Found something interesting

[Falkon45]

So, I pulled my head to do the titanium valve retainers, and found this

Found my coolant consumption issue. Crazy, because not a single BHG symptom. No overheating, no oil in water. Just a CEL after I installed the rapid bike, and a lot of liquid in my crank case vent.

Glad I pulled this thing apart. Finding a few serious issues before they became catastrophic.

 

[Superpacman13]

So, I pulled my head to do the titanium valve retainers, and found thisView attachment 5782

Found my coolant consumption issue. Crazy, because not a single BHG symptom. No overheating, no oil in water. Just a CEL after I installed the rapid bike, and a lot of liquid in my crank case vent.

Glad I pulled this thing apart. Finding a few serious issues before they became catastrophic.

That is totally normal for an RC. The headgaskets blow on the exhaust side and not the intake. The clean spot you are seeing is actually my biggest issues with the RC, the design of the combustion chamber creates a hotspot at the very back(intake) side of the piston and head. This is why I don't run any ignition timing in my builds because 9 times out of 10 it creates more heat in that area and blows itself to shit quickly.

 

[Mr 6 speed]

That is totally normal for an RC. The headgaskets blow on the exhaust side and not the intake. The clean spot you are seeing is actually my biggest issues with the RC, the design of the combustion chamber creates a hotspot at the very back(intake) side of the piston and head. This is why I don't run any ignition timing in my builds because 9 times out of 10 it creates more heat in that area and blows itself to shit quickly.

Same problem here

Sent from my Mi A1 using Tapatalk

 

[Falkon45]

That is totally normal for an RC. The headgaskets blow on the exhaust side and not the intake. The clean spot you are seeing is actually my biggest issues with the RC, the design of the combustion chamber creates a hotspot at the very back(intake) side of the piston and head. This is why I don't run any ignition timing in my builds because 9 times out of 10 it creates more heat in that area and blows itself to shit quickly.

Well, that I didn't know. You learn something new everyday. Interesting. Does head work do anything to help that issue? I have the thing apart. Might as well see what all I can do.

Also, one of the dammed ferrules for the head bolts fell into the crank case when I pulled the jug. I need to find a magnet to attach to my borescope and fish that thing out.

What other preventive measures should I take while the engine is in pieces?

 

[chevaliernoir]

I had the same ... at the same location...
I checked the cylinder head flatness and it was not flat at all, with a kind of cavity where the gasket blew.

So In any case I recommend you to not simply change the gasket, but rework also the cylinder head.
I did it by myself with almost no tool (except a glass table from the kitchen)
Story is > here <

 

[Superpacman13]

Well, that I didn't know. You learn something new everyday. Interesting. Does head work do anything to help that issue? I have the thing apart. Might as well see what all I can do.

Also, one of the dammed ferrules for the head bolts fell into the crank case when I pulled the jug. I need to find a magnet to attach to my borescope and fish that thing out.

What other preventive measures should I take while the engine is in pieces?

I have not found a solution besides good fuel and no timing. The only thing I do before reassembly on the combustion chamber is polish the bejezus out of it, not sure if it helps but it makes me feel better!

 

[Falkon45]

I had the same ... at the same location...
I checked the cylinder head flatness and it was not flat at all, with a kind of cavity where the gasket blew.

So In any case I recommend you to not simply change the gasket, but rework also the cylinder head.
I did it by myself with almost no tool (except a glass table from the kitchen)
Story is here

That's kind of what I was thinking. While looking at the gasket, the coating around the tiny hole on that coolant port didn't look like it made good contact with the block. I'll take this into consideration with what superpacman said also.

Like I said, I've been consuming coolant. If this helps stop the problem, I'm happy with that. I'll probably clean the valves also.

 

[Shaharidan]

Yes get your head checked and machined flat if needed, generally it's not too expensive to have it done and apparently most of them are warped, mine was.
I had mine done at a local speed shop that mostly does Harleys, I don't remember the price, but I'm pretty sure it was under $100 and I had it back in a couple of days.
You may have to hunt around to find a local place, I'd also check places that do cars, it shouldn't make any difference to them if it's for a car or a bike.
Worst case you may have to ship it out somewhere.
You may as well do the thinner head gasket while you're at it.

 

[ReidMcT]

Well, I have joined the club. I have not had any overheating problems, but coolant has been disappearing for quite some time, and the oil has been getting milky, requiring frequent changes.

I also found some damage from the cam chain rubbing, presumably because of my failed tensioner. I had to smooth the head surface damage, which fortunately was not in a gasket area. Smoothing it will let me try to flatten the head using Chevaliernoir's DIY method of emery paper on a glass table.

Question: How do you check the flatness and find the low spots? With a flat edge and feeler gauges I would guess, but I've never done it.

 

[chevaliernoir]

I'm happy my repair could be useful for other.
In order to measure the flatness, I used this kind of tool :

but you don't really need it : when you start, with "500" emery paper, you will see very fast the portion of the surface that touch the paper and the area that does not touche the paper. Here for example, the complete surface was not touching the paper, and this prove the surface was not flat at all.

Then you know you have to continue until you get a uniform surface, then change emery paper for 800 then 1000 emery paper (no need to go further)

 

[ReidMcT]

Thank you again, Chevaliernoir! Your posts are always informative, and your methods and ideas are always most helpful and practical.

I am awaiting delivery of my emery paper and look forward to seeing the results next week.

 

[ReidMcT]

Yesterday I flattened the head using Chevaliernoir's method. I think it worked well. As he had noted, it took a LONG time.

The first photo is after about 15 minutes. The low spots are not hard to see, and I can easily imagine coolant finding its way from the water jacket to both the combustion chamber and the cam chain way.

The second photo is after well over an hour of sanding with progressively finer grits, ending with 1500. There still remain some machining marks on part of the head, but I do not think these were causing any trouble previously, and they are shallower now.

One more problem I have is that I found the cam chain was damaged because of the broken tensioner. It has many tight spots. I have ordered a new one.

 

[1JZSupra]

About how much would you say you are into as far as parts go? (Money that is)

 

[ReidMcT]

About how much would you say you are into as far as parts go? (Money that is)

If you are asking me, on this particular adventure my parts costs are:
Head gasket ($? I had one in stock),
Tensioner ($47 used),
Chain ($50),
Emery papers ($10),
Oil and filter ($20).
I will reuse the coolant.

 

[1JZSupra]

If you are asking me, on this particular adventure my parts costs are:
Head gasket ($? I had one in stock),
Tensioner ($47 used),
Chain ($50),
Emery papers ($10),
Oil and filter ($20).
I will reuse the coolant.

exactly what I was looking for, thanks!

 

[Razor1]

I did the glass self-resurfacing on my 2016, in my particular case, the top of my cylinder had a large low spot all the way around the bore, took longer to clean up than the head. Couple pics attached. My stock gasket never blew, i just decided to do this as a preventative measure.