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S15 Spec R conversion to RB26DETT

Tardo

By Tardo,
in General Automotive Discussion

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Tardo Explorer

Tardo

Posted
Posted

Soo, looking to re engine an S15 with an RB 26 coupled to an R33 gearbox and drive train. I know S15's have had their RB20DET coupled to an R33 g'box using an adapter plate. The 26 won't need a plate, so I was wondering if it was pretty much a drop in bolt up situation. Anyone have any experience with this conversion?

Tardo

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GTSBoy Grand Master

GTSBoy

Posted
Posted

No S15 ever had an RB20 from the factory. You're thinking SR20, and SR20 connected to RB gearboxes is, as you suggest, a tried and true thing to do.

RB20/25/26 into S chassis has been done so many times that you will only find about 13 gonktrillion threads about it all over the internet. Search.

Tardo Explorer

Tardo

Posted
  • Author
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Thanks, GTSBoy, you were correct about the SR20, one too many chardy's! Sadly, that option evaporated. While in the negotiating process, the seller actually came to the conclusion that an RB26 was a good idea and pulled the pin. While internet searches are great, I like , and have found, meeting face to face with guys who have done this mod, to be a better source of free flowing info.

So the project begins. All I have to do is convince the Millennial to get his hands dirty!

  • 1 month later...
Tardo Explorer

Tardo

Posted
  • Author
Posted

So we have an S15, nice car, and we have started the collection process. Got the RB26, and have had the sump modified. In the meantime, the car is not running well. Missing completely on No4 cylinder. The SR20 has numerous mods including GK Tech rocker arm stoppers, Tomei valve guides etc. Have checked/changed coils and injectors. Compression is great, cylinder leak test (valves) coming up. My mechanic mate is thorough and professional, but he is not Jap fluent. In fact , he is a Europe/ Pom specialist and I am a little concerned he may be out of his depth in the analysis of the problem. Anyone know a Nissan specialist in Brisbane apart from the guys up at Caboolture?

Kinkstaah Grand Master

Kinkstaah

Posted
Posted

Having gone through engine conversions, I think the smart move here is not to put a RB26 into a S15, mainly because the amount of power the SR20 can do is going to be enough for most sane applications in that platform.

Plus you could probably sell the RB26 and more than pay for a reasonable SR20 rebuild and have a fun vehicle ?

GTSBoy Grand Master

GTSBoy

Posted
Posted
10 hours ago, Tardo said:

I am a little concerned he may be out of his depth in the analysis of the problem

Don't need to be a specialist. These things are as common as muck and as sophisticated as a toilet plunger. If you can diagnose the complicated crap the Euros pump out, you should be able to diagnose a dirty old Nissan in seconds.

  • Like 1
GTSBoy Grand Master

GTSBoy

Posted
Posted
37 minutes ago, Kinkstaah said:

Having gone through engine conversions, I think the smart move here is not to put a RB26 into a S15, mainly because the amount of power the SR20 can do is going to be enough for most sane applications in that platform.

Plus you could probably sell the RB26 and more than pay for a reasonable SR20 rebuild and have a fun vehicle ?

VQ25 would the fun choice.

robbo_rb180 Grand Master

robbo_rb180

Posted
Posted
15 hours ago, Tardo said:

So we have an S15, nice car, and we have started the collection process. Got the RB26, and have had the sump modified. In the meantime, the car is not running well. Missing completely on No4 cylinder. The SR20 has numerous mods including GK Tech rocker arm stoppers, Tomei valve guides etc. Have checked/changed coils and injectors. Compression is great, cylinder leak test (valves) coming up. My mechanic mate is thorough and professional, but he is not Jap fluent. In fact , he is a Europe/ Pom specialist and I am a little concerned he may be out of his depth in the analysis of the problem. Anyone know a Nissan specialist in Brisbane apart from the guys up at Caboolture?

how do you know its not the injector or coil?
Checked cas? Properly checked coils with multimeter? Cleaned Injectors? injector fires when cas is spun?

I've got a rb25 swapped sil80 and wouldn't recommend it unless a drag car due to keeping them cool, ac still working and getting around the ABS unit and triple the cost of what you think it will cost to be done properly- no temp problems, working ac, sump clearance, sway bar clearance and meeting emissions etc.

