Thread: Overkill on my head modifications.

Thought I may as well post this since someone was asking about modified rocker arms. I hope this helps those of us who choose not to go with a VE head.

I bought a SR20det (W11 engine). Everything looked new inside but a leak down test showed some loss. The exhaust valve stem seals were worn. It probably would have been OK once it ran a few miles, BUT anytime something is worn it's an opportunity for an upgrade… so I took the head into a machine shop.

The exhaust valves were great but some of the intake valves has some surface corrosion (probably from sitting on the docks in Japan) so I replaced those with factory Nissan valves.

The exhaust valve guides were also worn but even though the intake valves guides were good, I ordered JWT bronze valve guides for BOTH the exhaust and intake sides. They transfer more heat out of the valve stems, are self lubricating, and last much longer than the stock stainless ones. They only cost 110.00 shipped for the complete set, from Greg V, just a little over 50.00 more than the stock set. Of course I replaced the valve stem seals, also from Greg.

Here's were a good machine shop is important. (I used O’Neil’s Custom Engines in Spokane WA.)
When bronze valve guides are installed the soft metal deforms and rubs against the valve stem. I talked to JWT and they said it would be OK to just ream the guides out some till they clear the valve stems.
O'Neil's owner, Don, explained the when you ream bronze valve guides you are removing metal and thus change the inside diameter, so the guides actually wear faster. Fortunately he had the tool needed to straighten out the guides after they’re installed, then a special gauge to measure and make sure the inside diameter was exactly the same through out the length of the valve guides.

I’ve thrown rocker arms/lost shims before and never want to re-shim a head again so I researched threads by ashtonsser and Andreas Miko, (Thanks guys!)

I learned that the right leg of the rocker arms can be cut down to allow the grooved shim/keeper to fit both sides of the rocker arm.
This helps keep the rocker arm stable at high RPM in case of some valve float.
Unlike shims they replaced, the grooved keepers are all the same thickness, so after modifying the rocker arms,the grooved keepers need to be ground down to match each individual shim they replace.

What O’Neil’s did instead of grinding the grooved keepers down, was to measure and grind down the end of each valve stem until everything was set at the correct height. Something he does on most heads.
Don also went ahead and engraved the underside of each rocker arm to identify it’s place in the head, I= (intake) E= (exhaust) 1, 2, 3, 4….

Now if I throw a rocker arm, no more re-shimming. All grooved keepers are the same thickness, so if one is lost, it can be replaced with another stock one. I will even know where each rocker arm came from. The only tools I’ll need is a socket set.

More research on the forum (Ashton and Andreas again) revealed that the lifters (hydraulic lash adjusters) from the 00-00 Roller Rocker SR20 are better. With a high volume oil pump they can come close to solid lifters.

Here is a quote from Andreas: (link below)

The HL from the RR with the large hole on the side lets more oil in and with the small hole on top lets less oil out. This causes the HL to not collapse as quickly. You combine this HL with a high volume oil pump and you got a high rever.
Well there is also one more mod and that is converting all the shims over to the groved shim you will need to shave the other side of the rocker arm to acomodate groved shims on both sides.

Grooved shims on both side
Valve springs and retainers
RR lifters
VE oil pump
This setup will rev to the sky.

http://www.sr20-forum.com/all-motor/6412-improving-lifters-should-i-andreas-miko-check-thread-plz.html

I got lucky, my W11 head came from the factory with the RR HLA’s, plus DET’s have a high volume oil pump (although the VE oil pump is higher).

I decided to go with Brian Crower valve springs/ titanium retainers.(BC0200) Got those for 205.91 shipped.

I didn’t have the head ported and polished, just cleaned up some of the casting marks. O’Neil’s charged me only 369.75 for all the head work they’d done.

Almost used my budget up but didn’t want anything to happen to this head so I ordered the Mazworx head stud kit, 185.00 + shipping and the Nissan VE metal head gasket from GregV.

Overkill for my eventual goals of 300+ HP? Definitely! (8000-9000RPM?) Once I started I couldn’t seem to stop (damn sr20-forum).
I can’t afford cams for now and I’m running my W11 with headers NA, but my head will be (over)ready when I go turbo.
However I’m thinking my next upgrade will be a 6 speed, no point to having power if you can’t get it to the pavement.

Looks good, I loved it. You head will be good to 9k easy. People spend this huge amount of money to make a 9k rev capable de/det head when all you need is the simple stuff. Dont even need RAS as the rwd guys swear by them and wonder why they bent valves.

I reved my DE head with twin groove shims, BC Springs and Retainers, RR lifters, VE oil pump, on C2 cams to 8700 all day long. Put the limiter at 9100 just to say it could do it and pounded off that several times 1st-4th gear and kept wanting more. With my setup power was still climbing at 8700 so i figured why not. lol.

Simple cost effective setup. Especially when you have most of the stuff to do it laying around.

I didnt go into as much detail as you did on having to cut the tops of the valves to get proper clearances. Mine were all perfect all the way around on my head and the second head i put on after i burnt some valves. Just tossed them in, verified the clearances on both sides of the rocker pad were the same or close to it (within .002") and all was good. Never had a problem and didnt have to shave shims or any of that.

Off the top of my head stuff, maybe a little off.

DE pump goes to about 45-55 PSI hot
DET pump goes to about 75-85 PSI Hot
VE pump goees to about 105-115 PSI hot

When you use the highest presure pump the chance of the lifter colapsing diminishes drasticly. The higher the presure the pump has, the more the lifter will start to act like a solid lifter.

If you look at the importance of these mods I would say.

1st Valve Springs and Retainers
2nd Grooved Shims
3rd VE pump or DET pump next
RR Lifters ( dont go out and get these unless you can get them cheap )

If you have a DET dont go out of your way to get a VE pump even. If you have a DE motor just get a VE pump.

ITT: good things.

Thanks guys.

For years, Andreas has sharing these head mods he figured out, but people still go all out with solid lifters and spend mega bucks. For what?

I also knew that Ashton has been using these same mods, and no one on the forum consistently pounds on engines like he does. I figured "if it holds up for Ashton, I can't break it".

I wasn't looking to build a high performance head, I just wanted it to be dependable and easy/quick to fix myself if I ever threw a rocker arm. When I needed new valve guides I thought "now is the time to try this".

What's great about these head modifications is that performance comes automatically with dependability. They're simple, effective, and can even be done a little at a time.

The idea was to share the parts I used, and show what they cost, so other members can see there is no "Rocket Science" to this and have a kind of quick reference guide in one place. If I put a head like this together anyone on here can.

Good stuff guys.