BosoMKII's project! 56k cut your head off

BosoMKII

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I had one day of driving the car with few problems. ONE. And it was fantastic! All my hard work finally paying off, and my dream realized.

Then something new happened. I start the car and a HUGE cloud of white smoke billows out from the tail pipe! And now the engine won't idle, and generally doesn't feel right. Worse than before.




I didn't bother running another compression test. I decided the cylinder head just has too many issues, and I want to replace it.

So I found a replacement cylinder head (more on that later) and got to work pulling the old head. It's a lot of work to drain the oil, coolant, pull radiator, intake manifold, and everything else attached to the head!



Spark plugs. You can see the really cruddy plug with lots of oil fouling and water corrosion is cylinder #5, the problem cylinder.

 

BosoMKII

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Everything removed, undoing head bolts.



Cylinder head off! Didn't even put up a fight.



Close ups of the cylinders. Bores don't show much of the hone marks, but they are still there. Cyl #4 had a score mark, but I couldn't feel it with my finger. Hopefully it's not an issue.





No signs of a blown head gasket so far as I can tell, but that doesn't mean anything. I may just not know what to look for.

Valves look dirty, but nothing is obviously wrong



EXCEPT THE MASSIVE GAPING HOLE



Well, there's my problem. If I only had one that is.
 

Grandavi

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I got to where you were and threw in the towel. Had a built short block shipped for 2400 and head tested/rebuilt. My thinking was, when you are that deep in... Start fresh with a full rebuild.

Wasn't cheap, but I'm happy.
 

IchibanEye

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Thats interesting...I thought the cressys where front sump? But yeah, thanks for the advice. If the 2M pan didn't fit, I was going to use a 7M pan, oil pump, and pickup from a Cressida. Dunno yet really. Just going to have to take stuff apart and see what works.

Thanks for all the compliments guys! This is a really fun project so far.


And this just in!! My wheels arrived today!! My brother just sent photos ( I am at work )



The specs are 15x8 zero offset. As soon as I do a test fit with tires I will know how much I can lower it. Going to go for a "nice" drop. Not too slammed, but defininatly low.
That is a good looking wheel.
 

BosoMKII

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I got to where you were and threw in the towel. Had a built short block shipped for 2400 and head tested/rebuilt. My thinking was, when you are that deep in... Start fresh with a full rebuild.

Wasn't cheap, but I'm happy.
I wish I had that kind of cash to spare! That would be the best route to go, but I don't think worth while for a non-turbo 7M
 

BosoMKII

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Earlier I alluded to finding a replacement cylinder head.

I was at Performance Options in Oakland the other week and asked what was under the tarp in the back corner:



Performance Options had a customer bring in a Supra with a recently rebuilt engine that had slight rod knock. Instead of repairing the engine, they just swapped a 1JZ in. The fresh 7M just sat there until I came along.

]

I struck a deal with the shop and pulled the cylinder head so I could just swap onto my existing block without having to pull the whole engine or have to rebuild the current cylinder head. Easy fix!



I also got ALL the accessories to the engine. Intake manifold, sensors, ECU and harness, 3 inch downpipe, rebuilt turbo. Everything.

Oh, did I mention this is a 7M-GTE?






:tu:
 

BosoMKII

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The intercooler pictured earlier was me being impulsive. First, it's one of those cheap eBay intercoolers. It weighs a ton and is painted. I'd be surprised if it's actually aluminum. Second, it doesn't fit. Too big for the space I've got to work with.

So I searched around and found a stock Mazdaspeed MX-5 intercooler for $45. It's small at 8x8x3, but will likely cool better than the bigger, lower quality flea bay unit.



Progress has been slow as I've been busy, but mostly smooth. Then disaster struck! I dropped a bolt, a spring, then another bolt down into the timing cover. :evil:



In order to remove, the crank pulley bolt needs to come off. This is no easy task. I need to figure a way to keep the engine from turning in order to break the massive 195 lbs-ft of torque bolt.