Can recommend East Coast Customs at Northgate. I have used them in the past with my cars from head gasket replacement & full tunes.

Tardo Explorer

Tardo

Posted
  • Author
Posted

Thanks, all, for the advice. I hear you loud and clear, but the millenial is set on doing this and I'm just along for the ride. The S20 has new coils and plugs swapped out and the injectors cleaned and tested. I'll talk to East Coast and see what they can do.

  • Like 1
  • 3 weeks later...
Tardo Explorer

Tardo

Posted
  • Author
Posted

Update! Much stuffing around! Idiot who installed Tomei cams managed to bend the intake cam to the point where the intake valve was opening too late to allow fuel to match ignition in number 4 cylinder. All ok after $2K investigation/restoration! I now have a lot of time, sweat, (Brisbane) and effort invested in this car, only to see the engine parked as the Millennial pursues his clean hands, fully skinned knuckles approach to the RB26 conversion. I know, I know, don't castigate me, he will turn out to be ok. I think.

  • 3 months later...
  • 5 weeks later...
Tardo Explorer

Tardo

Posted
  • Author
Posted

Installing an RB26 into an S15 using R33 front crossmember and RB20 engine mounts. Has anyone got info on the clearance between the rear of the head and the firewall? Looking to install an oil drain on the rear head which will add about 30mm to the head length.

robbo_rb180 Grand Master

robbo_rb180

Posted
Posted
28 minutes ago, Tardo said:

Installing an RB26 into an S15 using R33 front crossmember and RB20 engine mounts. Has anyone got info on the clearance between the rear of the head and the firewall? Looking to install an oil drain on the rear head which will add about 30mm to the head length.

Got plenty of room or just smack it with a  hammer to make room.
Need more than just a drain to help with oil issues- cam baffles, baffled sump, restrictors, oil pump, oil returns in the block, not hanging off limiter.....

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
3 hours ago, Tardo said:

Installing an RB26 into an S15 using R33 front crossmember and RB20 engine mounts. Has anyone got info on the clearance between the rear of the head and the firewall? Looking to install an oil drain on the rear head which will add about 30mm to the head length.

Forget the rear oil drain. If you anticipate having oil control problems read (say the last third) of the oil control thread for some solutions.

  • 2 weeks later...
Tardo Explorer

Tardo

Posted
  • Author
Posted

Thank you for those replies. What we have is a 1994 RB26 with 145K on it and all cylinders above 150 compression. There are several Tomei mods. What we have been able to establish is:

1. A modified large capacity baffled sump post transfer case removal, (we did this),

2. Baffled rocker covers,

3. over cam oil diffusers,

4. N1 oil pump, new.

We are not about to remove the head to investigate oil restrictors.

We are not going to remove the sump to drill an access port for an oil drain.

We are going to install an oil drain at the rear of the head going to either the rear turbo crankcase port, (going single turbo), or through a banjo fitting to the sump oil drain.

The car is primarily a show car, not an all out race car in any driving format, so engine stress will be limited and monitored.

Thanks again for the inputs and the info made available through the various forums.

 

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
15 hours ago, Tardo said:

Thank you for those replies. What we have is a 1994 RB26 with 145K on it and all cylinders above 150 compression. There are several Tomei mods. What we have been able to establish is:

1. A modified large capacity baffled sump post transfer case removal, (we did this),

2. Baffled rocker covers,

3. over cam oil diffusers,

4. N1 oil pump, new.

We are not about to remove the head to investigate oil restrictors.

We are not going to remove the sump to drill an access port for an oil drain.

We are going to install an oil drain at the rear of the head going to either the rear turbo crankcase port, (going single turbo), or through a banjo fitting to the sump oil drain.

The car is primarily a show car, not an all out race car in any driving format, so engine stress will be limited and monitored.

Thanks again for the inputs and the info made available through the various forums.

 

I would just reiterate that the so called "oil drain " at the back of the head performs no demonstrated  function.  Then again it also will probably do no harm. There is little room between the RB engine and the bulkhead. How it fits on your car you should be able to discern by measurement. 

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