timing and cam stamping

[shoman455]

Ive had nothing but problems with this car since I got it. My issue now is the cam positioning and the markings. When I got to the cams they were all series 2 (ie RI2 RE2) except for one of them it was a sxeries one. When I allign the timing marks etc. for topdead center of the compression stroke, the right bank appears to be fine (both series 2) but the left bank looks like the intake is 90 degrees ********( this is the series 1 LI1. Also the koa stamp has been ground off) Ive ordered through private parties all 4 series 1 cams and I am still in the same boat. I try to start it and it fires through the intake( the cataletic converter caught fire!) What do I do or where do I go from here? Im lost!


93 ATX

------------------
Will

 

[sdpatt]

Give us some information. Why in the heck are you replacing the cams in the first place? What cams are you talking about? Series 1? Series 2? Where did the originals go?


------------------
Scott

1991, 254K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
Class II hitch, Silver award at the SHOklahoma Car Show

 

[shoman455]

The reason Im replacing the cams is that I was told it wasnt a good idea to mix and match the different series of cams. The car had a RE2, RI2, LI1, and LE2. I tried to locate a LI2 cam but everyone that I spoke with said that the 3.2 SHO had the series 1 cams so I had to get the replacements for that. Ive still got the "original" cams that came in the car when I bought it. upon examining them, it would appear that the series 2 cams have a more aggressive grind but i could be wrong as I am not a trained professional.
It started by my noticing a lag in power at high rpm. looked under the hood, 2 spark plug wires were ripped and the number 5 spark plug was covered in oil. blown head gasket and a bad harmonic balancer. all repaired and now the timing. I had a friend help tear down the motor, and he took out the cams so we had no I dea where the timing marks lined up when we took it apart(he forgot to set tdc before he did anything. Our fault) But it is set now and I line up all the timing marks and the right bank has about a 90 degree seperation in the cams, while the left appears to have about a 180 degree variance between the cams. Im basing this off of firing order. #1 cylinder is at tdc compression and lobes are perfect. #4 cylender is next to fire and the intake cam looks to be 90 degrees ******** from where I think it should be.


------------------
Will

 

[jthomas68]

You`ve mentioned the cams in the timing,but not the crank.Did you also set the crank pulley mark?What exactly was wrong with the pulley(harmonic balancer)?I`ve never heard of one going bad except for the keyway getting worn.

------------------
Jeremy Thomas
Juiced 91+
SHO Pic Of The Week:

 

[fredhurderjr]

These sound like the old Genesis Cams - Stage 1, Stage 2, etc., and the RE2, LI1, etc. Right Exhaust Stage 2, Left Intake Stage 1..

So I think I get what's going on, and if so, you're right - you shouldn't mix the cam profiles in the same valve set (intake to intake being different profiles). So, from what you're saying, you have a Stage 2 intake cam on the right bank, and a Stage 1 intake cam on the left bank.

I believe it is possible to put the gear that drives the cam off by 120° each way - I think there are 3 bolts that hold the drive gear to the cam (from memory here). So, if that's what happened, your lobes would indeed be off by that much using the gear's marks.

IF that's the case, you're incredibly lucky there's no valve & piston damage, as the Stage 1's are borderline interference, and the Stage 2's ARE interference profiles.

A lot of this is of course, pure conjecture on my part.

I'll go look at a cam we have on the shelf when I get home tonight to see if it's possible to re-position the drive gear like I described. As for the crank position, JT's question makes sense, but I think the other cams would be off then.

I personally wouldn't want to run the 2 different profiles - that would make the engine's firing pulse strength off, which could be why the dampener was possibly shot - you were shakign the engine with the mismatched cam profiles - you'd be making more power on one bank than the other.

Also, does anyone else know about ATX's running the Stage 2 cams? I thought that was a rare occurance, as it made the car not idle well at all.

