General Question on Pistons

[voltage007]

Hi All,
Can anyone help on or knowledge of KB pistons for the marauder? I own an 03 with 73000 miles and had an oil issue and ended up damaging a connecting rod. Since the engine needs to be pulled and done I am looking into upgrading the pistons and such and going .030 bore and am looking for some advice!!! Thanks in advance.

[RF Overlord]

<threadjack>

I can't answer your piston question, but if you don't mind, a little more info on your "oil issue"?

Thanks

[voltage007]

Sure I bought my MM 2 years ago from of course a widow who's husband worshipped this car. He passed on and I bought the car for $9800 with 36,000 miles and I even have the leather Jacket. I have loved it ever since I bought it. Well last week I was driving it on a 2 lane stretch and stopped at a light and changed the radio station and in the moment of silence I heard the tick... I immediately pulled off the road and listened. To my dismay the tick was a lower end noise and sounded like a bent connecting rod. I drove the car to a better spot about 1000 feet up the road and called for the tow truck and had it towed to my mechanic. Upon his investigation it seems that the call lost oil pressure due to sludge that was there and it loosened up and clogged the filter lowering the oil pressure causing the problem. The worst is that the stupid oil pressure gauge never told me a dam thing. I have read up and found out that it is a useless gauge and will be replacing with a mechanical one while doing the other work.

[Zack]

You have a lot to learn.

No one does a .030 piston unless some serious damage was done to the cylinder walls.
Most engine shops will buy a .003 over piston nowadays because the cylinders can be honed perfectly.

If you want a good piston buy a Diamond, and a set of H Beam Rods.

[voltage007]

Hi Zack,
You are right I do have alot to learn and thanks for the information. Just trying to figure out the best solution to a bad problem. What do you think is the Hp handling ability of a stock lower end on these engines? I would like to do pistons and rods and not have to do a crank to but can these engines handle say 500HP with a stock lower end??? Any and all advice is greatly appreciated!!!!

[RacerX]

^ What Zack said! You do not want to bore the iron siamese cylinders in an aluminum block because they are thin enough to begin with. Hone, yes!

[voltage007]

Thanks for the input like I said any and all info is helpful. But like I posted before what kind of HP can the stock lower handle any ideas???

[Zack]

Thanks for the input like I said any and all info is helpful. But like I posted before what kind of HP can the stock lower handle any ideas???

1 Hp less than when it broke.
That is honestly the most accurate answer you will ever get.

[blazen71]

Never heard of any crank issues. Try reusing and see what happens. Get the crank polished though!

[RacerX]

You damaged a rod. You allready have to tear the engine apart. You may as well do a forged bottom end and not worry. Get a forged rotating assembly from livernois. Have a good local machine shop go over the block. Do a light valve job. Then you can get it sc'd...

[voltage007]

Thanks RacerX what I am trying to do is have the block cleaned up and honed and the crack (Crank is the cobra 8 bolt) cleaned up. Run the stock crank and just replace the rods and pistons. Going with KB or Diamond pistons and Manley rods also doing the timing gear mod. The car has the sct chip, K&N air intake and 4:10 gears. Just want to make sure the lower end stays togeather. This is all the mods I will ever do!!! At least until it comes off the street for good and I go totally crazy on it....

[Zack]

Thanks RacerX what I am trying to do is have the block cleaned up and honed and the crack (Crank is the cobra 8 bolt) cleaned up. Run the stock crank and just replace the rods and pistons. Going with KB or Diamond pistons and Manley rods also doing the timing gear mod. The car has the sct chip, K&N air intake and 4:10 gears. Just want to make sure the lower end stays togeather. This is all the mods I will ever do!!! At least until it comes off the street for good and I go totally crazy on it....

What sir is a timing gear mod?

And FYI Keith Black pistons are old technology.

And another FYI the stock MM crank is a CAST, 6 bolt.

[voltage007]

Thanks Zack I guess it is Diamond pistons... I live in New England and there is a very rep. modular motor builder in these parts that has told me that they retarded the cams in the merc about 7 degrees for emission purposes. He says that replacing the timing gear and returning the cams to zero really will improve the preformance of the car.... As for the crank why was I told the it is an 8 bolt???

