ok, will it hold?

[cmc]

My .02. Yes forges pistons rattle on cold starts b/c they expand when hot, so you overbore the cylinder a little. I have Ross pistons on eagle rods. And I have no problems. Takes 2min to heat up, and I'm gone. They do clank when cold!! CLANK CLANK CLANK CLANK CLANK CLANK
But its not bad. I like the 1g big rods alot. they hold alot of power, but the 2g piston is not as tolerable.
Good luck, I feel like I'm walking on egg shells!

 

[larryd]

so you have the eagle/ross combo and you like it but you said you also like the 1g big rods? well WHICH IS IT MAN, CANT DO BOTH .. j/k

 

[cmc]

Sorry, I think that the eagle rods are better, but if you buy a 6bolt block w/ rods and your on a budget, the 6 bolt rods hold very well. They're twice the size of the 2g rods! (or about)

 

[larryd]

im just thinking the difference between using 91/95 and something forged is like 1000.00.. I mean I know Ive spent more on other things. I just always try to be logical and determine do I really need to spend this other 1000 bucks on forged interals and the answer is yes if I plan on revving over 8000 and running nitrous..

 

[cmc]

The pistons definitly are the weeker of the combination, so go forged there, rods, you could sell the 1gs and get eagles . If you don't plan to bust over 450 the rods should hold!

 

[rdrkt]

Guys when you have seen motor blow what goes first the piston or the rod? It has been my experience that a rod will bend due to detonation a lot quicker than you will crack a piston. I have 91 rods and I make above 400hp they seem to be surviving for now. Obviously that is not a very good permanent solution but I still have a WELL running car for now and I have a bit more time to collect the pieces for my “race” motor.

Crower rods and ross pistons will more than DOUBLE his already VERY expensive bill to get his car back on the road. We are not talking about a few pennies here. A forged internals motor on top of a 6bolt conversion would cost a small fortune. Who here can drop 5k to get their car up and running just like that?

For the people that said if he is planing on upgrading he will be screwed the green is only really rated for 450 or so hp to the wheels. I have seen properly machined 91 rod 95 piston motors take 500+ hp for 30 thousand miles and more. So IF he gets more serious with his setup he will still have a pretty decent safety window and plenty of time to save up for a forged bottom end.

I have seen a few people here respond saying that a forged piston can work properly with proper machine work. I 100% agree with that. However you are going to have some driveability issues until the car is warmed up. Larry only drives 4 miles to work every day. For the majority of his driving the car wont optimal. He will end up spending twice as much time letting his car get to temperature than actually driving the thing not ideal for a daily driver.

 

[rdrkt]

Larry a t-28 will not make power to 8 grand. A green will make power at that rev range but you would need an optimal setup and even then it isnt reccomended on pump gas.

 

[NosLaser]

rdrkt,

Look at my post again. Yes, you are right. A rod will usually bend under horsepower before a piston breaks. But he's talking about going to 8500 rpm. I don't see a stock rod or piston handling that rpm AND 400+ hp for any lenght of time. It's more the rpm than the horsepower, but combine the two, and it's that much worse.

Regards,

 

[trooth]

Originally posted by NosLaser
rdrkt,

Look at my post again. Yes, you are right. A rod will usually bend under horsepower before a piston breaks. But he's talking about going to 8500 rpm. I don't see a stock rod or piston handling that rpm AND 400+ hp for any lenght of time. It's more the rpm than the horsepower, but combine the two, and it's that much worse.

Regards,

Aslan,

You seem to have this infatuation with the fact he mentioned holding until 8500 RPM. The DSMLink he also mentioned allows him to change this limit at will. So, put them together and he will have the ability to run to 8500 if he chooses. Sure, will it hold? Probably not if he does it from stoplight to stoplight. However, with his current setup and *assuming* its machined properly, even YOU admitted he COULD hit 8500 from time to time. So get off the 8500 RPM kick.. if you are that stuck on it, how about asking more questions like, "Are you planning on doing that everyday?" "Your engine may be able to hold it, but will your turbo make power that far into a RPM range?"

