EGR removal

[DzlDk]

1987 D21, Z24.. In the process of removing the head to replace the headgasket, im having trouble removing the the large 1 1/4 nut under the egr valve. 

 

I was thinking that I would just Sawzall the connecting tube and making a plate to cover the opening. Crimp the tube going to the exhaust manifold. Block the manifold off somehow. All of the other emissions parts have been disconnected for years.

 

Any advice TIA

[datzenmike]

Just pull the hose off the EGR to deactivate it and forget it. No work involved and no chance of an exhaust leak or vacuum leak from a home made lock off plate later. If you're expecting more mileage and a power increase you'll be disappointed after all that work. EGR can actually slightly increase mileage and power will be the same as there is no EGR at full throttle.

 

Blown head gasket? You are aware that the timing chain tensioner needs to be blocked from falling out inside the timing cover? Failure to secure it and having it fall out when the cam sprocket is removed adds a few more hours work and some gaskets. Once out, the entire front of the engine has to come off to get to it. Best to avoid this.

 

[ggzilla]

that's what I was thinking, why do all the work to remove the EGR valve

 

On the other, if the tubes are leaking, I've seen where folks crimp the ends. On my Datsun engine swap, I unbolted the tubes and put a nickel over the opening and tightened the nuts back down. It did not leak 

[DzlDk]

3 hours ago, datzenmike said:

Just pull the hose off the EGR to deactivate it and forget it. No work involved and no chance of an exhaust leak or vacuum leak from a home made lock off plate later. If you're expecting more mileage and a power increase you'll be disappointed after all that work. EGR can actually slightly increase mileage and power will be the same as there is no EGR at full throttle.

 

Blown head gasket? You are aware that the timing chain tensioner needs to be blocked from falling out inside the timing cover? Failure to secure it and having it fall out when the cam sprocket is removed adds a few more hours work and some gaskets. Once out, the entire front of the engine has to come off to get to it. Best to avoid this.

 

Yes the timing chain wedge was the first thing that I came across on the site. Thank you for the heads up. Wish I could find the big blue wedge. Gonna grab some 3/4in hose and put a big barb or something on the end so I can hear it clink like someone talked about in another post.

 

The egr tube is metal, it runs from the exhaust manifold around the back of the engine to the egr valve/intake. I will try to put a pipe wrench on it tomorrow. Unless I cab get either fitting loose, idk what other option i have.

[DzlDk]

And just to confirm, TDC, both valves on cylinder 1 are closed, intake came lobe looks to be about 10/11 o'clock, exhaust side 1/2 o'clock and timing mark on balancer lines up with the Zero 0 on the block

 

Eta- i don't see the options to upload pictures.

Edited April 16 by DzlDk

[datzenmike]

Yes.

 

10 hours ago, DzlDk said:

...

 

The egr tube is metal, it runs from the exhaust manifold around the back of the engine to the egr valve/intake. I will try to put a pipe wrench on it tomorrow. Unless I cab get either fitting loose, idk what other option i have.

 

Well as mentioned you could just leave it. This is a lot of work for nothing.

 

Cut the pipe at EGR and manifold and flatten and crimp the ends. If dead set on EGR removal don't bother, just make a block off plate and gasket on that end. If you can get the fitting on the pipe off the exhaust you can put a pipe plug in to seal.

 

 

[NC85ST]

You’re thinking of cutting the egr pipe in order to get the head off, correct? You’re probably too far along to try this, but running the engine in order to heat up the exhaust manifold, will sometimes make it where you can turn that 1 1/4” nut. 

[DzlDk]

26 minutes ago, NC85ST said:

You’re thinking of cutting the egr pipe in order to get the head off, correct? You’re probably too far along to try this, but running the engine in order to heat up the exhaust manifold, will sometimes make it where you can turn that 1 1/4” nut. 

Yea i already have everything stripped. Maybe a map torch or something if the pipe wrench doesn't get it

[DzlDk]

3 hours ago, datzenmike said:

Yes.

 

 

Well as mentioned you could just leave it. This is a lot of work for nothing.

 

Cut the pipe at EGR and manifold and flatten and crimp the ends. If dead set on EGR removal don't bother, just make a block off plate and gasket on that end. If you can get the fitting on the pipe off the exhaust you can put a pipe plug in to seal.

 

 

I know but the other end of the the tube is in the exhaust manifold. I was hoping to lift the intake and head off as one

[datzenmike]

Heat either end with a propane torch. Get the pipe wrench adjusted and ready first. Get it as hot as you can.

 

Or cut it at the EGR leaving several inches of pipe. Get the head off and then crush the pipe with vice grips and curl the end over OR if deleting the EGR go right to making a block off plate and gasket. Do the same with the other end. Probably easier to do it with the head off. May not be enough room to shorten the pipe.

[DzlDk]

3 hours ago, datzenmike said:

Heat either end with a propane torch. Get the pipe wrench adjusted and ready first. Get it as hot as you can.

