rebuilding black top sr20det, need opinions!!

[crookedcop7]

I have a black top sr20det motor, no problems with it yet but I want more horsepower and torque so I want to build a reliable motor from the bottom up... well here my questions

1. when I got the motor it had 32,000km on it when I change the pistons and rods do I really need to bore the block or can I stay with the stock 86mm piston size??

2. I know the stock headgasket is .8mm with a 86mm bore but im having trouble find a stock size metal headgasket I want to run 22psi safely should I increase the size to a 1.0mm? (i dont want cosmetic)

3. While doing the head I still want to keep it streetable and I know the lifters suck in this motor any recommendations to upgrade this issue?

I all ready have 720cc injector w/ a standalone ecu and a gt2871r w .64 arall other safety issues (oil) have been address I just dont want to buy a new motor every year and rather spend the money on building a very reliable motor over the winter my buget w/ labor is going to be around $4500 key things I want are streetable, reliable, and throttle response. I want around 420whp right now I have 328whp and I dont think it will be to hard

All input is welcome thanks in advance

My thoughtsCP Pistons for SR20DET $500Crower Connecting Rods for Nissan SR20DET $730Tomei Valve Guides for Nissan SR20DET $320GReddy Valve Springs for Nissan SR20DET $190Crower Titanium Retainers for Nissan SR20DET $170HKS Step 1 Intake/Exhaust Camshafts $450HKS Cam Gears Nissan SR20DET $330ARP head studs (have)Apexi SR20DET Head Gasket $195 1.0mm 86mmSR20DET OEM Oil Assembly $240SR20DET OEM Water Pump $90SR20DET Full gasket kit $240OEM SR20DET Timging Chain $85OEM SR20DET Timing Chain Tensioner $75parts come to $2885$1700 for labor

[crookedcop7]

Im also going to change the bearings and resurface the crank(free)

[Hijacker]

stock rods will hold your power goals quite well. The weak link in the bottom end when it comes to durability are the pistons. And that's only when the fuel delivery is improperly handled. I've seen many SR pistons melted, but never seen a rod bent or thrown.

You could instead take the stock rods, and have them worked over and still save some money.

Stock headgasket thickness should be .9mm I though. not .8. Either or, if you want to go with an aftermarket gasket, apexi and greddy make great solutions. Cometic is a good gasket as well, people who use them tend to cheap out and not have the proper preperation done to the block and head (checking and decking) and they leak. The ones that use the more expensive gaskets tend to be the ones with money and do the prep work. So I think Cometic gets an unfair reputation that way. I also tend to shy away from increasing gasket thickness. A thicker headgasket gives more surface area to interact with the combustion process. When it has more surface area seeing heat like that, it is more likely to see failure. It's why I hate stepping up HG thickness to reduce compression. And why I love CP Pistons (can retain stock CR)

I would skip the Tomei guides and get Jim Wolf bronze guides. They're very affordable and if anyone in the states knows SRs, it's Jim Wolf.

Go ahead and get the full chain kit. The old guides are plastic while the updates are coated metal.

As far as boring a block goes, the mileage isn't the deciding factor. Damage to the cylinder walls and personal preference are. I'm boring my block out .020" only because there was scoring in the second and third cylinder, otherwise I would have stayed stock.

[Slipstream]

Also when going with the JW guides, make sure to get the JW vlalve seals with them. Good price and stock won't fit them. And if you're cheap like me, shop around for parts, you'd be amazed what deals you can find if you take the time to look. I think I bought parts from half the sponsors here.

[Hijacker]

The stock seals won't fit? That's good to know as I just had a set of bronze guides installed on my rebuild head, but had used OE stem seals.

Are the OE seals too large/too small, or do they install right and then leak?

EDIT: Just looked at the JWT site and didn't see valve stem seals on their product lists for SR valvetrains

EDIT EDIT: Just got off the phone with Ben at Jim Wolf. He says you don't need special stem seals for the bronze guides and that OE will work just fine. Our guess is that slip had gotten the exhaust stem seals for the 6mm exhaust valves from the FWD motor whereas the RWD motor has stem seals for a 7mm exhaust valve.

[crookedcop7]

good to know so... I guess I should wait on ordering parts till I get the motor apart to know what size pistons to getAlso .8 is the stock size for the headgasket

[redtop91]

Unless there is scoring on the cylinder walls I'd stay with the stock bore.

[Hijacker]

Typically, let the block decide the route you want to go with pistons. Like redtop said. Boring should only be done if you need to fix some imperfections. You're not gonna see a massive gain from the extra .01 liter you gain in a .020" overbore. And since we run sleeved aluminum motors, you really want to try to avoid overboring unless necessary because you thin out the cylinder walls. .020" is what I would say is recommended for boring. you can sneak by with .030", and I would say .040" is asking for trouble.