Personally... I think he should go with forged internals. He hasn't skimped out on purchasing anything else not up to that standard. (Head internals) so why start with the block. Then again, I am not a fan of rebuilding a 7-bolt block to possibly run into a crankwalk issue.

One major issue I see most people who build DSM cars, no one excluded, is not tuning the car properly. Everybody guesses, but nobody spends the time on a dyno or using datalogging to actually make their car safer. Time spent doing such will go a long way in your engines success and lifetime.

 

[NosLaser]

...You seem to have this infatuation with the fact he mentioned holding until 8500 RPM. The DSMLink he also mentioned allows him to change this limit at will. So, put them together and he will have the ability to run to 8500 if he chooses. Sure, will it hold? Probably not if he does it from stoplight to stoplight. However, with his current setup and *assuming* its machined properly, even YOU admitted he COULD hit 8500 from time to time. So get off the 8500 RPM kick.. if you are that stuck on it, how about asking more questions like, "Are you planning on doing that everyday?" "Your engine may be able to hold it, but will your turbo make power that far into a RPM range?" ...

He asked if he could rev to 8500 and make 400+ HP on stock internals. Maybe 4 out of 10 cars can and do, but do you want to make that chance? Only a DSM'er would flame someone for suggesting that he should do things the right way. I'm outta here.

 

[rdrkt]

Originally posted by NosLaser
Only a DSM'er would flame someone for suggesting that he should do things the right way. I'm outta here.

Aslan I know that you value your own opinion. Im sure you know more than most DSM guys out there. But you just cant get your panties in a bunch everytime someone disagrees with you.

 

[95GST]

If you're going to use stock 90 rods and 95 pistons, keep it close to the stock rev limit and don't run nitrous.

If you're really set on higher rev and nitrous (which your head is prepped for higher rev already, so why not). Go with forged internals. It's better to be safe, it adds to the total cost but doing it right is cheaper than do it twice.

Keep in mind driving short trips is not healthy for the engine, the effect is worse with forged pistons due to expansion properties.

BTW, you really need DSMLINK to manage a 6-bolt swap properly; when you get rid of the 2G crank angle sensor you'd want to disable the misfire checking.

Personally I went with the stock internals with ARP fasterners, because I won't be doing high-rev or nitrous ever.. basically I cannot afford to go that fast (450wHP +). Each person's goal and budget is different.

 

[kilurv8]

I am not going to get involved in this whole forged rod/piston thing, but I will say I am always a firm believer in preparing a car for the power before the power comes, not at power and play catch up on safety. If you want to run NOS, get the pistons at least. Al Blaha went 10.73 on big rods and 95 pistons in his 91, and even went 10.50 when he absolutly gutted the car. But if you want to be safe, do eagles and some sort of pistons. I have Arias and they rock. I don't even get a single clank on start up. The only downside is they only make 1mm oversized. If you are not ready for this or do not have the money, then just put a stock block in and save your money for this winter and tear the car down during the winter. I disagree with Aslan's approach on most things but I do agree on his ideas, do it once right and never do it again. It is that simple. Hope that helps.

 

[cmc]

rdrkt, I agree most of the time the rod goes before piston, but on a nitrous setup, and I know very little about that, would there be a higher percentage of pressure on the piston than that which is created on the rod!? I gues that I'm amazed by the fact the 1g big rods are so...well... big, and the 2gs are toothpicks

 

[NosLaser]

...Aslan I know that you value your own opinion. Im sure you know more than most DSM guys out there. But you just cant get your panties in a bunch everytime someone disagrees with you....

It's not about getting my panties in a bunch. It's about getting shot down for giving good advice. It's not like I'm giving bad advice, so I really don't see where the argument is. It's like coming on here saying that winning the lottery is better than having a flaming stick shoved through your eye, and having people argue with me.

Regards,

 

[larryd]

what, you dont like flaming sticks??

 

[NosLaser]

Apparently not as much as some others..

 

[larryd]

heheh..

