I know this question has been asked before in LT1 Tech, but I'm looking for more than a yes or no answer

I have heard that if you plan on running the car as a daily driver, that a 355 is a much wiser choice than a 396. Is there a reason why?

FYI, I drive about 800 miles a WEEK, and most of that is on the highway, however I do like to get on it every once in a while, along with take it to the track a few times a year.

The buildup that I am considering in the (far) future consists of:

- 4-bolt spayed mains (If necessary, which I think it probably will)
- Stock LT1 heads ported by someone who knows what they're doing (Phil?)
- 6.00" Eagle H-Beam Rods
- Maximum Compression on CA Oxygenated Premium (is 12.5 liveable?)
- Unsure of pistons, maybe SRP or JE, but forged.
- Impy head gasket
- Forged Callies Dragon Slayer crank (3.875)
- XE 230/236 Cam
- 1.6 "R" RR's
- 36 lb/hr injectors & Walbro 255lph in-tank pump
- 58mm Throttle body
- Accel 300+ Ignition
- Dyno tuning by me

(I have a M6 and 4.10's. I'd like to have the possibility of a 125hp shot of NOS, but in all reality it will probably never see it)

I am already aware of stroker sidewall loading, but I figure a 6" rod will minimalize that. I do remember hearing that forged pistons are not good for daily drivers because of the loose tolerances, and nasty piston slap. Is that still true, and if so would a hyp. piston make things any better? Is the nasty cam profile what reduces life, or is that also a wash because of the roller lifters? Is the high compression a deadly combination? I guess I want to know why people say that a stroker is not a long-living engine. After all, the parts in it would be much stronger than stock, right?

Last question, is the above setup good for 500rwhp with MAC shorties, High-Flow Cat, and a 3" Dynomax Exhaust?

I hope this is in the right forum, if not no biggie, I'll catch up with it in LT1 Tech

 

I think you already covered it with the side loading issue. I think there is a reason chevy engineers built motors with the stroke to bore ratio they did. For durability. When they built the 400 they didn't just increase the stoke alone. I think there is a point you go past with stroke to the cylinder size that can cause excesive wear issues. The additional forces being created by the longer torque arm(the rod) are being spread over a smaller area with the bore of the 350. That creates higher pressures on the parts in contact. How much are these differences I don't know. That theory just seams to fit my small knowlege of mechanics.

But then again the 305 kept the same stroke as a 350 and reduced bore size. And 305s have been known to last a long time.

 

Here's something to think about..............the LS1 has a longer stroke and a smaller bore than an old 350 (or LT1) --- 3.62" vs 3.48" stroke, and 3.9" vs 4.0" bore. So in essense, GM "stroked" the LS1........................................IMO, if you use good parts, there's no reason a stroker will have a short life (it just depends on how much / how hard it's used ).

BTW: I'd like to build my LS1 as a stroker one day --- I miss my '81 with the 383 (and I still kick my a$$ for selling it...............I was 18 with a 13.xx second car, and now I'm 20 with a 14.00 second car ). I absolutely loved the torque of the 383...................it was f'in awesome!!

 

Why don't you consider driving a beater car instead of putting 3200 miles a month on your f-body? That's like 38K miles a year! Not only will be cost less in maintenance, it will consume a lot less (expensive) fuel.

I am super glad I have my Integra instead of beating up my Z everyday. It gets 28+ mpg no matter how I drive it. The 396 Z? 11mpg.

Oh, and that setup will not make 500rwhp with that cam on MAC shorties.

-Alex

 

the 383 is fine
gas milage is not
i'm pulling a healthy 15-17 avg mpg in mine ALL HIGHWAY over a 700 mile road trip

there were a lot of hills and I do have MAP, o2 sensor codes as well as 3.73s and leaking exhuast so maybe i'm not the best guage

but seriously-
its a ****LOAD of tq-
tires break loose with traction control on on accident some times
and I got 255 instead of 245 and its try out...

 

Ok, I've been doing some more reading up....

There seems to be an ideal 1.75 rod/stroke ratio. Interestingly enough, the 327 hits it exactly

While this is physically impossible to do with a stroker, it can be done with a 350, provided you get 6.125" Rods.

In any case (stoker or long-rod 350) you have pistons that have a compression height of around 1.250" When you have a short CH like that, the piston rocks more in the bore, and scuffs the hell out of the side of the piston. Hmmmm I wonder if you can get a long skirt - short CH piston

So, possibly, the reduced sideloading of the longer rod is cancelled out by the increased piston wear of the rocking in the bore of a shoft CH &/or skirt piston. Then you can try and combat that with coatings, but I fear they'd wear off with my crazy driving.

Of couse, the piston itself is weaker because there is less meat between the ringlands and the piston pin as well with short CH pistons. I've heard Fred tout 5.85" rods before, I think all of this is finally coming together

Maybe if I step down to a 383 and run some 5.85 rods, I could minimize piston scuffing, and also minimize side loading, while maximizing piston strength.

