attempting to replace head gasket.

[USMCgetsome]

Is it really nesscessary to remove the intake manifold and exhaust manifold w/turbo? According to the r33 manual you have to basically take apart the whole damn engine just to get to the head gasket.

I have the understanding that i do need to take off the belts and also the valve covers and the cylinder head itself. Or do i need to go more. I only ask because this will be my first major do it yourself project that i'll probably ever do to this engine. Any pointer will be taken.

[yellow_jacket]

You will want to take the manifolds off the head before removing the head. On some cars, you can remove the head with the manifolds attached. For the RB25 weight is going to play big role because the turbo manifold and turbo weigh a good bit. The other reason to pull both manifolds it to make sure that everything is disconnected. Sometimes if you don't pull the manifolds off there will be a vacuum line or connection tucked somewhere that you can't really see.

Also, you will probably want a friend to help you pick the head up off of the block. You will definetely want someone to help you place it back on. It will make life much easier and you won't knick the new gasket.

[goofynick6]

This is a major job which requires high accuracy in removing and reassembling the head. Even taking the bolts out of the head in the wrong order can warp it and make it so it won't seal properly again. By the questions you've asked so far, I'm thinking you might wanna get someone to help you that has more experience.

Nick

[USMCgetsome]

very well. I'm not touching it. I'm just gonna paint the valve covers and timing cover as well as the plastic island that has the 2500 on it.

Thanks for the response. I'm definitely gonna take it to a professional.

[Slo_240sx]

Smart man. If you lived in MI I'd help you change it for free.

[Bluefire]

Yeah Headgasket change is a big job. The right tools, a friend, and a fsm is what you will need. Also I'll give you a little tip if you do plan on doing it. The exhaust manifold does not need to be completely removed. Just remove intake, downpipe, and undo all exhaust manifold nuts. Then use a pry bar to pull the manifold away from the head enough for the head to come off. The hardlines will bend slightly but when you push the manifold back on the will bend back. As for the intake manifold; if you got a greddy it'll take 30 min to pull off. If its stock make sure you got different size extensions and flex sockets.

-Bluefire

[USMCgetsome]

thanks for the heads up. I'm not doing it myself. Having a certified tech do it for me. I'd end up screwing something up.

[Nameless EJ6]

That's not the attitude you should take!

It's NOT hard. I suggest if you're scarce on money that you give it a shot.

Remove the manifolds, valve covers, timing belt, cams, head bolts (from out to in).. then you have it.

It's a heavy ***** though. But it's easy. With a service manual.. anyone can be a technician. Certifications are for technicians with experience. It doesn't take experience to read and follow instructions the first time around.

Like Nike says.. "Just do it". That's the only way you'll learn.

[Slo_240sx]

heres the way I always do it and it seems easier this way. undo the oil lines manifold vaccum lines and ect and just pull the intake with the head. I'd say pull the exhaust mani with it but its turbo'd so don't bother. If its turbo pull brackets off and pry the mani. away fom the head like blue said.I can so walk you through it. *We* can so walk you through it.-Alex

[Darius]

Could you leave both manifolds attached, disconnect the oil lines etc., and then lift everything together with an engine hoist? This would make my life 100X easier than having to remove both manifolds even though the motor is on an engine stand.

[Nameless EJ6]

Could you leave both manifolds attached, disconnect the oil lines etc., and then lift everything together with an engine hoist? This would make my life 100X easier than having to remove both manifolds even though the motor is on an engine stand.

yes you could do that. Make sure it lifts straight up. Not at an angle and do it carefully.

personally, I don't really like doing any work like this with an engine in the car. Much easier out and on the ground or on the stand...

[Darius]

In the straightest way possible, I love you man!

I'll take pics and show you guys how it goes.

[Nameless EJ6]

Sounds good looking forward to seeing 'em. And I love you too, cupcake. :p

[Bluefire]

I would do a leakdown also before you pull the head and check to see if any of the valves could use some lapping. Changing the valve springs at this point would also be a nice time saver also . This way you don't have to worry about dropping a valve into the cylinder, while changing the springs

-Bluefire

[Darius]

When selecting a head gasket, which thickness and bore is best? I have heard that thickening the head gasket negatively influences the squish band. Therefore, I would like to keep it stock, but I am having a hard time finding the stock RB25DET head gasket thickness. I see that most aftermarket gaskets have a 1.2mm option though.

Next question is about bore. I see that manufacturers produce 86-88mm for the RB25DET. Stock bore is 86mm so are they just offering larger sizes if people bore out their motor or is there an advantage to having a head gasket with a larger diameter than the cylinder bore?

[Dano]

Next question is about bore. I see that manufacturers produce 86-88mm for the RB25DET. Stock bore is 86mm so are they just offering larger sizes if people bore out their motor or is there an advantage to having a head gasket with a larger diameter than the cylinder bore?

no, there's no advantage to haveing a gasket with a larger diameter than the cylinder, you want a nice tight seal, the gasket is only an link between two areas... like your manifold gaskets... you want the same size. They offer larger sizes in case you either have to do machining work or want to put different pistons in.

-Dan

[gawdzilla]

When selecting a head gasket, which thickness and bore is best? I have heard that thickening the head gasket negatively influences the squish band. Therefore, I would like to keep it stock, but I am having a hard time finding the stock RB25DET head gasket thickness. I see that most aftermarket gaskets have a 1.2mm option though.

Next question is about bore. I see that manufacturers produce 86-88mm for the RB25DET. Stock bore is 86mm so are they just offering larger sizes if people bore out their motor or is there an advantage to having a head gasket with a larger diameter than the cylinder bore?

cometic makes a very nice gasket metal gasket. it isnt nearly as expensive as the JDM ones (tomei/hks/greddy/etc.) they only offer one thickness iirc. its slightly thicker than stock, but not by much.

[Darius]

Okay, I tried to remove the entire head, intake manifold, and exhaust/turbo manifold tonight and ran into one minor problem. That Gat-damned auxilary head bolt #3. There is no way to get at that thing without taking off the intake manifold, so I spent a couple hours tonight taking that thing apart and off. NOW, I am ready to remove the head bolts and proceed with the show. Totally sucks that I had to go through this, but I guess it could be worse. I'll post some pics after christmas when i'm on vacation.

[supersayianjim]

wow bump from the past! how did this head job turn out??

[USMCgetsome]

Turned out great considering i didn't deck the block or polish the head. I was such a noob back then! That was my first successful engine swap and it got easier after that. Lesson learned. Watch the damn idler and tensioner bearings for the timing belt. I'm on my 2nd RB swap after I got another S13.5. I missed my RB terribly. Sr20s are fun but can never replace your 6cy feel and engine tone.