Rb25 Engine Rebuild

[DaveB]

Hi all,

Just thought I'd post some info here about the process I'm currently going through with my series 2 RS-Four (V). It all started with a rather nasty tappet rattle (which I thought was just the change to Castrol 5w/30 oil) in September. But it turned out to be something rather worse than that and it has been at the mechanics getting a full engine rebuild for about the last month.

Cause turned out to be sand blasting grit getting into the oil. This wore the head quite badly and deposits of the alloy paste from the head and some sandblasting grit can be seen in this photo of the sump:

How did the grit get in there? Well, probably when I got my rocker covers powdercoated about 6 months ago. I took all the usual precautions, including taping every orifice (and tape was still on there even after the powdercoating process) and blasting out the baffles with 100psi compressed air and solvent afterwards. I didn't notice any grit coming out. But it must have later on. A stupid thing to do maybe but oh well, we don't repair - we improve...

So I managed to get hold of another NEO R34 head off a forum member on SAU for $300 and got it rebuilt at a machinists; the block has been hot-tanked, bored, the crank washed and micro-polished etc. and the bottom end has been rebuilt with CP pistons at first oversize. Things are progressing and I have got some photos of the rebuild which I will post some of after I've checked them out over the next week.

So getting it back together... slowly. Will eventually have something with 0 kms on it though, which sounds bloody good. Especially since even at 130,000k's it still sounded/felt new. Oh, and fingers crossed but for those of you who may be considering it, it does look like you can get a decent rebuild with forged pistons for under 10 grand... but wait until I've got the first few thousand k's on it yet before I can say for sure

[Tangles]

yeah you can get a whole kit from ebay (ericsperformanceparts on usa - Ive bought a few grand of gear from him for the head and he is a great bloke to deal with)

the kit for under $1500 aus delivered includes:

CP pistons 86 or 87mm

Eagle Hbeam conrods

arp rod bolts

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...RK%3AMEWAX%3AIT

there was another one, same price, that included acl race bearings as well but forget where I found it on ebay - deal might be off I suppose.

so add in $350 for acl race bearing kit, another $1000 for gates timing belt/pulley kit + N1 oil and water pumps, full Cometic gasket kit for everything to be replaced for around $450, and $200 for fuel filter/oil filter(s) and oil(s)

thats around $3500 for parts, and then the labour.

could be rebuilt for around the $6000 mark IMHO

.... well that will be my aim when Im ready to go down that path, and that with the $4000 ported head/tomei cams = $10k for the whole engine build from top to bottom

[_Ryan_]

yeah you can get a whole kit from ebay (ericsperformanceparts on usa - Ive bought a few grand of gear from him for the head and he is a great bloke to deal with)

the kit for under $1500 aus delivered includes:

CP pistons 86 or 87mm

Eagle Hbeam conrods

arp rod bolts

http://cgi.ebay.com/ebaymotors/ws/eBayISAP...RK%3AMEWAX%3AIT

there was another one, same price, that included acl race bearings as well but forget where I found it on ebay - deal might be off I suppose.

so add in $350 for acl race bearing kit, another $1000 for gates timing belt/pulley kit + N1 oil and water pumps, full Cometic gasket kit for everything to be replaced for around $450, and $200 for fuel filter/oil filter(s) and oil(s)

thats around $3500 for parts, and then the labour.

could be rebuilt for around the $6000 mark IMHO

.... well that will be my aim when Im ready to go down that path, and that with the $4000 ported head/tomei cams = $10k for the whole engine build from top to bottom

your budget seems about right. Do you have an overlay of before/after with the cams?

[KiwiRS4T]

Blew my engine (well it still runs but with a few broken rings huge blowby etc) and considered the options. Thought about a stock recondition like Dave - great for peace of mind knowing everything is new - and should be able to handle up to 270awkw comfortably.

However looking for more power next year. Full recond with forged components, balanced etc heading towards $10k. Second hand RB26 too much of a gamble and still need money spent to get more than the 245kw i had with the present RB25 so now going with an RB30. Should be good for around 270kw (stage 1 with the GCG turbo) and will stand around 300 to 350 with a bigger turbo etc later next year. Well that's the theory...will let you know how it pans out.

[Angus Smart]

try look at import performance parts in the usa http://www.importperformanceparts.net/

if they dont have it, give em the part numbers. i got mahle pistons and pauter rods landed here for a tad under 1500us iirc

[_Ryan_]

Blew my engine (well it still runs but with a few broken rings huge blowby etc) and considered the options. Thought about a stock recondition like Dave - great for peace of mind knowing everything is new - and should be able to handle up to 270awkw comfortably.

However looking for more power next year. Full recond with forged components, balanced etc heading towards $10k. Second hand RB26 too much of a gamble and still need money spent to get more than the 245kw i had with the present RB25 so now going with an RB30. Should be good for around 270kw (stage 1 with the GCG turbo) and will stand around 300 to 350 with a bigger turbo etc later next year. Well that's the theory...will let you know how it pans out.

Going a RIPS bottom end with your head and one of their sump adapters?

[KiwiRS4T]

Going a RIPS bottom end with your head and one of their sump adapters?

RIPS do quality work - their price $5000. However have confidence that local engineers can do the job for 10 - 20% less. I need to save some money for the Link (Vipec).

[pintaline]

ill also be going down the RB30 route very soon, already have a RIPS block sitting in the shed waiting for the time to put it all together

D.

[DaveB]

Nice pintaline and Rob... wish I had the time & access to more RB30DET resources. But my rebuilt RB25DET is finished and ready; another set of rocker covers are getting colour matched to the "precious steel pearl" powder coat of my original ones (but in plain old enamel this time ) and tomorrow it's back into the car hooray... mechanic is very confident that it's all going to be happy and will not bind/have large clearances etc etc. Makes me feel better too...

Have some photos which I will get back tomorrow or the next day of the build and (hopefully) install. A stagea with an empty engine bay is a sorry sight Engine is all rebuilt now though and it looks great. Block's been hot-tanked and painted with new welsh plugs... really looks the part. Now just need to get the rocker covers coated again and should be back looking like new. The guys who are assembling it have really made light work of such a big job (for me, without a hoist)... it's not gonna be real light on the wallet but oh well, I'll only be doing this once I guess, may as well enjoy it while I have the chance to have a 0km engine

Edited December 15, 2009 by DaveB

[Duncan]

I've just put a 30 block in mine with CP pistons, spool rods, acl bearings. pretty cheap price for bits these days.

[DaveB]

Nice. How much for RB30 sump adapter kits? I know the full-on baffled sumps are damned expensive...

Well I have finally got the stagea back on the road!!! Rebuilt engine is running v nicely... can't really tell much difference from how it was before, except that the loud as rattle is gone, and sounds very nice and smooth. Idle is better, doesn't rev out to 1,500-2,000 rpm at startup. Sounds nice and 'burbly', a little more like an RB IMO. Total bill for the rebuild, including labour, was about $5k + bits (for me I would add $800 for the pistons so that's ~$5,800 so say 6 grand). Not cheap but *everything's new* (or rebuilt anyway). All nice and shiny now Got to get hold of the photos of the assembly...

Edited December 17, 2009 by DaveB

[stageaharts]

Sounds awesome mate, I'm sure you're happy to have her back

[DaveB]

Cheers Hartley, surrrre am! The break-in sucks already though and I've only done about 150K's (of 1,000)

The difficulty I'm having is that the instructions were basically "drive it off-boost, between 2k-4k rpm, up hills is good (give it a 'light workout' - accelerate moderately up to ~4k rpm) but NO BOOST!" (well 1-2psi is ok lol)

...this is hard because

a) the stagea drinks fuel when driven between 2-4k everywhere (I've locked out overdrive - gearbox in '3') and

b) with the hi-flow and exhaust, driving at those rev's, it's pretty hard to keep the stagea OFF boost

so break-in is fun but I can say... even off boost, the stagea is faster than a few cars I have driven So glad to have power steering and climate control back too.

[KiwiRS4T]

If you run it in too gently you will just glaze the bores and it will always use oil. Can you lock it in any gear? i.e. get rid of the freewheeling? Turn the overdrive off?

