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4k timing chain broke, great fun replacing.


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Very interesting, how local conditions in a particular part of the world "spawn" a whole different way of fixing an everyday automobile issue of the engine bore eventually wearing out.

I had the house to myself last night, as wife was interstate visiting son, & daughter was working all weekend, & staying with friends.

So I "binged out" on the complete 5 episodes of MCM of the Honda VTEC B16 engine transplant, into the Japanese Mini Minor, which is a classic.

https://www.youtube.com/watch?v=NQ8RLM8eWRU

So I'm Googling after that marathon, on the difference between Honda & Toyota variable valve timing techniques  VTEC vs VVT-i, & all the other variates of those that have come since.

I also Googled which was the better, & that was a good read, from both sides of the perennial argument.

In doing so I came across a website, which lists all the Toyota engine variants that were offered to Russian Toyota customers.  

http://toyota-club.net/files/faq/03-08-16_engine_eng.htm

It describes the good & bad points of each engine series marketed there in Russia.  There was two particular comments, that drew a smile.

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Despite the criticality opinions, it should be remembered - even relatively unsuccessful Toyota's engine is more reliable than most creations of the local russian automotive industry.

The other was the comment, regarding our beloved K series of Toyota engines.

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The absolute record for longevity among Toyota engines belongs to K series, that produced since 1966 to 2013. In the period under consideration, these motors were used at commercial versions of LiteAce / TownAce family and at special machinery (forklifts).
Extremely reliable and archaic (camshaft in the block) design with a good safety factor. The general lack - poor characteristics, corresponding to the time of the first appearance of the series.

5K (1978-2013), 7K (1996-1998) - versions with carburettor. The main and practically the single problem is a too complicated fuel system, so instead of trying to repair or adjust, it is optimal to install a simplest carburetor from older local cars.
7K-E (1998-2007) - later version with fuel injection.

So that got me thinking about another series of Toyota engine in the 1.3 - 1.8 Litre range that could ultimately be used to transplant into a KE Rolla, with all their later technology advantages.

I've broached this subject before, when I fell in love with the NZ-2FE & NZ-1FE engines used in the Echo & Yaris cars, which after 2004, had a pretty good VVT-i setup.

The problem with all these engines, is that they come from east-west front engined cars, & placing them in a north-south orientation, requires a very difficult, if not impossible requirement, when it comes to a gearbox adaption, & engine mounts.  Maybe, simpler to drop in a late model MX-5 engine + gearbox, and be done with it. 

Jeremy's comments regarding the sleeving of K Series engines in the Philippines, reminded me that the NZ-1FE Toyota engine is a sleeved engine, in an aluminium block. I've never really thought about that, as I've never had to sleeve an engine in my whole life.  A little research on the NZ-1FE engine, appeared to indicate, that the engine cannot be re-sleeved, after the bore is finally worn out. According to some comments I read, once the NZ-1FE engine bore is worn out, the block is a throwaway.  What really surprised me, that Toyota originally, apparently, only designed this particular engine series, for a life of 200,000 klms. As my daughters Echo has clocked just over 195K klms, that point is fast approaching.

However, maybe Toyota were being too conservative, as forums indicate, many Echos & Yaris Toyotas have achieved 250K - 350K klms with no major mechanical  engine repairs, other than regular service.

I would believe those figures, as I did a major service on my daughters Echo last weekend, after changing the clutch, (which is another story), and found oil colour, spark plugs & everything in extremely good condition.

I whipped the induction idling actuator off it, & soaked it, to clean it thoroughly, as these do become an issue, & there was a belt that squeaks, for the first 5 mins of run time, which indicates it is on the way out.  So it will probably do another 20-25K klms again this coming 12 months, without issues.

Here's an interesting comment regarding the common Echo/Yaris squealing on a cold start up, that I am experiencing. The sound in this video, is exactly what I'm hearing. https://www.youtube.com/watch?v=HRrVMtyIqIY    It is not the battery; that was brand new last week. 

