am i stupid?

Post Wed Oct 03, 2007 9:49 pm

right, doing my turbo conversion i have had ups and downs, lots of them...
its almost done, just finishin my stainless 3" downpipe into 2.5" strait through to muffler.
untill when i pulled the rocker cover off for painting i stupidly decided to retorque the nonstretch bolts for good measure since i have had it running,
SNAP!!!
Again goes the same bolt i have done before, except last time i was luck that the bolt snapped and i got it all out,
All the others were torqued to 80ft/lbs and this last one i got to 70ft/lbs
so i thoought as its been left for a while i would go the extra 10 bit by bit,
this time i i think i have puled the theads in the block as ithe bolt is still intacked but no sign of thread from the block on it,

my question is, is there anyway i can fix this without takin the head off, as i dont want to waste a brand new mls gasket that is very expencive!!!

Post Wed Oct 03, 2007 11:06 pm

carnt the mls gasket be re used?

i had a few problems with my head bolts
but once i cleaned the treads in the block and refitted them it felt betta
but the only advantage i had is the engine was on my stand not in the car

dont think theres a lot you can do unless you take the head off and inspect whats happened

Post Wed Oct 03, 2007 11:15 pm

yeah i really dont wanna go through it all over! startin to get really pissed off now! i have spend over 6 grand on this conversion in the last six months and too much time!
was wanderin if i could stick a tap an dye bit down there an clean it an see if it will tighted? or is that just stupid?

Post Wed Oct 03, 2007 11:24 pm

dont think its possible to get a tap a dye set long enogh

i felt the same a few days ago with my turbo conversion
but have a good rest and try again tomorrow

at the end of the day mate if you have a dout about anything do it and put your mind to rest
theres no point in cutting corners on thing like head bolts or anything todo with the head/block

im afaid your gonna have to take the head off to see why the head bolts giving you trouble

esspecily when your turboing your engine

Post Wed Oct 03, 2007 11:34 pm

Hmmm, sounds similar to what happened to my 2.7 !!!! headgasket blew, so i changed it, was fine for 1 day but would still mix oil and water and lose power... until i decided to change engine to standard 2.5... out comes the 2.7, took the rocker off and saw 1 headbolt sticking up halfway... still seemed as though the thread was ok but on closer inspection, it stripped the blocks thread..

Post Wed Oct 03, 2007 11:40 pm

yeah i belive thats whats happened to mine, its just a waste of over 150 quid of gasket!!

Post Wed Oct 03, 2007 11:59 pm

rossle did you torge the headbolts to 70ft/lbs and did it feel ok?
and wen you did the extra 10 it snapped?

Post Thu Oct 04, 2007 12:16 am

when i was retorkin that one it was 70, so put it to bout 73, fine, 76, fine, just under 80, snap,
unscrewed it all the threads were there with no signs of the threads from the block, so screwed it back in and it tightens then goes loose, would be so much better if i didnt have to take the head off!!!!

puts me back at square one!!

Post Thu Oct 04, 2007 10:30 am

If it just made a cracking sound/feel then was ok then it may have just been binding a bit, slipped then started moving freely in the block thread again. If it won't tighten at all now then you must have stripped the threads or be twisting the bolt up (less likely!). Can the block be helicoiled, is there enough material around the holes?

Re-tapping stripped threads to the same size won't fix them unless you tap them deeper and put longer bolts in to go past the damage (not sure if you can with the head bolts, I'm talking in general terms). You'll need to go oversize or fit inserts.

Just check it's not something stupid like a washer seating suddenly as you torque the bolt up (I'm guessing they don't have washers though

) before you pull it apart.

jk

Post Thu Oct 04, 2007 11:05 am

think the threads are def gone, im not too fussed about takin the head off again but i am fussed if i have to get a new mls gasket??

Post Thu Oct 04, 2007 11:32 am

Is the MSL gasket bonded to the head like the decomp. plates or just used like a normal gasket?

Post Thu Oct 04, 2007 12:36 pm

Hi

I thought the advantage of MLS (from VAC) was that they could be reused.

Jason

Post Thu Oct 04, 2007 4:56 pm

MLS CAN be re-used, just make sure you check it really well before refitting. There three sections are coated in a special sauce

and this can burn off if not sealing correctly.

There are many so called "experts" who say that they can be reused a few times, others say less.

IMO take a look and decide but like the bolts they are sold as re-usable.

HTH, Mark.

Some info: Block holes are 25mm deep, the threads are aprox 20mm deep.

Post Thu Oct 04, 2007 5:20 pm

are you using the washer with the bolt ??

has the head been skimmed or block decked ?

Post Thu Oct 04, 2007 6:12 pm

well i was thinking maybe i could get away with putting a bit of a longer bolt in?
it cant hurt to try eh? it saves worrying about the gasket.
do you think this is doable like that? i took a quick measurement and i measured it as being about 10mm or more over the length of my bolt.
also the nonstretch bolts slightly different on the thead that the standard bolt, dunno if thats because its a stetch bolt but i have noticed a few on e30tech have said this too, thats why i checked..

hey mark, you got your new engine yet?

Post Thu Oct 04, 2007 6:22 pm

Be careful using longer bolts, I worked out that 150mm was the longest you could use with a stock HG, you can use the 160mm ( As Hass is ) with the decomp plate.

IIRC with stock HG thickness you would have 9.6mm of unused thread, so 160mm will bottom out.

The decomp plate adds an extra 3mm, so you can get away with it.

Alex was toying with the idea of drilling and retapping them all deeper but the waterways in the block run close and I'd be worried that you could drill through one and well that's that really, even with the head tightened down I've heard the water will run up the head bolt and piss into the head.

No new engine as yet, new intercooler is here tho and one charge pipe is kinda sorted. I'm just getting over how much of the front of the car I'm gonna have to chop off! Still, it'll be a light e30 if nothing else!

Mark.

Post Thu Oct 04, 2007 6:54 pm

ha ha yeah i just saw the pics you emailed me!!
thats the same size as mine an i had to cut most of the front out, top mounted it too so lost the mainbeams but looks really agressive seein the intercooler and blue hoses where the two inner lights are meant to be! il get somes pics an post them up...

well il try then if not the head will have to come off, done it once so at least i know what im doin now an know a few short cuts!!

Post Thu Oct 04, 2007 10:11 pm

Are the threads cut full depth anyway? Its normal to have the last 1 > 2 threads tapered even with a bottoming/finishing tap and these often stop a mm or so short of the bottom anyway to leave space for the chips. You shouldn't redrill then re-tap a hole to deepen it, you'll end up with a substandard thread and it sounds like they're already marginal. The initial drill size is greater than the hole bore will be once tapped, the tap not only cuts but it extrudes material from the wall into the thread as you run it down. You wont get an 8.5mm drill shank into an M1.5 tapped hole despite having just used it to make the hole. Inserts might be your best bet.