Rebuild questions

[Lynn5907]

When should I replace engine bearings, rings and head gasket in the 2.4l twin cam ? Everything seems fine starts right up every time ( 1 or 2 revs ) no smoke, no extreme crank case pressure, no blow by or very little, burns a quart of oil every 1500 to 2500 miles 

[TWO LANE BLACK TOP]

There is no set time or mileage for rebuilding...

Realistically as long as it is running OK....With good oil pressure and no overheating issues you are probably better off to just leave it alone...For example they use torque to yield bolts..95% of the time they cannot be reused...New bolts for it can be a bit pricey..Chances are that during the disassembly the threads in the block will come out with the bolts and will require most if not all the bolt holes to be helicoiled which in turn causes other problems with the thin castings which are very prone to cracking anyway...If you do get lucky and the threads stay in the block if you try to Chase the threads with a tap to attempt to clean them up... it will loosen them to the point that they won't tighten up or will strip out

The cylinder head is very prone to cracking in the combustion chamber's between the valves they also have weak valve guides that is one of the main reasons they tend to burn alot of oil....The head castings are so thin that even cutting it just enough to get a flat surface for the head gasket to seal can render it useless...GM has three or four different head bolt tightening sequences depending on the year and casting numbers if it is not followed exactly the head gasket is almost guaranteed to fail in a fairly short order...

There are too many idiosyncrasies with rebuilding the Quad four engine to even try to list them all...That is why I have only mentioned some of the most obvious ones.....Again I am not trying to be negative just realistic...

Also noticed that you are in Greensboro... I'm in Winston-Salem

Edited September 29, 2018 by TWO LANE BLACK TOP

[BearGFR]

+1 - There's no need to open it up unless you've got good reason to suspect a problem.

[Lynn5907]

Thank you both. The whole if its not broke don't fix it thing. I just worry about motors when they get 230k on the clock. Cuz the just driven miles noway to tell how long it been idleing or started you know. Thanks two lane black top for that. Had no idea how weak the block is. That is just craziness

[TWO LANE BLACK TOP]

15 hours ago, Lynn5907 said:

Thank you both. The whole if its not broke don't fix it thing. I just worry about motors when they get 230k on the clock. Cuz the just driven miles noway to tell how long it been idleing or started you know. Thanks two lane black top for that. Had no idea how weak the block is. That is just craziness

The quad four engine is pretty much a throw away engine..... NOT designed to be rebuilt...GM 3.4 V6 engines and V8 Northstar Cadillac engines among others are the same way....Although they can be rebuilt and make good power if they are done correctly...The cost and man hours...Aggravation.... Associated  with doing so...Not mention finding a competent machine shop....Makes them completely emotionally and economically unviable  for the average person to do so.......

Edited October 14, 2018 by TWO LANE BLACK TOP

[Lynn5907]

The machine shop is always my worry. My pops has a three bay shop with all the necessary tools so I'm lucky there. Not trying to make a super car or anything. Like you said if it is running that good just leave it alone.

[Lynn5907]

Let's just imagine here for a minute two lane.. say I got the supercharger kit and changed pull sizes to squeeze just a few more psi. Can the regular internals handle the pressure? I'd like to say the the engine (ld9) has 230,214 miles. I've run the car for about 6000 miles on the current oil and it has only burnt 2/3rds a quart also still has color. Normally I change the oil every 3 to 4k always just checking the health so to speak

[Lynn5907]

18 hours ago, Lynn5907 said:

Let's just imagine here for a minute two lane.. say I got the supercharger kit and changed pull sizes to squeeze just a few more psi. Can the regular internals handle the pressure? I'd like to say the the engine (ld9) has 230,214 miles. I've run the car for about 6000 miles on the current oil and it has only burnt 2/3rds a quart also still has color. Normally I change the oil every 3 to 4k always just checking the health so to speak

Just noticed you said Winston Salem cool beans man

[Frosty]

On 10/14/2018 at 8:44 PM, Lynn5907 said:

Let's just imagine here for a minute two lane.. say I got the supercharger kit and changed pull sizes to squeeze just a few more psi. Can the regular internals handle the pressure? I'd like to say the the engine (ld9) has 230,214 miles. I've run the car for about 6000 miles on the current oil and it has only burnt 2/3rds a quart also still has color. Normally I change the oil every 3 to 4k always just checking the health so to speak

I think you can run the supercharger kit with no problem. I wouldn't go crazy with pulley sizes to try to add too much boast since GM didn't do that - probably for a reason. My guess is they didn't strengthen the bottom end to handle the additional horsepower. So without rebuilding the whole motor (which is what we recommended above), you could run the supercharger, but don't stress the engine out much more with additional boast. I think that would lead to its demise. 

