13 * retard

[SappySE107]

Its not too hard at all really, and with the 94+ type lock rings its even easier. Im not sure about getting a degree wheel in there but I just make a mark on the pulley with the leg on mine so I dont have to deal with the pointer.

The computer will need to be reprogrammed to get the most out of it, but I havent done tuning with a stock motor and just the timing mod done. I only know what it does with ported heads.

[Gemmer]

Dude, please don't take this wrong, but if you don't know the answer, DO NOT TRY THIS AT HOME! Cam timing is for the experts. Again, sorry to sound harsh, but your troubles over 3000 are a direct result of you not knowing what you're doing. You are lucky if you don't burn a valve or worse.

huh? I dont have any problems over 3000. I think you are confusing me with the guy who started the thread.

u are retarding the cam 6.5 cam degrees or 13 crank degrees. u turn the crank 13 degrees.

Gotcha, makes more sence now that I reread the post. I thought for a split second we weren't talking crank degrees

[pontiacjeff]

Here's my way around the issue of how to hold the cams retarded. I installed the cam holder and, using a sharp Sharpie, indexed the intake cam to the cam carrier in the "straight up" position. Then I locked the exhaust down flat-zero. Using the degree wheel, I rotated the crank to 10 deg ATC, checked my index mark to make sure the intake was still "up", and locked it down using a sprocket holder. It is within +/-1/4 of 1 degree, which is a close as you can get even with the cam holder.

I think I will degree the crank pulley before installing the engine. I'll bolt the degree wheel on again and make some temporary marks on the pulley, then scribe them permanently with a hack saw. Marks every 2deg. should do it.

[pontiacjeff]

Sorry Gemmer. The first part of this thread was very confusing with all the quoted replies and multiple ??? by different folks.

It was meant for 93vinx. ANd I'm sorry it sounded like a reprimand. I fix alot of broken cars for folks who"tried this at home".

[SappySE107]

Do you have more pictures of the 96 cams? Im interested to know how much smaller the lobes are as well as the weight of 1 cam.

[pontiacjeff]

Why do you think the lobes are smaller?

Thats the only picture I have of the cams.

[SappySE107]

96 cams use 33mm lifters instead of 35mm like the 91-95. I figured the cam lobes would also be narrower and from that, lighter. Just curious if that is the case because I havent had any 96 parts to look at.

[ez112]

If you need pictures of 96 stuff, shoot me a pm and I'll provide exact what ya need no problem.

[DavidDeerson]

Here's what I found............I did a baseline dyno run and got 178hp to the wheels.NOT the 215 alot of people believe they have.This confirms what others have seen on the dyno(such as Mike Smith).BTW,I also have a '92 3.4 in an '88 Fiero that I use on the track only for open track days.
Then I retarded the cams 4deg int and 14deg exh and took another run.The result?I LOST PEAK HP!Down to 170,BUT spread the power out 700rpm more (extended the rpm range).But I still got the extreme drop at 6500rpm.This is surmised to be a hardware issue such as restricted intake,exhaust,cams or a combo of all.But the suprising thing we noticed is monitoring the exhaust with the wideband O2 sensor with the dyno program and overlayed with the hp/rpm is that the motot is EXTREMELY rich over 3500 rpm!The ratio goes over 9to1(air/fuel) much of the time with 12.5-13 being a good target.Then I installed a "piggy-back" controller(Perfect Power SM6) and modified just the fuel curve.By taking fuel out of idle it even smoothed out the "lope" associated with performing the 13deg retard.Then we did some more pulls(7 in all)and we picked up 20 MORE HP over 5500rpm!We got 11 more peak than original(190hp peak @ 6000),but the curve was dramatically fuller over 3500.The power was flatter from 5-6500 and now was more useable.Power still dropped off a cliff at 6500,but we expected this.This winter after the season is over the top end will get freshened up with some headwork,intake cams,headres and some expeimenting with intake design.I have been in contact with Mike Smith and have used alot of his notes in my project.But I must add that one of the biggest improvements came from one of his ideas not with the engine.His idea that I needed to get the gear ratio better suited to this motor led me to build a V6/Quad4 hybred gearbox.this lowered the final drive to let the motor really rev up was a great "bang for the buck"project.
BTW,using a digital level that can be re-zeroed when placed on the head can be used to check the cam setting.Re-zero the level,then used a parallel block to place on the cam flat while the crank is at TDC.The reading is how many cam deg advanced of retarded you have.If you're looking for 13deg ,then just make sure the exhaust cams reads 7.5 and all the guesswork and potential for error are reduced.

