Head Gasket And Studs Rb25/30

[beau_32]

hey guys, 99% sure iv done my head gasket

its for my rb25/30, has a few mods and makes decent power, runs around 17psi

but thought id see what gaskets and studs you guys are using and how long for??

any help would be great, thanks in advance

cheers beau

[Dobz]

Just a few Q's, if you're sure it's head gasket you need to diagnose what could've gone wrong with yours before you ask anyone else about their setups.

Who put the engine together?

What gasket and studs are in there now?

What turbo?

What engine managment do you have, was it tuned properly and do you how much power you have?

[beau_32]

im guessing it is as my temp gauge went to 130 the other day and was going up and down heaps from like 80 to 110 to 90 up to 130 etc etc so 1st thought was sticky thermostat, replaced it with new 1 and booked it in for coolant flush got that done and its still going up and down heaps in temp and this morning its started to blow white hazzy smoke like coolant burning so i thought head gasket straight away, been rong before though... i bought the car from a member on here (cef11e) with mods done, he gave me a list of mods when i was first talking to him about buying it and there was nothing about head gasket, he just said all new gaskets and seals were used when he built it... (my fault for not asking i guess) so to answer your questions, he did everything he could do himself, im not sure what gasket or studs in it now, its a holset hx35w and it has a remaped ecu that he also tuned himself... its got 175000 on clock and he told me build was done at 140000 so not to many ks since... i mite add this is the 1st real issue its had in the 18/19 months iv owned it!

cheers

[Dobz]

Yeah that does sound like head gasket, did you notice it start smoking when it was at a high temp? You'll need to get the head re-surfaced and depending on what the head was bolted down with it's a good idea to get a set of ARP head studs as a bit of added insurance. With a set of ARP head studs and a genuine nissan head gasket you'll be sealed up well.

As for whats causing the temp fluctuations... that's a tough one. Are you using an engine fan or thermo? I'm guessing the condition of the coolant that came out was good so we can rule out blocked water galleries and/or radiator... am i right?

Who installed the thermostat and did the coolant flush, was the system bled properly?

Edited July 9, 2011 by Dobz

[beau_32]

yeh was wen i 1st pulled up this morning was sitting around 100 and then seen the smoke in mirror. it was chemicaly flushd at local natrad and i did thermostat myself... genuine nissan unit! just using engine fan, and fella said there was abit of shit in coolant but nothing out of ordinary. yeh a few people have said ARP studs!

cheers

[r33_racer]

What sort of power is it making at 17psi?

If there was coolant leaking in the cylinder it would only get in when the engine shuts down. Whilst running the combustion gas would be blowing into the water system and your temps would skyrocket everytime you were giving it some gas and then immediately reduce when you back off. Is that what's happening?

[beau_32]

well on 19psi it makes 326rwks so abit less then that.

yep sounds about right mate, although i didnt put my foot down but road i was on was a little hilly so under load it increased yep!

cheers

[TiTAN]

from memory, he used an OEM head gasket when he put it together.

[r33_racer]

You can do a c02 test on the water system. With the chemical die and it changes colour if combustion gas is leaking into the water system. Ususally pretty definitive. But it does sound pretty well like a blown headgasket.

You could also do a water system pressure test too, see if it holds pressure. I guess for future reference.

[beau_32]

Thanks TiTAN.

yeh I think it has to be head gasket... I will try and get both test done soon and see what comes up!

Cheers

[beau_32]

so yep its head gasket and im just ordering some parts now and im wondering what gasket and studs to use? rb25? rb30?

vct is disabled btw...

cheers

[JonnoHR31]

25 studs. 26 or 30 gasket, 25 wont work.

[beau_32]

cheers mate, how come 25 doesnt work??

[JonnoHR31]

the vct oil feed overlaps with a water gallery on the 30 block which is why you need to get the head welded when doing the conversion. so once you weld it both the block and the head have the same pattern as non vct RBs, so you have to use a gasket to suit.

[tazzy]

i will* be running ARP head studs and a cometic MLS head gasket. have been told it should be pretty reliable.....

[beau_32]

ahh ok sweet thanks JonnoHR31 so 26 and 30 gaskets are the same or they will both just work?

cheers tazzy, looks like the way i will be going also...

[JonnoHR31]

they're not identical but they both have the same pattern (all the bolt holes, galleries etc all line up). 30 gasket is cheaper than 26 from nissan

[beau_32]

ok mate, thanks for help! do you think a nissan gasket is the way to go? or should i look at cometic or somethimg like it?

[JonnoHR31]

if everything else is still standard (bottom end, head bolts etc) then i'd just stick with a nissan gasket. 30e gasket is around $95 from nissan

[beau_32]

Yeh bottom end was rebuilt to stock spec he said, im not sure what head bolts are in it though, thats a fair saving on the gasket though if im not going to gain any benifit from a cometic or something like it...