Thread: N1 Pistons with SR20VE Head with PnP

I have decided to rebuild our SR20VE engine to near near N1 spec on out Pulsar VZR N1.

I will give a bit history to save any confusion.

I purchased a VZR N1 which the engine sounded goosed, turned out to be a missing bearing so the engine was then stripped. I then popped in an SR20VE there and put in the N1 cams and had it remapped using Nistune and an SR20DE UK Almera ECU with the NATS removed. She has ran flawlessly, however from other builds and brand new builds we want more, as some of you can appreciate.

We want to have a fresh feeling engine, so we had a few ideas for it.

Rebuild the whole N1 engine using the N1 head but having a 2.0 displacement. The issue though is Pistons and Compression Ratio. Using N1 Pistons with 2 litre rods gives me about 14.5:1 compression ratio (give or take, not exact figures but near enough when calculated). Obviously this is too high for pump gas. I also planned on getting the N1 pistons skimmed, deeper valve reliefs and a thicker head gasket, but in fairness I want to use Stock Nissan gaskets as gettign additional head gaskets can just bump the price up. Another option on this setup was using SR20VE Pistons which we have, but this looks around 11.2:1 compression which is a little low for my liking, and I don't want to skim the N1 head any more.

Second was use the SR20VE head, Port and Polish the head to N1 spec, but keep that extra 1mm. use N1 Pistons, with 2 litre crank and rods. My caluculations shows around 13:1 Compression Ratio, which is not too bad but still a bit high, so I was thinking about getting say 0.5 - 1mm shaved off the pistons (not worked out exact yet), which would bring it down, but I was thinking that if i was port and polishing the head would this raise the compression ratio or would that not make a difference.

I plan on using a 4cw SR20DE crank which will be balanced which is sitting here in a pillow ready to roll.

Another idea was to have the quench zones removed and have the cc's of the head then work this out, unless someone already have this data.

Now I am not saying these figures are correct, so I would like any information that anyone might have. I want to get my order finalised with gspec, engine built, ran in and remapped by the end of august.

Forged pistons out of the budget? You could get custom CP's to meet your compression goal?

We already have a set of N1 Pistons sitting here though.

sr20ve 2nd gen (20v) should drop u exactly where u wanna be. approximately 12:1

keep the N1 head and try and get those or some custom pistons

peace

can you recommend a good place to get custom pistons made up?

CP pistons already makes VE pistons. They make a 12.1 for the SR20VE.

Like i said, I have a set of N1 pistons sitting here, and would like to use them, but I don't really want to modify them unless I have to, and paying around £600 for a set of custom pistons is pretty pricey for what the car will really do. The car will be a daily driver most of the time with the occasional blast down the drag, so I don't really justify that kind of money when I have the parts sitting here.

Basically with the setup using the SR20VE head and N1 pistons unmodded, would the engine run fine with pump gas? I was also thinking about getting perhaps deeper valve reliefs cut so I could fiddle with the cam timing when she is getting remapped.

So you have a full sr20ve and a sr16ven1 with munched bearings. I would think this is obvious....

1. Get de crank, or buy de

2. put n1 head on current ve

3. Put ve head with n1 pistion in de block. Clean up the combustion chamber a bit. Keep quench pads but smooth them. use n1 head as guide for ports.

4. Have 2 high comp engines that can run on pump gas

My guess is one would be just under 11.5:1 and the other just over 12.5:1. keep which ever runs better. Sell the other one.

5. Profit.....

Got DE crank, and block for VE is sitting here stripped and ready for rebuild.

My plan was to get some manley rods, So you do you think using SR20VE (port and polished)Head, N1 Pistons (unmodded, just notches done), N1 Cams, SR20DE Crank, fresh rings ect, and a new remap with 370cc's. n1 intake will be fine on pump gas?

Why not check miko for a 16VE crank and possibly rods if any are damaged? He may have from the engines he has previously parted. That way you can replace the damaged components in the N1 engine.