Jump to content
HybridZ

Positively Displaced


Xnke

Recommended Posts

  • Replies 234
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

FULL STOP.

 

Pulled the head again, since a headgasket swap didn't fix the pressureized water jacket.

 

Cylinder head is cracked between 2 and 3. Crack is so small I missed it the first time.

 

Compression ratio will drop from 9.72:1 to 8.3:1...I have a P90 solid lifter head casting here on the bench.

 

Other options include a Maxima N47 for 9.75:1 compression. I have both heads available, but I have a squareport header. The P90 is the clear choice here.

 

The bottom end still is in perfect shape; but I built with 9cc dished pistons. Later I'll swap to flat top forgings for a 9.0:1 compression ratio, so the cylinder head will be skimmed to produce that compression ratio in that configuration. That will also allow me to recover a little compression in the mean time.

Edited by Xnke
Link to comment
Share on other sites

Intake valves unshrouded this evening; hands started giving up so I called it a night. Exhaust valves get unshrouded in the morning. This casting is shifted just slightly in the favor of the exhaust valve. Intakes will remain 44mm, but the exhaust valves may go up to 36mm...I'll know when I get the chamber finished up. Better to have a slightly smaller valve than to have a big shrouded valve. Still have to pull a broken stud out of the head; but that's not a big deal. This head will have all 11 exhaust bolt holes helicoiled.

 

After I get this cylinder head fixed and on the car, I'll get the N42 casting checked out, then I will repair the crack and it'll go back on the shelf.

Link to comment
Share on other sites

  • 3 months later...

Finally got the head back on the car, and the manifolds and new water line installed. Took a vacation, went to Montana and had my header ceramic coated while I was gone.

 

Built some new shelves, collected a few new parts, built some new parts for the supercharger, did a little studying on throttling and MAF sensors. Also started painting a bike for my little brother...All while the Z sits, neglected, in the driveway.

 

I've had about enough of that, so it's time to get back on the game and get this thing rollin'.

 

New shelves...this area was previously unusable space, full of garbage and accumulated crap.

 

IMAG0625_zps8a5a4d5c.jpg

 

Still full of accumulated crap...and a good fridge!

 

IMAG0642_zps07cc2507.jpg

 

Header was coated at Nitroplate in Nashville, TN. Cost me 200$, flat, and it's the first inline-six header they've done. They do big V8 drag headers, mostly...and almost all the ceramic coating for Ford exhaust parts. Been around a long time, but only been doing custom coatings for a few years.

 

IMAG0689_zps6b5b9369.jpg

Link to comment
Share on other sites

Still fighting ignition timing issues. Static timing is spot on, but I think the switch to MS2.5 has me with some settings in a whirl, I am running a codebase that has a lot of MS3 code backported into it.

Link to comment
Share on other sites

Still fighting a heat issue. Temperatures creep at idle, and on 90+ degree days sitting at idle will have the engine hovering at 210F in minutes after startup. Running the A/C actually cools the engine down, bringing idle temperature to 190F, even though the thermostat opens at 160F.

 

I am looking at ditching the supra radiator and going back to the stock copper and brass, and just shoving the engine back another inch to make it all clear. It would take maybe a day to do the job, if I was piddling around, and since I need to make a new transmission mount anyway it's not like I'm out any real trouble there.

Link to comment
Share on other sites

Heat issue solved. So far, the supra radiator has only one issue, that's the frame rail notching needed...the loose nut behind the steering wheel had an overheating problem with it caused by a PEBKAC error in the tuning.

 

Initial tuning will start tomarrow, with a fresh tank of 93 as soon as it reliably drives down the road. Once it's tuned from 30-100kpA, the supercharger will go back on, and tuning from 100KPA to 180KPA will commence!

Link to comment
Share on other sites

I will not be able to cram the ford MAF into place anymore. Not until I can find a lower profile air door, anyway! I really am trying to avoid relocating the battery, but if push comes to shove, I'll move it. If I do move it, i have ALL KINDS of room to work in, but it just seems like so much work to relocate the battery safely.

Link to comment
Share on other sites

Still looking at battey relocation, going to see about getting a PC925 battery to stash in the spare tire well. it's too small to hold a 17" wheel with the proper offset, mostly due to my smashing about with a hammer to get it straight-ish again when I repaired the rear deck of the car.

Link to comment
Share on other sites

  • 1 month later...

Might have skipped off a valve stem seal; Cylinder 4 is oiling up a plug but has perfect compression. Causing a misfire, but running that plug in #5 cleans it up in 50-60 miles. In that same 50-60 miles, it'll oil-foul the plug I replace it with...black, oily, but not sooty.

Link to comment
Share on other sites

  • 2 weeks later...

Still oiling up the intake manifold; still missing, miss is getting worse. Drove it under boost to work this morning...felt really good, strong, no miss under boost. A little soft in some spots, some VEAL took care of that and it was smooth sailing this morning. Still was rich at idle, one of my 450CC injectors *must* be leaking.

 

Pulled the intake boot off the 65mm ford throttle body and was going to drive home N/A to save some tire smoke. Manifold still had some oil in it, even though the PCV valve has been relocated. The intake manifold exploded when I tried to start the car to come home from work. Blew the plenum up like a balloon, and shot a huge plume of oil smoke out the warped up throttle plate.

 

Didn't damage or even tweak the runner tubes, but the fire extinguisher cylinders used for the main plenum puffed up over an inch and a half. The main plenum assembly is toast.

Link to comment
Share on other sites

Wow!

 

I've been following this build for a while. I would have never thought something like that would happen. You would think a fire extinguisher would be stronger. Why do you think it happened? There must have been a lot of pressure in there. Hey, at least your welds held up.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...