250 grams lighter, big difference?

I weighed a stock rod and piston tonight and then weighed one of my ross pistons with pin and an aluminum rod and i came up with 254 grams difference. is that going to be a noticable difference from your standard steel rod and trw piston combination? just trying to decide if it might be worthwhile to step up and buy a TA oil pan so that i could use the alloy rods

 

Bob - 254grams is a ton, so to speak!! Engine will rev quicker, less stress on the rotating assembly(along with the block),etc.

Generally speaking, anything you can do to lower the bob weight is a good thing!! :TU:

 

Lighter weight parts free up some HP and Revs a little faster. Aluminum Rods have less shock to the Crank and Rod Bearings. All the Aftermarket Steel Rods i have seen are always Heavier over the Stock Steel. I no the aftermarkets are stronger. But you are not freeing up any HP going Heavier.

 

Like Scott said, 254 grams per combo totals out about 4 lbs.
That is TONS when it involves reciprocating weight!!

 

Bob,

I agree that 254 grams ia a bunch but there is a difference between rotating weight and reciprocating weight. I have attached a link that describes it much better than I ever could. The article is from Cirlce Track magazine which in my opinion has some of the best tech articles I have ever read.

Another thing to think about... not only are you removing weight from the rod and piston but if your new rods and pistons are lighter than the old then additional weight has to come off of the crankshaft. So.... there is even more weight that will be removed.

For anyone who does go to a lighter weight assembly PLEASE MAKE SURE your machine shop removes the weigh off of the crank by PUTTING IT ON LATHE and actually reducing the overall diameter of the crank. DO NOT let them just drill holes in the counterweights. That ugly and doesn't reduce the wind drag of the crank spinning in your engine.

http://circletrack.com/techarticles/ctrp_0504_engine_balance/

Later

 

Will make a huge difference Bob.I believe thats why I got 950+ runs on the 'ol Scat motor before problems,the light weight takes a lot of stress off the bearings,caps,and crank.
gary

 

A little more.

Just to add a little more to this thread. I weighed some parts in the shop tonight, but my scales only go to 500g. I use them for my sons pinewood derby cars that only weigh 5oz.

Wrist pin-136.2 grams
snap rings 4.7g
rings- 54.7g
JE flat top .038 pistons were over 500, stock rods and Howards aluminum rods also.

What are the weights of the pistons and stock rods? How much weight is usually saved by going to aluminum rods? And will the combo stand 7000 rpms?

Anybody got some used scales they want to part with?

Thanks

 

I bought a used set of scales that go to 300lbs! :laugh:

 

Do they weigh in .01g increments?

 

You could put 10 sets of rods on it and divide by 80! :TU:

 

That should help with balancing my next engine! I beleive I will go out and buy 10 sets of aluminum rods. :eek2: