Engine Lifespan..?

[AcIdBuRn02ZTS]

Hey alls...

I searched but couldnt find the answer....

Is there any pros/cons of going forged when it comes to overall lifespan of the engine (7m)?

Im wanting to go forged however would probably reconsider if it cuts the engines lifespan...

Thanks
-AcId-

 

[gaboonviper85]

If the machine work is good and assembly was good and your tune was even better then it should last another 20+ years

 

[hvyman]

^yes and no. kinda completely depends on the owner/driver and how well it was taken care of or how much it was beat on.

what you said tho has a lot to do with it.

 

[Flateric]

I think how it is driven has an equally as great an influence on the motor lifespan myself. Perhaps even more.

I've seen alot of excellent motors with excellent tunes last for very short periods of time with bad/idiot/bagging drivers.

Nothing is impervious to stupid.

 

[Poodles]

Forged engine isn't going to lower lifespan if the tolerances are right... If anything it would improve it at the same power levels (depends a bit on piston design as well, but now we're splitting hairs)

 

[hvyman]

I think how it is driven has an equally as great an influence on the motor lifespan myself. Perhaps even more.

I've seen alot of excellent motors with excellent tunes last for very short periods of time with bad/idiot/bagging drivers.

Nothing is impervious to stupid.

if it is built properly and tuned properly it should not just last a short time. there is a human error in that part that prolly is not admitted.

 

[IJ.]

Most forged piston sets run a thin ring pack and this WILL have an imact on engine durability, Also forged motors tend to be run harder at higher output.

 

[quake]

^^^lol finally. Factory motors are built for emissions and built to last. Forged motors are built to take a beating. The very nature of the parts you are using, require frequent tear down and inspection. I usually go about a year and a half then tear down and check about 20kmiles . This is driving everyday all the time at full throttle making around 550-600rwhp on pump. If you drive less crazy then you can go much longer. With a good tune and machine work you will still wear the rings and bearings.

 

[IJ.]

Constantly amazed at this generations mindset, today we routinely build these cars with production based engines to make 5>600rwhp running on pump fuel, compare this to an F1 car of the time before the 1500cc/Turbo era and we actually make more power without the sniff it and die jungle juice they ran on.

Yet their engines were replaced sometimes 4 times per race weekend we expect ours to go 1000's and 1000's of miles with little to no maintenance, in the late 70's early 80's I raced motorcross and it was a given to replace the rings each meeting then the piston every third to keep performance "sharp".

HP costs, if you make xxxrwhp wear will increase, think of an engine as having XXX number of revolutions in it from the first crank, this empties as the engine wears, if you increase the RPM it operates at or increase the power output it empties faster.

 

[Poodles]

Hence my "same power levels" comment

 

[quake]

Hence my "same power levels" comment

it still will wear faster with the thin ring pack. Extra clearence needed will also create more wear on the piston and motor. Short skits used and the list goes on... It's in the design of the parts and also the reason it is not used for the most part by the factory.

 

[Poodles]

Forged pistons don't have to be made that way either

You're missing the main point though. You rebuild an engine for the power levels. Even though someone has done over 700HP on the stock internals doesn't mean it would live for a long period of time. A built motor would arguably last far longer at those power levels.

 

[prsrcokr]

I waited until the engine had 17 years on it and 190k miles to get into motorsports. Amazing that it's held up to that abuse but it doesn't hold the power like it used to, guess the seal degrades with use.

I still wouldn't be surprised to find some hone marks at teardown like we did 10 years ago when patching it up with new rings (wanted to reduce oil consumption to get to school and back) That said I think it's dependent on the situation, when I go to forged pistons (stock rods are already forged) I'll stay at higher rpm more often where I tend to give the engine a break at times. Also sitting is one of the worst things for a car and the more specific you build the car, the more they tend to sit between uses.

 

[GrimJack]

Meh... IMO, an engine's death, 99% of the time, is due to owner abuse. Low oil, overheating, driving on BHG, failure to run more than straight water in the cooling system, running no air filter in the desert, etc, etc, etc.

I've seen hundreds of dead Supra engines, and I've literally never seen one that flat wore out.

 

[IJ.]

Ditto the 7M blocks have the hardest cast iron I've come across in 30+ years of playing cars!

 

[gixxer750]

it still will wear faster with the thin ring pack. Extra clearence needed will also create more wear on the piston and motor. Short skits used and the list goes on... It's in the design of the parts and also the reason it is not used for the most part by the factory.

Agreed. On a forged engine that I build for a customer, I generally recommend a tear down and refresh between 25000-50000 miles depending on power output and type of use that the engine sees.

(stock rods are already forged)

When did this occur? Every 7m I've seen has cast rods. GOOD cast rods, but cast rods nonetheless.

Meh... IMO, an engine's death, 99% of the time, is due to owner abuse. Low oil, overheating, driving on BHG, failure to run more than straight water in the cooling system, running no air filter in the desert, etc, etc, etc.

I've seen hundreds of dead Supra engines, and I've literally never seen one that flat wore out.

Ditto the 7M blocks have the hardest cast iron I've come across in 30+ years of playing cars!

I have seen 1 "worn out" 7m and 2jz's Both had upwards 250K miles on them. The 2jz-ge had 345000 miles. The owner replaced the engine in his GS300 because he felt like with that many miles it needed to be replaced. I stuck a new ring in the cylinder and the gap was around .032" Probably smoked like hell.

 

[wiseco7mgt]

Ditto the 7M blocks have the hardest cast iron I've come across in 30+ years of playing cars!

Spot on Ian, i have a cressy block in the shed that had done 320,0000 klms on crap oil most of its life and yet the bores had nearly zero lip, you couldn't physically feel it with finger nails.
Can't say the same for some old 186 holden motors i had played with in the past that had done half that range.

 

[manzai]

Meh... IMO, an engine's death, 99% of the time, is due to owner abuse. Low oil, overheating, driving on BHG, failure to run more than straight water in the cooling system, running no air filter in the desert, etc, etc, etc.

I've seen hundreds of dead Supra engines, and I've literally never seen one that flat wore out.

I'll tend to agree w/ Grim. There isn't much that will actuall wear out on these motors. Engine failure whether forged or not will be due to Tuning (detonation), over heating or poor machining tolerances. The owner,tuner or machinist will typically be the downfall, not "wear" issues. Forged internals or not, tuning and maintenance are your best friend. I run forged pistons w/ stock rods. Just tune properly and take good care. . .

 

[smokemkevo]

Take good care of it , but dont spoil it, i think life span of a motor is just luck lol bc it depends on so many things.

 

[Nick M]

Meh... IMO, an engine's death, 99% of the time, is due to owner abuse. Low oil, overheating, driving on BHG, failure to run more than straight water in the cooling system, running no air filter in the desert, etc, etc, etc.

I've seen hundreds of dead Supra engines, and I've literally never seen one that flat wore out.

What was that about 99%???...