Balancing !
- Thread starter FeNder
- Start date
350ep70gr
Member +
yeah that will be fine, to be honest not a lot of people go to the trouble of balancing the internals of an engine when rebuilding so there wont be a problem
I take it you are jocking mate! Am i right guessing this?
Chris
MentaLEP91
Member +
ofc u have to balance them or they your engine wont last long mate imo.
350ep70gr
Member +
Hey Fender
I see you cant find someone to balance your parts so i will try to find an easy solution for you (as accurate as possible)
First weight all pistons one by one,rods one by one,ring sets (all the rings for one piston including the clips),then all the pins and finaly all the big end bearings (by two). Mark all the parts and write down all the weights.
Then mix them each other to be as close weight each other.
Example piston 1 101gr
Piston 2 102 gr
Rod 1 103 gr
Rod 2 104gr
Pin 1 11gr
Pin 2 12gr
...... ....
Your combination should be piston 1+rod2+pin1+..... =216gr
Most pistons set like ross you use come with +/- 1gr balanced
Same for the rods so will be easy to make them each other less than 1gr
If you could dont mix the pistons pin.If it is not possible tho to match the weights then its ok.
This is the half job.
Now you need to balance bolt-crank pulley-timing belt gear-crank-flywheel-flywheell bolts-presure plate-pressure plate bolts as A COMBINATION and not each part individually.
For doing this you must put them together and mark crank and flywheel and pressure plate so when you have them apart you can install them again in the same position.
After you need a base with two point where you can spin the crank assemlpy by hand.(you can find this base in any machine shop).After you secure the crank spin it by hand and mark on the flywheel end where the crank will stop. Then turn it again and again and again and mark all those times. If those marks are close each other means that there should be metal to be removed (from flywheel or pressure plate)dont touch the crank by any way (reducing or adding weight).
You reduce weight by slight making a start of a hole. Then turn again till the crank stops in different places.
This is your best possible think to do and really can be compared to a proffesional job wich will stimulate 10000 or more rpm with the rod-piston weight on the journals and crank in real stress situation.
If i was you i will sent all the parts outdoors for balancing.
You after +/- 1 gr in total.
Chris
350ep70gr
Member +
Jumping the balancing step can cause from nothing to...everything...!!!
Listen the Greek guys!!:rockon:
Chris
59bhp
Member +
really?!?! i was almost positive that all the engine internals came pre balanced anyway,
i thought that balancing them to each other was just neccesary if going to large rpm's?
in fact i dont know anyone of my mates with forged internals who have had all the internals balanced to each other and they are spot on so not sure where you got that from.
Its pretty rare over here to have an engine blueprinted actually.
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350ep70gr
Member +
Think like your bent a wheel in a bump or when you loose a balance weight. All the system will start to vibrate and this will eat your bearings and what else is involved. Same is with the internals but in a higher degree because of the higher rpm and higher mechanical stress.
It is basic physic and weight off centre torque trying to escape towards outside in every single turn. Sorry cant expain my shelf better in english but hope you get it.
Also when balancing 95% times you notice a more free reving engine.
Chris
59bhp
Member +
yeah i knew that but i know it isnt neccersary. I understand the concept of balancing, simple harmonic motion, torque and the bent wheel etc but thats to a much higher degree. When the internals come pre balanced to within a gram of each other it isnt going to cause the engine to explode if not blueprinted. I dont think any of the traders on here offer a balancing service as part of the engine rebuild without etc cost.
Although to be honest if you can afford it and know its going to be done properly it would be preferable.
Although to be honest if you can afford it and know its going to be done properly it would be preferable.
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350ep70gr
Member +
thats good read 350ep ill do my best weighing them against each other ,
we got that machine to turn stuff like balancing bent alloys ill try using that and see my luck ! cheers 59bhp rep added all
If you watch again the video in my user profile you will see clearly how you need to drill on the flywheel and pressure plate.
You cant use a balancing machine without the special weights on the big end journals.
If you like to test ONLY for test propose it is ok to test. But dont do any job based on this machine.
Chris
Toyota does an excellent job with the balance of their components. Therefore on a standard 5E or 4E the balance of the reciprocating parts, (crank pulley/crank/rods/pistons/flywheel) is very good. When you change parts such as pistons and rods and flywheel it will now upset the balance of the engine. A well balanced engine will rev more freely with reduced harmonic vibrations. You may not have too much of a problem when fitting new forged pistons and steel con-rods because these parts are normally within a gram or two of each other. Dont confuse blueprinting with balancing. Blueprinting means checking the exact tolerances for each component and if that component does not have the exact tolerance then it is discarded and replaced with another component. Balancing weighs for example all four pistons and then 3 pistons are brought down to the weight of the lightest piston by drilling small dimples in the underside of the piston. The balancing of the rods is more involved because each end of the rod is balanced separately and then 3 rods are brought down to the weight of the lightest rod. The crank pulley and flywheel as well as the crankshaft are balanced on a balancing machine where the crank is fitted and spun up to 10K RPM and a strobe light points to the area on the crank or pulley or flywheel that needs metal removed to bring each of these components into balance. This should only be done by a trained machinist. The beauty of balancing is if you damage a piston or a rod, all that is needed is to make these two components match the lightest one in the engine and the engine is once again fully balanced.