Then accelerate briskly (keeping the boost to a minimum) to 5 -6k revs and then lift off letting it go down to 2-3K and repeat. Watch the temp guage. Listen for any strange sounds, watch the temps and now and again look under the bonnet for any leaks etc.

if there are no problems kep increasing the revs to 5, 5500, 6000, 6500 without flooring the pedal. I would do my running in in one day and then get the car back asap to get the head retorqued and change the oil and filter.

[wolverine]

^^^^^ x2

[DaveB]

Thanks for the advice. Yeah I was recommended "light hills work" and to keep rev's between about 2 and 4/4.5. I have to do 1,000K's apparently before I take it back to get the first oil change and inspection. Also the head bolts are apparently not going to be re-torqued, as this is a feature of the 3-layer metal head gasket. I'll go do some 'light hills work' sometime soon lol.

hearing a bit of a funny noise around the passenger footwell area at about 3,000 revs or so; like the climate control fan makes when it has leaves in there; doesn't sound engine-related but I'll mention it to the workshop on my visit in the new year.

[wolverine]

Dave here is a link to some of the current thinking.

http://www.mototuneusa.com/break_in_secrets.htm

[wolverine]

from another site

http://www.flyinmiata.com/tech/breakin.php

Keep in mind that there really shouldn’t be any metal to metal contact happening within your engine, other than the rings to the cylinder walls. The rings are the ONLY things we are interested in breaking in or seating. What seats rings is cylinder pressure. Rings and pistons are designed so that cylinder pressure sneaks behind the compression rings and forces them out against the newly honed cylinder wall. Why do I mention this? Because I want you to take your warmed up car out on the road, find a nice straight stretch and do a couple of heavy throttle runs in third or fourth gear from about 2500-5500 rpm. Each time you hit 5500-6000 rpm, snap your foot off the gas and let the car coast down to 2500 rpm while in gear, to pull high vacuum in the cylinders. Repeat this step about five times and you should have a nicely mated set of rings and cylinders. NOTE: When I say “heavy throttle”, I am referring to a normally aspirated engine. For a turbo or supercharged car, modulate the throttle to achieve about zero on your boost gauge, rather than full throttle. This would be roughly equivalent to full throttle in a normally aspirated car.

[KiwiRS4T]

Yep Wolverine is spot on. I was taught by a very qualified engineer to do my running in mostly in the first couple of hours. The only top to bottom recondition that i did when I was a mechanic was on my own six cylinder Austin Healey 3000 and I ran that in (and subsequent engines that i bought) that way.

Basically you want to push a lot harder than just 2 - 4500 revs. Give it heaps as they say here avoiding only labouring in too high a gear or hammering the rev limiter.

Wolverine describes the process to a T in the above post.

[DaveB]

Thanks guys, yes that sounds pretty good. I didn't realise break-in should be done so early.

But if it's in the first couple hours of "engine time" (eg. running time) then I managed that... it was on about the 3rd day but after only about 80-100k's of driving.

I took it to some hills roads and did a few runs, mostly in 2nd, from ~2,000 revs to 4, 4 1/2, 5 or thereabouts, trying hard to keep boost on zero. This is not easy! Especially when you have the split front dump, the hi-flow cat, the ball bearing turbo, the straight-through exhaust etc. etc. all tuned to make boost by 2,000 in 2nd... so when you say "hard", I am not sure if what I'm doing is "hard"... but it's as hard as I can make it without making more than 1-2psi max boost.

Pretty sure I have the idea though thanks; I have been increasing the rev's a bit; haven't tried in a lower gear though like 3rd or 4th as a) boost builds too easily b) doing warp speed by 4,000 revs and c) I subsequently run out of road

I wondered about coasting down after accelerating or just changing gears to let the rev's drop quickly (because I'm in an auto, coasting back to 2,000 revs again can take quite a while) but I read somewhere that suddenly dropping the rev's was bad, so I coasted Sounding and running great so far, haven't lost any coolant or oil so fingers crossed... will be the new year before I can get that first oil change though.

Edited December 20, 2009 by DaveB