I'd love to get a daily driver, but the problem is I don't want to drive anything other than the Z28 In all honesty, I'd love to get a Jetta TDi, (50+ MPG is good for the miles I deal with) but then I'd have no money for mods That's why I deal with the extra miles, and why the Shell guy knows me by name

 

don't kid yourself with an "ideal" rod stroke ratio.

as Reher-morrison put it.. the Rod is just there to connect the piston to the crank!

maximize rod length with the ring pack you need, and put the bitch together.

 

The difference between a 355, 396 and a 383 stroker will be negligible. Don't waste your time thinking about it. If you want go for longevity, keep the revs down. Wear increases dramatically at high revs, both in terms of wear from friction and stresses on parts that may lead to breakage over time. So a setup that gives you the desired performance at lower revs should last appreciably longer.

If you want put really high miles on the combo, don't go for a 355, 383 or a 396. Both of these are 0.030" over. At 0.030" over you will be pretty close to the limit for a stock block. You can go 0.040", but not more and have decent ring seal. If you go 0.010" over you will get better ring seal (=more power, lower emissions) and have three more rebuilds left in your block!

Obviously, another key to long motor life is high quality components, especially rings and bearings. Proper assembly is a must. Use synthetic oil. Don't allow it to overheat, but run it a little hotter (no 160 degree thermostat).

Good luck.

Rich Krause

 

FWIW, my mild 6500 RPM 383 quit after 32K miles of daily driving at 500 miles/week. If ya make it back out West, feel free to stop by and check out the defunct block once its pulled for your "long term stroker wear" documentary.

IMHO, just stick with a heads/cam 350 for a daily driver. The machine work and balancing associated with a stroker will probably cost just about as much as a budget rotating assembly!

 

Thanks for the info guys. 32k miles Yikes! Sorry to hear 'bout that

All of this discussion about non liveable stroker's has me thinking of another question? What is the best way to make a long living streetable engine?

Is the secret super/turbocharging (I really didn't think it was), or maybe occassional N2O (Again, I think worse than a stroker), or is there no way to eek out more power without severly affecting long term life? Maybe the answer is just a bigger engine (454 or 502) although that would be fun to shoehorn in there.

I know the answer lies in that if I drove less I could handle any/all of the above, but it would suck to have such a nice car sitting in the garage, when you got to drive a POS for 3+ hours a day. I tried that once before, and a few months after getting a beater, I started sinking money into that, just to try and make it faster

 

Rich~ Will you explain why not to run a 160 thermo? First time Ive heard that but Im sure there is an explanation for it..I have one in my stroker and it runs at 170 at ALL times(meziers water pump also)...Is it bad for it to run that cool? Seems to me it runs great cooler..Doesnt heat wear things out quicker also? I know GM put a 180 in the LT1 for a reason but I dont see why running a 160 thermo will hurt the motor in the long run..

Cody

 

I was generalizing about the 160 stat, and like most generalizations it's not always true. FWIW, I run one. But my car has very frequent oil changes and doesn't see many miles between rebuilds, and it is usually driven for at least an hour at a time. The problem is getting the oil up to temp (quickly). Oil, even very good oil, lubricates much better at higher temps.

Just IMHO, probably not really a major factor in longevity, but I thought I'd throw it in.

Rich Krause

 

My uncle is a mechanic and he told me the same thing about using the low-temp therm. He builds engines by himself(30+ yrs!!). I believe him too.....ever see that the LT1s last so long and GM made them run so hot? The low temp fan doesn't come on until 225* and the high at 240*+. I didn't understand much of what he said, but it was something to the effect that as the temp of metals increase, their tendency to "rub-off" on other metals decreases and tolerances are increased yada yada yada.... he's the reason I never installed a 160 in my car. That and I'm starting to learn these things in engineering at school(mechanical)....give me a couple more years and I might fully understand it.

 

Long living street engine = cheap beater car with no HP, very easy on parts!

Sorry to hear about that Jim!

 

The short answer? Just stick with bolt-ons.

Expecting a stroker to last as long as a factory motor is just wishfull thinking No way in hell it's gonna happen.

On the bright side, for most performance buffs, longevity - at least factory like 100K plus miles - isn't an issue since you start looking for bigger and better things almost immediately after buttoning up a new motor. You'll be sick of a new motor set-up before you know it

Kinda works out nicely

FWIW, when this motor starting running like s**t and eating coolant, I really didn't give a rat's ***

IMHO, leave the bottom end bone stock - save for the rod bolts - and put the cash saved into the heads/cam. A nice set of 320+ CFM AFR's and a nasty solid roller outta be good for 500 HP to the tires. No machine work, no fresh rotating assembly, no balancing, no BS. Just lots o' cheap power. If it blows, happiness is just another affordable junkyard shortblock away