Other progress has been going well. I forgot that the 7M-GE block doesn't have oil fittings pre-drilled. So I ordered an oil line kit from Drift Motion specifically designed for this conversion.

Test fitted the turbo. Not sure the down pipe will clear. Harness in.


 

BosoMKII

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Making a little progress here and there. Right now I am trying to learn all the new components and layout, and working to figure a few things out.



One issue is that the EGR valve now interferes with the throttle pedal arm as it exits the firewall. So I either lose the EGR (bad for cylinder temps and emissions) or convert to throttle cable. I'm leaning towards converting to throttle cable, as even without the EGR the turbo throttle body is in an inconvenient place and makes rigging linkages difficult. Not sure exactly how I'll manage the conversion.

Another issue is how fast I'm running out of space in the engine bay. The intake tube puts the air flow meter right up against the sheet metal with no room for an air filter. I don't know if shortening/changing the air intake tube geometry will upset AFM readings.



Intercooler piping will actually be pretty straight forward. The factory intake pipe is in a good location. The turbo to intercooler pipe needs to be made.

The downpipe also doesn't clear the steering arm. Looks like that will be an easy fix for the shop though.
 

Grandavi

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The deciding factor for the EGR delete for me was its location and the fact it's unmonitored. The emissions aren't a concern where I live due to our not having to do emission tests.

As for decreased heat in the exhaust, im not sure that is enough of a factor to really consider for a 7M really. I'm not sure that 100 degrees at WOT would be noticeable realistically.
 

BosoMKII

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Thanks for the advice!

Know anything about the AFM placement? How critical is the accordion hose to accurate readings?
 

Grandavi

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Not sure what you mean. The AFM shouldn't care about anything behind it.
The accordian hose just has to be between the AFM and the turbo. (As long as it's not kinked or cracked)
Not many options in that area though.
 

BosoMKII

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Thanks for the reply.

What I mean to ask is, if I were to shorten the accordion hose or make a custom air intake tube, will doing so upset the AFM readings?
 

BosoMKII

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Not much to report lately. Been super busy with life and not working on the car much, save for here and there.

Plumed oil lines and oil cooler, and made intercooler pipes. I went to Performance Options and scrounged in their spare parts area and made all my pipes with couplers for $60.

My car is put together with so much hardware store stuff and random parts it's starting to look like a pirate ship. Whatever, so long as it works properly.




Tried to start the car yesterday, but it just catches briefly then dies. Will need to wire up the check engine light to see what codes come up, and go from there.
 

black ice mike

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This thread is awesome!!! I spent most of class reading it and just finished so now that you have the turbo and everything what kind of power are you looking to make?
 

BosoMKII

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Thanks!

First goal is for the engine to run like stock, and be reliable as a factory car.

After that, 300 wheel horsepower is totally attainable.

That is a long way off however....
 

Grandavi

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From my supra journey... The most fun is a ct26 upgrade running 300-350 at the wheels. Quick pulls and a lot of "yeehaw!".
Huge power usually trades some of the fun with later more powerful pulls, but the fun factor is a bit less because you gotta be a lot better controlled. More focus on safety...
 

BosoMKII

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Grandavi,

No experience with the 7M making that kind of power, but I suspect I will agree with you 100%.

I drove a 400whp, 1st gen RX-7 once, and it was just like you say. Big lag, then the power would just explode and spin the wheels.

Certainly entertaining, but sketch. Not useful unless you're pointed totally straight either.

For a street car, readily accessible torque is key.

And hella fun
 

Grandavi

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My 7M kicks ass but it doesn't truly hit until 4200 rpm... I miss the 3200 rpm pull... But it's nice to have the pull go all the way to redline without the falloff that the ct26 suffers from due to the small housing. It's very well suited to the 7m though considering the lower RPM. The torque on my 57 trim at the wheels was 348 with 300 HP.
 

BosoMKII

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Been too busy to work on the car much lately. Also, stumped as to why it won't start. Got the engine to run for a few seconds today, but it barely did. Kinda acts like a huge air leak, or way too much fuel. Not sure.

