Black oily plugs idle nightmare

[clovertex]

Got myself a KE70 wagon with a 4K roughly two years ago as my first project car and have been working on it on and off. The whole time I've been struggling to get it idling nicely. I've refreshed the entire ignition system, replaced the intake maifold gasket and isolated every vac system to elimiate potential vac leaks, but I'm still having issues. Anyway, I notice after the car has sat for a while, every spark plug is either wet with fuel (or oil I can't tell) around the plug and pooling underneath the metal boot thing they sit in. There are also usually carbon deposits around the tip of the plug. After giving them a clean she will idle for a while nicely only to start stalling and spluttering again.

I feel as though it could be running lean, however adjusting the idle mixture screw is very touch and go. Any advice would be appreciated, thanks.

[Banjo]

Hi Ben,

            Welcome aboard !   What you describe is not unusual, & probably been experienced my mamy on here, with older K Series engine.

 

There are two quite distinctly different issues here.  

 

The aluminiun spark plug tubes, are soft, as they are aluminium.  They play two important fuctions.

1.  The flat section of the bottom on the tube, through which the threaded section of the spark plug protudes, is "clamped", between spark plug & head, when you tighten the spark plugs up.  Over time, this area of the tube gets thinner, & sometuimes even cracked & worn; as a result of the spark plug "tightening down action"; is not perfect, & in worse case can suck oil into the cylinder.

 

2.  The second function is to prevent oil return path, from rocker oil feed, to sump, from leaking.  It has a rubber under the top lip, to seal at that end, & the spark plug tightening on the flat at the bottom, to prevent from the bottom end.

 

Because tha aluniniun is soft, the tube can effectively "elongate", & it will not seal properly on the rubber seal at the top.

 

Solution, new aluminium tubes & rubbers.

 

Bear in mind, that in your first picture, that whole void in there is wet with hot oil return to the sump, whilst the engine is running.

 

Also check the sump breather relief valve on the top of the rocker cover.  If that is blocked it will exaserbate oil leaks inside the sump/block/head area.

 

That valve feeds back into the inlet side of the head, so you can easily understand the implications, if that is stuck "open".

 

The "wet" spark plugs would maybe indicate a mixture too rich, rather than too lean, & maybe an issue with the needle & seat & float in the carby, not cutting off fuel flow properly.

 

Maybe time to remove the carby, & completely clean & reassemble.

 

Don't forget the  crankcase pressure valve that protudes from the top of the rocker cover.  Often neglected, which results in them being fully open, or fully closed.

 

Take your time, & work through these three (3) areas, & I'm pretty sure, you will resolve your current issues.

 

Cheers Banjo

 

 

[altezzaclub]

Those tubes are used on the early Great Wall utes, which had Toyota motors. They are much cheaper than from Toyota if you can find them at a Great Wall dealer.

The starting point for the idle mixture screw is turn it right in until it gently seats, then turn it out one and a half turns. A motor with nothing wrong should be within a 1/4 turn of that. With a warm motor at idle you should be able to turn the screw in and out by 1/4turns and pick the smoothest, fastest idle with the screw furthest in.

[clovertex]

Cheers guys I've read countless numbers of both your comments and posts on this forum so appreciate the reply. I'll get a new PCV valve on it today, order new aluminium tubes and set that idle mixture screw out one and a half turns. Just been for another can of carby cleaner too so will give it another wash focusing on the idle circuit. 

Will keep this updated 💪

[clovertex]

So mixed news! After taking apart the carb, cleaning out the idle circuitry and reajusting the idle mixture screw to one and a quarter turns she was finally purring nicely at idle. I'm embarrased to admit that through all this I found a vaccum port the size of a small planet running straight to the manifold that I neglected to plug up. I got her out of the shed and took her for a proper spin for the first time which was very rewarding.

Also got the new aluminum spark plug tubes in and a fresh PCV valve installed, despite the old one looking mostly fine.

Throughout the week she started to deteriate and the idle problem creeped back, and I'd be stalling every time I'd coast to a stop on the road.

After retesting for vac leaks with the old soapy water spray bottle trick (pictured) whilst spraying compressed air into the intake, I discovered a worsening leak on the intake manifold gasket. I'd literally replaced the gasket a week prior so really didn't expect this to be an issue. I did't use any gasket sealer, as non of the litrature on the engine mentioned it (and frankly I didn't know it existed) but after talking to some local buddies they recommended it. What do you think? I've sanded the aluminum face of the intake as flat as I could (pictured) to remove any pitting on the surface, and torquing the bolts any tighter doesn't seem to have an effect.

Anyone who's had their 4k intakes off know they come in two pieces and the gaskets are wierdly combined with the exhaust ports and the intake ports, and come in two serperate pieces for each end. I think there are some aftermarket ones that come as a single piece.

On a different topic, the bottom of the door panels are really starting to crumble. I will work on getting a clear picture up soon. I've got no experience with metal work, so I'd would have to be a shop job if it were to be patched up. I've seen some decently priced door skins available though, so might it be more efficient to replace the entire thing? I'm really not sure of the work involved on those, but each time the door opens more bits fall off haha.    

Any recommendations or wise words would greatly be apprecitated, thanks! 😁

[Banjo]

Yep, that is a problem area, many Rollaclub members have experienced.

 

This post explains the issue & ways to fix it.

 

https://www.rollaclub.com/board/topic/82146-new-to-rollaclub/?do=findComment&comment=731487

 

It is imperative that before you fit the mainifolds, that both exhaust & inlet manifold faces, that bolt up to the head, are alreeady in line. Check with a straight edge, before fitting.

 

 

The one piece gasket is also a must.

 

This thread might assist your understanding of the manifold issue.