350ep70gr
Member +
if i had a £1 for every engine i have seen which hasnt last that long due to being imbalanced - i would be a rich man
why people bother spending a fortune on a forged engine and neglect such a paramount part as balancing is beyond me. Balacing is pretty cheap for the importance is has.
the flywheel for example only has to be imbalanced a few grams to have a drastic negative effect on bearings/ shells etc.
if your going to spend £XXX on an engine, pay the extra few hundred quid and have it balanced guys
why people bother spending a fortune on a forged engine and neglect such a paramount part as balancing is beyond me. Balacing is pretty cheap for the importance is has.
the flywheel for example only has to be imbalanced a few grams to have a drastic negative effect on bearings/ shells etc.
if your going to spend £XXX on an engine, pay the extra few hundred quid and have it balanced guys
59bhp
Member +
so youve seen at least 100,000 4e's expire due to inbalancing? wow thats impressive man. How do you know the engines internal inbalance is what caused the failure?
okay what components are you lot buying that dont already come pre balanced, do you realise how much of this stuff is done before being sold?
flywheels, rods, pistons........all balanced before leaving the factory, if you buy crap or want to rev the engine beyond the normal rev limit then yes you will HAVE to balance it all. If not you do not HAVE to and it WONT have any detremental effects. not opinion, fact.
sx_turbo
Lifer
brand new pistons and rods that are built specific for the 4e/5e engine, do not need balancing if you are just using the stock rev limit.
IF however you are reving past the stock limit then you will need to get the bottom end balanced,
on the 4e you can put a lightened flywheel bought from a mjaour manufacture like zep etc and NOT have to get the bottom end rebalanced.
i bet dave burwash never balances bottom ends, i bet toytuning never, and i know for a fact that my current engine builder isnt balancing the bottom end.
IF however you are reving past the stock limit then you will need to get the bottom end balanced,
on the 4e you can put a lightened flywheel bought from a mjaour manufacture like zep etc and NOT have to get the bottom end rebalanced.
i bet dave burwash never balances bottom ends, i bet toytuning never, and i know for a fact that my current engine builder isnt balancing the bottom end.
who said anything about 100,000 engines and who said they were all 4e's? its a figure of speech, dont take it literally
No engine will ever be perfectly balanced, that's a fact, but can you improve on the balance of mass produced engines and components? YES
If you truly believe you cannot improve on the balance of an engine after you've built it because the rods/bearings/crank/flywheel come balanced at factory then that is your decision
what i'm trying to say is why wouldnt you want to get it balanced for the sake of a few hundred quid? - i dont see the logic
GTti
Member +
It keeps suprising me about the number of users on this site randomly offering their wealth of knowledge or experience.
I think the moral of the story is everything in moderation, if you're replacing OE parts then it's unlikely to be a concern.
If on the other hand you have aftermarket rods, pistons, flywheels etc then a comprehensive job should be done by a reputable company - afterall this is usually a job that will be done in a single stage and as mentioned above it's well worth the peace of mind knowing your engine will not shake itself to destruction.
And no, I doubt Dave or Toby balanced engines which is probably why they never offered a warranty with their work
that's the point i was trying to make;
why spend £5k on a tuned engine and not have it balanced?
if your rebuilding an engine and going to potter about to the shops and back then yes, probably no need to balance
but i still stand by my point that mass produced engines & components can be improved in balancing terms.
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350ep70gr
Member +
Have seen one unbalance broken and was way bad enough for telling if was a balance fault or not. Was reved few hundrend rpms more than stock tho and usually those problems will give a dissaster higher the reve range.
You may notice a quick worn on bearings(not equal footprint),vibration and unstable high rev if you know what i mean about this.
Dosent really maters what componets all buying. Most pistons and rod set will come balance at +/- 1 gr but you really can have 2 gr unbalance if you not much them each other (and thats only from piston and rod only) Other rotation parts like rings set,clips,bearings can add more to this.
Flywheels and pressure plates usually come way more unbalanced that +/- 1
At least some off them i have seen and mesure in the past.Even if we can accept they are balanced before will not be balance as a set with the other rotation parts.
Maybe if you use genine parts and standard rev limiter you can get away with skipping this step. A balanced engine tho with the same parts WILL be BETTER and SAFER.
Also dont forget that toyota balanced this engine 15 years ago with the way they have at this period of time. Nowdays thinks have been change a lot. An also over the years the crank could be off balanced due to the streess he takes.
If i cant convince you again i leave it to your opinion!
Chris