------------------
White 95 SHO MTX
"Jezebel"

Teases me with occasional great runs in between break-downs.
3.2L SHO Shop Long Block
9psi Vortech S-Trim Supercharger
Eibachs, Tokicos, 96 Brakes, SFCs, STBs
PP Y-Pipe, Custom Stainless Cat-back, Bullets
http://members.home.com/fhurderjr/sho.htm

Mocha 91 SHO
"Monique"

Hi-Revs Jr. Clutch
Dynomax Cat-Back
"The Reliable Winter Car"

 

[Blast7]

You should really use the same cams for your engine. I think you can mix and match by putting Stage I intake cams in and Stage II exhaust cams. I'm not sure if I am correct here but I think that is what Ransom did. However, I don't think it is very healthy to have one intake cam a Stage I and the other a Stage II. That doesn't sound very good.

------------------
Car of the Moment

1991 Black MTX
K&N Filtercharger
PP Motor Mounts
PP Y-pipe
Rod Shifter
Blazer Tech Fogs
"ur gonna love that sho, and everytime something breaks down..your gonna swear to all your friends that its going up for sale. and the minute you get it back you fall inlove all over again."~Blue

 

[shoman455]

Yes. I had set the crank timing mark. The harmonic balancer was shot because, I dont know why. All I know is that everytime Id Crank the motor over the balancer would come to a new tdc when I would set it there.
The cams are all stock so far as I can tell. But on the stamping there are different numbers that I distuinguish as different series. The left bank was the one with the "series" 1 intake cam. All of the others were "series" 2. Ive taken the #2 cams out and installed all #1 cams in the car. The timing marks are all set and on the left bank it looks almost textbook. The intake is about 45 degrees after closing the valves and the exhaust is about 45 degrees before opening the valves. (Keep in mind that these numbers are estimations.) The left bank intake cam has the lobes resting right about where the valves just closed and the exhaust cam has the lobes sitting about 180 degrees after the valves were open all the way.
Between the right bank lobes there is about 90 degrees of seperation. (Im talking about the number 1 cylinder.)
Between the left bank lobes there is about 150 degrees of seperation. (Im talking about the number 4 cylinder)
My reason for concentrating on the #1 and #4 cylinders is that is the firing order chiltons gives.1-4 2-5 3-6. I figure if i get those cylinders right all the others will fall in line.
Also, in the left bank, with #1 set for tdc, There are absolutely no valves open. no intake or exhaust. And Ive got all of the timing marks on the entire motor lined up.
What in the heck should I do?


------------------
Will

93 ATX, k&n filter

 

[shoman455]

With the intake cams being driven by the timing belt, and the timing chain driving the exhaust cams from the intake cams, I cant see how you can possibly mess up the timing. There are marks on the belt gears that allign the intake cams and those gears cannot be put on wrong because they are keyed. Now with the exhaust, they can be put on 180 degrees off. The chain gears can be fliped and that could screw things up. It would be impossible to screw up the chain gear on the intake because the timing marks in one place wouldnt line up. With the exhaust it could be flipped but then the koa stamp on the top of the cams that designate the top of the cam would not be on the top and visible. It seems almost impossible to install them wrong if you line up the chain links and the gears and the marks on the timing belt itself. Why is there such a difference in the banks of my car and what do I do?

------------------
Will

93 ATX, k&n filter

 

[NotSoSlowSHO]

Does anyboedy REALLY know the difference between the RI1 , RE1 and RI2, RE2?? shrug

Im in the process of replacing my cams (my factory cams have some pitting and ugly wear) and until now I was totally unaware of any variation in cams... squint

My FACTORY cams are '2's

and the replacements are '1's


SO whats the deal? shrug am I in the process of DOWNGRADING performance? Do these cams in fact have different profiles??

I hate surprises cuss

 

[NotSoSlowSHO]

Update:

I just got my new(used) cams in.

I measured valve gaps with my old cams, and with the new cams. No difference whatsoever. Good for me (dont have many shims to hunt for), but does this confirm or deny and difference in cam profiles between the two?

Shouldnt the difference be in the lift (being the tip of the lobe, right?) shrug