In positive progress news, got an old boost gauge off ebay for cheap. I like the plain styling of it. Even better, it fit perfectly into the open space in the center console.




Also got the altitude correction sensor. Don't want to loose power driving up to Yosemite!

 

BosoMKII

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Thank you!

Check engine light revealed two codes: 41 and 51

51 was the idle speed control valve. I knew that was a problem, as several of the wires were broken. I went to the junk yard today and there just happened to be a Supra there. Easy to clip the connector off and solder the replacement in. Code gone.

41 is the throttle position sensor. After checking a few values with my multimeter, it I think the TPS is cactus. Bought a new one off ebay and now just have to wait for it to arrive.

Hopefully that does the trick!
 

BosoMKII

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Fixed all the error codes, still no start.

Well, the car starts but dies immediately. Does not respond to throttle, won't start with the throttle open.

I've got fuel, 40psi at the rail. Backfires through the intake, not sure what causes that.

I've got spark, verified with a test light. Only verified on one plug wire though, so maybe need to check them all.

Verified mechanical ignition timing. Cyl. #1 at TDC. Triple checked by putting an extension bar down the spark plug hole: either direction I move the crank, the bar falls.

Verified the cam gears are on the cams correctly: pin in the middle guide hole on the gears.

Verified the Crank Position Sensor is aligned correctly.






Replaced the Throttle Position Sensor, and calibrated with my multimeter according to the factory service manual. Pulled all the fuel injectors and tested that they click by using a 9V battery, and replaced all the grommets and o-rings. Tested resistance of the ignition coils. Got 1.2 - 1.4 ohms for each. That's higher than factory spec, but I tested all 5 of my spare coils and got the exact same readings, so maybe my meter is goofy? Tested compression, got right around 160psi for each cylinder.

I'm stumped!

Advice?
 

kakanator

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did you check the wires that on into the clip on the cps side and also on the harness side? IF they are just crispy or lose just a bit it wont start. It happen to me sounded like it was going to start then just nothing and it was one of the 4 wires from the cps.
 

BosoMKII

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did you check the wires that on into the clip on the cps side and also on the harness side? IF they are just crispy or lose just a bit it wont start. It happen to me sounded like it was going to start then just nothing and it was one of the 4 wires from the cps.
The wires at the CPS have torn insulators around the clip. The whole harness is a bit dodgy, actually. Has been repaired in several spots. Thinking of replacing the harness for a better one I recently acquired. Thanks for the advice!
 

BosoMKII

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Spray the filter with starting fluid.
If it starts, it's probably the ecu signal to the fuel pump relay.
I don't have the harness/ECU wired like stock. The fuel pump runs right off the battery, switched on by a relay tied to accessory power.

Does the ECU need to have a fuel pump signal from somewhere?

Thanks for the advice
 

BosoMKII

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I went back and tested all the cylinders for spark, and found that #5 was the only one sparking!

Looked like some dodgy wiring repairs at the coilpacks, so decided to just replace the whole harness. Too many repairs everywhere. The spare I pulled from a junkyard actually looks pretty good, just needed a few repairs of its own.

Harvesting clips from the old harness, I made a few repairs and installed.

No change! Still the only cylinder getting spark is #5! What gives?

Swapped ignitors, swapped ECUs, nothing.

Still no check codes.

Retested the CPS and I get values all over the place. Currently searching for a replacement.
 

BosoMKII

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SHE RUNS!

Turns out it was the CPS. Got a replacement from someone on the forum and the car fired up straight away. Easy.

Bad news is, I've got a loud tapping noise coming from the cylinder head. Sounds really bad. I checked over the valves, and the shims seem to be in spec.

[video=youtube_share;23n7zP_np6g]http://youtu.be/23n7zP_np6g[/video]

Any ideas what it is?

Here's a few shots of the car after parking it on the street. Just because I like looking at the car.



 

BosoMKII

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YES!! Finally she runs! Did you ever decide on the wheels?
Almost runs, need to fix this tapping noise. Hopefully this weekend I get some time.

I found a great set of wheels, well beyond my price range of course. I'll stick with what I've got for a while.
 

