OK so I'm cryin in my beer tonight....Here's why.
The "Green bastard" (my crx) which I have built over the last 9 months (swapped, tucked, full colour change, turboed) sits in my skanky garage tonight with a wound that, even if I took a picture, no-one could actually see, yet it has ruined my motor.
The motor: stock block b20, b16a2 head, crower stage1 cams, JG cam gears, Garrett 57trim t3/t4, tial wastegate, evo 560cc injectors, msd coil/cap, etc, etc.
So, the other day I'm doing a 3rd gear pull at 13psi, and I smell antifreeze. I pull over, and pop the hood - antifreeze sprayed out the rad cap.
Damn.
Oh well, after trying a new rad cap (hey, I can hope!) I know that the head gasket is toast. Fine, whatever, so I pull the head off last night, and I notice 3 of the head bolts are looser than the others, and I think "hmmm - I KNOW I torqued those right, used a $napon TQ wrench thats awesome, etc. So I concluded that somehow the bolts loosened , but think, oh well , I want to up the boost to 17psi when Its back together, so I picked up a set of ARP head studs, just as more of a piece of mind deal. Then the **** hit the fan.

As I threaded in the studs, I noticed that 3 or 4 of the studs sit higher than the others, yet they are all "bottomed" (tight) - weird. So, I pull them out, and check that they are all the same length, and , yup they all match. Fine. Thread them all in - same deal - 4 sit higher than the rest...WTF??? So after doing all I can to thread them down, I decide that I'll sit the head on the block and see if they all have good thread on the top end of the studs, which they do, but these four are still high. GRRRR. So finally I decide to put it all together. As I torqued the second stud down it happened. firmer, firmer, SOFT!!

Oh ****.... I pulled out the stud that went soft, and saw 3/8ths of an inch of aluminum threads stuck to the ARP stud...**** me.... And then I knew my perfectly good b20 block is ****ed because there are at least 3 others just like that one - streched, ****ed aluminum threads. Bye bye B20.

Then I realized what had happened that lead to this. My cheap *** had used stock b16a head bolts when putting the head on, and they are long enough to tighten down into half of the blocks threads, but ultimately its just not enough to take the load from the headbolts for any length of time.

Moral of the story: when building a b20 vtec, spend the extra bucks for the PROPER ARP B20/vtec studs from the start!!!!


Well, plan B - put in my spare b16a for now and crank the boost!!!!

 

Just an old picture once the engine bay was painted, but no turbo in this pic....I just dont take the time for pics like I should, I guess.

 

damn man that sucks to hear, atleast you have another motor to drop in!

 

just use timesert's on the threads and you'll be fine....

 

had a similiar problem, had the block sent to the machine shop and the put in some time serts in two holes and it cost me $80. thing holds just like stock. so its not totally over for the B20.

 

True. You must ALWAYS match the headbolts to the block, not the head. So if you would have used the B18C headbolts, it should have worked no problem. I'm not sure, but the B20 headbolts may even be the same as the GSR ones.

 

Well, I guess over this winter I'll send the b20 block out for machining, and I guess its an excuse for a forged piston/rod bottom end , as it'll be apart anyhow.... I was kinda hoping to push the limits of a stock bottom end first. Are you huys talking about helicoil inserts, or is a timesert something else??

 

use time inserts its like $300 for the kit to replace all the threads

holds up fine at 700whp on my old motor

 

oh good! glad that there is hope for my block. Last night was one of those "is this for real?" nights.

 

Look around, you can probably find a bare b20 block somewhere for 100 bucks or less. Use GSR studs this time though.

 

8 of the B20 bolts are the same. The center 2 on a LS/B20 are longer.

 

i think you have that backwards buddy. if you do an ls/vtec or a b20/vtec, you should use the head studs for the head you are using, NOT the block.

 

no you always use gsr studs for a hybrid motor like that, hence the OP's problem.

 

you can drill the block out for 1/2 headstuds, or heli coil it

 

I know for a FACT that you don't use B16 headstuds on a B18 block. So I am not backwards. B16 headstuds are shorter then B16 ones. I guess what I meant to say is to not use B16 headstuds/bolts at all.

 

like the OP said go to a 1/2 inch head stud and problem solved

 

Just takle the block out of the car and get the correct tap and heli coils and drill the bad ones out and heli coil them.

if you used b16 studs and only pulled the tops of the threds out then there is plenty of thred left in the block for a gsr stud so you could technically just run a tap down there BUT imo at least drill them out and run in double heli coils. ive done it on a few blocks and it held fine. heli coils are stronger than stock threds and stock threds hold stupid power.

or you can go the timeserts route which is topnotch but very expensive

 

well, I'll look into the options, but a bare b20 block might actually be the cheapest. I already have the ARP studs , so this wont happen again. It was funny, but the b16 bolts held up OK for a while, ( 3 months) but as I was tuning to higher and higher power levels, I guess the added pressure finally made the minimal threading rip right out. Oh well, B20's are cheap, and my "extra" b16 will do for the rest of this year. Lesson learned.

 

1/2 inch stud ..problem solved

 

Exactly, I had one of my threads do that when I tore mine apart. It had almost 500whp for almost 3 years. No big deal, the machine shop put a Helicoil in and fixed it. It holds just as good, if not better, then the normal threads