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I looked over what I considered to be repeated D.O. questions, and in my search I found that many of them had to do with crankshafts
By Roy Berndt
For those of you who have your own children or you are exposed to them on a regular basis, you know that at some point in time you are going to hear the phrase "Do Over!"
What is a D.O.? It usually occurs after you have a complete and utter meltdown; a screw up; a brain cramp, as I like to call them. In the innocent world of a child it means you forget whatever it was that happened and you get to "do it over" as though the original crash and burn never occurred.
In the world of remanufacturing, unfortunately, a D.O. is called a chargeable warranty, the one thing you want to avoid like having a picnic on top of an ant colony.
Well, here we all are in a New Year hoping that it will be better than the last, so I thought that I would look at some situations that keep rearing their ugly heads. I looked over what I considered to be repeated D.O. questions, and in my search I found that many of them had to do with crankshafts. I thought that we could look at them together to avoid them as D.O.’s for 2004.
The first is the 3.8L Buick OHV V6 engine, in particular years 1994 and ’95. 1994 was still the Series I engine that used crankshaft-casting number 4737 and had a counterweight diameter of approximately 6.6˝. In 1995 the introduction of the Series II engine with crankshaft-casting number 2170 appeared and had a counterweight diameter of approximately 6.0˝. It has been referred to as the lightweight crank (See Photo 1). Here’s the caution: the 2170 crankshaft will certainly fit into the Series I engine but you’ll have a shaker on your hands and that is an obvious D.O.
Next is the 3.5L Chrysler SOHC, V6 engine. Introduced in 1993, it used the same crankshaft with a cast iron block through 1997. 1998 saw no 3.5L production, however there was a changeover going on for ’99 in which the 3.5L crankshaft was now housed in an aluminum cylinder block. It is also the year that the 3.2L SOHC V6 engine came on the scene, which impacts the crankshaft identification process for the 3.5L. The 3.5L cast iron block engine (’93-’97) was unique to itself, so there are no real identifiers to lock onto for that crankshaft. Although that in itself is the identifier, which you will understand as we continue (see Photo 2).
In 1999 Chrysler had a problem on its hands: there needed to be some way to distinguish between the 3.2L and 3.5L crankshafts because by visual inspection they look nearly identical. However, if you look at the rear of the last counterweight beneath the bearing select fit designation stamping you will see a "2" or "5" stamped into the crankshaft. No number is a 1993-1997 3.5L, a number "2" indicates a 3.2L 1999 on up and a number "5" is used on the 3.5L 1999 on up. The 1999 and up piston is approximately 3 oz. lighter than the earlier cast iron block version for the 3.5L so once again you can end up with a shaker if you use the wrong one and that is a D.O.
Next, let’s talk about the GM-Chevrolet 4.3L OHV V6 engine crankshaft. Because this engine was manufactured in both Tonowanda and Romulus engine plants, each has its own nuances that may result in a knocking/ticking noise that changes with RPM.
If you install Romulus connecting rod(s) on a Tonawanda crankshaft the result may be sounds that range from a ticking noise similar to a lifter to a knocking sound at idle like a crank with too much end play. The Romulus crankshaft can be easily identified both by the large casting lug on the No. 1 rod throw and connecting rod by the wider thrust face. Make the mistake of using the wrong part and you’ll have a D.O.
The last one is the SOHC Ford 4.6L V8 crankshaft. The 1991-’95 Romeo engine plant production crankshaft with the casting number F1AE had a front counterweight thickness of .960˝-.977˝. If it’s installed into a Windsor or 1996 and later Romeo block there is a very good chance that you will have interference with the back side of the front main bearing saddle of the block. That is actually the good part of that situation: if the crank does clear the saddle during assembly there is an excellent chance that once the engine is running and full endplay comes into effect you will have a knocking that is intermittent and we all know that will end up as a D.O. as well.
I hope that you all have a great and prosperous 2004 and that these helpful reminders will contribute to that. I hope you’ll also be sure to visit www.PERA.org to order your copy of the 2004 PERA Engine Application and Identification Catalog. For more information you can contact me at sourcePERA@pera.org.
For technical questions, contact the Production Engine Remanufacturers Association (PERA) at: firstname.lastname@example.org