3 10mm bolts from head to block rb26

[MoMnDadGTR]

hey mates i think this will be an easy question for some but i just finished building another 26 and have always wondered what the purpose of the 3 10mm bolts that go from the head  to block are(2 at back of engine each corner, and one in the front on intake side side). are these crusual for sealing the water jacket ports on those corners or are they even necessary. there kind of a pain and i would leave them out if there not necessary. cheers interested to hear some thoughts on this.

[Duncan]

I've never put them back, and never had a head gasket issue (not that the race car runs big boost or power)

[MoMnDadGTR]

On 18/05/2022 at 6:19 AM, Duncan said:

I've never put them back, and never had a head gasket issue (not that the race car runs big boost or power)

thanks yet again duncan. cheers

[Rusty Nuts]

On 5/18/2022 at 9:19 PM, Duncan said:

I've never put them back, and never had a head gasket issue

I have ALWAYS put them back and never had a head gasket issue. Nissan do not put parts in for fun.

[MoMnDadGTR]

On 18/05/2022 at 6:57 PM, Rusty Nuts said:

I have ALWAYS put them back and never had a head gasket issue. Nissan do not put parts in for fun.

correct, on that note i was wondering if they are considered a "clamping force bolt" at all and more a less a holder bolt to ensure its lined up once all said and done? i was leaning towards them being kind of important as they are only on the corners with the larger water ports. to be dead honest i was almost positive mine was leaking without them. i pulled the head off had it decked yet again and replaced the headgasket with the 10mm bolts installed now all is well. that being said last time i put the head on i didnt clean the stud holes enough nor clean the faces enough so that was probably the issue for the blown headgasket first go around. most rb26 engines i see around here dont have them installed because engine builders just dont know about them not do the owners and doesnt seem to effect much. of course for me it may have because wierdness follows this cat around all the time. cheers

 

[GTSBoy]

I suspect that Nissan think they need them to even out the clamping force, to make sure that it is high enough in those corners to grab the gasket. It is quite possible that people like Duncan get their experience of successful clamping without the extra bolts because of upgraded head studs providing more total clamping force and maybe the corners stay above Nissan's desired/minimum threshold even with the uneven distribution of force resulting from leaving the bolts out.

And maybe Nissan put them in because the is enough clamping force with the stock head studs without the extra bolts, but there's not enough safety margin. That's the difference between OEM and aftermarket/modifiers. OEMs have to comply with the hard won lessons on how much safety margin they have to have in all their specifications. Modifiers get half of their gains by using up all of the margin and don't care (or know) that they are now 1% away from failure instead of 30%.

[TurboTapin]

They don't put them there for nothing. The three bolts cost all of 5$. Use them. 

[MoMnDadGTR]

Nissan Skyline R32 GT-R Workshop Manual (plmsdevelopments.com)

page en68 in my bnr32 manual labels the 3 bolts as "cylinder head bolts" so im sure they are considered a pretty important bolt. id say thats a wrap on this thread. there was no stubbornness on not using the bolts ill use them everytime, just was curious on the thoughts of others on the bolts. verdict - use the damn things as cheap insurance everytime. cheers

 

  

[Rusty Nuts]

On 5/19/2022 at 10:12 AM, MoMnDadGTR said:

kind of important as they are only on the corners with the larger water ports.

I think you are on the money, with the water ports. 

[BK]

Visual reference on the 3 bolts for others wondering location, as just put the head on the white 32 today

 

[MoMnDadGTR]

On 22/05/2022 at 12:09 AM, BK said:

Visual reference on the 3 bolts for others wondering location, as just put the head on the white 32 today

 

thanks for the reference pictures ben. hope all is well good buddy. hope the gtr's arent sucking the wallet to bad these days like my car is lol....cheers mate

 

[hardsteppa]

I didn't use them after a head gasket once, and yes a weep started. I use them again now every time.

[MoMnDadGTR]

On 23/05/2022 at 10:59 PM, hardsteppa said:

I didn't use them after a head gasket once, and yes a weep started. I use them again now every time.

seems to me some people have had luck resealing without them when running lower horsepower/ have an extremely good mating surface on head and block and have very good block without cracks and good studs etc. that being said i have deemed them being extremely important and will never not use them for what its worth. i would highly recommend them being used, im surprised they actually didnt use larger bolts on all 3 corners. cheers. oh yeah if you have some little cracks on your block and want to add some insurance on the jb weld you already added, throw some block seal in there and you will be amazing how it can seal up a block semi reliably. i pulled my thermostat and did a few heat cycles with block seal and it instantly sealed my block up and ive been hitting 27psi since with a fresh thermostat in. cheers

[MoMnDadGTR]

that being said im going to try 30 psi on e85 today so we will see how the old cracked block can handle that......lol cheers mates

 

[MoMnDadGTR]

The little 10mm bolts are holding for dear life. 30 psi on ethanol/meth injection and things are feeling fricken spicy now! I hope the boost gods are with me at this power level feels like my face is going to the back of my head now.