Another E30 GRM Challenger

[Mgriz]

Time for another update after a busy weekend.

When I got home from work Friday I was greeted by this beauty... Picked it up used off a guy on cumminsforum.com, it's a stock HX35w from a Dodge Cummins diesel.



It's in pretty good shape, spins nice and has no shaft play. I took the compressor housing off to clean it up and have a look at the compressor wheel.







Here is a look at the hot side. Nothing much to see just a bunch of carbon soot... Something I didn't realize before, the internal wastegate only vents one turbine inlet. I'm wondering if this is going to be an issue if we go with a twinscroll manifold? I guess ideally we would have two external wastegates for this kind of a setup...



We then towed the car to a local car wash to blast some of the gunk out of the engine bay. It did a pretty good job, so its somewhat decent to work in there now. We also dragged along the transmission and diff but the pressure washer barely put a dent in the caked on grime on them...'





We had some scrap steel laying around and fabricated solid engine and trans mounts.



We took xwill112x's advice and smoothed out all the combustion chambers. We ground down the pits then blended the section into the rest of the chamber. I think it came out pretty good.



We also uncovered an issue with the steering rack as we worked at blocking the power steering ports on the rack. The rack moves about an inch as you cycle the wheel back and forth... that'll make for some sloppy steering. Not sure what the issue is but we'll definitely have to sort that out before getting her on the road.

A couple of us started attacking the chassis wiring harness. We really should have labeled more when we were tearing it down... it's looking like quite the nightmare. Fortunately not much of it has to actually work, but figuring out what we do and do not need so we can clean up the wiring would be nice.

Thats all for now. Next weekend I think we're going to throw the engine back in the car to mock up the turbo manifold, if we can scrounge up some scrap tubing. Our plan is to use the stock exhaust manifolds and fab up something like this... except with a divorced T3 flange.

[Lof8]

I've been using an oem sachs e30 clutch on my S50 swap trouble free for 2 years now. I'd recommend sticking with what you've got there. As for the sloppy steering rack, replace it with an e36 rack - they're quicker.
good luck! I'll be there to check out the event again this year.

[silence]

Brings back memories... Welcome to the GRM club, can't wait to meet you all, keep up the good work.

[acolella76]

what did you do to smooth out the head? My head has the same thing on one of the cylinders...

[Mgriz]

what did you do to smooth out the head? My head has the same thing on one of the cylinders...

We used a rotary carbide burr bit (like pictured below) on a pneumatic die grinder to very carefully remove material from the combustion chamber focusing on the area with the deepest pit. When the pitting was no longer visible we blended the once the area into the rest of the ridge to mimic the original shape of the combustion chamber. Once that was done we hand sanded with progressively finer sand paper until it was sufficiently smooth.



There are a few spots that were too close to the valves to really do anything about (especially with the valves still installed) but the major pitting is all taken care of.

[Jonny Cash]

Maybe I missed it. What kind of wheel/tire combo do you guys plan to run?

This event is alot of fun, youll love it.
Good luck getting the car together.

-jay

[acolella76]

We used a rotary carbide burr bit (like pictured below) on a pneumatic die grinder to very carefully remove material from the combustion chamber focusing on the area with the deepest pit. When the pitting was no longer visible we blended the once the area into the rest of the ridge to mimic the original shape of the combustion chamber. Once that was done we hand sanded with progressively finer sand paper until it was sufficiently smooth.



There are a few spots that were too close to the valves to really do anything about (especially with the valves still installed) but the major pitting is all taken care of.

sweet, thanks for the info

[sandlock]

Keep up the good work.

[Mgriz]

Brings back memories... Welcome to the GRM club, can't wait to meet you all, keep up the good work.

Thanks, we can't wait either. Sooo much to get done though... Hopefully we'll be half as fast as you guys.

Maybe I missed it. What kind of wheel/tire combo do you guys plan to run?

This event is alot of fun, youll love it.
Good luck getting the car together.

Thanks, the wheels and tires are still up in the air. The tires are going to be most critical for autocross so the plan is to let that determine what wheels we need.

[Mgriz]

Two more weeks of progress, time for another update...

We rented an ISKY tool from Moosehead Engineering and cut o-ring grooves into our block. We decided to stick with the copper wire instead of opting for stainless like many do. We cut the grooves to a depth of 0.025" which with the 0.040" diameter wire gives us 0.015" of interference with the head gasket. We decided on a figure 8 pattern based on the tight spacing between the cylinders. I know people have done individual cylinder o-rings on the M20 but I felt figure 8 was more appropriate.





After the first go around with the ISKY tool I had a lot of trouble getting the copper wire to stay in place in the groove. After a bit of scratching my head and swearing I took a couple measurements and found that we had not cut the grooves as deep as we intended. After getting back in their with the cutter and fixing the groove depth the wire went in fairly easily. The grooves were way off to begin with (not sure why) and without going to at least half the wire depth there was nothing to hold the wire down...






Head reassembly... metric blues were the obvious choice given the budget constraints.




And it's back in the car sans transmission. Soo much easier going in without the transmission. Now its time to mock up the turbo plumbing.




Time is flying by and we still have a ton to do. I still have not gotten the Megasquirt together. We wanted to have the car running by next weekend, don't see that happening. I've also been neglecting the growing pile of parts I've got to get rid of, need to get some money back for the budget...

[Earendil]

Any updates? I'm interested in how this thing is coming along!

[Mgriz]

That's just about how it sits at the moment, with the competition only a few days away... Needs a lot of work still, I'll throw up a more extensive update after the challenge. :D

[FunfGan]

I love you.

[ForcedFirebird]

Those pits in the head were probably from a broken valve at some point in it's life.

Can't wait to see it tomorrow! Good luck!

[2002maniac]

looks great! Hopefully you don't have the teething issues that plague many challengers. Good luck!