BosoMKII

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Fixed the ticking noise.

One of the valves was missing a shim. Couldn't find it in the cylinder head, so who ever "rebuilt" this head forgot to put it in!




I scrutinized the cam lobe and bucket for damage, and nothing was obvious to the eye. So I pulled a shim out of the old cylinder head, and reassembled.

Purring like a kitten!

Set timing and went for a drive.

Drives awful. Major hesitation and bucking at light/part throttle. Once you get the thing rolling and give it more gas, seems to run just fine. Hopefully just a TPS adjustment issue.

The greatest part was feeling the turbo spool and hearing the BOV!

I've worked so hard, and dealt with so many frustrations to get here. Just a quick trip around the block is enough to lift my spirits a feel like celebrating.

So I opened some bubbles to mark the occasion!



Still so much to do, but I'm winning the battle. Bit by bit.
 

BosoMKII

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New parts!

HKS air filter

Brand new OEM throttle position sensor, hoping this cures the severe lurching and hesitation the car has at part throttle

And a new boost gauge. A few intake backfires ruined the old gauge. The needle is upside down!



The rain ought to clear this weekend so I can get back to work.
 

BosoMKII

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New turbo outlet installed. The difference between the stock and aftermarket is pretty huge.





New TPS in. All the others I've been trying to get work, I was having a really hard time adjusting to proper resistance specs. The new one was super easy to set. Hopefully that means my drivability issues were in fact the TPS.



And finally, an air filter. I know the foam type filter the least well, but I just don't have room for a long cotton cone type without making a custom intake. In order to fit in the space, I made my own mounting surface from a piece of tin sheet.




p.s. that clear tube you see is my $6 hardware store plumbing parts solution to attaching the BOV. Once the car drives without issues, it goes back to Performance Options to get the BOV welded to the intake pipe just before the 3000 pipe so I can ditch all that junk.
 

BosoMKII

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Ladies and Gentlemen, this saga has reached another milestone!

The turbo conversion engine ran today, and I got to drive the car!

I fixed the water leak. I fixed the oil leak. The new throttle position sensor did the trick, and the engine ran smoothly.

Here is the engine bay as it is now:



Everything works as it should, even if a few things are pretty ugly. The fun part about being at this stage of the build is, I now have a driver and I can finish and polish stuff as I go. Do things like make the PVC system look nice with an oil catch can, and ditch the crimp connectors and do a proper soldering job on the wiring and loom it all up.

Mostly though, I am just really happy all the hard work paid off and I finally drove my very own turbocharged car!

[video=youtube_share;XrUH-Ktaspk]http://youtu.be/XrUH-Ktaspk[/video]

So my wife and I jumped in and went for a drive around town, and to pick up a christmas tree



Merry Christmas everyone!



p.s. all the ornaments in the tree are all Hot Wheels. Among them are a 1st gen RX-7, a Toyota 2000GT, and an RA21 Celica.
 

BosoMKII

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Re: BosoMKII's project! 1973 Corona 7M-GE swap

The car has had a bad vibration approaching 40mph that kept me from doing anything but scooting around town at low speeds. My prime suspect was the center support bearing. The old one was completely rotten.

But you can't just run out and buy a replacement for this car. So I started looking for other cars that might be compatible. I bought the part a few months ago, so can't remember exactly what model, but I found a center support for an old Cressida that also had an "M" six engine.

Sure enough, the new part fit perfect. However, the mount tabs were too long for the propeller shaft tunnel. Some trimming and grinding took care of that.



SO MUCH SMOOTHER! Wow! Pretty obvious why the new part made such a huge improvement. Also took the car up to 70mph, car runs along just fine. 5th gear seems noisy. Hope the transmission is good.

I can actually give the engine full throttle now! The car is fast. Smokes the tires a little too easy. Things got rough in the higher revs and felt like the engine was down on power. Wondering if the fuel pump is keeping up. I have a Bosch 44 to replace, but have to get an adjustable fuel pressure regulator first.

Pretty happy with today's progress. Still so much to do, but I'm getting there.