340 Piston to valve clearance w/RHS heads

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70aarcuda said:
340 + .040....not luck..just skill

plus .020..030..040..060

http://www.flatlanderracing.com/trwchry.html
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Yeah and when I called a few places last spring, was told they can not get them anymore, Summit, Manici. I was on the phone for 15 mins while summit was checking for ANY .040. Only cast and hyper's they could get

Trw joined the bankrupt, out of buiness party

Good luck, maybe U have better luck than me. Manici was sure they don't make them anymore, maybe Ebay come through for U.

Those old trw are heavy thou, @ 6,000 it be like the hypers turning 6,500. It live either way. I wanted trw at first also.
 
goldduster318 said:
Those are for a 4.00 inch stroke (stroker kit), not the stock 3.31.

Summits showing the TRW's are still available.
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This is what I recommend even though you say you don't want hyper pistons:http://www.kb-silvolite.com/kb_car/performance.php?action=details&P_id=135

I used KB hyper's in my 360 for years, stock crank, stock rods and went 10.50's. Now the rotating assembly's in a customer's 360 he street drives.
All I can tell you is don't be afraid of them. They are light, have plenty of valve pocket, just open up the top ring gap and let it EAT!
Brian
 
I think hyper pistons are fine except in a stroker that sees the high piston speeds. In a normally asperated 340 they will work fine. And why not machine a little off the tops of the pistons to zero deck them?
 
I got the same KB 243's, mine were made Dec 2009. Again I beated on that engine a quite a few times. I shift most times at 4 to 5,000 rpm's. Its got a 10 inch tci streefight con and i got a heavy foot:love10:

Since we live so close maybe come late March early April U could check it out some place--Tim Horton on 12 mile maybe?

I got dual Carters on it, police wheels and speedo, an old Direct Connect steering wheel from the 80's made in Italy. 5 amps, subwoofers, its a blast, just needs lots of fuel.

Its got the rev limiter set @ 6,500, U free to see if U can break the engine--no neutral slams allowed, not for the engine but my trans or rear end might break
 
well either way, they both have the same compression height...so...same problem.

I prefer forged as they are the be all end all of durability...even if they are heavier. I would consider getting those machined. That alone would drop a little weight.

Believe it or not, the KB 1267 CAST pistons that came in the engine are zero deck.
 
70aarcuda said:
yes trw is out of business...speed pro now makes...

http://www.summitracing.com/parts/TRW-L2316F40/

say they would ship on feb 7, 2011

too heavy of a piston...i would use the kb243 also...

Used a set of Kb191 hyper for ever...ran a best of 10.70s with them...
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Well maybe now they are making them once again. Last spring nobody could get them for me, I tried. Resale value of the motor likely be higher with forged, looking back thou my motor is quiet on starts and if it holds up I be happy
 
I seen a 340 at one shop getting cast pistons.

Your young, U should build an over kill engine cause heck in a few years U might be winding it out sometimes to the upper 6,800 ranges--U might want juice, etc.

U could shave the trw pistons down for a bit of extra clearance (even if not really needed) and mill the heads down and get an honest 10 to 1 compression. Those close chamber heads should lose alot of cc on each .010 cut and likely are thick deck heads and can be easily cut .040-.050
 
Yes, I want it to be overkill because I really only want to build it once...so it will last hopefully for most of my life anyway. At roughly 1000 miles a year it would only have to make 50-60k miles...sounds doable anyway.

I was actually planning on buying this kit provided my crank still polishes up at 0.010/0.010 (looks like it will). Seems like a hell of a deal when the pistons alone would be $415. http://www.summitracing.com/parts/FEM-MKP713A-411/KitComboContents/
 
Gee they didn't have stuff like that last spring. Kit looks cool.

So your not going to hit the car shows and see some drag strips in Ohio/ Summit has a cool strip past ceder point. I'm planing on it, maybe get some highway gears, like 3.23 and cruise. Miles rack on fast.

Oh, it should last well over 50,000 miles those short stroke motors not revved to 7,000 daily, lol. The forged pistons will burn a bit more oil over times. When the motor is cool the hyper pistons seal better, why most all new factory engines have hyper pistons, for better emissions. I don't think hyper breaks down and gets weaker over time?
 
I swear they've made those kits for a long time....maybe not for 340's, but I remember looking at them for my original 318 like 5 years ago.

I've got the 3.23's and fairly short tires and 70mph=3000rpm...not quiet (side exit exhaust), and I like A/C so I tend not to take it on road trips (and the current 360 barely pulls 10psi per 1000rpm)
 
Wear shorts in the summer and the nights are most often cool up here. A/C takes up too much room and its hot for just 3 months over here.

Last spring nobody was making those trw/speedpro pistons. Manici said they tried, summit said the same thing.

Yeah 3,000 gets a bit old, I run 4,000 @ 70mph, windows all open, stereo blasting--I really should act my age. Traffic moves so quick now--75 mph min--2.94 gears would work.

Check these mufflers out, I'm thinking of them, quiet can be nice some times.

http://www.summitracing.com/parts/JEX-Q414A/ quiet
 
On my 410 the pistons stuck out of the hole .016-.018 Just like yours. I am using RHS Heads from Brian at IMM. I have all forged internals with H Beam Rods. I used the SD Felpro gaskets that are .054 Compressed, 4.172 Bore. The reason I used the Felpro 519SD is I was gunna hit it with some NOS and at the time Cometic did not make gaskets for the RHS Heads. Now they do!