EDIT: On the headgasket note: Enthalpy and Heavy Throttle list the stock thickness as 1.1mm for DETs and .9 for FWD NAs. I've got a stock headgasket sitting out. I'm gonna measure it tomorrow. But it will be uncompressed

[homeslicej2]

Check ebay for riverside (?) infinity. They sell new SR20DET oil pump/front covers for 160 + shipping. A new OEM water pump is $65-70 (get an S14/S15 one, supposed to flow better than S13 one and fits even though it has an extra bolt hole that's not used). Enjuku sells what they call "ER Spec" rods for $280 last I checked. Look for them on their website, but basically, they are lightened and re-conditioned stock rods, with ARP rod bolts. Supposed to be good for 400-450 whp on a good tune.

[crookedcop7]

alright I was wrong the correct thickness is 1.1mm according to rs-enthaplythis is off his website:

SR Compression Ratio Calculator

Want to determine the compression ratio of any engine build? This little guy can help. The spreadsheet is setup fro a stock RWD SR20DET. It works like this:

Enter Bore (mm)Enter Stroke (mm)Displacement per cylinder is calculated

Enter number of cylindersDisplacement of engine is calculated

Enter head gasket bore (mm) (as a rule this should be 0.00 to 0.50mm greater than the bore) NOTE - RWD/FWD SR20DET is 1.1mm thick stock. FWD SR20DE (NA) are 0.9mmEnter head gasket compressed thickness (advertised thickness on multi layer metal gaskets)Gasket volume is determined

Enter deck clearance (mm) (positive for edge of piston below deck surface)Deck clearance volume determined

Enter piston volume cc's (negative for dish pistons, positive for domed)

Enter head cc's - SR20DET/DE heads are 45-46.5cc depending on a few variables. NOTE - The head cc's listed on the Wiseco piston website are wrong. I have never in my life seen a 60cc SR20DET head - redtop, blacktop, s13, s14, s15, gtir, bluebird, even NA sr20de they are all 45-46.5cc. As a result Wiseco has incorrect compression ratio info on their website for their pistons. I would like to see a 60cc SR head that has not had headwork if anyone can produce one.

[Slipstream]

I used the seals from the gasket set, but I had the +1mm valves and I believe a 8mm guide. Just on the exhaust side. They were worn when I mic'd them. Intake side was perfect, so I stayed with stock.

Here is one thing that helps with changing the guides, use a warming plate like a griddle for pancakes to warm the head before driving the old ones out and the new ones in.

[Hijacker]

I used the seals from the gasket set, but I had the +1mm valves and I believe a 8mm guide. Just on the exhaust side. They were worn when I mic'd them. Intake side was perfect, so I stayed with stock.

Here is one thing that helps with changing the guides, use a warming plate like a griddle for pancakes to warm the head before driving the old ones out and the new ones in.

That changes everything. I'm using stock RWD sized guides, that's why I was confused. I didn't realized they offered an 8mm guide

[redtop91]

Tomei Valve Guides for Nissan SR20DET $320GReddy Valve Springs for Nissan SR20DET $190Crower Titanium Retainers for Nissan SR20DET $170HKS Step 1 Intake/Exhaust Camshafts $450

If you are upgrading your valvetrain to that extent, why not go with step 2 cams? According to HKS they probably would suit your goals better than step 1's, are the same price, and you will be already using all the valvetrain reinforcement necessary.

[crookedcop7]

I heard that the stage 2 cams have idling problems???

[ILikeMy240sx]

I wouldnt really call it a problem per se... Yes your idle will be a bit lopey and unstable but its not that bad. Also you can always tune it so that it idles like stock.

For example, I have 260/270 cams and without tune the engine idle was very lopey but with raised idle (1000 RPM) it was very drivable but shook too much for my liking. So, I emailed Chris over at Enthalpy and he sent me a new tune. Now people can't even tell that I have cams unless its really cold out and the car is warming up.

BTW, Brian Crower stg 2 cams idle very close to stock cams.

[redtop91]

Did you go with the Tomei pro/poncam staggered or end up keeping your BC cams?

[ILikeMy240sx]

Tomei Procam made for solid lifters

I originally went with 270/270 then the intake cam got fubared... So I changed to 260/270 which seemed to give a bit more low end torque.

[redtop91]

What happened to it? You have a redtop right?

[ILikeMy240sx]

the cam oilers were slightly bent from shipping which I didnt notice. This led to the #1 lobes of the cams to hit the oiler and the tip of both oilers broke off. This led to insufficient oiling of #2 lobe on the intake cam and about 3mm worth of metal was ground off haha.

Fubared the cam and the rocker arm on #2 bank of the intake side. But surprsingly everything else was fine including the exhaust cam. So I just swapped the intake cam, re-shimmed everything.

[redtop91]

3mm worth of metal was ground off haha.

[homeslicej2]

Whoa! That could have been very bad.