GM 3.1 / 3.4 Crank Scraper

GM 3.1 / 3.4 Crank Scraper

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5.0 average, based on 2 reviews


Product Information

This scraper is designed for the 3.1 MPFI, 3100, 3400, and 3.4 DOHC engines.

Ishihara-Johnson crank scrapers are a very simple but effective way to improve the performance of your engine!

During normal engine operation a significant amount of oil adheres to or becomes entrained in a cloud surrounding the spinning bottom end. This oil eats up horsepower your engine is making by increasing the rotating mass and also creating parasitic drag. A crank scraper mechanically strips off excess oil by coming close to, but not touching*, the moving crankshaft and rods. It also interferes with the pressure differential that draws oil into the so-called windage cloud.

Our crank scrapers are constructed from 12 gauge mild steel (about 2.5mm thick) and include installation instructions.

PDF of the installation instructions


Product Code283400CS

Customer Reviews

Average Rating: 5

That Passive Little Extra Little Bit

I have a 2001 Pontiac Aztek and at 243+ K miles a gasket that normally failed at about 80K miles in other vehicles gave up and put too much water in the oil. Since the engine was out ond on the bench at the engine shop to be redone that was the time to put in all the tricks that BEN offered so I put in the scrapper. It cost over $1,000 just to R&R the engine and have taken to the next town to be rebuilt so I also did a scrapper. Money was adding up so I went with this one instead of the Teflon one, still getting a good product and function. The shop said I did not miss a trick. Since I wanted it to run on 87 Octane I went with stock 9.5:1 compression. On a lark I put some premium in it and found all the extra go I thought I was missing. Had I known what was what I would have gone with 10.5:1 but I am not changing now, especially since Covid - 19 put the stomp on one of my incomes. Getting back power in a passive manner is always a good thing to improve the net horsepower. May everyone be blessed and escape the CV-19 virus. David A. Williamson (17 Dec 2020, 09:00)

A Little Bit More

I was rebuilding a daily driver because gasgets that normally go out before 80K miles had gone out at 243+ K miles. I used ALMOST every option Ben offered on this site. I was not going into serious competition so the teflon scraper was not required. The engine rebuild shop I used said I did not miss a trick so they were impressed that I used a scraper whatever the kind. After we started this rebuild the engine balancer came in. Instead of the normal 12 to 14 gram tolerance most engines come to mine was within 1 to 1 1/2 grams which is negligible. It will run 7 mph at factory idle of 650 rpm on level ground. It used to be that I had to use the throttle pedal to get it to move. The high torque cam did its thing with all the other improvements. Thanks Ben for offering this site and products. At this writing it is now the time of Covid - 19 and the performance packages are not being offered now. Reason unknown at this time. May all of you be blessed and safe.David A. Williamson (3 Dec 2020, 02:03)
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