EGR removal?

[kentw]

     In an effort to simplify and improve my 84 executive I am replacing the exhaust manifolds with headers, removing the air pump system along with all the rotten vacuum hoses, replacing the carb with an edelbrock 1411, and switching to an open style air filter.   
     Has any one had problems after removing the EGR valve and blocking it off?  I do not have any emissions testing to comply with so that is not an issue.
     If I understand how it works, it only opens during part throttle/low load situations and actually lowers the exhaust temps.  It seems to me that part throttle situations are pretty rare in this heavy beast.

[MotorPro]

No problem with removing egr. Lots of problems with open air cleaner. The air in the dog house is very hot. You need a system (stock or aftermarket ) that pulls cool air from the front of the motorhome.

[Rickf1985]

Removing the EGR will cause you to have issues with pre-ignition, or pinging. The removal of the exhaust gas in the intake charge allows much higher combustion temperatures so you will have to back up the timing a couple degrees, or run mid-grade gas. Try it first, when it will ping is at cruise speed and light throttle. That is when you have the most advance in the distributor, full mechanical and full vacuum. Mine will start pinging at around 55 and light throttle. I am going to start backing up the timing 2 degrees at a time. Eventually I will be ordering a DUI distributor from Performance Distributors (http://performancedistributors.com/). They will set one up for the best timing curve to eliminate any pinging but still give the best performance without all of the constrictions that were built into it with the emissions controls.
And as Motorpro said, too hot for open element. The stock air cleaner moves more than enough air and is actually quite well designed. Just make sure you have a good hose on it to clean air which it actually did have stock. You can eliminate the heat riser and block off the tube for that BUT, if you run in cool damp weather you WILL have problems with carburetor icing.

[kentw]

Thanks for the replies.  My plan was to build a cold air intake later on so maybe I will add that to my current list.  We don't use the rig in the winter so icing shouldn't be a problem.  I think I will leave the egr conected for now so I can run cheap gas.  Dui distributors looks ike a good solution but i want to replace the timing gears first and degree the cam.  My engine only has 30k miles on it but as I remember the mid 80's chevys had plastic coated timing gears that were problematic and should be changed.
       Here's an idea-remove the egr and connect the distributor to manifold vacuum instead of ported.  At light throttle the engine should have less advance and reduce pinging.  Manifold vacuum should drop when the throttle is even slightly open and the distrubutor should have 10 to 15 degrees less advance.  Any thoughts?  I may be over thinking this!

[Rickf1985]

Your distributor should be hooked to manifold vacuum now and yes vacuum drops at throttle opening but advance does not move right away, you need a certain amount of drop before advance starts moving. You can get adjustable advance units, that is what is used on the DUI units. Mine will ping until I am in the throttle about a quarter throttle. The entire advance curve was set up for the emissions system so you are not really going to be able to make that distributor work without changing the mechanical weights and putting a adjustable vacuum advance unit on it. Then you will need to take it somewhere and have it recurved. This is all done on the Performance distributors distributor before you buy it. You tell them what it is going into and they set it up for you. When you say you are going to degree the cam what are you planning to do? If you change the cam timing that will change the everything all the way down the line.

[cncsparky]

If you get some time, read through my P30 project thread.  I've done several of these things you are talking about. 

http://www.classicwinnebagos.com/forum/index.php/topic,9139.0.html

[kentw]

Rick-It sounds like the DUI distributor will be the way to go after I finish my modifications.  Around here somewhere I have some books that mention the mid 80s 454 engines having 5 or so degrees of retard built into the cam.  I wont be messing around with that for a year or more so I am going to use the stock distributor until then.  Do you know if the 454 had the nylon coated timing gears like the small blocks had?  If the gears are steel I will probably never dive in that far.  Thanks for your help

cncsparkey-thanks, I will read your thread tonite.

