replacing exhaust manifold - request for input

My front exhaust manifold cracked (after 36x,xxx miles) and I'm replacing it.  I pulled a used manifold (did not think Dave's was still for sale), got OEM (Felpro) metal sandwich gaskets from RockAuto and have replacement bolts on the way from ZZP (they are not here yet).

Got the junkyard manifold because I'd read that the 'new' replacements were not so good.

I'd like to know what you suggest I must do / should do to the replacement,  before R&R the manifold.   No comment too small or unwelcome - apart from pulling the old one without destroying it, I pretty much need to be told what I must do/should do from here forward.

I was thinking to clean it, myself, or take to a machine shop as well as have the shop check for flatness to .020" or so and plane it if needed.

I also was thinking I might:

- paint it (black or silver)
- port it (although I do not plan to port the block)

Constraints - I should to do stuff to it this week, and R&R it this coming Saturday morning.

Comments?  Thanks in advance.

Albertj

Albert, if that happened to me, I'd replace it with this,

https://zzperformance.com/products/stainless-power-log

That front exhaust manifold is the most restrictive part of the Riv exhaust.

Not much you really can do to it prep-wise unless you let it sit. I'd spray the crossover studs with penetrating spray and let them soak for a couple days. The manifold job itself is easy. I think by sending it to a machine shop, you may be going a little overboard. Unless that junkyard manifold was sitting on something funny for years, it should be straight....especially if it was bolted to an engine. Even then, that's what the gaskets are for. If it were meant to be a perfect, machined surface there would be no gasket.

I like Larrys idea about the P-log....

Looks like that P-Log is currently unavailable. My friend Steve (71stagegs) just installed one. Maybe he will comment.

LARRY70GS wrote:

Looks like that P-Log is currently unavailable.  My friend Steve (71stagegs) just installed one.  Maybe he will comment.

I emailed ZZP about availability of new or used P-log. We'll see. Would be good to have comment from Steve.

Albertj

albertj wrote:

LARRY70GS wrote:

Looks like that P-Log is currently unavailable.  My friend Steve (71stagegs) just installed one.  Maybe he will comment.

I emailed ZZP about availability of new or used P-log.  We'll see.  Would be good to have comment from Steve.  

Albertj

I just talked to Steve, he said he will be on later to comment.

Abaddon wrote:

Not much you really can do to it prep-wise unless you let it sit. I'd spray the crossover studs with penetrating spray and let them soak for a couple days. The manifold job itself is easy. I think by sending it to a machine shop, you may be going a little overboard. Unless that junkyard manifold was sitting on something funny for years, it should be straight....especially if it was bolted to an engine. Even then, that's what the gaskets are for. If it were meant to be a perfect, machined surface there would be no gasket.  

I like Larrys idea about the P-log....

I removed the replacement manifold from the NA 3800 Series II engine on an '01 Park Ave (not ultra) at the nearby pick-n-pull. I could not decipher the windshield scrawl (usually they mark if the engine/transmission/what not are good/bad and the mileage overall) on the car. Engine still had the *original* numbered wires but they were so welded to the plugs, I broke a couple plugs trying to get the wires off. And you could read the cyl numbers printed on the coils. Dipstick oil looked good, though.

I sprayed Deep Creep on the crossover and manifold bolts and had *no* trouble getting them loose on the donor car. I mean, *zero* issues. Gasket was the GM OE metal sandwich.

I had trouble getting the bolts away from #2 port because I didn't know where the heatshield bolts were (have to loosen heatshield by the ig module first) and I had a little difficulty getting the ig module off (ground plate corrosion - need to move it, the cable blocks the wrench somewhat). The dipstick was a pain too, I think my problem there was it was cold and I was stiffening. It would have been easier to pull off the manifold from the Series III SC grand prix, in hindsight. There is a heat shield on it but nothing of consequence in the way except those dogbones on the radiator support.

I told my dad about the manifold pull and he talked about getting a new one, "they crumble when they come off" I told him yeah maybe if you're ham handed doing the pull. They do a pretty good job casting them in Warren and all you have to do is back the bolts out in about the reverse order you would torque them down, the manifold is not on that tight to begin with, so after 3-4 rounds of a 1/4 turn backing off each one in a spiral from outer to inner, you're home free. As for my manifold cracking - they eventually all do I am told, if you run them long enough. Mine accumulated 20 years of use (363000 miles give or take) before developing a crack.

I won't send the manifold to a machine shop for flatness but will check it with a straightedge (don't have a gauge). I am not sure porting this manifold will buy me much, except that I can say I did it. I *just might* take it to a machine shop for cleaning however it seems to me that a can of brake or carb cleaner and an alumium roasting pan ought to do the job.

