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Chris (aka-Moose)
Chris (aka-Moose), Auto Technician
Category: Toyota
Satisfied Customers: 44444
Experience:  16 years of experience
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Scion xB: I own a 2008 Scion xB. Engine has been running with

Customer Question

I own a 2008 Scion xB. Engine has been running with significant valve tapping and loss of power.
I have pulled the engine valve cover, and cylinder head section of the Engine.
The valves show no visual evidence of damage. SHould I replace all valves and piston Rings as well?
Submitted: 1 year ago.
Category: Toyota
Expert:  Chris (aka-Moose) replied 1 year ago.
I am sorry for the delay in getting a response to you. Sometimes we get alot of customers and just can not keep up. Sometimes you just have to wait for the correct tech to login.Do you even still need help. Sometimes customers seek help elsewhere or figure it out on their own before we get to each and everyone.I am sure I can help a lot or a little at least something if you give me a chance and work with me. I am going to get an answer to you regardless if you reply or not sooner or later.If your concern is urgent reply and let me know and if you have anything more you think will help me, to help you, let me know. I work on here normally 3pm-3am central. Thanks Chris
Customer: replied 1 year ago.
Are you available to discuss my question now? Also, I have removed valves and I see no damage, no bent valves, just carbon buildup below spring line. Should I plan on replacing all valves to be certain or is there a way to determine which valves need to be replaced?
Customer: replied 1 year ago.
Original Question:I own a 2008 Scion xB. Engine has been running with significant valve tapping and loss of power.
I have pulled the engine valve cover, and cylinder head section of the Engine.
The valves show no visual evidence of damage. SHould I replace all valves and piston Rings as well?Read more: http://www.justanswer.com/toyota/95uyl-scion-xb-own-2008-scion-xb-engine-
Expert:  Chris (aka-Moose) replied 1 year ago.
Are you sure its a valve noise and not pinging from spark knock. While you have it apart, yes I would have the head rebuilt where as they test the springs, check the valves and seats and grind if needed, and replace the seals. If its spark knock then it can be from incorrect plugs, high head temps, incorrect fuel ratio. You want a excellent 5 star answer & I would like to be rated the same for providing it. Consider I don't know your skill level & I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies. Try your best to respond with good detail so I can do the same. I normally log in at 3pm and work late. A rating is required. Your rating me, what I type. I am not an employee of this website, nor have control over the fees or the time it took to get a response. If you rate negative or not at all you still paid, but I get nothing. I want you pleased with me and my efforts, so let me know if your experience here has come up short.Thanks Chris
Customer: replied 1 year ago.
My experience has been extensive rebuilding two stroke motorcycles, ( many rebuilds due to racing), and a few four stroke motorcycles, due to age, abuse, and poor maintenance. Piston rings on two strokes are easy to get to due to the lack of OH cam's. 4 stroke i have seen however require disconnection at the drive shaft to remove the piston head and more labor at the re-installation for torque and lubrication and the plastigarade application. I want to be efficient. Best results for reasonable labor.The engine is a 2ACFV? Toyota / Scion 2.4L inline 4.16V. Valves: intake valves are $17.79 ea, Exhaust are $19.29ea. I'd like to replace as few as possible. I have tested valves by adding brake cleaner to spring side to test for leaks using a paper surface under the Cylinder head chamber. I could Identify three valves that appear to have leaked. Valves have typical carbon buildup after 110K miles, nothing excessive.Valve have no obvious visible evidence of bend or brake. Piston rings I plan to replace due to the TSB issued on excessive oil usage / burning.Should I order 16 valves or only the ones that evidence a leak? SHould I clean contact sufacebetween valves and Cylinder head? is stell wool a bad thing to use to remove carbon? What solvents do you reccommend? I have my own favorites.Thank you.
Expert:  Chris (aka-Moose) replied 1 year ago.
Should I order 16 valves or only the ones that evidence a leak? SHould I clean contact sufacebetween valves and Cylinder head? is stell wool a bad thing to use to remove carbon? What solvents do you reccommend? I would see if the valves and seats can be ground, because is a valve is leaking the seat is likely to be equal to blame. Yes clean everything, I use a steel wool, a brass brush, and auto zone brake cleaner.
Customer: replied 1 year ago.
Should I separate the crankcase section of the engine from the middle section or remove each piston from the crank shaft and slide them up and out through the Cylinder head side?
Expert:  Chris (aka-Moose) replied 1 year ago.
If you wanting to replace the rings, it would be best to get the engine out, the crank off, and then remove the pistons out the top of the engine so you can better control the rods and not damage the cylinder walls.
Customer: replied 1 year ago.
Don't you mean remove the pistons out of the bottom of the engine? Wouldn't that be the purpose of removing the crank?
Expert:  Chris (aka-Moose) replied 1 year ago.
Pistons come out the top where the heads are. A ring compressor clamp would be in the way and not allow piston installation from the bottom crank end of the engine, much less the bores do not continue all the way through the bottom of the engine.

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