[Rickf1985]

Yes on the nylon gears. Unless you are pushing 100,000 you generally don't have to worry about them. If you are worried just have someone move the engine back and forth with a breaker bar on the balancer a tiny bit and see how much play there is in the chain in each direction before the distributor starts to turn. (how far the pulley turns before the distributor turns) It will not be instant but there should not be much play there at all.

And by the way, retarded cam timing moves the power band up so you would have a better top end power. If there was any retard built in it would have been in the grind of the cam not in the timing of the cam. The 454 with a few obvious exceptions, has always been a bottom end grunt motor for trucks that need torque for pulling. There were the exceptions that were made for high performance but they are the ones that got the special cams, not the RV and truck and emissions motors.

[cncsparky]

I'm with Rick, mine had around 65K and the timing gears weren't that bad.  There was a little play but not much.  Unless you are going through everything on the front of the engine like i did, probably not worth the work.  And it is a lot of work!

Also heard that there is 3-5 deg retard ground into stock cams.  I would be more tempted to get an aftermarket hydraulic roller before worrying about modifying the stock cam timing.  Do you know how to degree in a cam?

[kentw]

Yes, I know how to degree a cam.  I have only done it on new builds though and after thinking it through I can imagine it would be difficult if not impossible in the chassis.  Trying to find the lift specs and open and close degrees on this old engine would be challenging too.   Once again I have attempted to over think the situation.  The gain, if any would not be worth the pain.  I will stick with removing the air system and the egr-if it pings I will back the timing off a couple of degrees.  Thanks or all the helpful info!

[Rickf1985]

Since I am running short on time before my trip I am just going to plug the EGR back in for now. I saw no gain in power nor gain in mileage. The biggest problem with later emissions motors is that the entire motor is part of the emissions system. The compression, cam grind and all of the external emissions crap are all designed to work together. When you remove one part of the puzzle the rest do not always fit well. You can gain power and mileage on these motors but it is going to cost money, a substantial amount of money so you have to decide whether it is really worth it. When I first joined this forum I posted a lengthy article on how to build a 454 for mileage and pulling power and subsequently got in trouble due to all of the people arguing with me and telling me it "Can't be done" and "it is impossible to get good mileage from a 454". I was told that I would be allowed to post that kind of info if I could substantiate my claims. I cannot do that since those motors were built years ago and the dyno sheets are long gone. I will say it can be done, I have built quite a few of them. They are not cheap. I am NOT going to get into the details of how it is done on here and risk getting in trouble again. I would not build one for myself for a 26 year old motorhome that I paid 4,000 dollars for since the motor is going to cost almost double that, is that coach really worth 12 grand? You will never get that back in gas savings unless you drive 50,000 miles a year for many years.

[kentw]

I agree Rick-the cost would not be worth the gain.  Diesel pushers are getting cheaper all the time! Back to the egr,  I will leave mine in place but bypassed for a short trip next month and see how it goes-I can always hook it back up.

[tmsnyder]

I'm in the middle of similar cleanup on mine.  The twin AIR pumps are gone, and the manifold ports are plugged.


Did look at the EGR valve and it allows exhaust gas into the intake flow by pulling the valve open with a vacuum signal.  Removing the EGR and blocking the top opening off with a plate would seem to me to actually not stop the EGR, but instead would allow unrestricted re circulation of the exhaust gas into the intake.  So I just left it in place but not connected, for now.  I may actually hook it back up later on if pinging is noticeable (thanks for the post above citing this as a reason to keep EGR).    It actually doesn't seem that bad to keep this working.


Along the line of "maybe these things aren't so terrible", I've already hooked the PCV valve back up, b/c right after disconnecting it the rear main seal started to drip a little.   Restoring PCV stopped the drip right away.  Just in case you were thinking about changing PCV.

