3K engine - high compression in #4 cylinder

[Tonka500]

Hello,

 

Love the forum and the cars it covers!

 

Just hoping to get some advice from people that know these engines inside out.

 

I've got a stock 3K engine in a KE16. It is fumy so I did a compression test and the result are attached.

 

Cylinder 4 has way higher compression that the rest at 230PSI. The spark plug is also very oily and oil sprayed out when doing the compression test.

 

Where would be the best place to start in tracking down the cause of the problem?

 

Thanks heaps in advance for any advice!

Andrew

[Banjo]

Welcome aboard !

My guess is, that your compression test on No: 4 cylinder, is not just compressing air. Air compresses much more easily that liquids, & my guess is that is an amount of oil, water; or combo of both present; in the cylinder.   Whatever it is, there is little point in discussing at length, what is causing it.   It is now time for the head to come off: & all would be revealed.

Whenever, K Series engines have issues in a particular cylinder; it is often cylinder no: 4. Cylinder No: 4 has the poorest water circulation of all the cylinders. That is because the coolant enters & leaves the block, through the front of the engine.  I've seen K series engines with so much rubbish around the outside of the No: 4 cylinder, that there was almost no water coolant flow at all. 

Off with the head, & all will be revealed.  The original manufacturing moulding blank or plug on the rear of the head, often rusts through.  Somewhere on this forum, I described a mod I did on my K series, which externally returned the chot coolant to the front of the engine.

https://www.rollaclub.com/board/topic/73676-oil-pump-failure/page/10/#comment-714068

Cheers Banjo

Edited July 20, 2025 by Banjo

[altezzaclub]

Do it again! But clean around the spark plugs with a rag on a thin screwdriver this time.  Replace the alloy tubes that stop oil getting into the cylinders past the spark plugs if they are graunched where the plugs seat on them. You can get new ones for a couple of bucks from a Great Wall agent, off the 4Y or whatever the early Great Walls used.

The oil leaks out past the rubber O-rings on the alloy tubes and sits around the spark plugs. When you pulled #4 out the oil ran into the cylinder and filled up some combustion chamber volume plus sealed the rings better.

I expect they are all around 150, that's fine!

If it stays at 230 again, you can pull the head off...

Edited July 20, 2025 by altezzaclub

[Tonka500]

Thanks heaps for the welcome and replies.

 

That link you posted Banjo is really interesting. I'll get some snacks and have a proper read. Love the logical problem solving.

 

I'll do what you mention first thanks altezzaclub and cross my fingers. If no luck I'll pull the head as you said Banjo.

 

Never taken a head off an engine before but it will be a good thing to do with my two boys.

 

Love all the super 3K specific info you're able to give. Thanks heaps🙏

[Banjo]

Sure You'll find the issue, & it will be fixable.  There are people on here that have been playing around with K series engines for 20-30 years.  Even if you haven't got an engine workshop manual; there is enough info on here, to get out of the Wiki, to get You out of trouble. If You have a question; just ask. There will always be someone here, who has the answer You need.

Cheers Banjo