Bout to get more thumpy! How big is considered a big cam on the square port motors? I see all kind of ranges from what would be normal on a cathedral to big ones like what you got.

Out of curiosity too why so much lift on the intake but a good bit less on the exhaust .630/.604

Mainly asking cause I'm planning on getting a 5th gen as a daily somewhat soon and I have a Vengeance Kaotik cam in the garage already. Seems stupid big for a DD, but I really have no clue on these motors.

 

Oh gosh, I'm not the person to ask. I don't know much about cams and just let the pro's choose the cam for me.

I am guessing the exhaust valve lift is lower to maintain adequate piston to valve clearance. And the exhaust duration is quite a bit larger to help the LS3/L92 heads breath. If you look at flow numbers for intake and exhaust you will see that a LS3 type head has a larger "Int/Exh" flow ratio than the earlier cathedral port heads, and for that reason you will typically see larger exhaust duration with LS3 cams.

It may be that my cam does not idle any worse than your Kaotic cam in the LS3, given that my lobe separation is just a little bigger and I have a larger engine that evens out the extra 5 degrees of intake duration. This is probably the max cam for me at this time because I have probably run out of range of what RPM the intake manifold can support.

 

I'll tell ya, I'm getting sick of these brakes. I drove the car out of the garage today and no brakes. I have NEVER had so many problems with brakes. This is just ridiculous!!!


Car is parked indefinitely until things get sorted out.

 

Time to hydroboost?

 

How is hydroboost going to help? His problem isn't with the booster but the basic hydraulics to the brakes. Two completely separate systems.

 

It won't but it makes for a waaaaaaay cooler sidestory

 

FFrom brakes that don't work From having brakes that didn't stop the car as well as you would like (but still stopped the car reasonably well) to NO brakes kind of points to something fundamentally coming undone after the testing and measuring don't you think?
How's the fluid level in the master?

 

Oh yeah hydroboost is cool. My Super Duty has it. Very efficient and compact. I thought about doing it with my LS upgrade.

 

The SSBC proportioning valve failed. The fluid reservoir is drained and all that fluid has doused the paint and wiring on the frame rail.

I made a lot of phone calls today and started planning out Brakes Part Deux.

 

Also, if someone has a 1LE proportioning valve then please let me know.

 

Bingo! I figured something along those lines.
Now, I do have a 1LE prop valve however I'm saving it for my own repair. That said, Ed Miller at FlynBye might have them available still.

[url]http://www.flynbye.com/catalog/i40.html[/url

A phone call works best with Mr Miller, provided you can reach him.
Let me know how that goes for you.

 

Whats special about the 1LE prop valve vs the 4 disc brake prop valve?

I have a 1982-92 Camaro/Firebird Brake Proportioning Valve, Disc Rear i bought extra from hawks but didn't need.

 

The only difference is the internal spring in the prop valve. You can use a standard one with an upgraded spring. There is a write up somewhere around here, I'll see if I can find it.

I'm running a 1Le on my car because I spent the money before I knew about this. I have a couple spare regular prop valves and might even have the correct spring around here somewhere if you need one.

Edit looks like fly n bye still has some 1LE

http://www.flynbye.com/catalog/i40.html

http://www.flynbye.com/catalog/i172.html

And here is the thread on the higher rate spring

https://www.thirdgen.org/forums/brak...e-upgrade.html

 

Oooooh so thats what those springs on my workbench were for... I have 4 of them aswell then... lol (suppose i should put that in my prop valve huh?)

 

I've had a heck of a day, both good and bad. Decided to do the cam swap since the car is just sitting waiting for brake parts. Did everything right, blocked the lifters, got the old cam out okay, and then a damn lifter fell when I put the new cam in. I guess my lifter block was too small and the lifter squirmed by and fell down. So.... I'm pulling oil pan and a head and now into a lot more work than I ever wanted. Head is on the floor tonight and next I have to fish the lifter out of the engine.

What can be good about this, you say? Well, with the head off I got a chance to measure the true displacement of the engine and it is in fact a 4.06" bore making it a 427. And the pistons are already fly cut too. Somehow I got an iron 6.2L block, or it was machined. Either way, I'm glad I have the larger bore because nothing should be holding back power now. Hopefully this thing will sing a new number on the dyno when it is all back together.

 

i have cubic inch jealousy! keep it up!

 

This....




Caused all that. I got the lifter out of the engine using my braille skills and a lot of handy work with multiple magnet rods.

