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So when assembling my the two halves of my engine (BP05 block, BP4W head) I installed the ARP headstuds by hand and snugged them up with an Allen key and bottomed them all out. I then sprayed my headgasket with a copper spray, placed it after it had dried, and then put the head on. I then realized the headstuds in the rear of the motor weren’t long enough while bottomed out, and I remembered the headstuds were so far into the motor that the threads of the headstuds were about a quarter to half inch below the surface of the block. So I assumed it would be fine to back them out so that the nut would be able to fully thread on. I didn’t want to remove the head to check because of the copper spray which is why I come to you all for confirmation. I believe it was 4-5 turns to get enough length to fully thread the nut on. I then torqued it down to 65 ft-lbs in stages as ARP recommends.
But my point/question is that this is safe and totally normal? Why don’t the instructions or anything online mention this? I’m not at risk of stripping the threads in the block am I? I wonder why they don’t just give you two slightly longer studs? Maybe it would effect the required torque since it could stretch more?
If anyone who is more knowledgeable or experienced could just confirm I’m good to send it that would be great!
engine pics attached because I like shiny stuff. Ignore the mess, it’s the spare garage so there’s not much room for storage and I typically am a messy worker as it is.
I’ve personally never seen this after installing a dozen or more sets of ARP hardware on various BPs. The front two will sit higher, but threads are shallower and head is cast higher too, so they all have roughly 1 thread exposed above the nut once torqued. This is with all studs bottomed out.
just realized you’re the backwards head guy. So yeah, flip it and you’ll be fine. You have the high casting parts on the lower studs.
I’ve personally never seen this after installing a dozen or more sets of ARP hardware on various BPs. The front two will sit higher, but threads are shallower and head is cast higher too, so they all have roughly 1 thread exposed above the nut once torqued. This is with all studs bottomed out.
just realized you’re the backwards head guy. So yeah, flip it and you’ll be fine. You have the high casting parts on the lower studs.
yup I just realized this today. I’m a dumbass haha. It’s all good though just got to get another head gasket haha.
Originally Posted by olderguy
Also looks like you have only one guide bushing. Needs two.
Im not familiar with what you mean, could you elaborate? I didn’t touch the head or any of its parts. The machine shop assembled it for me, so I’m not familiar.
Guide bushings are the metal ring that goes around the stud and fits into the block. It's to make sure the head lines up correctly. The picture isn't very clear but it looks like you only have 1 bushing located in the corner stud closest to the oil filter.
Guide bushings are the metal ring that goes around the stud and fits into the block. It's to make sure the head lines up correctly. The picture isn't very clear but it looks like you only have 1 bushing located in the corner stud closest to the oil filter.
I gotcha. It didn’t even cross my mind, but I see it now. I’ll order one with my new headgasket. Thanks for pointing that out. Potentially saved me a good headache down the road.
I gotcha. It didn’t even cross my mind, but I see it now. I’ll order one with my new headgasket. Thanks for pointing that out. Potentially saved me a good headache down the road.
I gotcha. It didn’t even cross my mind, but I see it now. I’ll order one with my new headgasket. Thanks for pointing that out. Potentially saved me a good headache down the road.
honestly you’d probably be ok to reuse that one, since it never saw run time or a heat cycle. ESP with some copper spray ¯\_(ツ)_/¯
I would say avoid that copper spray altogether. If the head is flat (it better be!), and the block is clean, a fresh MLS gasket does the trick with no subaru headgasket fix techniques needed.
Fuuuuk no! Once it has been torqued it can't be reused! Plus it was torqued backwards and possibly misaligned with a missing dowel pin.
Yeah, I’m not risking it. 3-4 delay vs possibly pulling the head again is an easy choice for me.
Originally Posted by Fireindc
I would say avoid that copper spray altogether. If the head is flat (it better be!), and the block is clean, a fresh MLS gasket does the trick with no subaru headgasket fix techniques needed.
The heads flat, block wasn’t decked though. I wish he would’ve but I didn’t specifically ask for it. No clue if he checked it or not. I briefly did with a flat edge but it had seen some better days so it was hard to tell. It looked alright though. Are there any downsides to using the copper spray? I figured at worst it wouldn’t hurt anything.
I don't get the whole copper spray thing either, never touched the stuff. I have gone with the block untouched before, maybe find a quality straight edge and .001" feeler.
02-17-2023, 03:23 PM
Quick headstud length question
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