[SappySE107]

I noticed that I had to retune my car after doing the cam timing but I don't have anything for doing this on a motor without head work since that was one of the first mods I did to the car. Im a bit confused though, did you try 13 degrees or just the 4 and 14 on the dyno?

[DavidDeerson]

I didn't bother with just the 13deg on the exhaust.Between Mike Smith and I we think that any retardation of the exhaust will not have as much of a positive impact without getting rid of those restrictive exhaust manifolds and put some headers on it.That way we can take advantage of the scavaging from tha increase in overlap.So,as just an experiment between us,I wanted to see what just a cam phasing change would do to the numbers,be it up or down.He went 8deg int and 18deg exhaust with his headers and intake,I did not want to go as far due to the fact that I still need some mid-range with the road racing I do,not just the top end he wanted for drag racing.I'm sure the numbers will get better by getting the air to flow through the motor more efficiantly,but having the SMT6 I can go back and re-curve the fuel to any combo without bothering to burn a prom and experimenting.We just do a pull,check the graph with my exhaust numbers compaired to rpm/hp ,tweek it with the lap-top then do another pull.It takes alot of guesswork out of the loop when there are hard facts and numbers on the screen,not just relying on the old seat-of-the-pants dyno to check modifications.My car actually felt slower after changing the cam phasing but I actually extended the power curve out more,it just wasn't until I changed the fuel that I felt the car go better.

[quantum110]

Here's what I found............I did a baseline dyno run and got 178hp to the wheels.NOT the 215 alot of people believe they have.

Wheel HP and Crank HP are two different things, Chief. Manufactures Quote Crank HP, this is power directly from the crank...Wheel HP will always be a smaller number because of Parasitic Drivetrain loss...Usually 15-20%. Meaning your engine dyno'd approx 209-222 crank hp.

[DavidDeerson]

Since 1974 manufacturers have been listing NET horsepower(at the wheels,as installed with all emission and optional equipment) not GROSS(flywheel).That is why,horsepower numbers seemed to drop drastically from 270-300(1970-71 Corvette smallblock)to 190hp(1973-74) with the same engine specs and part numbers.Look what happened last year when Mazda rated their RX8's horsepower high for advertising,then when magazines and new owners took them them to a dyno(since it seems every town has one)they found out the motor did not produce the HP numbers as advertised.Mazda offered to buy back the cars and changed the ads.I've dyno'ed many GM cars,and rarely ever seen the car make advertised HP,from a Impala SS to Quad4.

[SappySE107]

"The major change in 1971 vs. 1970 horsepower ratings didn?t come from the change in compression ratio. Instead, it comes from the use of more realistic net hp ratings in 1971 (which included a fan, an air cleaner, exhaust system, etc.) versus the gross hp used in 1970. "

This doesn't mean at the wheels, it means crank hp still but now tested as it runs in the real world. You aren't going to get GM rated hp at the wheels unless you have say, an LS1 which was under rated and still produces what they claim at the wheels. This doesn't mean the rest of GMs lineup follows suit with more power than advertised.

Until someone tries 13 degrees exhaust 0 degrees intake, we still don't know what it does. What you have tried isn't exactly what we have been discussin here though what you said about fuel is interesting for everyone else im sure. How rich was the mixture with the stock timing? I have noticed in lighter cars that the engines don't require as much fuel. Is the weight of the fiero a factor on the dyno, cause I can see it being much richer than the same setup in a w body vehicle.

[gpse3400]

I still think I need Chevy 2.2 injectors. "Jeeze it's still too rich? Ok I'll just take out a shitload more! Oops!! I took out too much!! Oh no the pistons are melting!!!!" He He YEAH!!!