2.5 L KV6 Engine Head bolt torque

[Classic boy]

I am looking for some advice on the correct cylinder head torque specs for the carnival KV6 engine using the one piece gasket with rubber beading.

I have a factory manual but it is giving contradictory information.

It states first step 18nm initial torque, then the second step is tighten the bolts a further 90 degrees, then as a third step further tighten them another 36-45nm.

Unfortunately the bolt torque is already above 45nm after the second step.

I think it is a mis-communication when converting the manual from korean to english.

What have others been doing?

[Gidner]

Almost sound like step 2 and 3 are reversed? On all other cars i'v worked on, the "angle" step is usually the last one. But maybe I'm wrong. Did you look in kiatechinfo.com?

[Classic boy]

Unfortunately kiatechinfo doesn't cover the 2.5 kv6 engine.
But I do agree step two and three do appear reversed

[PeterBlue]

FWIW, I'm using the 'EM' manual kindly uploaded by Comglomerate (see http://www.kia-forums.com/kia-carniv...al-kv5-v6.html) and others.

Page EM-29 of that manual just states:

Pretighten 18.8 Ib-ft (25 N-m, 2.6 kg-m) and then tighten 90°

However there's no date or revision detail that I can see in that manual, and no indication as to what kind of gasket it refers to. Your manual may be a later revision - I assume its that paper copy you mentioned back in '09 that you purchased from a dealer a few years before?

Cheers, Peter

[Conglomerate]

G'day

I posted awhile back that I was using these single layer steel gaskets with a rubber bead.
But then I posted an update saying they were shit (better than MLS still).
The rubber beading keeps seperating from the steel shim, and allowing either coolant leak externally or oil into into coolant.

There was a good Australian supplier who made ones up out of composite.
Posted his link in another of my posts - "Copper gaskets" or suchlike.
He can still do 'em up - just no longer posted on ebay..
I'm finding these performing well.
Had to retension a couple of oil filler heads after about 50,000km..
higher temps on this head position - suspect fire rings getting pushed more up into the shitty head metal...
Back to good after that - clear sign was over pressurised coolant system with weeping coolant hoses surfaces...

Re the tension.
The manual is for the orignal head gaskets that are either MLS or such.
They usually had compression control built into 'em.
(thick edge banding)
The rubber bead ebay gasket also has this.
I found - not an ideal result for engines that had uneven tilted sleeves..
The composite one I now use just clamps the fire rings down onto the sleeves.
And that's the real limit. The fire rings essentially independent of next door neighbour.
I was going to experiment by removing the width control on the rubber beads, but I found the composite guy..
If not machining heads, the fire ring grooves are another reason part-turn method and gasket width control not best outcome...

So now - tightening only limited by bolt strength.
For the K5 engine studs - try 44 to 46ft.lbs (lubricated)
and only 56ft.lb if oiled(not recommended - always lube)
(conversion is about 62 N.m lubricated)
if reusing engine studs - pay careful note of the stud "feel".
(not worth it for firewall cylinder bank - too hard to get access to if they snap off.)
During retension - do it in stages over eight hours is good - lubricate bolts with a good moly compound.
And if its not getting tighter when you expect
- replace the bolt - its yielded and rotating about to snap. Ya can feel it...
Use some hollow alumin tube if bolt snaps off - you can also often unwind the snapped bolt using the broken section pushed down firm whilst rotating - lube remember...

New studs off ebay are good value.

Note: the part turn method is always a good system - just doesn't account for the shitty k5 engine alloy.

[razzledog]

I've just replaced the head gaskets with MLS gaskets from the UK. Bought new bolts too..
The manual I have clearly states pull them up to 18.8 ft lbs, then a further 90 degrees followed by a further 90 degrees. This is madness. The bolt threads are clearly starting to stress well before this is attained ..so I stopped at 45 degrees for the second sector turn. As Conglomerate states...you can 'feel it'.
I used MLS gaskets again as they were already fitted...and they showed no signs of failing.
If so many of the early Carnivals died, why do I see so many of them driving around each day... None are blowing smoke or overheating, so what's their secret?

[PeterBlue]

Originally Posted by razzledog

If so many of the early Carnivals died, why do I see so many of them driving around each day...

Plenty of them tootling around here in Tas too.

None are blowing smoke or overheating, so what's their secret?

Good question, maybe if they came out of the factory with good liner nip and haven't been mistreated (not overheated, maintenance kept up to them, especially the cooling system) they may be good as any other contemporary mill. The Rover guys seem to think so. Mine's been fine (although things were much improved by ’04).

Conglomerate's view if I understand it correctly is that once the engine has overheated (e.g. loss of coolant, heavy towing) the alloy in the block irreversibly changes & goes soft, which allows the liners to sink and have insufficient nip in the HG. Perhaps that could explain why many engines that failed, failed again after repair? Add to that the quality issues Rover had (and Kia unfortunately 'copied') with liner height and choice of HG.

It must be 6 years or so now since the last K5s shipped here, and 9 since the particularly bad ones, so it could be that the engines with build problems are out of the system now. The remainder are probably as good as any other as long as they are treated well, as all engines should be. The aero piston engines I fly behind are reliable & robust provided you treat them as if they're not.

I wonder how the Nanjing built KV6 is going.