Another motor another rod knock day.

[mercuryfreak200]

So I put in a used 7mgte motor started it up and it knocked right away.......lol. So I have another one in the back of my expedition and I was wondering about bearings today. So while I was working I looked them up on Znet and found a set of sealed power for 45 bucks. Then I got to thinking are they matched for the cylinders? What I want to do is "refresh" the bottom end so I called toyota they said they are matched, but yet the ones at work don't say wether they need to be or not. So my question is does it matter cause I'm going to do the mains and the rods together rather than just replace the rod bearings.

 

[nwoods29379]

This sounds quite familiar since I replaced the rod bearings in my 7M-GE not more then a couple weeks ago. As for them being matched to each cylinder, I actually doubt it UNLESS you have the crank reground, which may be necessary. You might be able to get away with just replacing the bearings as long as the crank is not damaged. TSRM bearing sizing http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=70 The Sealed Power set is all one size and is the same set I used. In the box there will be 2 packages of 12 bearings in sets of 2 and thats it. I can't find it in the TSRM, maybe one of the others will know, but my Haynes manual tells how to check the crank to make sure it is still in spec.

 

[te72]

Pretty sure you need specific bearings, being that this is probably the part of your engine where precision matters the absolute most. I'd wait until someone can confirm the proper way to buy bearings.

Do it right the first time, or do it twice (or more...), which would you prefer?

 

[CyFi6]

You need to measure the crank journals and the rod big ends/ block main bearing bores. After you have a measurement for each, you can then use the TSRM to figure out which of the 5 bearings is needed for each journal. Considering that it is knocking, you will probably find that the rod or crank pin is damaged and needs to be machined. Many people just throw a set of STD size bearings in, but that is not the correct way to do it. STD size bearings should only be used when the machinist has machined the engine to accept them. If you take a factory assembled block and put STD size bearings in, you may find that it will have uneven clearances throughout the bottom end and some or all may be out of spec.

 

[hvyman]

Get the crank machined/polished at a reputable machine shop and get it measured and get the right size bearings.

 

[mercuryfreak200]

Thing is I have another 7m with a good bottom end I just want to "refresh" the bottom end on it cause its been sitting in the garage for a year or so. The motor in the car is going to be disassembled and rebuilt over the winter this other motor is a get me by for 3 months while I have the block resurfaced and the head done etc.. I just want to make sure this other motor that ran and drove fine when it came out of the parts car is ok to use. I got it for a backup just in case somthing happened with the one thats in it. Now thing is its been sitting so long I'm worried the bearings need lubbed before I install the motor from being dry for so long. Thats my real worry. So I was going to remove the oil pan to check them, can I check clerances on the bearings, and if I just went ahead and replaced them now even if they check out it might stop a headache later. Does that make sense or should I just not worry about it?