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Discussion Starter · #1 ·
Hi and thank you for looking at my thread, I may have a simple or a difficult problem with an engine build its a custom engine I am trying to stoke an engine for a larger displacement but I have hit a wall..
my question is
I have a toyota crankshaft 48mm main journals and 44mm connecting rod journals the custom rods that I am using are 45mm (large end) so they work out to be about 1mm larger, can I have custom thicker rod bearings made for this engine or MUST I weld crankshaft I would hate to have to buy NEW rods for just 1mm difference
All answers welcome and if anyone has a machine shop that can preform the welding I am located in NJ but I can ship out if needed a rough estimate for the service
Thank you so much
David
 

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I assume you are measuring the crank journal rod 44 mm
Are you measuring the housing bore of the rod with the bearing in. 45 mm
If so you have .0039 clearance in thousands.
Can you go to the next under size bearing and recut the crank for the wright clearance.

If i,am following this wright.

The other thing you could do if that will not work is send the crank out have it hard chromed and then ground to the size you need.
 

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Discussion Starter · #4 ·
Hi
thanks for the quick replys the journals on the crank are 44mm according to toyota literature and the connecting rods are 45mm (Both measurements are with no bearings crank metal to rod metal) I dont have a bore gauge to measure but you can see a slight size difference between the stock rods and storker rods I dont want to go too crazy spending a large amout of money I wanted a safe reliable alternative if I can get thicker bearings to make up the difference then im happy with that
Like always thanks for your input any other ideas please reply and if you own a shop that can perform any of these services please message me
Thanks again David
 

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mr2erdave said:
Hi
thanks for the quick replys the journals on the crank are 44mm according to toyota literature and the connecting rods are 45mm (Both measurements are with no bearings crank metal to rod metal) I dont have a bore gauge to measure but you can see a slight size difference between the stock rods and storker rods I dont want to go too crazy spending a large amout of money I wanted a safe reliable alternative if I can get thicker bearings to make up the difference then im happy with that
Like always thanks for your input any other ideas please reply and if you own a shop that can perform any of these services please message me
Thanks again David
David, you have to fit up the rod bearings into the rod, torque to value and then measure the diameter of the big end.
 

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Discussion Starter · #7 ·
Hi Tech I understand what you are saying but I just wanted to know any tricks I can do to make these 1mm larger rods fit the smaller crank, toyota wont make this custom bearing (connecting rod) so I wanted to know if anyone rodders have had this problem or have they just made the crank thicker I have heard welding, chroming , but I dont want to pay 450-600 for the work if I can just go buy some custom billet rods and be done and not have to worry about 1mm too big syndrome
Thanks
David
 

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David, I don't think you're listening. If you are measuring the big end of the rods without bearing shells in them, then yes they are 1mm too large for the crankpin. Bearing shells are about 0.062" (or maybe in your case dealing in metrics,) 1.5mm thick. So two bearing shells will make the big end of the rod measure 42mm instead of the 45 you are seeing now. The question then is, can you grind the crank from 44mm to 42mm and have it live.
 

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If you can buy a bearing in a large undersize for the rod. (ie .25-.50-.75.-100mm). Or scan the different rod specs and find a bearing that has similar OD. Same or slightly larger. and the ID. that you desire (or close to it). Have the rod resized to the OD. of the chosen bearing and crank journal cut to the rod bearing ID. size. Drag racers do it all the time Chevy cranks/Honda rods etc.
 

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So tellme, what size bearings are available to you?

1mm is an awful thin bearing, especially since you need to include the proper clearance.

I would think that you would need to find out how far you can cut the crank and then check if a bearing is available that would be proper.
 
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