 

https://www.rollaclub.com/board/topic/74148-one-piece-manifold-gasket-k-series/#comment-715486

 

Unfortunately, it will require you to drop the exhaust pipe, & extract manifolds & carby, & start again.

 

Cheers Banjo

Edited April 19, 2023 by Banjo

[clovertex]

As with this example off ebay, my intake / exhaust bolt holes don't make perfect circles when the two pieces are bolted together at the back. The gap between the aluminium and steel is inconsistent between both sides also, and I'm thinking this could be screwing up the positioning of the gasket. Assumed this is due to the soft alluminum intake moving rather than the exhaust extractor. Considering sourcing a whole new piece at this rate.

[Banjo]

 

Hi Ben,

            The out of roundness, as you describe the gaps & spaces between exhaust & inlet, are not an issue, as very large thick washers should be used to clamp down both manifolds.   What is more important, is that the faces of both inlet & exhast manifolds are in perfect alignment, & perfectly smooth; when manifolds & gaskets are fitted to the head.

 

 

Bear in mind, that the inlet & exhaust manifolds are "bolted together", directly below the carby (see above).  It is always a possibility, that these have been seperated at some time, in their long life, & bolted back together, with both gasket faces not in perfect alignment.  Unfortunately, I've found over the years, these bolts will be almost "welded" to the exhaust manifold, because of the heat in that area.

 

The flanges on the manifolds, where the big thick washes clamp down; must also be the same thickness, so the thick washers sit flat.

 

 

 

 

A little bit of attention to detail in this area, & it will work, & your inlet sucking air in from unwanted areas, will be solved.

 

Cheers Banjo

 

 

 

Edited April 20, 2023 by Banjo

[altezzaclub]

Grab vernier calipers or put both manifolds face-down on a flat surface and grab feeler gauges. Measure the thickness of inlet and exhaust tabs where the washers press them onto the head and put a half-washer or bit of wire on the thin half... anything to make the washer push down evenly on the two manifolds. I had a set of washers with thin half-spring-washers brazed onto them.

[Banjo]

Good point !    Ben; remember that the inlet manifold (aluminium) & exhaust manifold (cast iron) are  made of two different materials, with different expansion rates, when heated  & cooled.

 

The use of a very thick hardened washer, is a necessity, to be able for the "pull down" on each manifold tab, to be flat & strong.   Don't be tempted to file down the exhaust manifold tab, on the outer side, if it is thicker.

 

I have once, long ago, filed the outer side of the aluminium mainifold tab/s; when it was the thicker, & it solved the issue, but it was not a lot of material removed. 

 

The really import fact; is that a straight edge across both manifold's gasket mating surfaces, should have no gaps of more than a thou or two.  The heavy & thicker one piece gasket, with absorb any small alignment gaps like that.

 

I can assure you, that I have done this job on 2-3 K Series engines over the years, & after, what I have described was carried out, the result was permanent, & I have never had to revisit them again.

 

We have had a number of people on this forum, over the past 12 months, that have learnt, that sealing of the "inlet manifold track", is extremely important aspect of getting idle & tuning correct.

 

All air entering the cylinders; must be air that only enters through the carby venturi, & not from elsewhere.

 

P.S.  One last suggestion.  Once you have done this, & the engine is running sweetly again, make sure you re-tighten/re-torque the manifold stud nuts. 

 

Cheers  Banjo

 

 

Edited April 20, 2023 by Banjo

[clovertex]

Pain. Misery.

I'm at uni so only get time to work on her some weekends, so I tend to order parts during the week. After removing the exhaust extractors and intake manifold for the millionth time and throwing away the shitey 2 piece gasket that's about a month old I took another look at the allignment of the faces between the exhaust / intake with a steel ruler and there was a discreptancy of around 6 to 7 thou on the feeler gauge as suspected.

The thickness of all the tabs (as banjo describes) were honest to god exactly the same. Thick washers were present on every bolt and stud securing the assembly to the engine block, so I had no concerns there. What I did notice is that the exhaust ports on either side of the piece were raised significantly higher than the 2 centre ports on the extractor manifold and also on the intake. I opted to sand the 2 offending faces down to where they were within a couple thou of the rest of the piece.

I've already had the alluminium intake sent to a machine shop to get refaced, where they actually mangaged to snap one of the mounting holes off that I needed to get rewelded, throwing another spanner in the works trying to get her alligned.

Anyway I got a new one piece, 3 layer fancy gasket and a tube full of high temperature RTV sealer that I generously spread on EITHER SIDE and left for 24hrs to cure after being torqued up to block.

I slept easy that night knowing that there was no chance of leak the next afternoon. I don't know what sin I committed in a previous life but it's done rock all and the vac leak is still horrendous. The whole thing is such a hideous mess that there is also a new crack that's shown itself next to the bolt holes on the aluminum.

I'm at my wits end so have ordered a new old stock 17110-13110 assembly with both manifolds that came up on ebay. The bank is now broken and student loan obliterated so I'm hanging my hopes on this new unit. Will keep this updated.

Edited May 2, 2023 by clovertex
spelling

[Banjo]

Hi Ben,

             Sorry to hear you are having so many issues with this particular problem.

My only comment at present is, that the special one piece gasket you have purchased, does not look like the the one, we have available here in Australia.

The one available to us, is quite thick, & tends to take up those small gaps, between manifolds & head face.

It appears from your picture to be a metal gasket, with "facing" added to it.  If it is metal, one would think, it wouldn't have the ability to "absorb", small clearance descrepancies between the inlet & exhaust manifold faces.

Cheers Banjo

 

 

Edited May 1, 2023 by Banjo

[Taz_Rx]

That's a genuine 7kc gasket Banjo