[Fot] TR4 continued race motor problems spun # 2 rod bearing again - input thoughts needed

[Mike Mehl]

Well -several of you are up to speed on my engine saga.  First it was the head 
(May), then the # 2 rod bearing (July 4th Pacific Northwest Historic's) and then 
new engine #2 and then # 2 rod bearing again (Columbia Classic in Portland).  My 
understanding that bottom end problems are not normally this bad.

So what changed. 
- #2 engine had a different engine builder do the engine.  He is very 
experienced and does at least one other FOT member engine.  He had 15 engines in 
the SCCA runoffs.  They know what they are doing. 
- The #2 engine had a new crank and all new forged rods.  The engine was running 
warm around 210F pretty consistently through all 4 sessions the engine ran an 
spiked up to 270 in a big hurry and that was it. 
- The engine is equipped with an Accusump.   
-  The engine is apart and there is nothing obvious that is wrong with the 
block.  Is there something weird they need to look for?
- The crank was not Nitrited (would that have made a difference this quickly)

Is there something we are missing?  I ran the engine between 5000 and 6000 RPM. 
 It had a 455 rear end gear so I was painfully slow down the straights at PIR. 
 Could stroking the engine at those RPMs have hammered the bearings?   Would it 
happen after a total of 90 minutes of run time?

In the mean time I have crank #3 on the way.


Any thoughts would be much appreciated.

Mike Mehl 62 Triumph TR4 - Vancouver Washington