Fun & games. 4 days to go. Saturday's supposed to be OK (above 40F).

...thank you Larry & Scott for your input so far!

Albertj

Hey Albertj If that manifold doesn't work out u can have my old manifold Ill put it in the mail.I put the ZZP Plog on and could hear and feel the difference.That said a week before I put 3"DP and hi flow cat on so maybe they work together. When u took off the manifold were u shocked at the bad design a 1/3 of the port is not fully open then 3 cylinders exit through that small tube must have been the same guy that designed the steering column.Im sure u know already I used 6 point socket on all bolts and put some heat on the crossover pipe bolts good luck.Dipstick is a PITA . Steve

71stagegs wrote:

Hey Albertj   If that manifold doesn't work out u can have my old manifold Ill put it in the mail.I put the ZZP Plog on and could hear and feel the difference.That said a week before I put 3"DP and hi flow cat on so maybe they work together. When u took off the manifold were u shocked at the bad design a 1/3 of the port is not fully open then 3 cylinders exit through that small tube must have been the same guy that designed the steering column.Im sure u know already  I used 6 point socket on all bolts and put some heat on the crossover pipe bolts good luck.Dipstick is a PITA . Steve

Thanks!  From an earlier adventure I already have a larger downpipe.  Still have the Factory crossover.  And yes the front exhaust Manifold is a study in backpressure, not sure why they did that.   Maybe noise?

I have the crossover bolts complete, did not buy replacements from ZZP.  I have the manifold bolts new from ZZP.   I am not expecting trouble getting the old one off.  When I pulled the JY manifold I used 6 point sockets and 'Deep creep,' worked great.

ZZP E-sales has P-logs, ha ha: https://www.ebay.com/itm/ZZPerformance-1997-08-Front-Powerlog-Stainless-Exhaust-Manifold-Header-3-8L-3800/173782973285?hash=item287645bb65:g:ligAAOSwKrhVZJP-

Ryan  got back to me from ZZP saying they will have more P-logs soon...

Again, thanks for your offer and comments. I will give the dust a few hours to settle.

One last thing - is the P-Log drone-y or noisy when cruising on highway?  That's  a problem foe me if so.

Albertj

Hey Albertj I didn't notice anything change in motor noise. its a good up grade good luck.Did you ever put the rear sway bar on that's another good up grade.

albertj wrote:

ZZP E-sales has P-logs, ha ha: https://www.ebay.com/itm/ZZPerformance-1997-08-Front-Powerlog-Stainless-Exhaust-Manifold-Header-3-8L-3800/173782973285?hash=item287645bb65:g:ligAAOSwKrhVZJP-

Ryan  got back to me from ZZP saying they will have more P-logs soon...


Albertj

That's about a thousand dollars more than they sell them for Is anybody that desperate or stupid?

LARRY70GS wrote:

albertj wrote:

ZZP E-sales has P-logs, ha ha: https://www.ebay.com/itm/ZZPerformance-1997-08-Front-Powerlog-Stainless-Exhaust-Manifold-Header-3-8L-3800/173782973285?hash=item287645bb65:g:ligAAOSwKrhVZJP-

Ryan  got back to me from ZZP saying they will have more P-logs soon...


Albertj

That's about a thousand dollars more than they sell them for   Is anybody that desperate or stupid?

I don't know how ZZP's eBay sales re managed. Ryan's talking 3 weeks from now, until they receive more P-logs. One would think the eBay ask would be $116.99 or so.

What I'll do:

- clean the manifold I got off that Park Ave at the JY;
- maybe port it (a nearly pointless exercise, operative word however is "nearly");
- maybe paint it if it got clean enough;
- try not to break it on the install (if so I will accept 71stagegs' generous offer - I appreciate it)
- R&R a P-log later - as many as ZZP have sold, a used one may appear...

I think I should get the cleanup done tonight.

Finally -- I **REALLY** appreciate the input. I want the Powerlog but I'm not apparently going to obtain one at fair price in time for this repair, and that's OK.

albertj forgot to tell u if you have any body and paint supply stores near u pick up some 80 green long board sand paper put it on a long board make a few passes that will clean up the surface well for the new gasket.

71stagegs wrote:

albertj    forgot to tell u if you have any body and paint supply stores near u pick up some 80 green long board sand paper put it on a long board make a few passes that will clean up the surface well for the new gasket.

Thank you I will do that.

Was just going to use 3M Utility Cloth I think I have sitting around, I think it's 100 or 120. Did not know I could use 80, it'll save me some time.

Albertj

I ported the JY manifold today.  Used a Dremel with a carbide bit to do the rough cut then a drill with fairly large bullet-tip stone to finish.   It was interesting how quickly the Dremel cut.