 

Sucks to have to do all that extra stuff, but at least you picked up some CI in the process

 

I completely feel your pain, Qwk. I had to fish 3 lifters out with the first block lol. And 2 of them were in the windage tray, so I had to constantly rotate the crank back and forth to get them.

 

Great build QWK! I remember drooling over the car years ago.

mw66, I remember when you first bought the car and set records with the 305. It's come a long way!

 

Finally fired up the engine tonight... only took 3 weeks and countless hours to do a cam swap! Now I have to rebuild brake lines and then get the car on the dyno again.

This is the first cam swap I have ever done so a lot of the delay was me going through the learning curve and repeating this over and over.... and over... and over again. But there were also real issues along the way and I had to keep ordering parts and tools which delayed things. Now I have a new IWIS timing chain, shorter push rods, Comp Cams rocker trunion upgrade, and a Cloyes Hex-A-Just cam sprocket.

It seems the crank keyway is off by quite a bit in my engine. I had to advance the cam 5 degrees just to bring the valve event to equivalent of "straight up" (hence the Hex-A-Just). This also might explain why the old cam just didn't ever run quite right.

I'm not going to make one of my usual picture story lines. Instead, here are some videos that are very good, for those who are interested.

LS cam swap (Comp Cams video at Westech Performance)

LS push rod length (Comp Cams video at Westech Performance)

Installation of upgraded LS rocker trunion

 

This has been a click-bait thread for me for years. I never once clicked for one reason; the title felt like one of those MUST SEE threads with no real content and a whole lot of talk. Plus you mentioned yourself in the title, I mean, come on man LMAO.

It's been 5 years and I'm over all that emotional nonsense. I'm a car enthusiast now and no longer just a car guy, that dude that likes Chevy's because Chevy's are number 1 and that's that. So here I am clicking this ridiculous thread title and what story do I find...

A story I find here is one I feel I may tell in some years. I've owned my first car, the IROC-Z since my first job and before that joined my first dedicated car forum...TGO (Aug 2006). It was new light for me. Anyway, 18, first everything, I went H.A.M. tearing out the AC, exhaust, intake, ignition, cooling, relays you name it. If it was maintenance related and something I could get to without much work it had to go.

Some 10 years later almost to the date (another reason for clicking this thread) my IROC is back on the road, and quite solid.

Sorry for the hi-jack, but I feel now that I read this I have to do what I've wanted with mine and tear her down again (a mock of your situation of this threads start), inside-out and begin another journey of downtime. But with learning all I have and after reading this, she won't go untouched for long this time around. Going to try and do it right. Anyway. Thanks for the commonimity. It was thrilling, especially since it was so close to my own experience (minus the big block of course ;P ).

Well, take it easy and good luck, I'll have to catch up on this thread now.

 

Curious about your cam timing. Which method did you use for determining the intake centre line?

(I've had my heads back since March and I still don't have the engine back together....)

 

Oh my gosh, my car idles sooooo much better now!!! And it doesn't even have a different tune yet! I dropped idle from 1150 rpm down to 950 rpm with no trouble at all. It will go lower than that before I'm done.

 

I didn't because that is the most difficult measurement to verify with good accuracy. I lined up on the valve open/close events because that is much easier to obtain and repeatable. There are different camps of thought, but one of the leading ideas out there is the most important valve event is intake closing. They say if you get that right then you'll make power.

You'll notice my cam card has measurements down to the gnats ***. ( https://www.thirdgen.org/forums/ltx-...ml#post6061876 ) Cam Motion runs every custom cam through a "cam doctor" so the cam card is as-built, not per spec. I already knew the lobe centers from the cam card. All I did was verify valve events and everything else falls in place. If your cam card is a print out of the cam specs, and not as-built, then it is definitely worth your while to measure out every detail to verify it was made correctly.

If you want a lobe centerline then you have to find the leading and trailing edge of the peak and then calculate the mid-point. If you try to calculate lobe centers from valve open/close events then it will probably be wrong because the lobe probably isn't symmetrical (opening ramp rates can be more aggressive than closing ramps rates). Basically, measuring a lobe centerline has the same level of difficulty and inaccuracy as measuring lift at 0.006", which is why the idea was born to measure lift at 0.05". Also, keep in mind to always take the slack out of the chain and make measurements in the same direction of rotation. The slack in the chain will give you different results going CW versus CCW. That also means locate TDC on your timing wheel with no slack on the chain.

