s13 low compression - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

s13havok · 01-23-2014, 03:09 PM

Ok I've got a 91 s13 with a sohc motor in it. I ran a compression test and found out that cylinder 4 is running at 60 psi. The car has an exhaust leak out of the manifold but surprisingly doesn't run all that bad considering. Is there a way to test whether its something other than the exhaust leak causing the low compression? If anyone has any ideas im open to suggestions. thanks

DJ 21o3 · 01-23-2014, 04:40 PM

Correct me if I am wrong but an exhaust leak should not effect cylinder compression.

s13havok · 01-23-2014, 04:53 PM

ive been told it does and that it doesnt. Not really sure what to believe. Always thought it didn't make sence. What could cause it?

DJ 21o3 · 01-23-2014, 04:55 PM

Compression loss is generally from the piston rings not sealing. I have no idea how a manifold leak could possibly cause a loss of compression.

s13havok · 01-23-2014, 05:16 PM

Is there a way to test whether it is for sure the rings without tearing down the motor?

Rustys14 · 01-23-2014, 05:21 PM

Quote:

Originally Posted by s13havok

Is there a way to test whether it is for sure the rings without tearing down the motor?

Pour a little oil (thicker weight helps) down the spark plug hole and redo the compression test, if you get a higher number its likely the rings. Its that simple

s13havok · 01-23-2014, 05:23 PM

cool ill try that. you wouldnt happen to know how much boost a ka24e can take on stock internals?

Rustys14 · 01-23-2014, 05:41 PM

Quote:

Originally Posted by s13havok

cool ill try that. you wouldnt happen to know how much boost a ka24e can take on stock internals?

My old DE made close to 300hp on a stock bottom end with out any problems before I sold it. 350 seems to be about the limit for a reliable stockish KA though and that's pushing it a bit. There is no real boost limit since it really depends on what size turbo you run etc. Remember horsepower (and bad tunes) break motors not boost.

It sounds like your motor is in no condition for boost though and judging from the types of questions your asking you should probably avoid turboing your car until you've done more research and have a better grasp on these things. My advise is to spend your time and money on basic maintenance and get your car reliable before even thinking about boost. A reliable stock single cam in a well sorted chassis will always be way more fun then a haggard unreliable turbo setup. Just my

01-23-2014, 03:09 PM	#1
s13havok Join Date: Jan 2014 Location: shawnee, kansas Age: 30 Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	s13 low compression Ok I've got a 91 s13 with a sohc motor in it. I ran a compression test and found out that cylinder 4 is running at 60 psi. The car has an exhaust leak out of the manifold but surprisingly doesn't run all that bad considering. Is there a way to test whether its something other than the exhaust leak causing the low compression? If anyone has any ideas im open to suggestions. thanks

01-23-2014, 04:40 PM	#2
DJ 21o3 Zilvia Junkie Join Date: Jan 2013 Location: Central Illinois Posts: 353 Trader Rating: (0) Feedback Score: 0 reviews	Correct me if I am wrong but an exhaust leak should not effect cylinder compression.

01-23-2014, 04:53 PM	#3
s13havok Join Date: Jan 2014 Location: shawnee, kansas Age: 30 Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	ive been told it does and that it doesnt. Not really sure what to believe. Always thought it didn't make sence. What could cause it?

01-23-2014, 04:55 PM	#4
DJ 21o3 Zilvia Junkie Join Date: Jan 2013 Location: Central Illinois Posts: 353 Trader Rating: (0) Feedback Score: 0 reviews	Compression loss is generally from the piston rings not sealing. I have no idea how a manifold leak could possibly cause a loss of compression.

01-23-2014, 05:16 PM	#5
s13havok Join Date: Jan 2014 Location: shawnee, kansas Age: 30 Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	Is there a way to test whether it is for sure the rings without tearing down the motor?

01-23-2014, 05:23 PM	#7
s13havok Join Date: Jan 2014 Location: shawnee, kansas Age: 30 Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	cool ill try that. you wouldnt happen to know how much boost a ka24e can take on stock internals?