: 4.6 Rod Clearance

02-07-12, 10:08 PM
I am building a new 4.6 northstar to use in my class 1 offroad racecar. I am mocking up my crank with rods. I am looking for the rod clearances as i am starting with new eagle forged rods.

I was told to measure clearance between the two rods when installed on the crank.

What should this clearance be?

02-08-12, 08:26 AM
Here is the procedure for a 2000 year

Note the orientation of paired connecting rods on each crankpin. The notches in the connecting rod cap must be facing each other.
Before removing the connecting rods, check the connecting rod end play using the following procedure:
2.1. Tap the connecting rod to one end of the crankshaft journal with a dead-blow or wooden hammer.

2.2. Using feeler gages, measure the clearance between the crankshaft counterweight and the connecting rod.

2.3. The connecting rod end play should not exceed 0.500 mm (0.020 in).

2.4. If the end play exceeds the specified limits, measure the width of the crankpin end of the connecting rod.

2.5. The width of the crankpin end of the connecting rod should be 21.745 - 21.805 mm (0.856 - 0.858 in).

2.6. If the connecting rod width is significantly smaller than specified and severe wear is present on the side of the connecting rod, replace the connecting rod.

2.7. If the connecting rod width is within specification and excessive scoring is present on the crankshaft journals, replace the crankshaft.

02-08-12, 10:45 AM
2002 gives .008" to .020" total side clearance.

02-08-12, 12:39 PM
If you have one rod or one journal out of spec, check for a bent connecting rod.

02-08-12, 08:00 PM
I would contact the rod manufacturer and see what side clearance they recommend.

Mark D
02-14-12, 02:08 PM
I'd like to read more about this little project. It has caught my interest.
Mark D.

02-14-12, 02:34 PM
For ideas on kit cars, hot rod, and sand rail Northstars, check out the CHRFAB website and search posts in CF by speedygman.