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Rb26 Compression

Don Dada

By Don Dada,
in Engines & Forced Induction

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Don Dada Mentor

Don Dada

Posted
Posted

Started a rb26 (R33) today "on the ground" from Japan.... Engine sounded good,revved out good, oil pressure was about 65psi when now started and went to 95psi or so when revved. Also was able to see about 10-11psi boost when revved hard,Is this too high for a stand still rev?

My main concern tho is after running the engine for about 5 mins i did a compression test with results as follows:

1--- 175

2--- 174

3--- 176

4--- 171

5--- 160

6--- 161

Now the R33 manual said the standard value is 170 psi and minimum vale was 128 psi with a variance between cylinders of 14psi

Are cylinders 1 2 3 too high? thus givin me a variance of 16psi across 3 & 5?

Probably with some running it will work in a little?

Don't know how long the engine was parked up for.

Also did a test on a running R33 RB26 (25 000km) as follows:

1--- 162

2--- 165

3--- 170

4--- 166

5--- 170

6--- 162

This looks a little more normal to me :)

What do u guys think about the first set of results?!?

Thanks.

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The Dan Grand Master

The Dan

Posted
Posted
Started a rb26 (R33) today "on the ground" from Japan.... Engine sounded good,revved out good, oil pressure was about 65psi when now started and went to 95psi or so when revved. Also was able to see about 10-11psi boost when revved hard,Is this too high for a stand still rev?

My main concern tho is after running the engine for about 5 mins i did a compression test with results as follows:

1--- 175

2--- 174

3--- 176

4--- 171

5--- 160

6--- 161

Now the R33 manual said the standard value is 170 psi and minimum vale was 128 psi with a variance between cylinders of 14psi

Are cylinders 1 2 3 too high? thus givin me a variance of 16psi across 3 & 5?

Probably with some running it will work in a little?

Don't know how long the engine was parked up for.

Also did a test on a running R33 RB26 (25 000km) as follows:

1--- 162

2--- 165

3--- 170

4--- 166

5--- 170

6--- 162

This looks a little more normal to me :)

What do u guys think about the first set of results?!?

Thanks.

I'd make a few suggestions.

1. You are worrying about it too much

2. Your compression gauge is not that acurate to tell you 176 it would be 175.

3. If it's straight off the boat and has made the trip over, chances are the battery is not too crash hot, and if you didn't use a really good jump pack for the test then the battery is likely to be getting tired by 5 and 6 anyway.

4. Did you keep the throttle open while cranking during the test?

Don Dada Mentor

Don Dada

Posted
  • Author
Posted

If u know the price we pay 4 a Rb26 on this side of globe u would worry too!

Its the same gauge i used 4 all 6 cylinders so i would expect some kind of consistency.

The engine was started outside of a car "on the ground" using a battery from a working vehicle and i actually thought it was getting tired too, so replaced it with another batt from another vehicle to test 5 & 6 and got the same results.

Yes had the throttle open.

Don Dada Mentor

Don Dada

Posted
  • Author
Posted
i would not worry about it. the engine is fine. make sure you use GOOD oil. Motul 300v chrono if you want the engine to last.

btw make sure you dont ping this one :)

I use Redline oils engine/gearbox/diff so i should be good to go.

Don"t think i'll be experimenting too much with this one tho....just 14psi and drive :)

On that note what do u think about using a SAFC2 to "tune" it a little at the 14psi??? since i already have it.

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted
I use Redline oils engine/gearbox/diff so i should be good to go.

Don"t think i'll be experimenting too much with this one tho....just 14psi and drive :)

On that note what do u think about using a SAFC2 to "tune" it a little at the 14psi??? since i already have it.

DO NOT TOUCH IT. chuck the safc2 in the bin. the rb26 computer will be more then capable of running the engine with heaps more power then what you were used to.

enjoy the motor, it will be good. don't destroy it like our 300kw stagea kid in the other thread lol

90% of engine failures are from the user.

Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted
Geeze.... just askin :)

Never seen anyone here use a SAFC2 on a Rb26 and i sure was'nt going to be the first!......

So 14psi good?

put the engine in and run it on no more then 10psi to start with. make sure everything is running fine. run no more then 13psi and you should be fine.

i also suggest putting a afr meter on it and checking the afr's

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