Need advice - blown head gasket

[Rambuctious]

engine began to run rough, and tone sounded off ( running on 3??)
Appears blown head gasket as two plugs show milky near threads (outside and inside)

so.............
I need to check engine oil
can I pull head and replace gasket without worrying about crank bearings?

how hard to pull head with cam timing?

how easy to find a replacement engine?
what cost should I expect?

Ramb

 

[MrSled]

engine began to run rough, and tone sounded off ( running on 3??)
Appears blown head gasket as two plugs show milky near threads (outside and inside)

so.............
I need to check engine oil
can I pull head and replace gasket without worrying about crank bearings?

how hard to pull head with cam timing?

how easy to find a replacement engine?
what cost should I expect?

Ramb

How many miles? This is not an easy project, not even to change the head gasket. Its 16 hrs job to do the head and like 3 days to replace the engine. If you can find an engine. I have done many. If you have to hire someone, you may as well part it out or sell as is. If you have nothing but time and know how to turn a wrench you are still looking at $1000 to $2500.

 

[kinger]

New head gasket is $100, will take you a good 3-4 days if its your first time getting 'access' to the engine. Its more time consuming then hard/skilled. Leaving the engine in the sled is also easier then pulling it. Personally I would sign up for VIP here at ty4stroke, get the service manual, and plan a week after work nights to slowly R&R the gasket. It will be rewarding for you when done.

Now larger question is why did it go? Its extremely rare. Did you validate coolant in the oil? I would reassemble with cheap oil, start let it warm up, then drain oil again, fill it will yamalube, and go.

Good luck!

 

[Mooseman]

Wow, really? I just did it on my 3 holer and didn't encounter that many issues or costs unless the Apex is very much different. It did take me a few days working a few hours here and there. Only variable here would be if the head or block is cracked. If the oil is OK, I wouldn't worry about the bearings. Removing everything to get to the head is a PITA. I also sanded my head surface myself using emery cloth on a piece of glass so that saves a few bucks to get it flat.

Before condemning it, do a compression check. If it's inconclusive, a leakdown test should say if the head or block is losing air, especially in the coolant.

 

[steiner]

How many miles on the motor? If close to 20k you are due for a valve shim inspection. I would do a compression test to verify the issue.
Can't see the plug tips but the exterior corrosion could be from a coolant pipe leak on the top of the head. Have you tried putting new plugs in and running the motor? Check to coils to make sure they are not shorting out?
Yes you can pull the head without worrying about the bottom end. It's a big job. I thinking swapping motors would be faster.
Was fairly easy to find replacement engines in my area. Found many people parting out sleds. Most prices in my area were around $1500
If you are familiar with wrenching and well organized it will take a good day to swap out the motors. If not, then it can take much longer. My 2nd motor swap took me 3hours to remove and 5hours to install.

 

[MrSled]

Wow, really? I just did it on my 3 holer and didn't encounter that many issues or costs unless the Apex is very much different. It did take me a few days working a few hours here and there. Only variable here would be if the head or block is cracked. If the oil is OK, I wouldn't worry about the bearings. Removing everything to get to the head is a PITA. I also sanded my head surface myself using emery cloth on a piece of glass so that saves a few bucks to get it flat.

Before condemning it, do a compression check. If it's inconclusive, a leakdown test should say if the head or block is losing air, especially in the coolant.

Time is money Its cheap for parts but I fear there is more hidden problems that caused this gasket to blow.. therefor I would not touch it for less then a grand in hand.

 

[MrSled]

How many miles on the motor? If close to 20k you are due for a valve shim inspection. I would do a compression test to verify the issue.
Can't see the plug tips but the exterior corrosion could be from a coolant pipe leak on the top of the head. Have you tried putting new plugs in and running the motor? Check to coils to make sure they are not shorting out?
Yes you can pull the head without worrying about the bottom end. It's a big job. I thinking swapping motors would be faster.
Was fairly easy to find replacement engines in my area. Found many people parting out sleds. Most prices in my area were around $1500
If you are familiar with wrenching and well organized it will take a good day to swap out the motors. If not, then it can take much longer. My 2nd motor swap took me 3hours to remove and 5hours to install.