     In an effort to simplify and improve my 84 executive I am replacing the exhaust manifolds with headers, removing the air pump system along with all the rotten vacuum hoses, replacing the carb with an edelbrock 1411, and switching to an open style air filter.   
     Has any one had problems after removing the EGR valve and blocking it off?  I do not have any emissions testing to comply with so that is not an issue.
     If I understand how it works, it only opens during part throttle/low load situations and actually lowers the exhaust temps.  It seems to me that part throttle situations are pretty rare in this heavy beast.

[Rickf1985]

You NEVER want to disconnect the PCV valve! You are lucky all it did was a little drip.

[EldoradoBill]

The 454 was designed around EGR. These engines run beautifully when everything is operating as intended. If you enjoy burnt valves and holes melted in the tops of pistons remove the EGR valve without modding the rest of the engine. Efforts would be better served by fixing whats wrong rather than randomly stripping the engine of components one does not fully understand the function of. 1973 has come and gone...


Bill

[circleD]

Putting the Edelbrock 1411 on mine and giving it a small adjustment was the best thing I did. It eliminated the vacuum hose mess. I also got rid of the EGR and that made more room to work on things and less possible failure points. Check out CNC Sparkys post for sure for great detail. It helped me out big time. And for the air intake Clydesdale Kevin and others have great info on those.

[tmsnyder]

The OP wrote: I am replacing the exhaust manifolds with headers, removing the air pump system along with all the rotten vacuum hoses

The PCV runs on a big vacuum line, so it is possible that the OP would end up without PCV if he strips it all away with reckless abandon   That's one of the things the 454 actually needs is good PCV.

I'd hook the EGR back up as well, it's literally one vacuum tube to the valve on the thermostat housing and a tube to the EGR.

But my point was you can't just REMOVE the EGR valve and put a plate over the opening;  that would allow unrestricted EGR  ie a major leak of exhaust gases into the intake gases.  That's what it sounded like the OP was considering. 

You NEVER want to disconnect the PCV valve! You are lucky all it did was a little drip.

[Rickf1985]

Actually you can put a plate over the manifold in place of the valve. Once the valve is removed the exhaust passage and the intake passage are both flush with the manifold surface and a gasket seals both.

[tmsnyder]

When  you say 'got rid of the EGR', can you explain how you did that?

Putting the Edelbrock 1411 on mine and giving it a small adjustment was the best thing I did. It eliminated the vacuum hose mess. I also got rid of the EGR and that made more room to work on things and less possible failure points. Check out CNC Sparkys post for sure for great detail. It helped me out big time. And for the air intake Clydesdale Kevin and others have great info on those.

[tmsnyder]

Wow the feds sure did wreck this engine!

1970 454 : 390HP and 500 ft-lb

then came smog motors
1972 454 : 270HP and 268 ft-lb

then came EFI

Here's to 'progress'!

The 454 was designed around EGR. These engines run beautifully when everything is operating as intended. If you enjoy burnt valves and holes melted in the tops of pistons remove the EGR valve without modding the rest of the engine. Efforts would be better served by fixing whats wrong rather than randomly stripping the engine of components one does not fully understand the function of. 1973 has come and gone...


Bill

[circleD]

I meant the A.I.R. pump on the PS bottom.    I've been working on my diesels EGR.

[tmsnyder]

Ahh that makes sense.

Actually you can put a plate over the manifold in place of the valve. Once the valve is removed the exhaust passage and the intake passage are both flush with the manifold surface and a gasket seals both.

[Rickf1985]

You have to remember that they went from brake horsepower ratings to net ratings between those early years so that cut the power rating down substantially. It also brought them inline with real world at the rear wheels horsepower. Also around that time compression ratios were cut substantially due to emissions regs.

[EldoradoBill]

It's that 385 lb/ft of torque that keeps our rigs moving on those 6% grades, not the 270 hp...


Bill

[tmsnyder]

Torque makes it go up the 6% grade,  how fast it happens is a function of horsepower.

It's that 385 lb/ft of torque that keeps our rigs moving on those 6% grades, not the 270 hp...


Bill