number 6 blown

[mrbassfla]

lost my number 6 cyl fri on my 250xb ,,,motor has been great up to thst point, going to rebuild, not sure all of them or just one ,the number 6, what does everyone think. also imput on anything else to look out for . injectors ? causes ? never over heated was running about 3500 rpms when it went down, seamed like it was running out of gas $2000 for one $2800 for all

[ol man river]

blown engines always suck.....better find out what caused it, or the rebuild will blow also......theyre funny that way .......

[mrbassfla]

yea i know , thats why i thought i needed some imput.

[EuropeanAM]

Teardown and inspection required to determine CAUSE.

Likely possibilities on #6 include:

-Hanging Thermostat on PORT bank
-Failure to warm up properly (Operator Error- Cold Seizure similar to above)
-Injector Problems (STRONGLY recommend Injectors be Serviced BEFORE reassembly)
-Reed Leakage/Failure

Be very cautious about rebuilds. Research the "builder"... their reputation, etc. That's a VERY low price (and if I were you, I'd want to know exactly what components are being replaced- ensuring they're OEM or TOP QUALITY ONLY).

[RiverRatMD]

sorry to hear about your Engine failure. A friend of mine recently blew his #5 on his XB. $2000 for One or $2800 for All is a crazy good price. Makes me wonder how they are going to do it for that!! My friends XB is getting done for $4000-$4500 ... And they are doing ALL pistons, sending out the injectors, and slappin' in new t-stats and impellor kit. That #6 sleeve will need to be removed, then a new one pressed in, then machined to spec. The crank will need to be inspected also. GOOD LUCK and let us know how things turn out!

[mrbassfla]

well after the tear down it seems that i had alot of debris around the t stats[as Don had said] , alarm never sounded , i guess we will have to check that out also, last motor had smart gauges , can not have with this motor.going to put in a digital gauge ,at least i can keep a eye on that, also spoke to my mechanic about the other thimgs that Don had said in his post. going to replace all 6 cyl , won't know the total $$$ till fri .. will post then . thanks for everyone imput

[EuropeanAM]

Good find on the T-stats.... that's likely the underlying "cause" (resulting in a cold seizure).

[mrbassfla]

Don ,what do you think about a water temp gauge, good deal or not, still have to check horn and sending unit, also still send injectore out ?

[EuropeanAM]

A temp gauge isn't a "bad" idea... but it's really only going to give you a general temp reading (you may not catch a thermostat that's sticking).

Keeping the engine and it's water inlets out of "nasty" water is the BEST option.

DEFINITELY have your injectors cleaned, tested, and if necessary, calibrated while it's apart.

[mrbassfla]

will do and thank you very much,

[mrbassfla]

well i got my injectors back ,,, number 1 was lean,2 and 6 was flooding at idle and part throttle 3,4 5, flooding all the time, 2 thur 6 were put back to spec , could not get num 1 , got a good used one, what the heck . glad i sent them off, how better will this thing run now, that motor ran great before that num 6 cly went down, i'am confused for sure, was it the t- stats or injectors ?

[RiverRatMD]

I feel ya! I just had mine cleaned and calibrated for maintenance. I thought mine ran great but when I got the report back, I had #4 running lean, #1 & #5 flooding all the time, and they all had dirty filter baskets. They all came into line but I wonder if I'll actually feel any difference....I'll let ya know! Good luck with the re-build....Whether the t-stats or injectors, I think you got the cause (I think likely the stat as your report showed #6 was flooding rather than lean).

[mrbassfla]

yes i think the same thing, should have it back on fri , hope all goes well and let me know how it runs , how was yours running ? smooth or alittle rough.


Modified by mrbassfla at 2:59 PM 3/5/2012

[EuropeanAM]

I'm going to say it was most likely the Port side Thermostat (or failure to warm up properly... even if just "once").

[Nikon Man]

Just an FYI for those who may not realize the importance of a proper warm up. I finally got my 300x back together after doing some work on the fuel system. Don went through all the injectors, I checked all the reeds and brand new stat's were installed. I put it on the hose and fired it up, set the idle and TPS, then let it run for 10 minutes. As it was still on idle, I then checked cylinder temps next to the plugs on 6, 4 & 2 and the readings were as follows:

#6 @ 98 degrees
#4 @ 107 degrees
#2 @ 121 degrees

As you can see #6 is always the cold one as it's further away from the stat and it see's fresh water flow first, then the water flow goes up to #4 and finally #2 and the stat, that's a 20 degree difference between #6 & #2. So with that being said, make sure you warm it up before you go to WOT.

Now think about this....if your temp sensor is between 2 & 4 then you'd be reading about 114 (avg the split) on the gage and you'd think that would be the temp in total of the motor...............NOT !!!! This makes me start thinking that maybe the 140 degree stats would be the way to go over the 120's on my application.


Modified by Nikon Man at 12:55 PM 3/6/2012

[mrbassfla]

got it back today,, complete with all 6 cyl done , injectors ,t stats, water pump , all filters , also put in temp gauge ,ran it today everything work as it should . just waiting for breakin,, to early to tell anything else . sucks running that double oil again, will keep posted when brakin is over,