Originally posted by Fierobsessed: 4. Found two slipped valve guides, pressed them back into place. I don't know how I'm going to prevent this in the future.
Keep the motor cool especially since it's turbocharged now, ~180ish. I had to buy a 160 degree thermostat and trim it to fit to help keep my temps in that range. I have a 3900 head that has a valve seat partially dropped from getting too hot.
sleevePAPA
APR 09, 08:07 PM
loctite the valve guides?
Fierobsessed
APR 09, 10:31 PM
They are pressed in, no real way to loctite them. I was thinking about notching the guide stem under the spring, and using an E-Clip under the spring shim to hold the stems in place. But notching is difficult, and the E-clips are a little large at the diameter I need them.
sleevePAPA
APR 09, 10:55 PM
quote
Originally posted by Fierobsessed:
They are pressed in, no real way to loctite them. I was thinking about notching the guide stem under the spring, and using an E-Clip under the spring shim to hold the stems in place. But notching is difficult, and the E-clips are a little large at the diameter I need them.
I know but if you coat outside of the guide there might be enough of a film to adhere to the head.
Fierobsessed
APR 10, 08:05 AM
Pic of a cleaned up head.
96-97 head, VS 91-95
Slipped valve stem, the one that is sunken in is the slipped one
Since I had the new oil pan off, I decided to add the oil return bung. I first cut a hole, then I removed the surrounding paint
New bung in place
Weld it!
What was formerly intended to be head studs, has become main cap studs. They happened to work out! With the spacers (washers), and the windage tray in place, the length is perfect!
A tool I made about 11 years ago, when I was first playing with the 3.4 DOHC. It's what I use to remove the cam cog bolts. Works FAR better then the Kent Moore tool!
I got around to actually documenting the cam specifications for the 94-95 3.4 DOHC. The numbers were almost perfectly spot on with what I have seen their specs quoted as.
Let me explain the wheel, Picture it rotating clockwise. You can see that the cams are naturally retarded 3 degrees.
A little note on the specifications. I found that the cam lobes are asymmetrical. Meaning the opening profile does not match the closing profile. They actually open aggressively, and close a little slower. My calculated centerlines and lobe separations are based on the averaged positions from the .050" marks. The centerlines are off just a tad for this reason. (they are actually about 3 degrees earlier then the averages). What this all means, is that these cams are 3 degrees advanced when the timing is done correctly based on the true Centerlines, but because the valves open and close differently, the exhaust cam is slowly closing when the intake valve gets ripped open, making it behave as if the cams are set in 3 degrees retarded. It's a little funky, but the numbers don't lie!
It does have a 112 degree lobe separation, which is good for computer control, and the durations are short by any stretch of the imagination anyway, so the lobe separation can easily be tightened up for higher, peaky performance. Now, this gets my gears turning, I wonder what I should do to these cams for the turbo...
Let me mension that my van, has a fairly aggressive cam in it. LT4 Hot cam, At .006 lift, the intake and exhaust have a 54 degree overlap. 3.4 DOHC cam, At .006 lift, the intake and exhaust have a 20 degree overlap.
At .050" the LT4 Hot cam has -2 degrees of overlap 3.4 DOHC has -15
So there is plenty of room to tighten up overlap, if that's what you want to do.
[This message has been edited by Fierobsessed (edited 04-10-2013).]
Joseph Upson
APR 10, 08:39 AM
Leave the cams alone. They are already optimized for a motor that breaths very well up top and a properly sized turbo which you appear to have can expand on that based on your turbine housing size plus any additional power goal you hope to achieve can be accomplished by turning up the boost.
In my scenario increased engine displacement and compression warrants a cam change to better match the mods above stock. That is likely why the near stock grind camshaft I installed in the previous motor and left advanced netted me ~33 mpg hwy and that's a low estimate despite one cylinder being very low on pressure due to a burnt valve and damaged rings. With current cam that has a little more duration I'm getting about 30-31 mpg hwy.
Stock cams perform very well under boost in my experience.