One thing was a little weird.  On the ZZP site I think part of the reason for buying a P-log is the ID of the manifold is too small at the crossover.  I did not see that on the JY manifold.  And porting it was not difficult -- basically at the inlets there is flash more or less on the inside of the ports to remove.  I mean, you could call it flash, but it is material that makes the mounting surface a uniform width.  It is not difficult to bevel it so that the openings are the same as at the gasket, and not that much material has to be removed.  

I then sanded the mounting flange flat using a piece of 3M sandpaper taped to a short (16") length of 2x4. Did not have 80 around, so I used 100.

Now I have a stupid issue... need to get an in-lb torque stick, mine is ft-lbs and won't read at the light torque for the manifold... figures...

Ever onward.   Thanks again everyone for your help!

Albertj

The (ported) manifold is on. No issues. Less than 2 hours effort.

So much for this adventure.

Thanks again everyone.

Albertj

albertj wrote:

So much for this adventure.

Easy-peasy

Epilogue: My 'butt dyno' says the porting effect is that the engine seems to wind out (accelerates) more rapidly. Truth -- knowing that leak is fixed would be enough to make my 'butt dyno' happy... I'll know this weekend if there might be a gas mileage effect in highway cruising. I seriously doubt it, though, but I am not sure how long the old EM had been leaking and I did not log a scan so I don't know if or how far it threw the O2 sensor off and maybe made the engine computer maladapt.

Update: I don't understand this. measured gas mileage using Torque on my smartphone. I'm now getting 34 MPG on the highway (through the Pennsylvania mountains?!?!).

Really? ...whathappened?

How does torque work?Albertj

71stagegs wrote:

How does torque work?Albertj

Torque is an app for Android.  Load it on smartphone then connect a wifi or bluetooth compatible OBD II dongle to the OBD II port.  Once connected, Torque will read and clear codes as well as take logs. So in this case it works by factoring fuel consumption against miles traveled as logged at the ECU.

My thinking is the 34 MPG is bullcrap. My surmise is the calculation represent a possible minor miscalibration of the ECU (how many tire revs in a mile?!?)  

However -- it takes not quite 3/4 tank (indicated) for my drive from Corning NY to Pittsburgh PA to see my dad.  More like about 5/8 or so.   280 miles on the nose end to end, mostly limited access highway except the first 3 miles and last 50 or so miles - and even that last 50 is mostly state highway posted at 45-55 MPH.  I do this drive every other week.  Results seem consistent past couple drives.  

I am not setting land speed records but I am keeping with the flow of traffic -- and when not on a holiday weekend, traffic moves with, well, a sense of purpose.  Definitely not a Mobil Economy Run.    If I gas up and eat before I start and then just take a 20 minute or so stretch break in the middle I can make it in around 4 h 45m - 5h. Probably in part because Pennsylvania has raised the speed limit on much of the route (very rural) to 70 MpH.

Using the Torque app I can see if I am in boost or not, if the shift points are hitting right (lock up or not dep. on calculated load), etc. The car is running very well.  I am actually a little concerned about my planned summer maintenance for concern that I will screw something up. I need to get over that...

I am kinda thinking the new manifold did not *hurt* anything but what I'm really seeing is measurement/calculation  error at the ECU. ext couple runs I think I will spot check by estimating gallons burned from fuel stop to fuel stop.

Albertj

My all time best was 32 MPG on a 400 mile trip.

LARRY70GS wrote:

My all time best was 32 MPG on a 400 mile trip.

Again, my thinking is the 34 MPG is bullcrap. I mean it *could* be about right but the GPS (on my tomtom navigator) reads less speed at highway speeds than the spedo. The weird thing is the speed delta is not consistent, which I think is in part due to the no mans lands I drive thru and in part due to standard GPS error.  My surmise is the Torque calculation represents a possible minor miscalibration of the ECU (how many tire revs in a mile, ?!?)  and if I can find out what that error is, I can back it out (because its from the sensors, which even if biased will be consistent).  

Granted, I use synthetic oil .  Usual fill is Mobil 1 *or* Mobil 1 4  qts with 1/2 qt and top-offs either Chevron Delo synth or Shell Rotella synth -- those oils are so slippery that if you dip a big screwdriver in them and grab the blade end you will likely drop the driver.  Other than Motorkote (which I have used from time to time), the diesel synths are mad slick. Only problem with Delo is (according to a trade rep who reps Chevron in this area ha ha) if you start using it you oughta/gotta keep using it because of how the additive package works.  Which he then explained -- explanation made sense in that all oils no matter what work themselves into the working layer of metal parts over time. Delo is cheap (cheaper than Motorkote) so...

Albertj

Albertj where did u get OBD 2 dongle thx