SR20 Dual Guide Conversion

[TomBec]

good info.. thanks for the input. read through it a couple times before putting my head back together today. was very careful with oiling/torquing everything and it runs great (so far). ended up going with oem guide shims all 'round. the motor even idles a little quieter.. i will update here if i throw another one.

[Tyler_240]

Nice...I got my top end back together yesterday and on the road after swapping in the new guides and bleeding the lifters really good...I removed my RAS and swapped in the OEM Oil Baffle and all my lifter chatter is gone...i've run the motor up to 7K RPMs with no issues.

[TomBec]

Forgot to mention I also removed ras and baffle.

[sidewaysil80]

Bumping this because I have a simple question. When performing the dual guide conversion, you need to buy 8 of Nissan p/n 13218-53J00 (guides). I get the concept of needing to machine down the "new" guides to match the "old" guides so the rocker stays level, but wouldn't it be possible to just simply replace all 16 guides at once? That way they are 100% level with each other and you are effectively “resetting” the rocker to cam clearance? Or would that make that clearance to tight?

[tb13]

Originally Posted by sidewaysil80

Bumping this because I have a simple question. When performing the dual guide conversion, you need to buy 8 of Nissan p/n 13218-53J00 (guides). I get the concept of needing to machine down the "new" guides to match the "old" guides so the rocker stays level, but wouldn't it be possible to just simply replace all 16 guides at once? That way they are 100% level with each other and you are effectively “resetting” the rocker to cam clearance? Or would that make that clearance to tight?

You can't just replace all 16 because the valve heights are more than likely not level. If you have your machine shop set your valve heights all perfectly level, you can just run a 3mm on each valve. 99% of engines will require different size shims on each valve because they are not the same height.

[sidewaysil80]

I think I got it. The FSM says replace all guides when servicing head because they are uniform in size. The shims, if kept, are offered in various sizes to compensate for valve height and match guide.

If replacing both guides they would be same thickness but whatever valve height is won’t be compensated for like it is with the various thickness of shims.

Thanks for saving me $50 bucks lol!

[tb13]

Originally Posted by sidewaysil80

I think I got it. The FSM says replace all guides when servicing head because they are uniform in size. The shims, if kept, are offered in various sizes to compensate for valve height and match guide.

If replacing both guides they would be same thickness but whatever valve height is won’t be compensated for like it is with the various thickness of shims.

Thanks for saving me $50 bucks lol!

Exactly. I believe from Nissan the motor should have 3mm shims to match the 3mm guides, but over time the valve stem can wear which is why different thickness shims are necessary for valve adjustments in used motors.

I know some guys have had success just dropping guides in, but it's probably better off doing it right the first time, measure it all up and then order Tomei guides in the correct thickness.

Sent from my ONEPLUS A5010 using Tapatalk

[sidewaysil80]

Originally Posted by tb13

Exactly. I believe from Nissan the motor should have 3mm shims to match the 3mm guides, but over time the valve stem can wear which is why different thickness shims are necessary for valve adjustments in used motors.

I know some guys have had success just dropping guides in, but it's probably better off doing it right the first time, measure it all up and then order Tomei guides in the correct thickness.

Sent from my ONEPLUS A5010 using Tapatalk

Okay great. I can get OEM guides for $4 each so I'll just order eight and grind them as needed. I'm thinking between the dual guide rocker arm conversion, roller rocker sr20de hydraulic lifters, and new valve springs I should have no issue reaching 9K rpm. I have been doing a lot of research of the sr20 forum since they have essetinally pioneered the n/a sr20 and a lot of these tips and tricks have been tested over there.

[TheRealSy90]

Pretty much. Dual Guides, RR lifters, good to go.

OptionS13 i'm pretty sure you didn't do something properly with the issues you had.

[tunermt]

Few tid bits from the bottom of the article to help choose your cams:
https://brewedmotors.com/blog/sr20de...m-install.html
"There are a large range or cam specs available for the SR20det ranging from 256 duration with 11mm of lift all the way up to over 285 duration and 12.5mm of lift for high rpm builds. Tomei has proven time and time again to make GREAT cams for the SR20det that deliver big gains and when matched with some mild head work/port n polish we see huge gains throughout the entire RPM range as well as a faster spool time from the turbo. We have also noticed the center line on the Tomei cams is VERY close to stock which means you can actually bolt these cams in with stock cam gears and see good results. Many other aftermarket cams will require a good amount more adjustment compared to the Tomei cams to "degree the cams" into spec.

-Tomei 256 Pon cam: These are the perfect cams for an otherwise stock SR20DET good mid range, smooth idle and can even work with the stock ECU.

-Tomei 260 pro cam hydrolic lifter: These cams are good for a small turbo build looking for decent idle and strong power from 3500-7000 rpm. **aftermarket springs and retainers should be used**

-Tomei 270 pro cam hydrolic lifter: These cams are good for a medium sized turbo build looking for decent idle and strong power from 4000-8000 rpm. **aftermarket springs and retainers should be used stock wont hold up well here**

-Tomei 280 pro cam solid lifter: These cams are good for a mid-large turbo build looking strong power from 4500-8500 rpm. **aftermarket springs and retainers must be used**​"

[tunermt]

Originally Posted by sidewaysil80

Bumping this because I have a simple question. When performing the dual guide conversion, you need to buy 8 of Nissan p/n 13218-53J00 (guides). I get the concept of needing to machine down the "new" guides to match the "old" guides so the rocker stays level, but wouldn't it be possible to just simply replace all 16 guides at once? That way they are 100% level with each other and you are effectively “resetting” the rocker to cam clearance? Or would that make that clearance to tight?

You need to make a tool to measure and correctly set the clearance. Any other method is just guessing as close as you can. Just measure once and do it right after all your going dual guides to not worry about the shims and rockers any more.