 

Or cut it at the EGR leaving several inches of pipe. Get the head off and then crush the pipe with vice grips and curl the end over OR if deleting the EGR go right to making a block off plate and gasket. Do the same with the other end. Probably easier to do it with the head off. May not be enough room to shorten the pipe.

That's what I wound up doing. I pulled the head. I see one spot in the back right/drivers side around the fire ring part of the gasket that is split.

 

The forums isn't giving me the option to upload pictures, just the option to link a url

[ggzilla]

The option to upload is "choose files" (desktop) or "add files" (phone), its at the bottom left of the reply box

[DzlDk]

https://imgur.com/a/rGiePRR

 

Testing to see if the hosting works

[DzlDk]

I don't think that is the original gasket, og is metal, right?

[datzenmike]

4 hours ago, DzlDk said:

That's what I wound up doing. I pulled the head. I see one spot in the back right/drivers side around the fire ring part of the gasket that is split.

 

 

 

1 hour ago, DzlDk said:

I don't think that is the original gasket, og is metal, right?

 

It's composite gasket with a metal fire rings around the cylinders. If previously replaced it would be similar.

[ggzilla]

5 hours ago, datzenmike said:

I don't think that is the original gasket, og is metal, right?

Few engines use a metal gasket because they are expensive. MLS (multi-layer-steel) gaskets were patented in early 70s in Japan but I never saw one until the 1990s and it seemed quite exotic at the time

[DzlDk]

Okay so it could be the original. 

 

The head is at the machine shop getting resurfaced.

 

I bought new head bolts, the fel pro, do I need to oil the threads or anything?

 

Torque to 40ftlbs then 60ftlbs

Thanks!

[ggzilla]

For correct torque, bolts and threads must be clean and dry. I oil the threads, then wipe off all the oil but don't rinse the thin oil film off

However, if you bought ARP head bolts, they sell a special lubricant and advise on torque readings

 

clean out the boltholes as they easily fill up with crap and the bolt bottoms out giving a false torque measurement. You can rinse the bolt holes with ether, then blow the ether out with a piece of tubing. Get the head, block surface bolts and boltholes clean (no grease, no tiny remnants of the old gasket). Use a scraper and maybe a little ether spray to chase it off. Make sure nothing gets in the cylinders or oil passages, and clean out the boltholes when done. Oil or water in the boltholes will prevent proper torqueing. In the worst case, oil in the bolt holes can cause hydro locking. You can use a straw to blow out the boltholes

 

I use an old head bolt, with a slot filed along one side, as a poor-mans "tap" to clean out the bolts holes. You can also use a can of compressed air.

 

If the head has been machined, ensure the bolts screw if far enough before putting the head back on

[DzlDk]

Awesome, thank you!

[DzlDk]

Finally going to try to get her back together, we have had a few guys out at work and OT has been brutal.

[ggzilla]

wish I could get more OT. The cost of the new 296 GTS has just gone up 10%

[DzlDk]

We have been covering for guys since August '24... union shop, they can't hire unless certain criteria is met etc etc 

 

I got her back together and she runs/idles great but as she warms up and I drive her down the road she gets a real bad misfire with black smoke, stalls out.

 

I dont see how blocking the egr valve off could have caused that, I labeled all of my plug wires, so the only thing I can think of is that there was some slack in my timing chain and somehow it skipped a tooth on the lower sprocket. I marked my upper sprocket and chain in several places- all aligned up and went together fine. The cams look like they are in the same position at TDC currently and when I put everything back together. I should have turned wrenched the motor over a few times to make sure my marks still ligned up before I put everything back together.

 

I really wont know for sure if the timing is off until I put a timing light to it. But that is my #1 suspicion as of now.

 

Tldr- Idles great, starts to miss and exhaust black smoke when warm, seemed kinda low on power.

 

If it did skip a tooth, I suppose the only way to correct it is to pull the water pump, timing cover etc to get full access to the chain and lower sprocket, get them aligned with the distributor and put everything back together.

 

[ggzilla]

Nah, slipped timing chain would not 

1 hour ago, DzlDk said:

runs/idles great but as she warms up

 

[DzlDk]

48 minutes ago, ggzilla said:

Nah, slipped timing chain would not 

 

So i should look elsewhere. The only time I think it could have slipped is when I reinstalled the cam sprocket is pushed the hose further down to try to push the tensioner in for more slack in the chain. But otherwise my marks lined right up and installing was a breeze.

 

New plugs, wires and a fuel filter wouldn't hurt. I did them last in 2017, just put a new distributor cap and rotor on her. She ran great before, aside from the blown HG. Idk how wires or plugs could have gone bad from being removed unless a wire or connector in the boot broke

[ggzilla]

New plugs, wires and a fuel filter wont hurt, but won't fix "runs/idles great" until she warms up

 

The black smoke is an unusual symptom. It points to the choke not opening as she warms up

3 hours ago, DzlDk said:

runs/idles great but as she warms up and I drive her down the road she gets a real bad misfire with black smoke, stalls out

To test this, let the truck idle, then when the gauge read fully warm, pop the air clear lid off and look. The choke should be 100% open, not just partly open