But getting back to the sleeving of K series engines. I think oversized pistons come in sizes up to +50 thou., where I would imagine the cylinder walls start to get a bit thin. Could you then fit a sleeve, & does boring the block out, to take the sleeve, break through into the water jackets ?  As I say, I've no experience with sleeving K series engines.  Also, as sleeves, then allow standard piston size to be fitted, can you then re-bore a sleeved engine, to take oversized pistons, after the sleeve has worn out to its limit ?

Any comments or info appreciated.

Cheers Banjo  

 

 

 

 

  

 

Edited by Banjo
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I'm sure that back in 1985 we were told that the newfangled 4AGE engines were not rebuidable. 

 

I remember Toyota hosted Celica Car Club Victoria for a model introduction night, and everyone deriding the idea, end of the world as we know it etc.

Edited by parrot
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apparently sleeving of the 4k is possible because the block is iron, the walls are thick enough to accommodate a sleeve, and they have loose enough tolerances in the first place to guarantee any sort of reasonable life expectancy.
This information comes from a foreigner friend i met here, another aussie bloke (older absolute drunk), who also has one of these jeeps but did it up with performance parts with no end to the amount of money spent. 
So with his information and what ive learned, a sleeve (semi finished liner) is able to simply be pressed in and out of the bore, with a 0.01-0.03mm (for older motors like this) interference fit, which means the liner is about 0.01mm too big. They can just be pressed with hydraulics, but this then requires a machine shop to then bore out the sleeve so that is is 100% perfectly cylindrical then honed, but with a loose tolerance motor like this, it can simply be pressed in while block is hot, and then simply honed quite vigourosly with a good computer controlled hone with even pressures to enlarge the clearance ever so slightly.
A new out of the package std liner and a standard piston, when held in my hands, the piston slides down the liner perfectly with little to no play. (i did it in the parts shop) but when the liner has been exposed to the pressures to install it using a hydraulic press, apparently it shrinks a bit so this is why it needs the machining or honing.
Saying all this, you can only get away with the easy method of press fit and hone, if the parent bore is 100% perfectly machined and there are no imperfections. Luckily for me, this engine has been around for an eternity, and therefore probably is pretty capable of accepting a hot press and hone type install.

With all this in mind, I'm pretty sure a decent rebuilder in a 1st wold country would laugh and say don't be ridiculous, bore the block and put oversized pistons in you idiots.

Banjo, the answer to your last question, no. The sleeve is designed for one size. Once its worn out, u press it out, and press in new ones, thats the beauty of it, its a never ending engine block.

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Hi Jeremy,

                  Thanks for that info.  That's great, & I'm now much better informed.  Do they also produce these cylinder sleeves for the 5K, which has have a nominal bore of 80 mm ?

The advantage of oversizing the piston & bore, when an engine gets to that point in life; is that you finish up with a slightly larger swept volume in the cylinder, which with the same head & gasket thickness, increases the C.R. a bit.  If you skim the head at the same time, that also increases the C.R.

P.S. Actually, I just looked up the Toyota factory "Yellow Bible", for the 2K-3K-4K-5K, & it says you can oversize 3K & 4K blocks to 1.0mm, but only 0.50mm for the 5K.  That indicates, that to fit the sleeve, with a 2mm wall thickness, you would have to bore the block cylinder out a whole extra 1.00mm, in excess of the normal maximum o/s bore size of 1.0mm. If that doesn't result in breaking into the water jacket, then there appears to be quite a bit of "meat" in those cylinder walls, in the block castings.

Cheers Banjo

 

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Yeh i always thought 5k was just impossible to even rebore or do anything to because its just a 4k block with bores that are bigger and bigger pistons??? No???

 

Does it really increase the C/R though.

I havent thought about it too hard I'm three beers in, but i imagine widening the bore also increases the combustion chamer size at the same ratio of increase in the swept volume..

Or is it because the piston just about nearly touches the head and the entire combustion chamber is only in the head.

I'm thinking of d dish pistons.

So i guess if its a flat top piston and the piston does almost touch the head then i guess i can see how it would increase the cr enough to make a difference.

 

Edited by rebuilder86
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Yeh tge compression ratio will remain about the same  on this motor, as the piston does not travel all the way to deck height.

For compression ratio to increase with a rebore, the piston would have to have always (before and after) reached absolutely 0 clearance between cylinder head and piston crown.

This is because, in my case, with the very small clearance between crown and deck, plus the distance between deck and cylinder head (head gasket), every bit the bore gets larger, means a larger "clearance volume" proportional to the increase in swept volume.

 

So unfortunately, i can't gain compression by boring out.

In fact i have evidence / proof.

The rollaclub wiki page shows blocks and associated cr figures. The 4ke and the 5k both share the same piston types introduced in 1982 just proportionally wider for the 5k with the same increase in dish volume. The 5k has less compression ratio due to its larger clearance volume.

4ke 9.5:1.

5k 9.3:1

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I think you will get a compression of the distance between the top of the piston/head gasket and the head, versus the stroke.  So the air column in your 73mm stroke is going to be jammed into about 3mm, about 25times.

Think if you kept the same combustion chamber and bowl in the piston, but bored it out to..  say, a metre!  There is a massive flat area around the piston bowl going up to meet a massive flat area around the combustion chamber, compressing that volume 25times.  Soon the combustion chamber and bowl in the piston would be so small that your compression ratio would be 25:1.

So reboring it wider must give you a compression increase each time, but small rebores will make a small difference. That's providing the piston shape stays the same of course, and it reaches the same stroke height.  Someone used VW pistons to get a flat-top piston a few years back, but I couldn't find one with the right gudgeon diameter and deck height. You might be able to get some really interesting parts we wouldn't see in Aussie.

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but thats only true if the combustion chamber isnt the size of the bore, which it is on these motors; the combustion chamber includes some of the bore when the piston is at TDC. The piston stops about a mm before the deck or something like that. So if u expand (bore out) that smaller compression chamber area along with the entire swept volume, you are in fact enlarging one half of the equation, the compressed half, meaning they both cancel each other out, mathematically.

That smaller half of the equation, (the little TDC combustion chamber) is more sensitive to change, because it is smaller to begin with, so increasing it marginally, has a significant effect on the entire equation.

Edited by rebuilder86
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On 6/16/2018 at 9:48 PM, rebuilder86 said:

Yeh i always thought 5k was just impossible to even rebore or do anything to because its just a 4k block with bores that are bigger and bigger pistons??? No???

All my suppliers sell .5,1.00 and 1.5mm(or .020, .040 and .060") oversize pistons. I also know of at least 5 83mm 5k engines getting around. So definitely can be bored. 

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Hi Jeremy !

 

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anyway so heres that damn chain, i found it.

So where is the missing link ? Did you retrieve it, or is at the bottom of the sump ?

To my knowledge, the chain is all one piece, with no removable link. That's why it is necessary, when fitting, to attach the chain, to the two sprockets, then slide them onto their respective shafts at the same time. The joiner pins in your pics, don't show any sign of wear, adjacent to the missing link, if it was rubbing against something. Was that how you found it, or was there some broken bits, still attached to the chain. I'm interested, as I've never heard of a K series chain breaking.

Cheers Banjo

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Thats how i found it. Yeh its still I'm the sump haha. No broken pieces anywhere to be seen.

Remember everything here is dirt cheap, so its possible its just an aftermarket piece that is so crap it just broke.

Kickn, so why are people always saying not to bore out a 4k to 80.5 mm for 5k pistons?

Does the 5k block actually have more meat on the cylinder walls along with thinner water jackets or s9mething like that? And if so, how is this possible when there is the limitation between the two middle bores. They are so close together even on a 4k.

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