Tomei Poncams

[ichi-go]

I'm running greddy cams on stock T28

No regrets

http://www.youtube.com/watch?v=kxB16K-ryDc

 

[craig8585]

Sounds good mate! Almost asif it has more character with the new cams

 

[LuPix_S15]

Nice little vid there to compare... deffo think it sounds a bit more urgent and raspy lol.


Bet she really sings when you've got her under load and revving towards the redline

 

[djmasterg]

Hi guys

My car suffers from vvt rattle (just started couple weeks ago, not so noticable, just when its cold and for few moments after engine start). So I thought that I will go for new cam shafts and pulleys. What is the best mod to suit standard engine (cam shafts from tomei, hks or greddy?). What values should I look for ( 256/256 @ 11.5mm or something else). I do not want to loose much power at bottom of revs. Do performance valve springs make any additional noise when installed? I would like to gain some knowledge before I spend money on theses parts.

Regards
Greg

 

[DeanS15]

if you are standard then i wouldnt bother mate - you need to do a bit of tuning first to make the best of them imo. also doing away with the vvt isnt meant to do the cars driveability a lot of favours unless your running very good power to make up for it. as for pulleys, i'd just go for an exhaust cam pulley with the cams for a little bit of adjustment if i was looking again but its not an essential. what makes you want to start with cams anyway?

 

[djmasterg]

HI

The problem is that nissan factory cam shafts and pulleys cost the same or more than a set from tomei or hks. And I know that the life of , for example: tomei cams is longer than oem ones. Mine are probably a bit worn (hence the rattle). And what kind of tuning are you talking about?

 

[DeanS15]

i have a spotless set of cams up in my loft that i changed for poncams as i'm sure lots of people have them kicking around, but i only fitted cams along with a bigger turbo and a whole load of other things to make the most of it and spread the power nicely right up to redline. if your cams are worn then you have a lubrication issue - blocked spray bars perhaps. if the vvt is rattling then its the vvt solenoid or the vvt sprocket which bolts to the end of the cam that needs replacing, not the cams themselves. other rattles can be the chain guides or tensioners, maybe even a sticky lifter rattling away....... cams themselves should last for the life of a well maintained engine imo.

 

[Kango]

Has anyone ported and polished as well as fitting cams. I'd like to get my head gas flowed as well and the get the poncams in.

 

[craig8585]

Just bumping this post up to ask about the valve springs again. Do you have to remove the head to change the springs?

Cheers

 

[DeanS15]

not sure, i think it would be hard without removing the head, but if you are going to that trouble then stick head bolts and a gasket in there for the extra safety margin

 

[craig8585]

Yeah, I imagine the valves would drop down as soon as the collets/retainers are removed. I'll probably just the springs then in that case

 

[_Wing_]

You don't have to remove the head to do valve springs, there's some secret ways that Unigroup Engineering figured out... mine got installed without taking the head off

I did everything on my car myself but valve springs is over my head (and over my tools) and it wasn't my place to ask how they do it so I gave the job to the pros.

 

[haz's S15R]

Just as a reference for pricing/possible group buys, poncams (256 11.50) can be delivered from the states for £335 (not inc. import tax) and poncams and type a springs are £473.:nod:

 

[ZDT515]

You can probably put each cylinder on top dead center and then pressurise the cylinder with compressed air.

This would be done by taking the spark plug out and screwing an adaptor in to hook up an airline. This should hold the valves shut.

 

[sjt47y]

Suggest you get someone who is really pro engines to do it. They can lead to other problems. Thats what happened to me.

also dont suggest you go for bc valve springs, understand they are one of the stiffest and i suspect becasue of this, it has caused my vct rattle. had to throw in another 350 pounds for a new vct.
valve springs in the head. I will check this vid when unsure haha... http://www.youtube.com/watch?v=FfTX88Sv4I8

I also think its better to do the engine at one go. to save labour charges and tuning charges. And each time you open up your engine, you need to change the gasket and bolts.

 

[GUEST_JDM]

I just did a full head rebuild with poncams 256 deg, kept the vct gear, full port and polishe to the head, BC valve springs with titanium retainers, BC 1mm over size valves. Im running a 71r and i made 244kw's only on 15psi. I also changed the settings for when the vct gear started to come in and got a little more torque range from the poncams through the wolf ecu. The power is all about flow, the porting job made my car so much more drivable the torque range is huge and the car almost feels na till boost starts to kick in, if you are going to take the head off its really is worth doing a port job while its off.

 

[sjt47y]

hi there guest_jdm, can i check why you increased the size of the valves, is it the port and polish thats why you have up by 1mm? I just sent my car for mapping and was told the the fly by gas is too high to tune properly.
this fly by gas i think meaning not reaching the compression needed. I got the parts all standard sized, and the garage i went to ported and polised the head.

So i suppose i should upsize the pistons and valves too? not sure if this makes sense.

 

[GUEST_JDM]

hi there guest_jdm, can i check why you increased the size of the valves, is it the port and polish thats why you have up by 1mm? I just sent my car for mapping and was told the the fly by gas is too high to tune properly.
this fly by gas i think meaning not reaching the compression needed. I got the parts all standard sized, and the garage i went to ported and polised the head.

So i suppose i should upsize the pistons and valves too? not sure if this makes sense.

Hey mate, i increased the valve size to get more flow from the head ( as the head was off it seemed a good idea to just do everything i can at the time).... im not sure what your tuner means by fly by gas, if he is meaning valve overlap where the exhaust valve opens during the same time the intake valve does, then that is a cam timing issue and should be timmed back up again. The hole reason for the port,polish,cams, bigger valves ect... is to gain more flow, a good way to make more power is by increasing flow either by force ( upping the boost) or by natural mechanical flow.

If you are doing a full port and polish make sure your machanic knows the sr head and does his research as there is a few little tricks to watch for, mine was done on a flow bench so all cylinder ports flowed the same, i did a full rebuild of the head, new valve stem seals, new vct gear the works ect, i would sugest you look at doing the same if you have the coin avalible and also put some arp studs and a metal head gasket to hold it all down. Im also not sure what your meaning by piston size either mate so you will have to explain to me a bit better unless i have covered it... cheers i hope this helps

 

[drifter]

You can probably put each cylinder on top dead center and then pressurise the cylinder with compressed air.

This would be done by taking the spark plug out and screwing an adaptor in to hook up an airline. This should hold the valves shut.

:nod: Just put the pistons at TDC, I had cams changed on my SR without having to fill the bores with compressed air

Be careful with the collets though as they can fall into an oil way. Best bet is to fill all the oil/water ways with tissue or something to block them off.