Guys,

This is going to be a little long, but here it goes...

I recently installed the following on my car:

-ARE Stage 2 heads
-2001 Oil Pump
-Cam Motion Turbo Cam
-LS6 Intake

My car is a twin-turbo car, but I had trouble with one of the turbos and both manifolds are now at Incon. I installed a set of stock 2001 manifolds on the car until I get my stuff back from Tom.

After installing the manifolds today (there is no y-pipe attached yet, so I know that the car will go into rich mode due to the unplugged 02s) I crancked the car and it sounds like it has no compression.

The motor seems to free-spin and sounds like it has no compression. There is no sound of valves hitting or the like.

I checked the following and had both....
-Spark
-Fuel

Here are some things that I noticed:
-I have 0 oil pressure (due to the pump swap???)
-The car isn't seeing any vacuum (Autometer boost gauge)

I was thinking that because I have 0 oil pressure the lifters may not be pumped up and that could be causing my problems...I also think that there could be a vacuum leak (am I supposed to have vacuum while crancking?)

Thanks,

Scott

 

Ok, here is some additional information...

I did a compression test on cylinder #1 and got a reading of 0 <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

So, I pulled the valve cover and loosened both rockers on cylinder #1 and got 200 psi of compression (I'm sure that this is a little high, but it is a cheap Pep Boy's gauge).

I then torqued the rockers to spec again 20 ft/lb on the first pass and 24 ft/lb on the second pass and the compression went away again...what the hell is going on?

Scott

<small>[ March 20, 2002, 05:42 PM: Message edited by: Scott 98Z M6 ]</small>

 

Sounds like maybe your pushrods are too long? What length did you use and are the heads milled? What lift on the cam?

0 oil pressure if the motor isn't really running sounds pretty normal. Usually takes a few seconds of running after a swap to get the pressure built back up to the point where it reads on the gauge.

 

The pushrods are Trick Flow 7.400" pushrods and the heads have not been milled (This is what I was told...I bought them used)

Thanks,

Scott

 

try your stock push rods just to see if it will fire up, if so get new pushrods <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

You need to get some shims to adjust the lifter preload! MMS sells them.

 

Ok,

I pulled all of the rockers off and pulled the plugs and did compression tests on all of the cylinders just to make sure that things are ok.

There seem to be some variances between the cylinders...the lowest was 140 and the highest was 240 (keep in mind this is an el-cheapo gauge.)

The car had been sitting for about 3 months prior to the installation of the heads and cam and about a month after they were installed.

What could be the reasons for the differences in compression between the cylinders? Do the rings need to re-seat after the car hasn't been run for awhile? Also, I was doing the compression test without unplugging the injector harness for awhile, which could explain the high compression readings in some of the cylinders. Could I have washed out the rings with all of the gas that was getting sprayed in there?

Terry,

How do you adjust the lifter pre-load? I thought that since the heads hadn't been milled and the pushrods are stock length that I wouldn't have to do that.

Thanks,

Scott

<small>[ March 20, 2002, 09:52 PM: Message edited by: Scott 98Z M6 ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Terry Burger:
<strong>You need to get some shims to adjust the lifter preload! MMS sells them.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

 

So do I need these shims or not??? MMS is about 5 minutes from my house, so if they will fix my problem then I will go get a set...they are only like $40.

 

Did you have to loosen the rocker arms to get compression?

 

Yep,

I tightened them to 22 ft/lbs. with the procedure recommended in ALLDATA and still had no compression.

The only way that I got compression was when I loosened them.

 

Is it possible that the cam was installed 180* off?

 

No I don't think that the cam is 180* off. I did the install on the cam, and although it was my first cam install I marked the crank gear and the cam gear before I did the install and then made sure that they were lined up afterwards.

Also, wouldn't I have bent some valves if the cam was installed incorrectly?

 

Here's how you can check to see if you have a valve bent or open for some reason. Untorque both the intake and exhaust the rocker for each cylinder, one cylinder at a time. Check the compression for each cylinder with the rockers untorqued. Both valves should stay closed durng cranking and your compression should be good (at least 160 or so on a stocker).

If all cylinders seem fine on compression, then there's a good chance you have a valve (or valves) open during the compression stroke when the rockers are torqued. Only way that could happen is if your cam installed wrong or the timing chain installed wrong. If the cam isn't opening and closing the valves with the correct respect to the comnpression stroke, then there will be very little compression.

It is difficult to get the cam in wrong since they are keyed with a pin. If your compression is good, then pull the front cover, ensure the motor is at top dead center, and make sure the little dots on the cam and crank gears are lined up.

This is all I can think of right now. Other ideas are:

Insufficient torque on heads and a leak from the gasket(s) (would normally result in coolant leaking)
Timing Chain broken or disengaged (would cause no compression and no oil pressure)
Bad Plugs (did you replace them?)
Did you change anything else? (like wires) That is where I start hunting first when something like this happens
Ground on back of driver's side head (should be 3)

Believe it or not, My car wouldn't start last week after reistalling the heads. Turned out to be the new Taylor wires I had bought. I had visible arcing from the valve cover to the head and the car wouldn't even try to start! I decided to try the stock plug wires and the car fired right up.

<small>[ March 21, 2002, 06:26 AM: Message edited by: Reckless ]</small>

 

Sounds like me back in 1999 when we did heads and cam on my car.

Turned out my 7.450 pushrods were too long. My heads were only decked .010 to clean them up. Yup, I was told to run some p'rods that were .050 longer than stock. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> I did buy them back in 1998.

My buddy Intmd8 came by and measured the lifter preload with a tool. I had too much. It was like .110 lifter preload or something like that. Kept the valves open.

My car was a 1998. My car would only run on one side of the motor.

Ended up getting some 7.350's and then it was okay.

 

dont forget to clearence your 98 covers to fit the valve springs.

yeah it happened to me... "Thanks Barry for the help on the phone! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> "

I got an email from another guy who had the same problem.

However our cars started and ran but extremely poorly

<small>[ March 21, 2002, 03:34 PM: Message edited by: PhantomTA ]</small>

 

Thanks to everyone that replied...I got the problem fixed today.

Many of you were right, the pushrods were too long and the valves were staying open. I went by MMS and picked up some 7.350 pushrods and installed them (nice to have a performance shop close by) and the car fired right up <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Open manifolds are loud!!! The car is pig rich right now due to the 38 lb./hr injectors that are in there. Luckily I already have LS1 edit and I will be playing with that stuff tomorrow.

I am getting some misfires on various cylinders and oil pressure dropped 20 psi at idle due to the contamination from too much gas. Are the misfires normal for a cam? It is a relatively mild grind 518/518 on a 114 LSA

Thanks again guys, I really appreciate it!

Scott

 

Glad you got it running Scott! Whew!
<img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />