quote Originally posted by RacerX11: Here is a diagram showing the GM DOD lifter: http://i70.photobucket.com/albums/i92/bigmikegxp/472ee3e4.jpg Here is a Chrysler MDS lifter (on the right): http://media.popularmechanics.com/images/lg_mdsvalvelifter-lg.jpg They both feature an inner and outer body with latching pins to lock the two together until oil pressure is applied. When locked, the engine runs normally. When unlocked, those cylinder's pushrods are disengaged and the valves don't open. Simple in theory, but there are still moving mechanical pieces that can fail.

Aren't you cynical?

FYI, that's exactly the same way that Honda's VTEC system works (oil pressure moving a latch pin) and that's been in use on hundreds of thousands if not millions of cars for over 15 years. I'm sure people said exactly the same thing about VTEC when Honda brought it out as you're saying about DOD/MDS now. Name something unreliable/unwise/overgadgeted that GM brought out RECENTLY. V8/6/4 was thirty years ago. That's not recent.

Not cynical...just realistic. Honda’s successful use of latch pins on rocker arms doesn’t mean GM can pull off latch pins inside multi-part roller lifters. The very fact that GM does not normally introduce many gadgets is more reason for me to suspect this type of system. LSx piston slap and 3x00 intake gasket leaks come to mind when I think about GM reliability. Quad4 head gaskets if you go back further.

Even if GM did all their homework, and it is a dead reliable system in stock form, there is no guarantee that when modded it will stay together. And that is the point of the thread, to discuss FIEROPHREK’s LS4 and its performance potential. Not the fuel-saving possibilities of DOD.

quote Originally posted by RacerX11: Even if GM did all their homework, and it is a dead reliable system in stock form, there is no guarantee that when modded it will stay together. And that is the point of the thread, to discuss FIEROPHREK’s LS4 and its performance potential. Not the fuel-saving possibilities of DOD.

Well at least someone understands LOL

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

quote Originally posted by RacerX11: LSx piston slap and 3x00 intake gasket leaks come to mind when I think about GM reliability. Quad4 head gaskets if you go back further.

Piston slap? Do pistons break or just make noise when cold?
Describe the 3x00 intake leaks. I'm not familiar with that one.

quote Originally posted by FIEROPHREK: Well at least someone understands LOL

Ok... you're welcome to throw away free mileage. Gas won't be getting much cheaper.

[This message has been edited by Will (edited 11-15-2006).]

quote Originally posted by Will: Describe the 3x00 intake leaks. I'm not familiar with that one.

Not to get too far off topic, but briefly the lower intake gasket on the Gen III V6 is hard plastic with flexible sealing material (rubber?) inserts. The plastic will crack and you'll get a very small leak - almost undetectable, but it will get worse over time. It can leak externally, where you get some coolant seepage, or internally and you end up with Dexcool in the oil or oil in the coolant.

It was so bad GM not only redesigned the gasket, but they have had a hard time over the last few years keeping them in stock. It's almost like cracked exhaust manifolds on a Fiero 2.8 - it's not a matter of IF it will fail, but WHEN.

I had to have mine fixed on my 99 Grand Am, 3400 V6. The total repair bill was about $800.00. I was lucky it didn't appear to contaminate the oil, although it does look like some oil got in the anti-freeze, so my cooling system has had to be flushed repeatedly. I may have to replace my heater core as well due to blockage. I'll know about that better as winter progresses.

Google "GM LIM gasket" and you'll find a lot of hits.

Now, back to the LS4 swap!!

Ok OK people SIMA DONNA , SIMMMAA DONNAA ! It seems you guys need more pics to calm everything down JEEZ !!

Pulling the damper


The front of the motor


The inside of the timing cover


The oil pump and timing chain


The rockers and springs


The DoD is probably a very durable design for a stock cam and springs. I don't want to take any chances breaking a lifter becasue i used a higher lift cam and heavier springs. Milage is a good thing but like i said a couple of times already "my toy. . . gas milage/fuel efficiency not super important" . I want to use the LS1/2/6 's computer since there are many aftermarket options and this will let me use intake manifolds, throttle bodies, rockers and such from the LS aftermarket even though the LS4 is "not compatible" since it has DoD.

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

quote Originally posted by RacerX11: Not cynical...just realistic. Honda’s successful use of latch pins on rocker arms doesn’t mean GM can pull off latch pins inside multi-part roller lifters. The very fact that GM does not normally introduce many gadgets is more reason for me to suspect this type of system. LSx piston slap and 3x00 intake gasket leaks come to mind when I think about GM reliability. Quad4 head gaskets if you go back further.

actually if you look back, GM has a long history of new technology introductions (if they didnt do it first, imports would have no where to go to for advancement) . Id rather do 3100/3400 intake gaskets than Honda 1.6 head gaskets which have about the same lifespan.

either way, for performance, ditch the DOD

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Fiero- mild 2.9 160hp
Caprice- wild 383 500hp
--Adam-- ASE Certified Technician
IM AOL: FieroGT5speed

quote Originally posted by Will: Ok... you're welcome to throw away free mileage. Gas won't be getting much cheaper.

