|
Post by in68jav on Nov 8, 2016 11:33:29 GMT -8
Hey guys, I know I fit into the mental fapping category sometimes, but I am the type of person that likes to plan something out in detail before starting a project. As such, I have a 360 block that I want to turbocharge and want to know if anyone has actually broken a 360 at the main webs before? Also, if you use ARP studs for the mains, what is going to cause the engine to fail there? Too high of RPMs? Too much boost? I'm considering keeping the stock stroke and going with forged rods/pistons. Anybody broken a crank on one of these? Just trying to sort out a plan of attack on the bottom end.
|
|
|
Post by sc397 on Nov 8, 2016 12:39:45 GMT -8
Being Captian Obvious here... the 360 bottom end is not as beefy as a 401 but are much beafier than the off-brand small blocks that I have looked at over time. Bigger Main caps, bigger bolts etc etc. I have never heard of anyone breaking a 360 crank but, I don't know anyone who put a lot of boost to one. Our buddy Mike Gardner threw together a 304 (same crank as 360) and twin turbocharged it with no major issues. He even kept the cast pistons and stock rods in it. There used to be a guy who made a Main Girdle for them but I can't remember who it was. Here is info on Mike's Cars. theamcforum.com/forum/304-turbo_topic22700_page2.html
|
|
|
Post by in68jav on Nov 8, 2016 12:48:40 GMT -8
See, that's great info, what a difference from asking on that "other" forum! One of the major benefits of running a turbo setup is HP without insane RPM, hopefully saving valve train and bottom end. If I ever get it together, a pair of HX35 Holsets would look pretty cool under the hood of the 68 jav.
|
|
|
Post by sc397 on Nov 8, 2016 13:20:46 GMT -8
|
|
|
Post by Captain Awesome on Nov 8, 2016 14:18:11 GMT -8
I'm one of the biggest a-holes on here, and don't consider this mental fapping. Nothing wrong with planning. But way out in left field unicorn stuff is another story.
Anywho, I've seen a couple 360s make some good power being sprayed and no problems. The 360s to me seem to be a very durable engine.
|
|
|
Post by spud on Nov 8, 2016 19:30:17 GMT -8
Every engine has limits. I say you have to give it a try before you can succeed or fail. Big factor in successful turbo installs is low compression for longer life, intercooling, oil cooling, larger cooling system capacity. These are important details, but get more important as boost goes up. since you dont need high revs the lower end doesnt have to deal with all that abuse. I would guess a 360 would take as much boost as you could practically throw at it with PUMP FUEL. I imagine a 10-12 psi boosted 360 would make plenty of power and live to tell about it. How stout is a stock slant 6 LOWER END? A guy on the turbo forums .com has been beating on one pretty hard with over 15 psi....and it has only four main bearings and lives. I think your idea of forged rods and pistons is good, but... you could go with a 390 crank and 401 rods and custom 8 to one pistons.... I think that would be plenty stout. If you wanted to go all the way you could find a 360 service block.... I know thats $$ and not in the scope of the question however.
|
|
|
Post by stickshifter on Nov 9, 2016 4:19:48 GMT -8
As has been stated, every engine has it's limits. And you omitted one very important detail, how much power are you hoping to make? Running a 360 at 8psi and around 500 hp, it should live a long life. Try making 1000hp at 40psi, and things will be different.
My son's 360 uses an old 390 crank that I got for $50 with a bad rod journal. It now has 2.00" rods and forged SBC400 pistons to make 382 ci. And I believe it will live a long life.
And there is also another point, any combo can grenade if it isn't built properly. This includes the parts chosen, the quality of the machine work, and the attention to detail during assembly.
BTW, the rule of thumb for cranks is: Cast = Max 500hp Forged = Max 1000hp Billet = Replace as necessary. Again, it's just a general rule of thumb.
|
|
|
Post by in68jav on Nov 9, 2016 6:40:21 GMT -8
All good info, this is really great discussion! I guess I should say that this would be going in a street driven car, not a pure drag setup, but I think it would be cool to do drag week someday (maybe). And I like the idea of it running on pump gas, as road tripping this thing is appealing to me. Its going to have some sort of modern 5/6spd manual and EFI for sure. I know an LS/turbo swap would be "easier" but no one ever accused me of taking the easy way out. This is my first muscle car; my previous and current experience is with imports (95 honda prelude on E85, 88 Nissan 300zx tuned and turbo'ed, and 93 Mazda rx7 twin turboed and tuned).
|
|
|
Post by 69Rebel on Nov 9, 2016 8:17:19 GMT -8
Spend a little extra $$ up front and do it right, you will be happy with the results. Now go build it. We demand pics.
|
|
|
Post by ghinmi on Nov 9, 2016 19:38:41 GMT -8
I pushed the head gaskets in my stock 360 at 45 psi, bottom end was still together. Doesn't really mean much since it was only a few seconds. But it survived all summer on low boost.
I personally think you'll walk the caps before you fail the main webbing on a 360. There's plenty of beef there. Like said before, you're going to have a hard time making enough power on pump gas to fail it.
|
|
|
Post by spud on Nov 10, 2016 7:27:18 GMT -8
I agree. Sounds like 8-10 pounds of boost would be plenty. What usually breaks things is detonation, not the boost or power. Plan ahead with low compression, intercooler and oil and water cooling upgrades. Electronic fuel should keep it from going lean, another big death factor in boosted engines. I think a stock lower end would be fine. I would spring for some forged rods tho.
|
|
|
Post by sc397 on Nov 10, 2016 7:54:35 GMT -8
I second the vote on Forged Rods. It's a nice saftey factor.
|
|
|
Post by spud on Nov 10, 2016 8:56:29 GMT -8
Yup. I know they "surprise" people with their "durability" but I have personally seen the iron rods fail.
|
|
|
Post by sc397 on Nov 10, 2016 8:58:39 GMT -8
Well, it is just a lowley 360... You can find one anywhere. Try it with cast rods first then upgrade on the next build and push it a little harder.
|
|
|
Post by ghinmi on Nov 10, 2016 13:37:37 GMT -8
Yep, no harm in boosting a stock 360. Worst case it breaks and you gained experience for pretty close to free. Plus you can get it up and running, and build a nice motor while you're enjoying it and learning. Then you plunk the new motor in and you've already got a pretty good handle on what you're doing.
|
|