removal of crossover pipe

[BJM]

Are there any tricks to this? I looked at it and I am wondering, do I just take out the bolts or are there nuts on the top side of the manifold flanges that have to be held while I turn the bolts?

Are there gaskets required to put it back or does it just go in dry.

 

[UNGN]

There shouldn't be any nuts, just four bolts. Use as many extensions as you can and a swivel to get the passenger side. They should be 14mm bolts, but 15mm is a typical oversize bolt if the threads get stripped.

No gaskets required. To reinstall, tighten, but don't fully torque any of the bolts until the pipe is exactly where you want it.

 

[OKTurbo]

You had better shoot some penetrating oil on them before you try to bust them loose. My personal favorite is called AeroKroil.

I had to hack saw one bolt when it wouldn't come out. The threads were stripped and it wouldn't come out....and it wouldn't let go. I was taking it off anyway to replace the cracked DS header....the bolt that was stripped was on the driver's side so I just dropped the header and crossover at the same time. Once on the garage floor I did a little "surgery" with a hacksaw and freeded it from the header.

I have this tendency to turn a 1 hour job into an all day affair!

Good Luck,
John

 

[tom h]

when reinstalling the crossover and bolts, spread a nickel-based antiseize compund on the threads (eg, Permatex makes one). That should keep bolts from seizing up or rusting, in the future.

 

[squeeze87]

I put stainless steel bolts back in to prevent rusting. Like the others said though, make sure the pipe is seated properly on the headers before tightening, cuz if it leaks...no boost!

 

[BJM]

Is it hard to get it all lined up before tightening it up? I don't want to make trouble for myself.

 

[Jeff]

I think I blew that lining it up part....
Could this also cause low vacuum and erratic O2 readings at idle?
Thanks,
Jeff

 

[OKTurbo]

BJM....No, it's not hard to line up at all. The bolts on the passenger side are kinda hard to get started. I've got long, skinny arms, so that helps !?!? Just make sure it's not hitting on anything once you get it tightened up. I think the key is to pull the slip flanges up parallel. Don't go crazy and put too much torque on those bolts....

A leak in the crossover shouldn't cause a low vacuum reading. The O2's at idle SHOULD be all over the place if the O2 sensor and computer are working properly.

John

 

[Jeff]

Aren't O2s supposed to have a specified range at idle?

When I say the O2s are all over place I mean from 200 or less to over 700 and everything in between. gnttype.org says that the O2 should be .450 +/- .100. Crosscounts are sometimes well over 100 as well, and should be much lower. The exhaust smells rich and it failed the emissions test pretty badly. I'm just trying to get this thing to pass so I can drive it while I fix/modify it.
Also, BLMs are pretty high at times.
I thought an exhaust leak could cause some of these systems if it's before the turbo, like at the crossover.
Thanks,
Jeff

 

[OKTurbo]

What scantool are you using Jeff?

The O2 cross counts on the Scanmaster start at 0 and count up to 255 (I think) and then the numbers start over again at zero. The serial data come through the ALDL at a cycle of about 1.5 seconds. For each 1.5 second cycle you should see the O2 cc numbers move up in increments of 10-20. If the numbers start to slow down it means that your O2 sensor is getting "Lazy" and it's time for a replacement.

Depending on what chip you have....What chip are you using?...the O2 millivolt readings at idle will be all over the place. The O2 millivolts reading at idle is pretty meaningless. Some chips, like the Thrasher, use an open loop idle that makes no fueling adjustments at idle based on the O2 reading.

You say it smells rich, but your BLM's are high. How high? If the BLM's are not TOO high...say 135...the computer is still in control of the mixture. If the BLM's max out at 150 or so...the computer has lost control and logically I would think the car was actually running lean. (I'm talking about BLM at idle here)

If you've removed your catalytic converter...the rich smell may be because of that. With no cat converter the car will smell different....like the "old" days.

An exhaust leak will make the O2 sensor crazy because there is unmetered (by the MAF) coming into the engine. This will drive up your BLM's....as will a bad vacuum leak. Either of these will make it hard for the computer to figure out the mixture. I would look closely for an exhaust leak or vacuum leak. This may be why you failed emissions testing.

Luckily we don't have emissions testing here in Oklahoma....YET.

Good luck, and let us know what you find out.
John