smackhead999

iTrader: (5)

i put together this motor, s4na with s4 turbo uim/lim. short my better judgement, i didnt tap a hole with threads for the center bolt on the lim that the t2 has and na does not. i used a mls gasket and i have a vacuum leak on this mating surface.

1 what im wondering is does anyone know off hand what the depth of this bolt hole is on their t2 block? not sure how far "safe" is. of course if i hit a fluid passage, it shouldnt leak.

2 there are 6 other mounting points strategically placed to carry the load, is this bolt all that necessary? apparently, unless my mating surface is warped?

3 i know others have done the turbo to na mod on the manifolds, and i read on thread on here before where the hole was tapped. is anyone succesfully operating with out it?

HAILERS

No. I drilled and tapped the hole/threads. I frankly don't remember the depth because this project was a long drawn out project that almost died due to lack of enthusiasm over a year plus time period.

I just measured the depth on a turbo intermediate housing and it's .600 inch deep. Most likely what I drilled on the six port turbo.

I never went without this new threaded hole.

I made my own gasket out of.....gasket material from PePBoys.

smackhead999

iTrader: (5)

good intel

HAILERS

Come to think of it, I had a real problem with the exhaust gasket leaking. Normally I reuse the exhaust gaskets, which I did, and it leaked. So I bought a brand spanking new one and installed it. It leaked also. A real pisser of a deal.

So I took it off, looked at it, seemed there was nothing wrong with it. Considered another new one. Said naaaah, It'll work the next time I put it on. Put it back on and still leaked.

Took that exhaust gasket to the band saw. Cut out the middle section altogether(that large area of material b/t the two exhaust ports) and now had two gaskets. Reinstalled and no exhaust leaks. I'm not sure why I had this problem.
I've reused exhaust gaskets many times before and never had a problem. I think its the hodgepodge of parts involved, maybe. Non turbo end plates and intermediate housing and new turbo rotor housings inbetween plus the normal non turbo rotors.

I drilled that hole you refer to because it's so near the intake ports on the intermediate housing plus I cutout what *seems* to be a freeze plug just below the intake ports so the ACV would work. That *freeze plug* hole, in conjunction with using turbo rotor housings, leads to the passage that feeds ACV airpump air to the exhaust ports on those two housings. Won't work if S4 rotor housings are used. Actually I just cutout only the top half of the freeze plug and then got a rotary file out and gouged out the intermediate housing to better match that rectangular hole at the bottom of the two intake ports. Just FYI.

Just blathering away. Gone for now.

OH. Removing and reinstalling the turbo to get at the exhaust gasket that many times was also a *real pisser* of a deal.

smackhead999

iTrader: (5)

well since i got my megasquirt operating properly, this has been my only major issue. i burnt up my waterpump from over heating too many times trying to figure out that i was overheating. it was the thermistat. a brand spanking new one. stant from advance auto. it just wouldnt let the coolant circulate. i did the boiling water test, and it worked as soon as water boiled. just wont work in the car. so i took it out. i dont need it right now.

i will just have to tap this hole. ill think i may do like .375" shouldnt need much just something to put 15ftlbs or so on it.

initial D is REAL!

If you hit the water jacket, Maybe some thread sealer might keep it form leaking. I never did this conversion before

scrip7

iTrader: (6)

Just a little FYI.....the LIM bolts work together to keep the clamp load as even as possible across the flange. Also note that aluminum expands at almost double the rate of cast iron, and with the exhaust manifold directly under the area where the missing bolt is, I would bet there is considerable expansion and air leak at that location, especially after warmup. Mazda re-designed the LIM-to-keg gasket from a conventional compressed paper design to a steel constrained-layer style that better addresses the expansion issues. There are raised ribs around each of the port holes that help seal those areas. Most aftermarket gasket sets don't include the steel gasket, so you might check into getting one from a dealer or Mazdatrix.

smackhead999

iTrader: (5)

yeah scrip i got one of those gaskets with the ribbing around the ports. i just called it a mls, cuz of the 3 layers. kudos on the expansion, totally an issue. what i had initially thought was that with the weight of the uim and tb and compressor plumbing hanging like it does, that would help to keep the top of the flange, where this bolt is, snug. not that i was relying on it all together to do the job, but i really hadnt considered the heat warping and whatnot. props.

scrip7

iTrader: (6)

Glad to see you found the problem and are fixing it right with the right gasket.

HAILERS

That six port metal gasket might be ok for you since you probably didn't use the water passages in the rotor housings for cooling the turbo. In my case I used two new turbo rotor housings and made my own gasket out of paper because it'll seal the water passages if the o'rings fail plus the metal six port gasket would not work for me because I'm using that rectangular hole below the oval intake holes on the intake manifold to feed the ACV air to the exhaust ports. That metal gasket wasn't about to seal the air passage on the intermediate housing.

Frankly, I don't think they make a metal gasket for the turbos. Might be wrong. But all my turbo engines have paper intake gaskets. Work fine for a plenty long time.

HAILERS

The more I dwell on the thought of the metal gasket with the ridges around the holes, the more I remember about how when that gasket was offered up to the intake manifold, how the ridges don't match the hole in the turbo intake manifold. Remember, the manifold was ground out with a die grinder (dremel in my case) to match the two holes in the gasket. But remember, when through grinding, there is but one hole in the manifold, not two like the gasket. So how would the ridges match the Single hole in the manifold.

Just one more reason I made a paper gasket (that and the ACV hole plus water passage holes in the rotor housings). You probably did not use the water passages since your non turbo housings didn't have any.