[FordNut]

Thanks RacerX what I am trying to do is have the block cleaned up and honed and the crack (Crank is the cobra 8 bolt) cleaned up. Run the stock crank and just replace the rods and pistons. Going with KB or Diamond pistons and Manley rods also doing the timing gear mod. The car has the sct chip, K&N air intake and 4:10 gears. Just want to make sure the lower end stays togeather. This is all the mods I will ever do!!! At least until it comes off the street for good and I go totally crazy on it....

Stock crank will be fine. If you go with the Cobra you'll also have to hunt down a flexplate. Bore it 0.010". You can probably get some good used Cobra rods for a lot cheaper than buying new Manleys. Use Diamond or CP forged pistons, personally I think the coatings are worth the extra cost (Diamond has a new process you might look into). Get a Melling oil pump, it comes with billet geears. Timing gear mod?? What's that?

[FordNut]

What do you think is the Hp handling ability of a stock lower end on these engines? I would like to do pistons and rods and not have to do a crank to but can these engines handle say 500HP with a stock lower end??? !!!!


Thanks for the input like I said any and all info is helpful. But like I posted before what kind of HP can the stock lower handle any ideas???

Generally 450 is considered the safe limit. Some guys run 500 ok, lots of guys blow up at 500.

[voltage007]

Real quick new guy here and rteally appreciate ALL the input and info.

[FordNut]

Thanks Zack I guess it is Diamond pistons... I live in New England and there is a very rep. modular motor builder in these parts that has told me that they retarded the cams in the merc about 7 degrees for emission purposes. He says that replacing the timing gear and returning the cams to zero really will improve the preformance of the car.... As for the crank why was I told the it is an 8 bolt???

Not true. They are the same grind and indexed the same for the Cobra, Mach1, and Marauder (and Aviator?).

[Zack]

". You can probably get some good used Cobra rods for a lot cheaper than buying new Manleys.

I have to disagree with this only.

New Manleys (or the identical equivalent) run about $479 new in the box.
Used Cobra rods are about 300-350 and by the time they are checked/straightened you will be above the cost of new rods.

...all this from personal experience.

[RacerX]

Maybe meant retarded timing (In the stock PCM tune)? 6 bolt, not 8. Reputation's getting thinner by the minute on that builder... :D

[voltage007]

Have you heard of the timing thing? And I may be the one who is wrong about the 6-8 bolt info...

[Zack]

Have you heard of the timing thing? And I may be the one who is wrong about the 6-8 bolt info...

Um.....NO :rolleyes:

[voltage007]

Thanks again Zack gues I will have to wait and see.... That scares me

[thathotrodlincn]

Generally 450 is considered the safe limit. Some guys run 500 ok, lots of guys blow up at 500.

Are we talking rear wheel, or flywheel?

[Pops]

That would be rear wheel.

[thathotrodlincn]

That would be rear wheel.

Great! And thanks. I feel more safe as I am at about 460 rear wheel.

[boatmangc]

Hmmm
I blew up at 377.

[boatmangc]

Better yet buy Impalaslayers Cobra SB and be done with it

[RR|Suki]

Better yet buy Impalaslayers Cobra SB and be done with it

Pretty sure his car is NA, an 03/04 cobra shortblock would be a very bad choice in that case.

[Seneca]

Better yet buy Impalaslayers Cobra SB and be done with it
Not to mention he sold it.

[boatmangc]

I didn't realize he sold it but the guy's asking about being safe at around 500 hp.

[RR|Suki]

I didn't realize he sold it but the guy's asking about being safe at around 500 hp.

He may have been asking about 500hp, but that seems like just curiosity as far as if stock bottom ends could hold that.

His mods:

The car has the sct chip, K&N air intake and 4:10 gears. Just want to make sure the lower end stays togeather. This is all the mods I will ever do!!! At least until it comes off the street for good and I go totally crazy on it....

[Mr. Man]

I thought Keith Black was a MOPAR guy?

[voltage007]

Keith Black is a mopar guy but does offer 4.6 pistons in various sizes... As for the 500hp question I was just wondering if the stock lower could handle it. If you look at the beginning post i have a connecting rod gone bad and I am having the motor pulled and machined and the heads done and I was just wondering if I should just do the pistons and rods or if the crank should be done too. I am keeping the motor mild and not ever going to add induction so I was just looking for info to see if the lower end could handle mild upgrading...

[Zack]

Hmmm
I blew up at 377.

Didnt you determine your intercooler pump was bad?