[Lynn5907]

Now you guys know I'm not serious about supercharging this car it's to old and risky for it. However at some point I might replace crank bearings and stuff as well as timing chain guides + water pump. That seems possible without changing head gasket so I can leave head bolts alone

[TWO LANE BLACK TOP]

Personally I would be extremely weary about putting a supercharger kit on any engine with 200,000 plus miles on it.....

 That being said...If you do supercharge it....Like Frosty said don't go crazy with the boost...Even then at the very least you will probably blow out the front and rear oil seals...Most blown engines have forged connecting rods and crankshafts...forged pistons with wider ring landings and beefier rings to help control the blowby better with the added cylinder pressure...On a high mileage engine chances are the added boost is going to cause exsessive blow by past the oil and compression rings into the crankcase and as a result the front and rear oil seals will wind up paying the price....Also any slack in the bottom end will for sure show up in a fairly short order..(Rod and Main bearings...Wrist pins..ETC...) 

One way you can get an idea if there is any slack at all in the bottom end...Is to get someone to hold the brakes with the car in gear..by hand under the hood Open the throttle up just enough to load everything up real good...But don't get the wheels spinning....Then let off the throttle real quick (You will have to listen real carefully)..If You here the slightest clatter at all when you let off the throttle that means the rod bearings are getting loose....

 

[TWO LANE BLACK TOP]

12 minutes ago, Lynn5907 said:

Now you guys know I'm not serious about supercharging this car it's to old and risky for it. However at some point I might replace crank bearings and stuff as well as timing chain guides + water pump. That seems possible without changing head gasket so I can leave head bolts alone

As I mentioned with the throttle and brake thing it is an exellent way to help gauge engine health anyway.....

Is it ever going to turn winter or fall even...here in NC...??

Edited October 17, 2018 by TWO LANE BLACK TOP

[Lynn5907]

Thanks man I didn't know that trick with bearings. This is the second grand am the first was a 95 quad 4 that was a bad motor had pistion slap or bad bearings not sure but it died anyways. Put it to 105 mph and heard a loud clank. Bad think I was 80 miles from home it made it all but 2 miles and froze up. I'm impressed it made it that far. I meant I babyed the hell out of it to get home knowing it was gonna die at some point. I will say this 2000 GA is way better all around car. 

I don't think so. Just gonna get rain, rain, rain. If you ever cut down a tree it just how it works with seasons. Some year we might get a white chrismas

[Lynn5907]

So yeah I did that. When I let go of gas I heard what sounded like valve rattle. It was a really quick tap tap and then normal. Is that what you where talking about?

[TWO LANE BLACK TOP]

14 minutes ago, Lynn5907 said:

So yeah I did that. When I let go of gas I heard what sounded like valve rattle. It was a really quick tap tap and then normal. Is that what you where talking about?

Yes.. but give it a few seconds to be sure everything is loaded up good before letting off the throttle....

Can run good for a really long time like that... it's almost  normal for high mileage engine to do that. Just don't jerk it around...you will be OK for awhile as long as it has good oil pressure and don't run it hot...

Edited October 17, 2018 by TWO LANE BLACK TOP

[Lynn5907]

Cool man thanks again. It wasn't massive noise more like three quick taps deep down sound. I did load it up and checked a few times. Loaded untill front of car lifted up a bit. For now it does not have a working thermostat ( stuck open ). 

