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Where To From Here.? Bad Compression..

TAS_SINFUL
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TAS_SINFUL Collaborator

TAS_SINFUL

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just had a desent mechanic from another city look at my car [GTR] as the launceston mechanics fail in all aspects regarding imports :O

compression in cylinders 2,3,4 & 6=150psi ;) cylinder 5 =125psi and cylinder 1 is an outstanding 25psi :)

so please correct me if i am wrong but i believe what i should now be doing is replacing my pistons.?

if this is correct ill be looking into getting arias pistons for it as the end goal for me is a 600hp track car.

any other recomendations on piston choice or direction from here.?

thanks guys ;)

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blind_elk Grand Master

blind_elk

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Posted

It will depend on why the compression is low as to whether new pistons will sole it. It is apparent that the engine needs to come apart, and in that case you may as well fit some new pistions. But simply fitting new pistons won't necessarily solve the compression problem. If you have broken rings, then new pistons wont fix it. If you have a crappy valve, new pistons won't fix it.

The next step is to get a leakdown test, to determine where the actual loss of compression is occuring.

PM-R33 Grand Master

PM-R33

Posted
Posted

Personally i'd go CP pistons and i think a lot of people would agree.

While your at it might aswell do the bearings (ACL race bearings or similar) and see what kind of state the rest of the engine is in. If it's all pulled apart might aswell do it all once now and save any hassels down the track.

sloutch Mentor

sloutch

Posted
Posted
just had a desent mechanic from another city look at my car [GTR] as the launceston mechanics fail in all aspects regarding imports :down:

compression in cylinders 2,3,4 & 6=150psi :D cylinder 5 =125psi and cylinder 1 is an outstanding 25psi :blink:

so please correct me if i am wrong but i believe what i should now be doing is replacing my pistons.?

if this is correct ill be looking into getting arias pistons for it as the end goal for me is a 600hp track car.

any other recomendations on piston choice or direction from here.?

thanks guys :)

If you are going to build a 600hp track car, you might as well take this opportunity to change the internals. Pistons, rods, rings, head gaskets, etc. Once the engine is out, you should be looking at doing all that and changing your turbos as well. For a track car, you'll need reliability.

Mandi Contributor

Mandi

Posted
Posted (edited)

Where to from here bub? To the land of SR XD hah j/k.

We really need a daily driver, with the R gunna be off road and the 200 off road also :S

May I suggest we look at pricing and sourcing all the bits as too put into it if your gunna pull her apart :( That way you wont have to take it off road again and reopen it up?

Edited by Mandi
grandmasterb Grand Master

grandmasterb

Posted
Posted

As others have said so many variables as to why its low on one cylinder Mitch and without opening it up for a closer look its all just assumptions and guesses for now.

Sorry to hear things didn't work out with the tune, sometimes its just not meant to be hey :)

I agree with CP over arias pistons, also if your wanting that 600hp track weapon (little overkill but anyway :( ) then like suggested the motor is open so you may as well do it all in one hit:

Pistons

bearings

rings

head rods/bolts

metal head gasket

head work (most likely needed)

oil pump etc

your always going to be up for BIG $$$'s when it comes to a 26 rebuild so dont rush into anything, look at all your options and have a look at 26 results thread and you will see what others are making with minimal mods :)

Good luck with it

Ben

blitzxtr Community Regular

blitzxtr

Posted
Posted

Everyone seems 2 like cp pistons what about Mahle Pistons there great teflon coated they look apart except for fitting requires a few mods to oil squirters but overall they are good couldnt say there better or worse than cps as ive never used them in my engines.

PM-R33 Grand Master

PM-R33

Posted
Posted (edited)

Not that this has anything to do with RB engines, but ive heard that Mahle were great back in the day on old iron blocks but on modern alloy blocks they dont seal as well or something along those lines? I know our blocks are iron so maybe they are fine, but on something like a SR which has a allot block SP pistons are pretty much the pick of the bunch and most people i know use them over Arias, Mahle etc.

Edited by PM-R33
blitzxtr Community Regular

blitzxtr

Posted
Posted
Hmm yeah true, forumla 1 teams use them aswell i think. I swear i heard something about the use of Mahle pistons and something about them, ill find out later...

Yeah Ya right F1 use them. Some WRC cars as well as Nascar

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