Tore into my KA today.

[VintageRice]

Been busy with bodywork but finally tore into my KA24e today.

 

Bought this motor for $75 knowing nothing about it. Got it home and turned it over by hand and could hear compression leaking through a intake valve. so I knew i had to at least pull the head.

 

Today pulled the head and there was valve indents in all four pistons, on the exhaust side. What is this from?? Looks like all four exhaust valves were hitting the pistons.

 

 

Also these chunks were in the pan, I've read thats common of the timing chain guides. Any worries here on the chunks inside or just clean, and replace timing set??

 

Also, what does the 30R and 05 mean on the piston? .30 over?? Rebuilt?? Cylinder walls look very nice.

 

Heres the oics. EDIT heres one. Photobucket is being very GAY.

 

 

 

Uploaded with ImageShack.us

 

 

[datzenmike]

Been busy with bodywork but finally tore into my KA24e today.

 

Bought this motor for $75 knowing nothing about it. Got it home and turned it over by hand and could hear compression leaking through a intake valve. so I knew i had to at least pull the head.

 

Today pulled the head and there was valve indents in all four pistons, on the exhaust side. What is this from?? Looks like all four exhaust valves were hitting the pistons.

 

 

Also these chunks were in the pan, I've read thats common of the timing chain guides. Any worries here on the chunks inside or just clean, and replace timing set??

 

Also, what does the 30R and 05 mean on the piston? .30 over?? Rebuilt?? Cylinder walls look very nice.

 

Heres the oics. EDIT heres one. Photobucket is being very GAY.

 

 

 

Uploaded with ImageShack.us

 

 

 

The air leak is likely bent valves from hitting the piston(s). No biggie as you already have it off anyway.

 

Chunks in the oil pan is common as the timing chain guides were plastic crap compared to the L and Z series and usually self destructed by 100K. Another cheapening of the product was the single link timing chain. (L and Z motors were double link in indestructible)

 

Cheap KA24E single sprocket, single row chain and plastic slack side tensioner. Compare to the Z24 below that makes about 65% as much power as the KA.

 

 

Found these tensioner chunks and more in the pan. By the time they blow the present owner doesn't care and just leaves them in the pan.

 

Which makes me wonder if the tension side guide destructs, is there enough slack for the chain to jump of the bottom or top sprocket? If so it would explain the exhaust valve strikes before the motor stopped.

 

 

 

Does the chain and guides look new?

 

 

I would lightly sand any sharp edges off the piston tops, replace any bent valves, replace the chain and guides/tensioner (if not done already) and run it. Good score.

 

 

 

 

Pistons are mass produced and are never exactly the 89mm required for a KA bore. A standard piston can range from 88.965mm to 89.015mm the bore must fall within 89mm and 89.05mm from the supplier. The bore is measured and divided into 4 grades depending on the width and may be stamped with a 1 to 4 number.The pistons are also divided into 4 grades. You can see the maximum (4) size piston will never fit the minimum size bore. (1) But a smallest number (1) piston will. This speeds up the assembly by simply selecting the corresponding piston size to the proper bore size. It would be very expensive if only exact 89.025mm bore blocks and only 88.99mm pistons were allowed. Grading allows for the inevitable slightly over or under.

 

Oversize pistons in 0.02mm, 0.50mm and 1.0mm are also available for blocks that are overbored due to cylinder damage. These three oversizes are also graded.

 

 

 

 

The 3 is likely the grade. The 05may be the 0.5mm oversize. The 30R may be something to do with KA engine parts. This is only a guess.

[RedBanner]

Looks like you skipped a couple teeth, not good, bent valve(s) probly, when you took the head off, did you check the timing first? Was it close?

[RedBanner]

Jinks you oh me some coke....

[Big Schlink]

Jinks you oh me some coke....

 

What kind of Coke our we talkin about here? lol

[VintageRice]

Ok, great info as always!

 

I guess I'll get the head rebuilt and replace all the valves, and whatever else is usually replaced. I am planning on getting a big cam anyway. Replace the timing set and slap it back together.

 

Mike, do you think I should replace the bottom end bearings and re-ring it too while its apart or just run it? I'd rather not to be honest, but if it's a good idea maybe I should.

 

Anything I can check? Cyl walls look clean with no scoring. Turns over smooth.

[datzenmike]

Who can know without running it if it's any good. You could have the bore measured. If way above stock bore maybe it's been rebuilt with oversize pistons already? Just replace the valves needed. Have them lapped and installed with new seals. Whatever the re-builder says.