Aslan.. lemme ask u another question.. what are the limits of the 7bolt 98 pistons/rods? power wise.. i may just get my block rebuilt, thinking of getting it balanced and honed and putting new rings on the pistons.. just curious how it would be with my current setup.. no nitrous and not revving to 8500..

Im thinking of doing this and saving up to drop in a 6 bolt if cw occurs.. all depends on pricing anymore

 

[NosLaser]

Well, in my '93 Talon with a 7 bolt, it didn't like horsepower at all. My setup was full exhaust, web cams, blaha MAS, stock 14b, 550's, AFC, walbro, turbo inlet pipe, FPR, upper IC pipe, and a 50 shot wet kit. The car was tuned rather well, and was real strong on motor for a 14b without a front mount (108-109 traps.) I took all the proper precautions, had a tank full of race gas, and a full bottle, and went to spray. First time, sprayed in 2nd gear, spun to redline immediately, almost like free-revving the motor. 2nd time, sprayed in 3rd, car spun hard, but pulled hard...I'm talking 116+ mph hard, and right around 5500-6K rpm, it sent 2 rods through the block. My theory on what happened is kinda tough to follow, and explain on the net, but I'll try. I had my base timing set to 14 degrees like I did on the Laser. I had it that way because the car pulled awesome on motor, and I was meaning to turn the timing down a bit, but it had slipped my mind. Now, take a look at what's going on inside the motor. With advanced timing, the spark plug fires before the piston reaches top dead center...X amount of degrees of crankshaft rotation more specifically. As the piston is traveling upwards (i.e. being pushed upwards) the plug fires, combustion begins, and it tries to force the piston back downwards. You can imagine the force being applied here...the crank is attempting to spin the piston upwards, while combustion on the power stroke is looking to push the piston back downwards. The result is the rod can't handle that kind of stress (and mind you, this happened at 5500-6000 rpm with a motor making maybe 400 crank HP; imagine you looking to make 400 wheel HP and spin to 8500rpm...get my drift?) and it took the path of least resistance which happened to be out of the block. This is why I feel you need a good strong rod that can handle some deflection under load. Rods are bending under that power ever so slightly, and the stockers just don't have the tensile strenght to handle the power. Now with upgraded rods and stock pistons, you've got this heavier rod that doesn't bend as easy, and can handle the stress, mounted on a stock cast piston. In that case, it's going to want to rip the wrist pin right out of the bottom of the piston because now the piston is the weak link; hence my recommendation for forged pistons as well. I'll get flamed for this I know it, but if you are going into the motor, it is my OPINION (yes, OPINION OPINION OPINION) that you should do the work once, do it right, and not worry about it. For some reason, that idea sounds absolutely stupid to people, and I'll never comprehend why. It's like saying you want to go skydiving...you can afford the flight up into the sky, and you can afford the first parachute, but figure you don't really need the reserve chute because it's another couple hundred bux. To each his own I guess...

Regards,

 

[IPT]

LArryd have you just thought about upgrading the rods and still using the 95 pistons. I know of a couple of people to do that. The pistons will hold out longer than the 7-bolt rods will so just replace the rods.

 

[larryd]

ok, this is what I intend on doing.. NosLaser you won me over

Im going to get a 6 bolt block, get it balanced and all that nice stuff, put in crower rods with ross pistons at .020 over... Im also getting rid of my AFC/pocketlogger and going with the DSMlink so I can get this thing going right.. an experience mechanic that has built a few DSMs is going to be building my car and then tuning it with his wideband o2 sensor.. ETA on the car being back up and running.. 3-4 weeks..

 

[NJGSX96]

Good deal. Do it once and be done with it. Good luck!

 

[larryd]

try telling my wallet that

 

[GRNDSM]

Larry,

Why would you go Crower rods over Eagle? I have nothing against Crower, but at almost 1/2 the price, Eagle seem to make much more sense...

 

[larryd]

well i get WD pricing on Crower so the pricing is alot closer then that actually.. that and ofcourse since I have no personal experience with either when it comes to rods Ive asked a few people and theyve both told me that Eagle is a little better then 91 big rods but if you want to go with something bullet proof then go with Crower.. so why not right.. nothing but the best so far so why back down now