[Frosty]

I am glad you are not serious about adding a supercharger with the engine in its current condition. I share all of Two Lane's concerns - especially when I wrote my response. However, I was answering the question. It's like that line in the "Hunt for Red October" - 110% is available on the reactor but its not recommended. As you know the engine would benefit from a complete rebuild, replacing all the torque-to-yield bolts with ARP bolts or studs, new bearings, water pump, etc, etc before attempting to add a supercharger. 

One thing I can't stress enough is the choice and quality of gaskets for a supercharged application. Talk to a reputable engine builder and see what they recommend. I worked at GM - both at the V6 engineering center along with the 3800 assembly plant. The naturally aspirated 3800 and the SC 3800 had different gaskets. The SC 3800 gaskets were designed to handle the added boost pressure the motor would experience. So high quality gaskets are a must in a boosted application.

[Lynn5907]

Yeah it was more of online shopping and I was like what supercharger haha naaaaa ..... Then like I need to know more. So thanks! Didn't know about gaskets eathier good info.  That junk about the hunt for the red October noooo I was like 8 when that came out. Omg my dad must have watched it like 25x lol.

Edited October 17, 2018 by Lynn5907

[Lynn5907]

Ok so the debate of the ages. Assuming I do a cai the right way and it gets cooler air will it add any power even tho the exhaust would remain the same? I don't think there would be any low end difference? Or would the power band change a little? I would imagine better MPG! No? 

[Frosty]

19 hours ago, Lynn5907 said:

Yeah it was more of online shopping and I was like what supercharger haha naaaaa ..... Then like I need to know more. So thanks! Didn't know about gaskets eathier good info.  That junk about the hunt for the red October noooo I was like 8 when that came out. Omg my dad must have watched it like 25x lol.

Thanks - now I feel even older since I read the book long before the movie came out. I have the movie on DVD too. It's one of my favorites.

15 hours ago, Lynn5907 said:

Ok so the debate of the ages. Assuming I do a cai the right way and it gets cooler air will it add any power even tho the exhaust would remain the same? I don't think there would be any low end difference? Or would the power band change a little? I would imagine better MPG! No? 

Yes, most cold air intake kits will generally add 5-15 HP without any changes to the exhaust. MPG still depends more on how big your lead foot is. 

[TWO LANE BLACK TOP]

  The actual pwerband of the engine itself will stay in the same RPM range....Might feel a tad stronger on the upper end of the RPM range (possibly psychological)....Pretty much takes about 12 to15 horsepower to actually be able to tell a difference from the drivers seat....Torque (Rotational Force) Is the key ...It's what gets you moving....That is what you actually feel and sets you back in the seat....As Frosty indicated gas mileage is directly related to the right foot.....

I like "The Hunt For Red October"...Too...... You're not alone  Frosty I feel old too....Heard AC/DC Hells Bells on the oldies radio station the other day......

Edited October 19, 2018 by TWO LANE BLACK TOP

[Lynn5907]

Talking about cai stuff.....( I just added 25hp to the car by removing this crap in 15mins or less). Look at this crappy piping stuff. Like forreal who makes this stuff haha.  I have a feeling by removing this from the fender well i will get better MPG. What you think two lane and frosty????  The air box still leads to cool air side btw

Edited October 19, 2018 by Lynn5907

[Frosty]

Sadly the OEMs do. They are in a constant struggle between the EPA (for overall vehicle emissions and MPG), vehicle performance, under hood packaging (e.g. any spare space in the engine compartment once the basic engine/transmission/suspension is installed),  under hood noise that might transfer to the cabin, hood clearance, time, and cost. This struggle does not lead to "pretty" designs most of the time. 

CAI manufacturers have the luxury of taking an OEM air intake design and improving upon it without the deadlines that producing an overall car requires. If it takes six months or ten months to develop a new CAI for (say) the 2019 Chevy Camaro ZL-1 - so be it. GM and other OE manufacturers don't have much luxury to beautify many of their designs. CAIs do.

Edited October 19, 2018 by Frosty

[Lynn5907]

Well put. Was not even think of that side of story. Will say my MPG went up 2-4 MPG on HW. Also seems to respond to my input just a tad smoother as well. Crazy thing I when in there to find a leak for the windshield washer rez. Seen that n was like hell na.