I knew that comment was coming LOL

What is the numbers on the heads, are they LS6's

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1987 Fiero GT
02 Z28:LS6 cam/LPE CNC heads, Power Tuner, NOS 5177, AM4 Transgo w/2600 Yank, SLP goodies, Hoosiers, BMR subs./lcr/loop, SLP "Y"/Borla
motor 334 rwhp, NOS (100 shot) 409 rwhp
1/8 ("Q") 91mph, 1.93 60ft (100)
1/4 (Fontana) 12.38@111.3 (50)

[This message has been edited by Trolleyman (edited 11-15-2006).]

quote Originally posted by 88GT5.0KILLER: In the earlier LS1 engines there was piston slap. IIRC Oil starvation, would make noise when it was cold. I dont remember reading about it in the lastest models.

Don't tell me that was like the oil "consumption" issue in early LS6's...

The LS4 guys on Ls1tech are actually having oil consumption issues . .well some of them.

Trolleyman the heads are the 243 (have to double check when i get home memory sucks) casting which is the same as on the LS6 and LS2 motor. It is stuffed with LS1 valves and springs. The LS6 used sodium filled valves that were lighter and could withstand more heat. So you can kinda guess what i'm gonna do with the stock valves .

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

quote Originally posted by Will: Don't tell me that was like the oil "consumption" issue in early LS6's...

No, it is not operator abuse. It is a design problem related to piston/wall clearance, not oil supply issues. Even later LSx engines (LS1, LS2, LS6, all trucks, etc) exhibit the problem.

[This message has been edited by RacerX11 (edited 11-16-2006).]

quote Originally posted by RacerX11: No, it is not operator abuse. It is a design problem related to piston/wall clearance, not oil supply issues. Even later LSx engines (LS1, LS2, LS6, all trucks, etc) exhibit the problem.

So they just make noise?

I've heard that piston slap is because of a cold piston flopping around in the bore. When the piston heats up it swells and reduces the piston-to-wall clearance and the slap goes away. I thought this was only a problem on engines running forged pistons because they swell more when heated. Not to sure though it might happen on cast pistons as well. one more reason to let your engine warm up before beating on it

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

I wouldn't attribute the oil consumption to a tolerance, I'd attritube it to piston ring tensions. And I've heard "piston slap" a LOT and I think people are just whining, it ain't that bad.

the piston slap was on the earlier 5.3. as said it was just a bit excessive piston to wall clearance and goes away once it starts to warm up and doesnt negitively affect anything. On all the 5.3s i worked on ive never heard anything that would seem like it would be a problem anyway

Do all LS4 come with the 4T65-HD transaxle? What is your final drive ratio 3.29?

Here is what I've found out: (M15) 2.86, 3.05, 3.29 or (MN7,MD7) 3.29

quote Originally posted by RacerX11: The 10% and 40% are marketing numbers. The actual real-world mpg increase is up for debate. I would like to see some hard data to back it up. LS1tech owners are reporting ~2-4 mpg instantaneous increase during steady-state highway cruise. Overall economy improvement numbers would be lower. .

I have an LH6 with Active Fuel Management in my truck. This is a gen IV small block not too different from the LS4 and I can verify that on the highway it's good for 2-3 mpg. In a full-sized truck that makes a big difference. Whether it's worth it in a Fiero is debateable. I probably would replace the lifters with standard lifters if that's possible. I've seen conflicting reports on whether that's possible or not.

I will tell you what little I know about the lifters and camshaft.... Reading was done back several months ago, and I see some updates to what is in the DoD and LS2's..

I use to think the cam will need to be sent to Comp Cams or someone that grinds cams. The profile is different on the DoD lifter lobes. You will want to replace all the lifters with the same lifters for the LS1/6 blocks.

Since the cam is getting a regrind, you might as well design some lift into it also. I was thinking about .563, or about the same profile as the TR224 Thunder Racing cam. This cam in the LS1's performs very well, and easy to tune the PCM to.

This cam...

Thunder Racing Custom Camshaft - 224/224 .563/.563 114 LSA 1700-6600 RPM Power Band. Excellent mid-range & high RPM power.

The LS4/LH6 cam is different from the LS1 cams in lenght, and design. Trigger for the camshaft sensor is the problem. What I am not sure of is if the LS2 cam is the same lenght as the LS4. Cam sensor trigger is the same, so it might be possible to use this cam in a DoD block.

