Top guided vs bottom guided rods for 2.4

[coffeeguy]

What are the differences between top guided and bottom guided rods?
What is gained and sacrificed when using each style?
Thanks

[tlwjkw]

Don't think there would be any advantage of either one. But unless ya do something special I don't think there's a 2.4 piston built for a Top Guided rod unless its tha new Wizards?.......T

[wrechin2]

All 2.4's were bottom guided, never heard or seen a top guided rod for them. I don't think the 91 175 fat blocks were top. The book don't show they were. You would have to have some sort of spacer to make them work.

You have the skinny (8118) and fat(5250) rods. I like the fat rods for the "stuffing" effect but he smaller rods with rev quicker. Depends on your purpose. Just my thoughts.

[Jay Smith]

I'll choose top guided over bottom guided ANY DAY ! There is less rotational drag with top guided rods.. And ALL top guided rods can be installed in any 2.4...

Some opinion is that the larger rods stuff and reduce volume , my thoughts are the bigger rods are in the way of the vapor path trying to get to the port. I will use 41 rods ( small ) over 5250 ( Large ) hands down in full out race to recreational use. ...And I have had VERY little issues with the small rod failing when they are prepped and installed correctly..

my .02
Jay

[T-REX]

Top guide rods are skinnier and in theory, block less ov tha rod slot at higher rpm...I wuz exsplaind this by an ole dude call'd "Professor O'B"...

I did build a stock 200 2.4 chrome bore for DSRA SS use'in tha top guide rods, and it did run sum what better than tha bottom guide rods, BUT wuz it tha rods, or juss a classic exzample ov one mota runn'in better than anuther???....I sold tha mota, and it continued to run quite well!!....

I stacked washers to make thoze rods work on tha std 2.4 cast pistons....

[wrechin2]

But there isn't top guided 2.4 engine though right? Just the top guided rods will work when stacking the washers. Is it 2 stock flat washers or the 2.4 washers or a combination per side? Is there a 2.4 piston designed for the top guided rod? I have heard of going the opposite way and using the bottom guided in top guided and cutting oil notches in them. Learn something today. Thanks Jay and Rex!

[T-REX]

James, It's a much simpler task to use a bottom guide rod in a top guide piston...Juss chuck up tha pisson in tha mill, and do a lil machine'in, an ya ready to go...I am not aware ov a top guide 2.4 factory pisson, but ya juss never know what will fall out tha woodwork!!!....Dean may offer sum, I reely don't know, but use'in washers makes use'in tha top guide in tha bottom guide pissons a easy task.....Now, they did have a single THICK washer that merc used in a 260 that made a top guide mota, use'in bottom guide pissonz...Jay may know tha numbers ov theze...

[Jay Smith]

Rex is correct in the 260 with the Mahle pistons/5250 rods combo they had a weird spacing and needed to use a super thick pair of washers. These came in this combo in 260/245 HP High Performance motors from 1992 to 1995 ish...

I have a 2.4 Bridgeport Wizard new top pinned forged piston here and after measuring it it IS BOTTOM GUIDED.....But as Rex described can be with washers be fit on a top guided rod...

Jay

[wrechin2]

So, there isn't a 2.4 top guided piston made. I have seen people cut the notches in for the oil passages like a top guided. Thanks again guys for the info.

T-rex... did you look at the pictures of the intake yet?? I will probably plug them off.

[coffeeguy]

Thanks guys for your time

[T-REX]

T-rex... did you look at the pictures of the intake yet?? I will probably plug them off.



Yes I did, Never seen one wit that small a hole in it....Plug them up, and Ya know it'll work!!:thumbsup:

[wrechin2]

Thanks!!! That what I had thought also. That is why I already tapped them!!!!