Quench was about .036. I have bounced this engine off 7200 RPM a few times. I usually shift it at 6500. Rev Chip is set at 6800 Rpm

The Fire Ring is a little wider on the SD gaskets. FYI
 
One thing to consider is if you go with the lighter hyper pistons it will rev much quicker and less weight is a lot less stress on the rods/crank/main caps. You just have to get the ring gap correct then the hypers will last.
 
Mad Dart said:
On my 410 the pistons stuck out of the hole .016-.018 Just like yours. I am using RHS Heads from Brian at IMM. I have all forged internals with H Beam Rods. I used the SD Felpro gaskets that are .054 Compressed, 4.172 Bore. The reason I used the Felpro 519SD is I was gunna hit it with some NOS and at the time Cometic did not make gaskets for the RHS Heads. Now they do!

Quench was about .036. I have bounced this engine off 7200 RPM a few times. I usually shift it at 6500. Rev Chip is set at 6800 Rpm

The Fire Ring is a little wider on the SD gaskets. FYI
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Cool:burnout:
 
Mad Dart...good to know. I'll have to price out what aftermarket rods would be vs re-sizing the stock rods+arp's.

I do wear shorts+t-shirt in the summer and use the handy dandy vent doors, but if you get into any traffic, it gets blazing hot in there....as the headers are right under your right leg, I have black interior, and the small windows. It tests out the deoderant, that's for sure.

I run T/A style mufflers with the same end inlet & outlet in 2.5"...they are Dynomax Super Turbos. They're actually pretty quiet until you get over 2500rpm. I wouldn't change it for the world as the sound is great. If I had A/C I could run with the windows up and it would be plenty quiet even at 3000rpm.

There are lots of 340's out there with the L2316F's...and stock crank and rods...I'm not too worried about overstressing. I'd like to stay away from hyper pistons because if you have any type of serious detonation, or lets say you drop a valve, etc...you get this: http://www.hotrod.com/techarticles/engine/hrdp_0604_ford_302_engine_parts_failure/photo_09.html

And then the block, heads, etc are junk. Get why some people call them hyperexplosive pistons? If for whatever reason the Speed Pro/TRW forged ones are not available, I'll probably call Diamond and get some custom forged pistons. Oh yeah, and I kept forgetting to say that the extra piston rock goes away when the engine is fully warmed up as the pistons have expanded to take up that extra clearance.
 
You could detonate the Hypers pretty darn hard and they will never come apart like the picture you posted. Drop a Valve & Yes it will look like that along with taking out cylinder walls and putting holes in the side of the block! Guess How I know that....haaaaa
If you detonate with a Hyper piston Naturally aspirated the most I see it doing is busting a ring land and if that happens someone did a seriously bad job on the tune. I say run the Hypers, tune correctly and it will be just fine! It will last for years with them no problem!
 
Yes the piston rock goes away when the motor is warmed up. Problem is the warm up. Those do run tight for a forged piston but looser than the hypers.

Most problems with KB hypers is not running a .030 top ring gap. That large gap closes up as it heats up, The top ring is higher up and gets more heat. Most engine builders today know that those hypers need large ring gaps. Hypers been out for over 15 years now i believe. Pushing 20 years.

If they were that bad they would not make them anymore. The lighter pistons make everything easier on the engine. This isn't 1970 anymore, why use 1970 tech. I see your going with a roller cam, I went old fashion and use Valvoline not street legal oil with zinc. But pistons I went the newer way. I don't baby my engine either
 
Yeah and by using the lighter hypereutectic pistons, you'd reduce the piston weight by around 100 grams. So you'd reduce the rod/piston combo weight around 7% and the total rotating assembly weight (not including balancer & flywheel) by about 2%. I doubt that is going to make that much of a difference.

Forged pistons are really not the dinosaurs that you're making them out to be. Still the ultimate in durability. All the really serious stuff uses them for a reason, the modified turbo guys use 'em. Chances are you could have built it with cast pistons like were in my 340 when I got it...previous owner had it in a 71 Demon with a 4-speed and 4:10's that was a race car. Spun it to 6500 all the time...and those never blew either. Just because it didn't break doesn't mean that I want them.

My daily driver Chevy has hypereutectic pistons from the factory. more than anything I bet they use them in there for weight savings for fuel mileage. It also has a knock sensor. Hell it even has a 4" stroke and revs to 6300 rpm. They're very light because the compression distance is also short on it.

Anyway you crack it, stock stroke 340 pistons are all HEAVY. They have to be with the stroke and deck height the engine has.

There are faster cars than mine with 7 5/8" ring gears in the rearends (4th Gen GM F-bodies) that run 12's out of the factory, but I'll still use (and pay extra) for an 8 3/4 because I know it won't break. Same thing with the forged/hypereutectic piston debate. I'd rather pay more and KNOW I've got the most durable thing that I can buy inside of the engine. Build the rest of it high tech but strong and enjoy it forever. I'll bet I gain more power with the roller cam than I loose with the heavier pistons.

One thing from an engineering perspective about the large ring gap on the hypereutectic piston...large is saying that the top ring (same rings on any piston BTW) is going to run hotter than it normally would so there is room for expansion. To me, that says they get VERY hot and probably have a decreased life as a result. You have to remember that newer cars that use these pistons stock also have thinner rings and most are in aluminum blocks that dissipate heat better than our iron blocks...and have oil squirters directed at the bottom of the pistons. It seems very likely that they run tighter than 0.030 ring gaps too.

There's another thing that's bad that they still make: Professional Products intakes. I had an 89 318 roller engine destroyed by one 15 miles after i put it in. The casting was designed improperly and sprayed water all over the cam and also messed up the bearings badly.
 
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