Ok, I found this article http://www.hotrod.com/techarticles/113_0504_general_motors_ls2_small_block_build/

It looks like the cam is the same for the LS1, LS4, LS2 in lenght and bearing sizes. The LS1 cam will have trigger notches on it for the rear sensor, but the LS2 and LS4 have the trigger on the cam gear. Looks like you can just buy a cam and replace the LS4, and then the lifters and push rods as well, that should kill the DoD part of that.

Loyde

[This message has been edited by FastFieros (edited 11-17-2006).]

quote Originally posted by Will: Ok... you're welcome to throw away free mileage. Gas won't be getting much cheaper.

cmon guys you forget this is an LS-series!!!

lets see:
Ls7=17-27mpg 3100lb car
Ls1=18-26mpg 3300lb car
Ls2=20-28mpg 3200lb car

The Ls4 in the 3700lb impala got 28mpg with dod and if what some people have said is true (that dod dosent make that much of a difference in mpg) than, in the 2700 or less lb, fiero it should get way more than 20mpg even with an agressively tuned high perf motor.

So he really dosent need to be worrying about gas mileage!

quote Originally posted by Will: So they just make noise?

Yeah, pretty much. My '02 Z28 sounded like a diesel for the first 30 seconds on a cold morning (that's like below 70 here in Florida). Other than that, it had no issues. No real oil consumption, good oil pressure (put a manual gauge on it to verify, cold and hot), and got 32 mpg cruising at 80 mph...gotta love double overdrive.

quote Originally posted by 4-mulaGT: cmon guys you forget this is an LS-series!!! lets see: Ls7=17-27mpg 3100lb car Ls1=18-26mpg 3300lb car Ls2=20-28mpg 3200lb car The Ls4 in the 3700lb impala got 28mpg with dod and if what some people have said is true (that dod dosent make that much of a difference in mpg) than, in the 2700 or less lb, fiero it should get way more than 20mpg even with an agressively tuned high perf motor. So he really dosent need to be worrying about gas mileage!

So if he can get 28, then he shouldn't bother with trying to get 32?
That's certainly the logic that put a man on the moon.
The DOD system will result in a BIGGER improvement in mileage in a small car beacause the engine will spend more of its time at very light load (and thus operating as a 4 cylinder).

And everyone is saying "well that sounds gimmicky and probably won't take hi po use", but NOBODY has actually looked at what might break in high performance use.

What's the diameter of the latch pins? what material are they made of? How much do the lifters weigh? Has anyone thought of doing some rudimentary shear strength calculations to actually FIGURE OUT how likely these lifters are to be a problem, or are we all just scared of new things?

[This message has been edited by Will (edited 11-21-2006).]

quote Originally posted by 4-mulaGT: cmon guys you forget this is an LS-series!!! lets see: Ls7=17-27mpg 3100lb car Ls1=18-26mpg 3300lb car Ls2=20-28mpg 3200lb car

Sure, but those cars had 6-speeds..

quote Originally posted by Steven Snyder: Sure, but those cars had 6-speeds..

What if you put a G6 6 speed?? check the MALL section a group buy is going on right now.

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Race-Tech Automotive inc. & The Fiero Shop.

Specializing in Fiero performance:
3800 swaps, custom 3800 and N* Aluminum flywheels, big Brakes, Engine rebuild, Aftermarket wheels, Bolt on performance parts, body enhancements, used Fiero parts, custom exhaust systems.
www.racetechauto.com

E-Mail racetech@bellnet.ca
Phone (416) 747-5728
141 Turbine Dr.
Toronto, Ontario, M9L 2S7

quote Originally posted by Team Race-Tech: What if you put a G6 6 speed?? check the MALL section a group buy is going on right now.

Correct me if I'm wrong here, but I don't think 6th gear in the G6 is 0.5:1 like it was for the Camaro and GTO...

-Chuck
'87 GT + LS6= ?????

quote Originally posted by Steven Snyder: Sure, but those cars had 6-speeds..

True but thats still impressive since were talikn about a 350 6.0 and 427 V8s and the vette is still considerably heavier than the fiero.

Ok finally got some time to work on the Ls4 so here are some pics.

Here are the heads . They have just a slight build up of carbon on em.



The lifter retainer in the block.



Here is the Dod lifter side-by-side with the stock non-DoD lifter.


The stock lifters fit into the DoD lifter bores so I'll be able to use the Ls1 style lifter. I'll have to remove a hump in the block, that acts as a keyway so that the lifter retainer cannot be installed wrong. I'll have to use an LS1 lifter retainer because the LS4 retainer has a portion removed to clear the lifters spring. No biggie though. I need to figure out where the LS1's cam position sensor reads from. I want to use a double roller timing chain but the LS4 has a pickup on the cam gear. I'm pretty sure the LS1's use a differant method. Well as soon as i drop the oil pan i can remove the pump then i can pull the cam and get some measuerments and check it agains a regular LSx cam. Enjoy

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

LS1 cam sensor is in the back of the block. AIUI, the early sensor cannot be fitted to the new block.