I did about every method possible to degree the cam and compared results (because I do that kind of thing). I can tell you that only one method worked for me. You have to get rid of the hydraulic lifter because the cup will move and throw off the results. Even if you don't think the cup is moving.... it is moving. And a tiny distance of lifter movement equates to several degrees of crank duration. I ended up cannibalizing one of my lifters to make a home-made solid lifter and then measured off that. You must remove the cylinder head to do the job. My dial indicator was too short to reach the lifter so I had to place a push rod on the lifter and measure from the tip of the push rod. I took a lot of time setting up that measurement to make sure everything traveled in a straight line (push rod and dial indicator).

I made the solid lifter by removing the retaining clip, pulling out the guts with a plier, and filling it with nuts and washers until there was no slack with the retaining clip installed. The finished cup height doesn't matter because I was measuring off the lifter itself, not the rocker arm. I am not re-using that lifter, it is just a tool now. When you're measuring a valve closing event, give the lifter a very light tap now and then to make sure it is falling in the bore. I found that it would hang when rotating the engine slowly.

Once I got all these details sorted out the measurements fell in harmony with the cam card. Basically, Cam Motion saved my butt by running that cam across a cam doctor because I had the answer key in front of me. Every time I made a bad measurement I kept refining method until it worked.

 

I hope to see your thread soon.

And be sure to come up with a ridiculous title so I can find it easy.

 

It certainly would be handy to go off an "as built" cam card. As it is, I'm stuck with Comps information.
Regarding the IC event and measuring, I don't argue it's value. In fact it's an inherent piece of data to have for calculating running compression ratios and such. I would think though, that measuring the ICL via the .100" before and after method would allow for better accuracy due to it's repeatably. Of course, it would be necessary to deduce or at least assume that the other valve events are accurate. Just the reverse of your approach. What I can't see is nailing down .006" lift event so as to get the IC precisely.
As for the solid lifter, yes that and the spec springs for any testing is the way to go. For those who have the link-bar style lifter, unfortunately ours aren't rebuildable as such. So living with the hydraulic lifter necessitates the use of checking springs. I'll have to live with any variances due to things not stacking up as they should. This is also about the only I could check P/V clearance with the heads on as well.
Do you the like Hex-Adjust? I think it's great. Moving your cam ahead brings that intake valve to piston clearance into play. My 4 degrees has brought me within .120", about a degree or two BTDC. Something to watch for.
Good to see you getting results.

You realise of course that your improvements have only made your traction on the street issue a little worse...

 

In my opinion, if you tried to degree the cam at the rocker tip with check springs and hydraulic lifters then you're screwed. Check springs are much stronger than the lifter springs and do compress the lifter cup. And the pushrods put preload (compress) on the lifters too. You've got to get on a stable surface like the rim of the lifter, or use a solid lifter, and measure lift of the cam lobe. It makes a HUGE difference to the readings. You can install a cam without removing the heads, but I don't see getting around the need to remove the head to degree the cam. The head just has to come off to do the job right.

No, you are just finding the midpoint. That may or may not be same as lobe centerline.

 

I dialed in my cam with the heads off. The dial indicator plunger was in the pushrod cup oiling hole and was very stable. The spring in the dial indicator has no impact on the lifter spring. That was easy. No pushrods or rockers to deal with. (I've tried the rim of the lifter and found the dial indicator tip would "wobble" somewhat and give a false reading but that may just be my equipment setup.)
It's the P/V clearance that has to be done with the heads on. And unless you have a easy way to compress the spring, in order to push the valve down into the rising (or receding ) piston, the use of a lighter checking spring is required. The springs I use do not overcome the plunger in the lifter. I don't have to tool that allows the spec spring to be compressed while the valve train is set up. I doubt anyone here does.
How you go about determining valve events is to each their own.
If I measure .100" on either side of max lift (and max lift is the lobe centreline) then I can zero in on the degree value with a little math. It's probably the simplest approach and the most repeatable.
I'm not sure where you would find a cam that doesn't have max lift as the lobe centreline. Is that what's indicated on your cam card?

 

Ya, we're saying the same thing. You're measuring from the leading edge and trailing edge of the peak. Earlier I thought you said lift at 0.001" which is the bottom of the ramp and that would not work out so well.

 

If you assembled the pushrod and rocker, then that check spring did put some preload on the lifter. Your PTV clearance might be less than you think.

I checked PTV clearance several ways and it was plain as day that Hydraulic Lifter + Check Spring = Hog Wash. I ended up checking PTV clearance without a valve spring by setting the valve on the piston and then measuring the rise until zero lash. And I repeated the measurement using a solid lifter with check springs and got the same results. Either method seems to be valid.

