KA 24 SOHC Compression

[mick]

My engine 2.4L SOHC measured 130psi compression. I just read that the min. should be about 150psi. So how good is my engine right now? Is it very worn out? Or average compression for a used KA?

[Truck]

Well, that does seem low to me. Where did you hear about the 150 comp numbers? Those are for the DE... yes, SOHC should not be the same ratio.

http://www.ka-t.org/forums/viewtopic.php?t=33571

There is a guy around here who has links in his sig to the SOHC service manual. I'm sorry, I do not want to search for him, but you should be able to find it if you look.

[mick]

My mechanic said 130 is normal for a used engine. I saw the specs somewhere on Nicoclub or 240sx.org.

[mick]

So if the compression should be 170psi and I only have 130psi.............Should I rebuild the engine at this point?And how much horsepower am I losing?Does this affect gas mileage?

[Vegascorbin]

If you have 130 accross all cylinders then I would not worry to much about it. You are loosing some performance and milage but as long as it runs good for you I would just let it go.

That said, I would think your engine is a good candtidate for a rebuild. If all pressures are near equal then the black and head are probably in good shape. If you can afford the cost and the down time I think you will be pleased with the result of a rebuild.

[mick]

I took the car to a Nissan mechanic and told him I wanted a rebuild if my engine wasn't good. Then my mechanic said 130psi was good. So I put in a new oil pump and timing chain and spent over $1,000 on the MAF, TPS and everything else. And when I found out 170psi was what it should be, I told him that I just wasted time and money on an old worn engine when I should have been told to rebuild or get another. Now I must save up and get a rebuild after all this.I've got $9,000 into the car and the mechanic said he thought I just wanted it to run and pass smog. He didn't understand I am restoring the car.

[Vegascorbin]

If you have the ability to re-build your own block then it will cost around $1,000 depending on your machine shop cost. The money spent on the MAF etc is not waisted as they are all external to the engine and can be used after your rebuild.

Once you rebuild the block with alll those new parts I would say just add a new fuel punp and you should be good for another 100,000 miles with just regular maintance for a daily driver. Less if you race etc.

Total cost of 2,000 to 2,500 for what you have allready spent then the re-build is not bad for a 100,000 mile car.

[mick]

Maybe someday......no hurry right now