TR2/3/3A TR3 Engine Noise Identified

[MGTF1250Dave]

Aloha All,

Back in February I posted a question (TR3 Engine Noise) about possible cause for a noise in my engine. I received lots of good tips and suggestions, but wasn’t able to identify the problem. I pulled the engine with the help of my son so the engine good be opened up to see what was going on inside. In June I posted an update (TR3 Engine Noise Update) with a photo of some metal bits found in the oil pan. I have continued to disassemble the engine ad it is now completely torn down and I’m preparing for the reassembly. The source of the metal bits has been found, the gudgeon pin bushing in number one piston. Here is what it looks like:

 

[Andrew Mace]

NOT a pretty sight! Any other obvious damage?

 

[MGTF1250Dave]

Aloha Andrew,

No other apparent damage discovered yet other than number one piston rings seem worn. It leaked down significantly faster than the other three. The bearings (main & connecting rod) showed signs of wear, the pistons and cylinders seemed fine and all rings were intact. The cylinder head and valves look fine also. The crankshaft is off to the machine shop and hopefully it will only need to be polished.

I'm planning on replacing all the bearings, piston rings and having the rotating parts balanced. The oil pump and timing chain all checked out fine. I believe the engine was previously refreshed because I happily discover I have 87mm cylinders.

 

[TR3driver]

Uh oh. Now you've got me wondering if that's why the 'project' TR3 makes funny noises!

 

[Tr4dude]

Make sure you check the ring groove clearance in that piston really good, it could have hit the head and show no obvious signs of being damaged.

 

[Hap Waldrop]

I'm guessing the bigger section of the pin bushing was still in the connecting rod. Hey thats a new one for me, I never seen that happen before. I'm thinking the pin clearnce at the busihing was too much and thats why it probably happen. The big thing to make sure of is that the small end bore on the rod was not damaged in all of this and the new bushing when pressed in goes in firmly.

 

[tdskip]

Aloha Dave! Yikes - sorry to see that. Spirits good?

Full rebuild time?

 

[sp53]

Hi Dave well the good news is that you found the problem. When I did mine, my machinist buddy had me bolt the rod caps together at torque and then he trued them for roundness before I put the rod bearings back. In addition, I had him hone out the wrist pins because my experience was limited.
steve

 

[RonMacPherson]

Schneiders's is by you, Waipahu... Genuine over in Kailua.. They are the two shops I recommend.

Definitely stay away from headhunters... One of the other large machine shops(I won't post his three letter name on the site, but you can call me if you are curious) sadly has become an overseller,, production dollars than repair to better than new, like Randy does at Genuine...

Wasn't able to make it to last month's meeting, so my advice may be delinquent...

 

[MGTF1250Dave]

The larger piece of the bushing was still in the connecting rod. It had about 80% of the total circumference still in place. My measurements did not reveal any damage, but all the internal parts are off at the machine shop for them to measure for any damage. I'm sure their tools and experience will be a better check than my inexpensive calipers.

 

[Hap Waldrop]

If worse come to worse and the small end diatemr was damaged in some way , you could always do what we do to press fit rods when converting them to bushed rods, bore the ID a bit to clean it up, then get some bronze bushing stock (I get mine for Mcmaster Carr) and make a custom bushing to fix the problem.

 

[hondo402000]

why not just purchase a new rod?

Hondo