No sir, I've seen many quality groove spacers with a LOT of time/passes on them, and no problems at all.
longer connecting rod
- Thread starter Twister79
- Start date
JUAN W said:
Way to many variables to say it is or isn't the rod in your combo Juanw (in my opnion) 6" rod in a 400? If it is a 1/4 mile at a time car and you all ready have it a part... HELL YAH! Every little thing helps. Street car, with all the grinding and the short, short piston not worth the headache.
I think it all has to do with stacking.What I mean is if you do one thing that helps power a tiny bit you want see any thing ,but if you do 20 -30 little things it will make a big deference. Like longer rod ,4/7 swap , thermal coating , scuff coating on pistons, roller cam bearing, windage trays, areo counter weights, larger bore lifters,costom rocker ratios,top secert cam grind.etc,etc,etc, Just one of these probably wont make a night and day deference but all of them together will. Just my 2 cents.
David
David
There has been many studies on short to long rods, google it, the longer rod always makes more power, maybe if your a novice and not understand dwell times at tdc and such, compression height benefits, ring locations, top ring land location etc, you should stick with your stock length rods, there are a million variables on the reasoning on a stock rod, and also do you think an engine builder like reher morrison just throws a dart at a dart board and says ''all engines today are getting longer rods and a lower compression height pistons'' YAY!! I think not, and the reason he didn't reply would be because if you are asking him that question you definately won't understand the answer so why waste his time.
eldabo said:
That's exactly right david, that shows the difference between a well built motor and a thrown together motor, there's always a reason for a good engine builders madness, of course a longer rod won't give you a huge gain in power but there are a lot of benefits for it, I will find some info on it
The main benefit of a longer rod is a lot less side load on the cylinder, think about it, the lesser angle of the longer rod when the cylinder combusts and the piston starts to travel down the cylinder there is less pressure on the side of the cylinder therefore having less friction with the piston skirt/cylinder wall which equals more power and less wear on the piston skirt, and the other benefit is a lighter piston, less moving mass is easier to move, is it easier for you to pick up 10 pounds rather than 20 pounds? Evrey gram of weight on a piston counts as 1 gram at 8000 rpm multiplies itself many times over.
The only benefit to running a shorter rod that I know of is for nitrous guys that need a higher compression height so they can get there ring land further down the piston as that makes the top ring land stronger and less likely to lift it, not saying that's on all applications but definately on some.
From what I've heard longer rods give you more low-end torque and high rpm horsepower. So then that means that they would be great for street/strip cars. There are many benifeits to installing a rod longer than stock. Most of them had already been said.
Man I got my pop corn to late but will bring this to the top, First thing you do is get a piston set-up the way you want it, spray and turbos the ring stack will be different from N/A get the piston done with your ring stack right then hook a rod to it and then to the crankshaft. its not the lenght of the rod that makes the power its keeping the air on top of the piston and not having it rock in the bore under load. If you put a 6 inch rod on a 4 inch crank the piston rings will be to high to spray large amounts or heat from the turbo will take them out. A lot of Motors have backed off the 6 inch rods and went to the 5.850 rods to get the piston right.
I'm going to jump in towards the end of this topic. Mnay years ago there was a build up of a sbc in on the car mags. It was a 400 block .030 over, with a 283 crank-only 3" stroke. Makes for a VERY high revving small block with unshrouded valves because of the large bore diameter. The catch was they used Ford straight 6 connectiong rods which are 6.209" long. This made for a good ratio, I believe almost 2.1. The compression ratio with the custom pistons and steel heads was almost 13-1 and they were able to run 87 octane, not by retading the timing but because of the rod ratio and dwell time at TDC. The engine made alot of horsepower at a very high rpm, but was very street friendly. I'll try to find the article.
**edit** the rods werent the reason the HP was made, but rather a good combination of parts that when totaled when a good package, like any strong running engine.
**edit** the rods werent the reason the HP was made, but rather a good combination of parts that when totaled when a good package, like any strong running engine.