 

The great QwkTrip had never done a cam swap? ...huh.. lol learn somethin new everyday

 

Nope, but I did stay at a Holiday Inn.

 

I redid my brake hard lines and prop valve with hopes of fixing the brake leaks that have plagued me all summer.

This time I did away with as many adapters as possible. I decided to use a Wilwood adjustable combination valve because it can be ordered with inverted flare fittings to eliminate the need for NPT adapters like used with most other prop valves. And the Wilwood unit has individual outlets for both front brakes so that eliminated the need for a tee in the front brake line. Downside is it only accepts 3/16" line so I had to use a few adapters for the rear brake line that has to go up to 1/4" size before mating to the rear axle. I used high quality Brake Quip fittings everywhere to improve my odds of success. Let's hope my brake woes are over!


Update: Further attempts to fix brakes in post #610
https://www.thirdgen.org/forums/ltx-...ml#post6083021

 

Did you ever determine the root cause of your braking issues?

 

Here is a little sound clip of the new EPS cam at idle. The sound is more thunderous in real life.

So far the self-learning of the Holley HP is adding fuel to the low- and mid-range RPM's in the maps. Haven't seen any change to WOT maps yet. But the fact it wants more fuel is a good sign. Throttle response needs a bit of help with the tune but it still fries tires on command at highway speed. Hope to get the dyno tune done this week.

 

All this summer I have been avoiding driving after dark because my headlight motors were on the fringe of failing completely. I finally decided to fix it because I want to go to the drag strip and that will probably be a night race.

Opened up my headlight motors and found the original bushings had crumbled into pieces.... many, many, many peices. Got a headlight motor bushing repair kit from Top Down Solutions and now it is fixed. Now I just need a new set of tires for the car trailer and I should be in business again.

 

If u need tunning help let me know. I have had the holley for years now running great. Its a great ecu

 

Thanks for the generous offer. I have a local guy I use and I want it to go across that dyno anyway so I can see if the cam did anything since last time I was on that dyno.

 

Hey Qwk, just an FYI. For the headlight motor bushings, many auto parts stores carry them under the Dorman name part #74410. These are F@#d window motor bushings. Exact same size but are not hollow, about $8 for a package of 3. Just used these on my 88 headlight motors and work great!

 

Posted this in the electrical section too. I am looking for a picture of a Firebird gauge panel to compare the connections at the tachometer. Anybody have one to compare?

I have yet to get the tach to work at all since the LS engine swap. It would be helpful if somebody could verify I am using the correct connection.

I have Holley HP EFI and have verified with an O-scope that there is a tachometer signal with a square wave at system voltage. I am running that signal through C100 D6 terminal (white wire). And I have verified the wire goes to the BROWN connector Pin 1 at the gauge panel, as shown below. The circuit trace from Pin 1 winds over to a connection at the tachometer with a negative symbol close by.

Is there anything wrong with the connection itself? Am I missing a screw in the empty hole next to the negative symbol? If not, then I suspect the tachometer to need repair.

 

Yep, I'm missing a screw. I'll have to hunt one down and see if the tach comes alive.

 

Ha! Tachometer works and it is really accurate too!

 

I took some vinyl tubing, cut it to length, then cut it lengthwise in one spot, curled it up to make it more rigid and put my headlight motors back together, been working for 3 years like that! (I needed the headlights to work as a temporary fix to get it to pass the safety when I bought the car and since they still work I haven't taken them apart again)

 

Is this one of your relatives?

 

Judging by the dyno chart, I certainly did not error on the side of too little cam this time.

Latest number is 480 RWHP with tires spinning. Tires just wouldn't hold more than 400 lb-ft for some reason. This new EPS cam spanks the old Thunder Racing cam. Car sounds meaner, idles 250 rpm lower, pulls to 7000 rpm, and cruises at 1600 rpm with no surge. Engine is very snappy and feels very linear. No power surge, no top end rush, just a sliding power scale connected to your foot.




Meanwhile, the Nitto NT05R tires were murdered on the dyno. They threw chunks everywhere behind the car, on the car, inside the car. The tires are nearly wasted. I'm not buying another set of those again.




This is the how the Nitto's looked before dyno. They were always badly feathered from regular hard spin in 2nd gear. Traction sucks with these tires.

 

Geoff at eps is a badass. great to hear! also not surprised about the nittos honestly. what are you going to replace them with?

 

I was looking at the Mickey Thompson ET Street S/S.

 

By all accounts, an excellent tire.
Are you still on 16"'s? They make a 255/50. Perfect for my IROC rims.

 

Had those before I switched to the Rival S, seemed like good tires.