Engine Builder Question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ka24det-power · 07-22-2005, 04:53 PM

My SR was running perfect but I just upgraded to a GT3071R so I decided to install head studs and a head gasket before I get it tuned.

I have built several Honda's so I understand the basics.

I pulled the head degreased it and cleaned the mating surface on both the head and block. They where both perfectly clean. I reinstalled the head with a Cometic head gasket and torqued the ARP bolts to spec. I put the crank at TDC and then installed the cams TDC 10 o'clock and 12 o'clock. (11 links between them). Everything matched to the JWT and Nissan manual instructions.

Now the problem, I have 20psi compression on Cyl 1 and 4 / 180psi complession on Cyl 2 and 3.

I checked and triple checked the timing I can't tell what it is. When I took it all apart I left everything in the same order shims/lifters/etc...

WTF, I have a tuning session scheduled for Sunday and I might have to miss it.

Motor - SR20DET Blacktop S13

ka24det-power · 07-22-2005, 08:47 PM

Ok so I drained the air out of the Hydraulic Lash Adjusters (HLA) and now the compression is 60 / 125 / 135 / 55.

I am thinking that as soon as I start the car the oil pressure will fix the rest, I just dont want to put both the manifolds back on if the head gasket isn't sealed somehow.

What do you guys think? anyone have similar issues?

TOMY · 07-22-2005, 09:24 PM

where are the fat asses?

chlatboy · 07-23-2005, 04:13 AM

Yea, your thread name is weird man!!!

DeatschWerks · 07-23-2005, 08:10 AM

Quote:

Originally Posted by ka24det-power

I reinstalled the head with a Cometic head gasket and torqued the ARP bolts to spec.
Motor - SR20DET Blacktop S13

Did you torque them in sequence per the FSM? There is more to it than just thowing the bolts on and tightening them to spec. You probably know this but just checking.

ka24det-power · 07-23-2005, 08:45 AM

Yeah I used the sequence from XAT starting inside and working out. I am trying to make use of those (DeatschWerks) 650's I bought from you last month.

I havn't started the engine since I took the head off - I am doing in the compression check with just the cams in. I am starting to think that because the lashers are controlled by oil pressure they wont work properly until I give them oil pressure by running the engine.

95zilvia · 07-23-2005, 09:20 AM

I dont know if this is true, but I think sometimes the piston rings dont seat properly? Maybe throw a couple drops of oil in there to help them seal better.
Well regardless, you could use the oil trick to check the condition of your rings.
Just a suggestion.

ka24det-power · 07-23-2005, 07:19 PM

Ok brothers of SR, I have the answer.

It was the HLA's, after the 10 seconds of the motor running, the oil pressure made the lashers adjust to the correct hight and compression is back to normal. 155 accross the board.

Time to get it tuned.

19 PSI Here I come!

WILDACEX187 · 07-23-2005, 08:56 PM

thats cool wish i knew how to do half of wat u do lol. good luck with the car, post some pix and maybe vids

07-22-2005, 04:53 PM	#1
ka24det-power Zilvia Member Join Date: Dec 2004 Location: Florida Posts: 188 Trader Rating: (0) Feedback Score: 0 reviews	Engine Builder Question My SR was running perfect but I just upgraded to a GT3071R so I decided to install head studs and a head gasket before I get it tuned. I have built several Honda's so I understand the basics. I pulled the head degreased it and cleaned the mating surface on both the head and block. They where both perfectly clean. I reinstalled the head with a Cometic head gasket and torqued the ARP bolts to spec. I put the crank at TDC and then installed the cams TDC 10 o'clock and 12 o'clock. (11 links between them). Everything matched to the JWT and Nissan manual instructions. Now the problem, I have 20psi compression on Cyl 1 and 4 / 180psi complession on Cyl 2 and 3. I checked and triple checked the timing I can't tell what it is. When I took it all apart I left everything in the same order shims/lifters/etc... WTF, I have a tuning session scheduled for Sunday and I might have to miss it. Motor - SR20DET Blacktop S13 Last edited by ka24det-power; 07-22-2005 at 08:52 PM..

07-23-2005, 04:13 AM	#4
chlatboy Zilvia FREAK! Join Date: Aug 2004 Location: Somewhere Posts: 1,252 Trader Rating: (0) Feedback Score: 0 reviews	Yea, your thread name is weird man!!! __________________ If you dont know SEARCH!!!

07-23-2005, 08:56 PM	#9
WILDACEX187 Post Whore! Join Date: Jan 2003 Location: QUEENZ, NYC Age: 41 Posts: 3,103 Trader Rating: (4) Feedback Score: 4 reviews	thats cool wish i knew how to do half of wat u do lol. good luck with the car, post some pix and maybe vids __________________ SR POWA COUPE LUVVV!!!

07-22-2005, 08:47 PM	#2
ka24det-power Zilvia Member Join Date: Dec 2004 Location: Florida Posts: 188 Trader Rating: (0) Feedback Score: 0 reviews	Ok so I drained the air out of the Hydraulic Lash Adjusters (HLA) and now the compression is 60 / 125 / 135 / 55. I am thinking that as soon as I start the car the oil pressure will fix the rest, I just dont want to put both the manifolds back on if the head gasket isn't sealed somehow. What do you guys think? anyone have similar issues?

07-22-2005, 09:24 PM	#3
TOMY BANNED Join Date: Mar 2003 Location: Chicago Posts: 237 Trader Rating: (0) Feedback Score: 0 reviews	where are the fat asses?

07-23-2005, 08:45 AM	#6
ka24det-power Zilvia Member Join Date: Dec 2004 Location: Florida Posts: 188 Trader Rating: (0) Feedback Score: 0 reviews	Yeah I used the sequence from XAT starting inside and working out. I am trying to make use of those (DeatschWerks) 650's I bought from you last month. I havn't started the engine since I took the head off - I am doing in the compression check with just the cams in. I am starting to think that because the lashers are controlled by oil pressure they wont work properly until I give them oil pressure by running the engine.

07-23-2005, 09:20 AM	#7
95zilvia Nissanaholic! Join Date: Jun 2003 Location: South San Francisco Age: 39 Posts: 1,860 Trader Rating: (0) Rides Gallery: 95zilvia Feedback Score: 0 reviews	I dont know if this is true, but I think sometimes the piston rings dont seat properly? Maybe throw a couple drops of oil in there to help them seal better. Well regardless, you could use the oil trick to check the condition of your rings. Just a suggestion.

07-23-2005, 07:19 PM	#8
ka24det-power Zilvia Member Join Date: Dec 2004 Location: Florida Posts: 188 Trader Rating: (0) Feedback Score: 0 reviews	Ok brothers of SR, I have the answer. It was the HLA's, after the 10 seconds of the motor running, the oil pressure made the lashers adjust to the correct hight and compression is back to normal. 155 accross the board. Time to get it tuned. 19 PSI Here I come!