I thought you had to use a cam and lifter hardware from an LS2?

Bump . Hey toasterman I am gonna have to use the LS2 style cam pick up. The LS4's is the same as the LS2 so I'll just re-use those components. Unless of course i can find a double roller for an LS2 . I was cheking out some picks of the lifter valley cover and i might not be able to use the LS1's. From some pics i've seen it appears the cam position sensor is mounted in the block at the rear of the lifter valley, on the LS1's. The LS1's lifter valley cover is made to fit around the sensor and might leave an open hole if i use it on my block. I might just mill down the boss for the oil pressure sender and stick a 90* fitting on it to clear the intake manifold. I'll have to leave all the DoD solenoids on the valley cover but the will not be hooked up. I found out that the 5.3's sleeving has the same outer diameter as a 5.7. All i'll have to do is get the block bored out to the 5.7 spec and i can use some nice forged 5.7 pistons . After i get some " OTHER" projects out of the way i can get back to the LS4 . Keep posted pics will be coming.

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

So hows this beast going?

We cant start on ours untll someone else figures out all the problems.

quote Originally posted by 4-mulaGT: So hows this beast going? We cant start on ours untll someone else figures out all the problems.

First off I HATE WINTER ! ! So since i hate the cold not much has been going on . Second i just got back from a business trip to bangalor India. I highly recomend not going there unless you want to see how much better the USA really is. I've been searching for differant pistons and rods and have narrowed down a few good pieces. I just need to make a descision and buy them. I ran into a little snag with my throttle body . I want to use a cable actuated one but depending on the reluctor ring tooth count i may have to go with a motor operated one. It has to do with the computer setup in the car. That just means more wires and parts to aquire. I'll keep everyone posted as soon as i get around to pulling some more things apart. I have some P&P work to do before i start fiddling with my own stuff, and since it's cold im not to motivated. . . . stupid winter.

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HARDCORE SBC CRONIE AND PROUD OF IT ! GOT TQ ?

Congrats: Going where no one has gone before. I think the accurate designation for the 5.3 is "LM4" which is an updated version of the LS4 produced for FWD only. It's specifically for the Impala and Pontiac GXP. The physical aspect of elimination of the adaptor plate for the engine to transmission is a space saving feature for a Fiero Swap. It should also be benificial to structual factory engine/transmission cradle relationships not to mention simplicity of installation. In short, it should be a natural for the Fiero as long as the factory transmission is used. The most difficult part is if a transmission change is involved. The LM4 comes with automatic and appears to dicatate that factory engine control is specific to the auto transmission. ECM function may be dictated by that. Specifically, if a manual is desired, the electronics will be a nightmare. With the DOD eliminated the whole situation may be simplified.

You are on the right track. GITERDONE.

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Sandman.

That's the nice thing about getting rid of the DOD system; the engine essentially becomes a smaller displacement LS2. You lose the fuel efficiency of DOD, but you can pick up the ECM manual trans capability from LS2 cars.

quote Originally posted by sandman3581: In short, it should be a natural for the Fiero as long as the factory transmission is used. The most difficult part is if a transmission change is involved.

Factory???

That Stock Sh!ts Stank!

quote Originally posted by sandman3581: Congrats: Going where no one has gone before. I think the accurate designation for the 5.3 is "LM4" which is an updated version of the LS4 produced for FWD only. It's specifically for the Impala and Pontiac GXP. The physical aspect of elimination of the adaptor plate for the engine to transmission is a space saving feature for a Fiero Swap. It should also be benificial to structual factory engine/transmission cradle relationships not to mention simplicity of installation. In short, it should be a natural for the Fiero as long as the factory transmission is used. The most difficult part is if a transmission change is involved. The LM4 comes with automatic and appears to dicatate that factory engine control is specific to the auto transmission. ECM function may be dictated by that. Specifically, if a manual is desired, the electronics will be a nightmare. With the DOD eliminated the whole situation may be simplified. You are on the right track. GITERDONE.

"most "no duh" comment of the year award goes to!....."

I have never seen the FWD 5.3 listed as LM4 RPO actually I searched LM4 and came up with nothing.
if you have information about the "actual" LS4 please post.

And we have been reprogramming OBDII PCMs for Manuals since it came out its nothing new.

Factory Transmission???

Ok Here we go ! I had to get another camera cause mine got stolen . How does a camera, and just the camera, disappear? Well anyway , i was able to get out in the garage and do a little bit of disassembly . Well here are the pics.

Flipped and ready


YIKES !!! sludge ! thats not cool.


The oil pump pick-up and a windage tray SAAAWEEEEET !

Get it done already. yyeeaaahhhh (Kramer voice)

Unless you want to have a almost finished engine on a stand for 2 yrs like me.