Well if we are comparing notes. I can have a motor in and out in a day

 

[kinger]

Well if we are comparing notes. I can have a motor in and out in a day

Ditto!!

 

[steiner]

Are we turning this thread into a "Challenge"? If so I have a video that proves I can do it in 5.5 minutes.

Ramb. Again, before you think about opening or changing the motor, do a compression test. These motors are very tough. Your issue might be simpler than you may think.

 

[steiner]

Ditto!!

Do you measure your time in hours or in beers?

 

[Rambuctious]

thanks for the feedback. much appreciated
1) I am an engineer.... have tools, heated pole barn, and a fridge for beer, and Motor Trend on the big screen for the lazy buddy who stops over on garage night and doesn't help. lol (oh and I installed a full wet nitrous system on my SRX to beat said buddy)
2) at this point, my short season is over so I can pick away at this and get it fixed right without rushing
3) I did replace the coolant inlets and their gaskets last year due to small leaks down valve cover. so it could have been leak down into the plug valleys maybe? but not sure that is root cause.
4) I did not get a chance to check oil. May do that tonight before heading out for the weekend with the wife (this will be the key indicator for me)
5) I will then do a compression check.
6) When she was "acting up" on the ride back I could first hear a vibration or grinding noise that would come and go... very confusing, and just before getting back to the cottage, I noticed it pulled only to 9200 at WOT, instead of 10,500.
6.5) when I ran it on the stand it would do it also. buzz coming and going. Exhaust tone was louder/flat making me think running on 3 cylinders.
7) I will attempt to pull the head with engine in, if I determine head gasket for sure.
8) I just have not read up on taking off the valve train and preparing for cam timing upon reassembly. (other than tie up the cam chain so it does not fall into crank case)
9) miles are only 7,200. only other engine component replaced was magneto pickup last year (after last years on trail failure uggg)
10) sled did get hot once last year, showing eng temp light, no power reduction, and cooled once we got off iced road.

if anyone finds a good pull out motor I may be interested as a contingency . I have searched and have not found one readily available. seems a sizable market for this engine install into light planes that are nabbing these.

tks

Ramb

 

[kinger]

Do you measure your time in hours or in beers?

Depends if I drop the motor or not once its out!

 

[kinger]

RAMB - I am thinking its not a head gasket. You have something else going on. CR test, and I have a leakdown kit you could borrow if you want. Its a PITA to get each cyl to TDC but it does help find the issue. My only head gasket failure was using ARP head studs and not TQ'ing to their new spec, coolant in the oil is the result, or smoking with lots of white smoke and low power. Your vibration could be a mis-fire and the gear reduction can make a racket when on 3 cyl. Could be as simple as a clogged injector. The hot light last year is of no concern. I also find it weird that you had to replace that coolant gaskets on the top of the head last year though. Again its not common. If you're not in a rush, get it in the shop and find that vibration/buzzing sound. You are about due for exhaust donuts, they can cause noises and backfiring is a tell tale sign. I would bet my fridge of beer your headgasket is fine.

 

[Rambuctious]

thanks Kinger. I will definitely take you up on the compression tester as I do not own one.
I like the comment that 3 cylinders can cause the rattle in the gear reduction. seems plausible and good that it may not be something else....

so.... oil check it is.... to know which direction and go from there.

FYI, I have the manual

Can the head come off without removing the cams? just remove the cam cover and gears? or is it simple enough to take them out? I guess I am concerned about cam alignment at reassembly.

and can you pull the head without remove the horseshoe frame?

oh, and donuts were replaced under warranty ( i bough used at 3 yrs old and just snuck that in)

 

[kinger]

@rxrider is your friend here! Awesome guy in Norway that documented so many things on the apex/rx1 chassis. Take a peek here. He even wrote a index to help navigate the extremely helpful garage on going thread!

https://ty4stroke.com/threads/rxriders-turbo-garage-pics-back-will-continue.47473/page-48

Upper steering frame (horseshoe loop as you call it) needs to come off, the best time saver here is leaving the bars and leaning it over to the brake side and just let it sit there. No need to remove bars or brake line, but you may have to unplug all the wiring in the rubber boot.