blakez28

I just bought a 95 z . Car has 52k miles . The guy who had it before me just did a cam swap . He had the cam and springs changed to comp xfi cam and beehive springs . Also added long tube headers and a 2500 stall. The car sounds good but it is really rich and is very lazy on revs. No trouble codes are showing up. My question is could he have got the #1 up on intake stroke when he put the distributor back on? Or would it even run if he did. Thanks

Injuneer

You don't need to put #1 at TDC/compression to put the distributor (Optispark) on. Your 95 has a "vented" Opti, driven off the cam dowel pin. There are 3 holes in the back of the Opti, and although the pin is only supplosed to fit in one of them, its possible to force it into the wrong hole. If its in the right hole, the distributor is correctly aligned to TDC. If its in the wrong hole, the timing is so far off, it probably won't even run.

Was the PCM tuned for the cam? If so, by whom? How big is the cam? What other mods are on the engine, besides the ones you listed?

Have you checked the valve adjustment?

Are you sure the headers are not leaking? That will cause it to run rich.

SPEED#1

Tuned or not? Valve may be set incorrectly. Bad or misadjusted TPS.

blakez28

It has not yet been tuned. I adjusted the valves last night . I did the as one starts to close I adjusted the one next to it on the same cyclinder . I went zero lash than 1/4 turn. It also has 1.5 roller rockers on it . No other mods . The car will idle smooth so I know the valve adjustment is right. I hooked a scaner to it and looked for codes and also datalogged it . The o2 seem to be working and it did go into closed loop. I do have a collector leaking . I will get it replaced on Saturday. I also did a leak down test on it . no problems noted there . The guy i got it from just threw parts at it and got mad and sold to me. It has the following new parts . plugs , wires , cap and rotor , coil. The only thing I see right off is it has 2.5 " pipe going back on both sides, then y piping into a 3" pipe than into a flowmaster.Seem a little much to be dumping two 2.5"s into a 3". Thanks

blakez28

My cam is the comp cams 260 xfi . 0.555 0.565 lift.
260 270 Dur.

Injuneer

A 3" intermediate pipe should not produce any problems with your liimited mods.

The stock rockers, while not full rollers are ~1.5X, so that's not a "mod" as far as the PCM is concerned.

JAKEJR

You started off incorrectly so everything that followed would also be incorrect.

You don't do it by the "I did the as one starts to close I adjusted the one next to it on the same cylinder" method. That's not correct.

You set the preload on intake lifter when the exhaust valve just begins to OPEN.

Then you set the exhaust with the INTAKE valve is about half-way down to being fully closed.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!

1badasZ

when you say headers leaking do you mean just anywhere at all? will a leaking collector cause this problem? im just trouble shooting everything on mine too. ive had pin holes welded up where the lil tube thing were cut off but i think they still leak i hope you find out whats wrong with it i know how frustrating it can be ive been battling for a while

Injuneer

The problem is caused by any leaks BEFORE the O2 sensors. Once you get well past the sensors, it doesn't matter. But with headers, the sensors are usually in the collectors.

blakez28

Got the header leaks fixed and still had the same problem . I checked the TPS and found it reading way off . Replaced it and now it seems to be doing better, still needs tuned .

blakez28

I guess dumb luck works then it seems fine.

JAKEJR

Here's what CompCams says is the way to do it. Years ago I wrote a more detailed, albeit longer, version of the same procedure inwhich I tried to not only say "what" to do, but also "why".

Setting Hydraulic Lifter Preload:

The correct amount of lifter preload is important to help efficiently control the valve train. Insufficient preload will cause valve train noise, while too much may damage the hydraulics of the lifter or cause low manifold vacuum.

By following the four steps listed below you will help ensure proper engine
performance and reliability.


INSTRUCTIONS
2
COMP Cams®
3406 Democrat Rd.
Memphis, TN 38118
Phone: (901) 795-2400 Fax: (901) 366-1807
www.compcams.com
Part #COMP4-116
Revised 12/9/08
Instructions:

1. Lifter Preparation: Remove your new COMP Cams® lifters from the packaging, and clean the lifters thoroughly in mineral spirits or an equivalent solvent. Remember, in order to protect your camshaft warranty new COMP Cams® lifters must be installed on flat tappet cams. It is not necessary to “pre-pump” hydraulic lifters full of engine oil prior to installation and valve
adjustment. It is actually undesirable to do so as the “pumped up” lifters will cause the valves to open during the adjustment process, rather than positioning the lifter plunger in its operating position as it is supposed to do. “Pre-soaking” hydraulic lifters in a bath of engine oil is a good idea, but not mandatory. Doing so ensures that the lifters are adequately lubricated on their outer surfaces prior to installation. It may also result in a quieter engine start up as the oil in the bath may displace some air from the lifter’s plunger reservoir. Coat the bottoms of all flat tappet lifters with COMP Cams® Cam and Lifter Installation Lube (Part #103) supplied with flat tappet cams. When you install the lifters, make sure they fit well. Flat tappet lifters should
rotate freely in the lifter bores. Any excess clearance or tight lifters can cause damage to the camshaft, leading to engine failure. Note: .0015”-.002” lifter bore clearance is minimum.