[This message has been edited by Joseph Upson (edited 04-10-2013).]
Will
APR 10, 08:46 AM
quote
Originally posted by Fierobsessed: 3. Cleaned the 94-95 heads.
The heads are getting the 96-97 valves. Why not? They are brand new! I checked them for compatibility, and they are 100% interchangeable. I also plan on using the cams and cam housings from the 96-97 crate engine.
The '96-'97 heads flow significantly more air than the '94-'95 heads. If you have the '96-'97 LIM, you should use the '96-'97 heads.
Fierobsessed
APR 10, 11:09 PM
96-97 heads don't flow much better. The intake castings are identical. The exhaust went with a slightly larger (in area) rectangular port, instead of the squareish port of the early motors. They probably flow a bit better, the exhaust valves are more tuliped, so I get that advantage from the 96-97's valves, but hardly worth the 9.7:1 compression those heads would leave me with. I deliberately chose to use the early intake, narrower runners are better for torque, and as a result, better spooling. Long story short, the 91-95 engine is better for boosting then the 96-97's are, for what MY goals are. If I really wanted to make 600 horsepower, I would have gone with custom pistons in a 96-97 engine, and a 1.06 A/R turbine housing. I'd be dealing with some turbo lag too. But I don't want 600 HP, I want 450ish as It's a daily driver. I also hope to retain 30+ highway MPG. And mid 20's in the city like I've been getting previously.
I got my clutch today! Very happy about that. I will post pics and observations later.
BV MotorSports
APR 11, 12:31 AM
Hey, let me know when you are ready to get started on the exhaust. I am plugging away at my car and should have it running in the next day or so. My crap exhaust can get me by for a little bit.... LOL
BTW, you are doing some top notch work. Excellent attention to detail. Long live the LQ1! Maybe I'll get around to getting mine running again. She has 60K worth of hard track miles on her and was built back in 1994. Apparently its the first known (and documented!) swap of its kind. You should see some of the work-arounds Garth and (IIRC) Greg Duncan did to get it running properly on the stock tune.
[This message has been edited by BV MotorSports (edited 04-11-2013).]
Fierobsessed
APR 11, 08:22 AM
BV, I'll PM you the details after this post. I've got some good news for you...
About the clutch. That too, I have some good news, but, there is some bad news. First, the good news. The clutch looks great!
Disc, pressure plate side
Disc, Flywheel side
The disc is well made. The diameter wasn't what I ordered, It is a 9-1/8" OD disc. I ordered a Firebird pressure plate. Since they had offered to match the pressure plate to the disc, I didn't realize that they were going to use a Fiero size pressure plate, and reduce the F40 clutch disc to match it. But that's OK by me. The 9-3/4" system has a bunch of inertia, and this disc has less. So that's OK. Believe it or not, this is still the good news.
Now, the bad news. The pressure plate is probably defective. I cleaned the surfaces of the flywheel and pressure plate, sandwiched the disc in there and evenly tightened the bolts down.
Once I had them all torqued down I could quite easily see 3 of the clutch fingers were sticking up much higher then the others. This could have prevented the clutch from disengaging altogether by sucking up precious throw-out bearing travel. So I put it in the press to attempt to disengage it. Perhaps, I thought, that disengaging the clutch would settle the internals, and even out the fingers. It didn't. I also measured the stroke it took to disengage. it was exactly .300" Which, while the HTOB could handle that. However, I wasn't about to accept the high fingers. I also tried spinning the disc to see if the high fingers followed it when it was released, with no effect.
I marked the high fingers, and pulled the pressure plate off, and turned it over. I found a problem, but I am unsure if it is the reason the fingers are wonky. This is how it was intended to be manufactured:
This is what I found near the high fingers
You can see the ring, and a plate are next to each other in one crimp, and stacked one on top of another on the next. I'm going to call them tomorrow and see what they think. I don't believe this pressure plate is useable. The fingers are all even when the pressure plate is not bolted up, but once it is they are clearly not right. That kind of wobble would probably destroy the HTOB over time.
