oil pressure away from the tensioner piston.

P.S.  Was the timing chain that broke, a single or double row type ?

Cheers Banjo

 

 

Edited by Banjo

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....Were the very front two (2) sump bolts, actually bolts, or threaded studs with nuts ? ...
haha u expect too much of me, I'm rough... when i undid the sump last, i just left the front 2 on each side off because the threads stripped. I ended up replacing them with smaller stainless bolts with nuts, and that was a bitch to undo.|

Right well, I'm now going to check out the tensioner more closely and start the engine, perhaps my lack of oil pressure on startup was the reason no oil was spat out, i still havent put that new anti-syphon oil filter on, waiting for some 10w-60 oil for the now Knackered piston - bore clearance ahahaha.

Timing chain was single. CBF trying to find a double. now that i know its completely non intrusive and i know how to change it.

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Hi Jeremy,

                  You can buy the whole timing chain kit on line, which includes both sprockets & tensioner & guide. There are some good aftermarket ones available like Rollmaster, but I'm sure in your part of the world, you have access to more Asian ones.

372360551_DoubleRowtimingchainkit.JPG.60bf30dd856da67b09940fc24ef98abd.JPG

I've always upgraded all my K series engines to double row timing chains.  Eventually, the chains stretch, & the rubbing block on the tensioner wears down to the point, where the tensioner at full extension, is no longer effective.  I've even heard & seen a K series engine, where the timing chain noise was so loud, as it was slapping against the inside of the timing chain cover.  Removal of the cover, & the marks on the inside of it, confirmed this.

Even my olde 3K engine, I'm converting into a coffee table, has a double row chain on it.

DSC02339.thumb.JPG.e6e9d8896ce5d0c09af2e6ba2faf14ec.JPG  

I think they were standard on the 3Ks, but then went to single row on 4K & 5K engines.  Seems strange change.  Maybe someone will correct me on that.

Cheers Banjo

 

 

 

Edited by Banjo

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I think early 4Ks had flat top pistons and double row chains (here in Europe almost every 4K has D dished pistons).

I also upgraded my 5K from single to double

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Hi Jeremy,

                    I've seen some loose timing chains, on K Series motors, but never a broken one.  Have you still got the chain, & can take a picture of the break ?  Was there any indication as to why it broke ?

P.S.  Just be thankful you didn't have a timing chain like this one break.  This is a  V12 Lamborghini Diablo engine from 1993.

1484743096_LamboV12TimingChain.JPG.045ed3c58ad364cf37dc64a67eca9a82.JPG

Cheers Banjo

Edited by Banjo

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nah just an entire link missing and somewhere down in the sump now, so my guess is that one side broke free of its pins , then the pins slipped out along with the other side.
The pinched (staked) bits on the pins probably just vibrated themselves to the point of shearing off the staked bits.
I think i will definitely get one of those double row chains online for when i do the complete rebuild, which is happening next trip.
I intend to take the block to a mob in cebu city to push the cylinder liners out and install new ones (involves heating and i have no oven), new D dish pistons, correct cylinder head, and new pushrods to suit.

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trying to find the chain to take a photo, but when something of mine breaks, the locals scourge through the rubbish trying to get the remains of what i throw away, its like treasure to them.

i think its gone now. basically, it just looked like a link was missing, and absolutely no sign of damage.
One thing that shocked me, is the design of the tensioning system, and how a little piece of plasticy rubber or whatever it is, can push up hard against a fast moving chain, (albeit lubricated) without completely grinding away. there was no sign of wear on it. I can understand and accept the big long chain guides on holdens and fords, but a little piece doing all the work defies explanation in my mind. 

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For what it’s worth, the TRD adjustable cam gear for a K is a twin row. 

Very curious why they went to a single row

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18 hours ago, rebuilder86 said:


I intend to take the block to a mob in cebu city to push the cylinder liners out and install new ones (involves heating and i have no oven), new D dish pistons, correct cylinder head, and new pushrods to suit.

K motors don't have liners. The block is a 1 piece unit.

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Google it and the only product ull find is by federal mogul, cheap china shit who pretend to be made in the good old US of A.

U have me interested now, i wonder what it takes, to sleevify a non sleevable motor.

I know first hand why they do it here, suppliers have to combat the absolute lack of knowledge the automotive professionals have here, for example:

Even the very best machine shop with computer controlled cylinder hones, all staff involved believe the purpose of honIng a cylinder is to make it smooth as glass so theres no friction. Therfore, they all; every single machinist, think the honing stones are  there to hold the back of the 4000 grit wet n dry while it goes up and down the bore.

 

I shit u not.

They wont listen when i ask for it t9 be done propperly.

Suppliers know this is the pits of the earth and therefor take advantage of the stupidity, while at the same time ensuring consumers get a cylinder bore that will seat a new set of rings, by making products that can simply be installed and removed, no intellect required.

 

Edited by rebuilder86

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The advantage of liners is that they are factory honed & ready for use, and always use standard size pistons. The head gasket seals on the lip at the top of the liner, so no problems there. They're the precision part and the hole you machine out is pretty simple.  I expect they are too expensive a system to use in Aussie, we can precision rebore a block easier.

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Here u can even get oversized ones hey. One thing ive never realy understood is why they call them semi finished. 

Semi finished apparently means u have to bore it and then hone it. To me thats the wrong term. Semi finished implies to me, that the walls of the liner are in a half finished state, meaning they need to be honed only.

my research into these particular liners from federal mogal, reveals that i can get semi finished liners, which need to be pressed in while block is hot (so there is no distortion), then apparently only honed slightly to size.

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