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The mkiv Supra Owners Club

Balancing crank, pistons and rods.


hodge

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Not quite. The main caps are the bit that goes round the crank and attaches the crank to the block. The big end is part of the rod.

 

 

I thought the rod bearings were classed as the little end bearings?

 

Big end = Main Caps

Little end = rod caps

 

This thread is going to be very interesting. I'm going to build up my engine myself but I'll be leaving all the machining & balancing to a machine shop.

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Would appear I was wrong Scott, not uncommon lol. But when rod bolts get uprated to, say ARP I (incorrectly) assumed thats what the caps were.

Suppose its a slang term of sorts, if someone said to me their big end had gone Id instantly assume the con rod bearing shells had gone.

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This thread is full of useful info :) Casting flash, I assume, is excess metal from the casting process when the block is made.

 

So if you were to balance your own rods, where woud you remove material from?

 

If you look in the block there is some horendous lumps of casting flash that you would not want floating around the bottom end !!!!

 

The bottom of the rod will have a pad of metal that is what has already been used for balancing, after market rods have excess metal , tbh any decent aftermarket rod set will have a balance sheet with it. If you are keeping stock rods its worth the £20 a rod to get them resized.

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Ive just fitted my engine back in after its rebuild and i spent £200 on having it all balanced and it was well worth every penny, its so much smoother you cant even feel it revving.

And i was also going to do it myself but then i was upto £2000 on parts i decided id rather not as i might balls it up so deiced to get my engine people to build it for me and im so glad i did as they do things i could never do and you dont just pay for there time you pay for the years of knowledge and experiance.

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What's casting flash??

And what's Glyptol??

 

Casting flash you will see , someone like Frost auto spares sell glyptol paint, this will stop and small pieces of casting flash etc coming away from the block and make the surface very slippy so the oil races back tpo the sump after it sprays off the crank etc.

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I thought the rod bearings were classed as the little end bearings?

 

Big end = Main Caps

Little end = rod caps

 

This thread is going to be very interesting. I'm going to build up my engine myself but I'll be leaving all the machining & balancing to a machine shop.

 

The little end is the end of the rod that attaches to the piston via the pins. There is no separate cap - you slide the piston pin through the rod. The big end attaches to the crank and is in two parts or you wouldn't be able to attach it. The two parts attach with rod bolts - all this comes with the rod. The rod bearings sit in the big end of the rod and go between the big end and the rod journals on the crank. The main bearings sit between the main journals on the crank and the block on one side and the main caps on the other.

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I work in a machine shop Simon so I've got everything at hand I could need really for weighing etc.

 

In that case, go for it! The cost of the equipment is the only reason I didn't do it myself. The place to remove material to balance the rods at the big end is in red on this pic, and the same at the little end. (These are carillo rods)

 

rodsbalancearea.jpg

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The little end is the end of the rod that attaches to the piston via the pins. There is no separate cap - you slide the piston pin through the rod. The big end attaches to the crank and is in two parts or you wouldn't be able to attach it. The two parts attach with rod bolts - all this comes with the rod. The rod bearings sit in the big end of the rod and go between the big end and the rod journals on the crank. The main bearings sit between the main journals on the crank and the block on one side and the main caps on the other.

 

Ahh makes sense, what is a little end bearing then?

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