2. Setup: With your cam installed, simply place the prepped lifters into the lifter bores. If you are using hydraulic rollers with a link bar, pay close attention to which direction the link bar faces.

The link bars on retro-fit lifters should face towards the valley of the block. If the link bar has an arrow on it, make sure the arrow is pointing upwards (↑). If your engine block was originally equipped with hydraulic rollers make sure the High Energy Lifter™ roller wheel is positioned to roll along the camshaft lobe. Failure to do so will result in camshaft damage and improper
oiling. Now that the lifters are in place, you can begin to install the pushrods and rocker arms.


3. Pushrod and rocker arms: Clean all pushrods thoroughly because most engines oil through the center of them. If the original pushrods are being used, be especially sure they come clean inside and out. Apply a small amount of COMP Cams® Engine Assembly Lube (Part #102) or
an equivalent lube on each end of the pushrods, and install them into the engine. Clean all rocker arms thoroughly. If the original rocker arms are used, examine each one for excessive wear, and replace any that are questionable.

Apply a small amount of lube on all contact areas of the rocker arm. With a clean rag or towel, wipe the tips of the valves clean and apply lube to
them where the rocker arms will come in contact with them. Also be sure to check the valve stem tips for excessive wear. Next, install the rocker arms. Make sure the pushrod is in the lifter and the rocker arm seat when making valve adjustments.


4. Adjusting preload: COMP Cams® High Energy Lifters™ can be used with adjustable and non-adjustable valve train designs. However, each type of valve train has its own set of procedures for setting preload. This section is divided into two parts: Section I describes adjusting preload with an adjustable valve train, while Section II explains adjusting the valves using a non-adjustable valve train.

COMP Cams®
3406 Democrat Rd.
Memphis, TN 38118
Phone: (901) 795-2400 Fax: (901) 366-1807
www.compcams.com
Part #COMP4-116
Revised 12/9/08

Section I. Setting preload with ADJUSTABLE ROCKER ARMS

Turn the engine in the normal direction of rotation. Start with cylinder number one (1). When the exhaust valve begins to move, adjust the intake valve to the correct preload. To reach zero, take the pushrod between your finger tips and move it up and down while you tighten the rocker arm. Once you feel the pushrod has no more vertical slack, you are at zero preload. Make sure the pushrod is in the lifter and the rocker arm seat when making valve adjustments.


As stated before the best setting is .030” to .040”, or ½ to ¾ a turn of the wrench past zero. Now, you can move on to the exhaust valve on the same cylinder. Begin by rotating the engine over again until the intake valve reaches maximum lift and is almost all the way back down. Then set the exhaust valve using the same method as the intake (.030” to .040”, or ½ to ¾ a turn of the wrench past zero).

Just passing this along trying to help and prevent you from having any problem down the road.

Jake

West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduaton Day Parade 20 May 2010!!!

ACE1252

The instructions with my Pro Mags stated to use 1/2 turn preload. I did and had no issues. I followed their instructions to the letter and had no problems. This was also my first time adjusting rockers, however I am mechanically competent. The steps I were not satisfied with was how tight to go with the polylocks and the pushrod twisting.

After some research on this board, I settled on locking the allens to 30 ft-lbs. Never had one come loose....every one of them were locked down when I disassembled my engine a couple of weeks ago.

The thing is you don't have to go through all that pushrod twisting BS when looking for zero lash with polylocks. After you rotate the crank to the rocker adjustment point, when you screw down the polylock...once it touches the rocker(with the lifter plunger against it's clip and the rocker resting on the pushrod and valve) you are at zero lash.

Here is where Jake got the info if you want it in PDF format.

Comps Instructions Page:
http://www.compcams.com/Technical/Instructions/

Pro Mag Instructions....
http://www.compcams.com/Technical/In.../Files/151.pdf

ACE1252

I was sitting here thinking about why on earth it was necessary to even screw around with the pushrod....and I think I have figured out why.

I do all my rocker adjustments with the intake off the engine. This gives me an advantage because I can watch the lifters themselves to see when they are rising and falling(to know when to adjust the valve...you can also make sure you are not inadvertently putting preload on the lifter when screwing down the polylocks by watching the lifter plunger....if it's not against it's clip...you have preload).

If you don't have the intake off, then you may have to feel for pushrod resistance....because you can't see the lifter starting to rise. Soooo, with the intake on the car, you may have to use the "pushrod BS". I've never tried rocker adjustments with the intake on the engine and can now see why it gives so much trouble....not seeing the lifter movement is a real disadvantage.