KA24det no woosh of air when spining crank - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Creamypies · 01-21-2014, 12:26 PM

so I rebuilt my KA, havent posted here in a while but I need some tech help, so I rebuilt it, fired it up, set the timing to 20 originally or so I thought I set it to 20, once I get the timing light on the crank it was reading at 30 and my idle was high(like 1500rpm),

so then I pulled the dizzy to make the timing at 15 which is where It needed to be at to work with my rs enthalpy. found out that I couldn't set it not at 180 out, so I pulled my VC to make sure the motor was on the compression stroke and now when I spin the crank there is no compression noise (aka that loud woosh of air when you spin the crank with the spark plug out of cylinder 1) and for the life of me I cant figure out why. anyways help is always appreciated

*brndck* · 01-21-2014, 12:52 PM

Ummmm then you have no compression. Either your rings are not sealing or one/both valve(s) are hanging open.
Have you bothered using a compression tester or are you just guessing because you don't have a "whoosh" noise?

Creamypies · 01-21-2014, 02:10 PM

Quote:

Originally Posted by brndck

Ummmm then you have no compression. Either your rings are not sealing or one/both valve(s) are hanging open.
Have you bothered using a compression tester or are you just guessing because you don't have a "whoosh" noise?

No I had compression before I pulled my VC, and I seriously doubt I have NO compression, I just rebuilt the motor for christ sakes haha, and it was working before I pulled my VC, I had a huge rush of air, could the rings have gotten worked like that ? / how would just removing the VC have done this? / I dont own a compression tester

Juantwo3 · 01-21-2014, 02:46 PM

Quote:

Originally Posted by brndck

Ummmm then you have no compression. Either your rings are not sealing or one/both valve(s) are hanging open.
Have you bothered using a compression tester or are you just guessing because you don't have a "whoosh" noise?

msg lngth

Creamypies · 01-21-2014, 06:00 PM

Quote:

Originally Posted by Juantwo3

msg lngth

it definitely isnt that I have NO compression

*brndck* · 01-21-2014, 06:20 PM

But you have no woosh!!!!

Creamypies · 01-21-2014, 08:19 PM

Quote:

Originally Posted by brndck

But you have no woosh!!!!

alright, so properly re installed the VC, got a little backfire with the timing set at 15, maybe I should bring it to 20 and try starting it ?

pacotaco345 · 01-21-2014, 11:00 PM

Idk if this is the same issue I had with my SR but it sounds similar. Freshly rebuilt motor, had maybe 5 miles and ~45 minutes of runtime on it when I installed my new (tomei pon)cams, new rocker arms and new oil squirters. I went ahead and threw everything back together, cranked the car and ... nothing. No "bwakakakaka" compression sound just a free spinning motor. Scared that I fucked up real bad and didn't tighten a cam bolt I pulled the vc back off and checked again. Everything checked out so I cranked the car with the vc off and still nothing. Got out and turned the motor over slowly by hand and it felt like it had compression once again. Got back in and cranked it and voila, compression. Re-assembled it once more and it fired right up...

This story probably doesn't help you at all but yeah.. good luck lol.

01-21-2014, 12:26 PM	#1
Creamypies Join Date: Jan 2014 Location: utah Posts: 4 Trader Rating: (0) Feedback Score: 0 reviews	KA24det no woosh of air when spining crank so I rebuilt my KA, havent posted here in a while but I need some tech help, so I rebuilt it, fired it up, set the timing to 20 originally or so I thought I set it to 20, once I get the timing light on the crank it was reading at 30 and my idle was high(like 1500rpm), so then I pulled the dizzy to make the timing at 15 which is where It needed to be at to work with my rs enthalpy. found out that I couldn't set it not at 180 out, so I pulled my VC to make sure the motor was on the compression stroke and now when I spin the crank there is no compression noise (aka that loud woosh of air when you spin the crank with the spark plug out of cylinder 1) and for the life of me I cant figure out why. anyways help is always appreciated

01-21-2014, 11:00 PM	#8
pacotaco345 Zilvia FREAK! Join Date: Jan 2010 Location: SoCal/Ft Worth TX Age: 31 Posts: 1,563 Trader Rating: (5) Feedback Score: 5 reviews	Idk if this is the same issue I had with my SR but it sounds similar. Freshly rebuilt motor, had maybe 5 miles and ~45 minutes of runtime on it when I installed my new (tomei pon)cams, new rocker arms and new oil squirters. I went ahead and threw everything back together, cranked the car and ... nothing. No "bwakakakaka" compression sound just a free spinning motor. Scared that I fucked up real bad and didn't tighten a cam bolt I pulled the vc back off and checked again. Everything checked out so I cranked the car with the vc off and still nothing. Got out and turned the motor over slowly by hand and it felt like it had compression once again. Got back in and cranked it and voila, compression. Re-assembled it once more and it fired right up... This story probably doesn't help you at all but yeah.. good luck lol. __________________