Nissan Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
189 Posts
Discussion Starter #1
Hi! I have a RPM switch for active the VTC but my engine have a custom falt top pistons (not notch). My question is... have problem with the valve and piston clearance? The intake valves with VTC activated "crashed" in the piston...? I have OEM Cams, stock head, stock OEM head gasket...! Thanks!
* sorry! I speak a little english.
 

·
Registered
Joined
·
4,211 Posts
Since no one has direct knowledge, the old school way to check this was to assemble and insert plasticine or a putty in the critical areas and hand turn over to measure the clearance.
You could also check the all motor section, and re-post there. ask nicely, they might know.
http://www.nissanforums.com/naturally-aspirated/
 

·
Registered
Joined
·
189 Posts
Discussion Starter #5
My engine are complete, and mounted in my B-11... :( this is the problem!!!!
Any suggestion? Thanks!
 

·
Registered
Joined
·
42 Posts
Are you saying they already crashed into the piston, and you want to stop the VCT from working?

Or that you're afraid they're gonna crash into the piston, and so you wanna turn off the VCT beforehand?

It runs off an electric solenoid, in any case, so disconnecting the solenoid will stop the VCT from engaging. However, that'll probably throw a CEL, and you'll lose top end power, but that's better than putting a valve through a piston. It's part 23796 on the below diagram.

130 Camshaft & Valve Mechanism :: Engine Mechanical :: Genuine Nissan Parts :: Sentra / NX (B13) 1991-1994 :: CourtesyParts.com

No guarantee this won't hurt the engine.
 

·
Registered
Joined
·
189 Posts
Discussion Starter #7
Or that you're afraid they're gonna crash into the piston...
I want the VTC but i scare gonna crash the valve. I can do a manual test to check this? maybe advance +1 in the timing chain. (VTC intake sprocket). This is correct? Thanks!
 

·
Registered
Joined
·
86 Posts
I think better way to test this migth be (like IanH told) to use some material witch you can put in the cylinder from the spark plug hole and then turn out the engine by hand. after that you can measure the clearance betveen piston and valve from that materia you put inside the engine. Just take it away and measure how flat it is.

But to get correct results you should somehow activate the VTC when turning the engine.

- No-Pain -
 

·
Registered
Joined
·
3 Posts
Sounds like to me you wanted the advantage of increased compression with pistons that have no reliefs. However this is telling me a possible stoke modification.

I did this to my 3.4L DOCH GM LQ1 with custom hyperetics and had to have the cams custom ground. This made my LQ1 a interferance engine so if the belt broke I would have to replace several valves.

To me it sounds as if a head shim may make the valves clear duration, however not sure what clearances you have.

Adjusting timing may not fix it as then the other end of the spectrum may collide timing wise after the power stroke effectively decreasing RPM limit. If you have to adjust timing then would it not make a flat top piston a waste of time as the valve would open late and close late. In this case it seems the valve would open full atTDC to collide.

Also to me I would get custom pistons that had reliefs but made in such a way to decrease piston to head clearance but maintain relief depth accomodated by head decking and block planing. We are talking few thousandths so the advantage of removing reliefs all together may not yield any practical results without other modifications.
 

·
Registered
Joined
·
189 Posts
Discussion Starter #10
The advanced +1 in the Intake sprocket is simulated the VTC activated. I realice the test this saturday and the valves no touch in the pistons, good for me! Thanks!
 

·
Registered
Joined
·
1,014 Posts
to my knowledge we do not have any interference in the piston to valve clearance, so you would not have to worry if the chain broke. the engines with issues are the Honda B18C or B16A motors or H22. the belts would break and good buy to the valves!!!

All you are doing is moving the vale timing a slight bit with the VTC a few degrees the same as the old honda can timing gears, but with electronic. The VTC in the GA16 opens at about 3,000 rpm. then retards it at I think 5800?? not sure on that one, but JWT advances the cam at 6200 I believe to open the cams up and let the air flow and we get like 25 HP boost at the top end. not sure on the torque because you are at the peak and torque usually falls off, bur Nissan engines pull linear in the curve, unlike the honda 170 HP and 120 Ft/lb torque!!!

Chris 92 classic
 

·
Registered
Joined
·
56 Posts
Im just wondering since mhy GA16DE has no VTC Solenoid but it has VTC port, my bar is 93 b13 super saloon, I notice in some nissan ga16DE it has VTC solenoid, what do i need to do in order to install VTC Solenoid, can I install SR20VE ecu and use SAFC to control VTC?
 
1 - 14 of 14 Posts
Top