Have you found this site useful? ...Help keep it on-line

Click a car to go to it's home page

back to Pauls' Triumph home page The Crankshaft
Thrust Bearing

     Well here's another one. Another subject lacking useful documentation on the net. Hence, the reason behind these pages, let everyone see what they're in for when dealing with thrust bearings and the Triumph 1500 series engine.

Thrust Bearings on the 1500 series engine are infamous for failing. There are a lot of sites that will tell you the trials and tribulations of failed bearing. Well here are a few photos of what this mess all looks like to go with the words.

thrust_before_in.gif (59025 bytes)
Looking straight down at the

thrust_before_out.gif (61682 bytes)
timing mark indicator
  .....Well I just checked my own little screamer......

   Oh man. Look at the photos! ...Notice the gap between the timing mark indicator and the edge of the pulley.

  I measured the free end play three times. The average says I have roughly 0.104" of fee movement. Time to change the bearings!

The standard bearings (as I measured them) are 0.090" thick. the thrust bearings can be purchased in 0.005", 0.015", and 0.030" thickness over sizes to take up (setup) proper end float.

      This is a must have tool. Not just for this job, but checking valves, and front wheel bearing end float are just a couple of other uses. This is my dial indicator with a magnetic base and adjustable arm.


thrust_gauge.jpg (12994 bytes)

    In the first two photos you can just see the tip resting against the pulley at the bottom edge of the smaller v-groove of the lower pulley.

    I went ahead and bought three sets of thrust bearings. One set of each of stock (0.090"), 0.015" over and 0.030" over, thick sets.  With a range of 0.097" to 0.104" as my measured free play, I'm guessing (hoping!) that one has simply dropped out.  

    At 0.104" of free play, subtract the stock thickness of 0.090" says I have 0.014" extra free play to try and make up for.   Looks like I'll need to pick up a set of 0.005" oversize as well. (...figures...the one size I didn't get) So IF.... one has fallen out, then one 0.005" oversize and one stock, will correct for the amount of free play I have in mine.

......  but who knows...this engine may already have two 0.030" in it...

check back to see what I find when i finally pull the lower end.

Update....Punkin 4/2000

    I finally got in there and replaced the bearings. Well I was right! One had simply fallen out. I was able to slip in an 0.005" oversize, but couldn't seem to get the second one in. So I installed one 0.005" oversize at the rear (fatten up the one that wears and falls outs) and one new standard size in the front.

    When I went back and measured the freeplay it was now at 0.004". We'll see how long they last. I'm going to keep checking them every hundred miles or so and see how they fare. 


          Update....Whitey 4/2000

75whitey_twgauge2.jpg (11589 bytes)

Here's a shot of the gauge in place on my 1975 Spitfire Whitey

75whitey_twlocation.jpg (13236 bytes)
Here's where they are located. Under the rear
most bearing cap. In this shot you are viewing
the #4 cylinder connecting rod big end and the
rear most bearing cap. The gray metal to the right
in this photo is the engine back plate.

75whitey_twgauge1.jpg (30044 bytes)
The photo text says it all.

 bearing rearward.jpg (8669 bytes)      bearing rearward.jpg (8669 bytes)
These two closeup photos (go with the gauge photos above)
show the freeplay visible next to the bearing cap. The yellow
arrows show the freeplay in the crank caused by well
worn thrust washers. As measured, freeplay was just over
0.007".   One +0.005" oversize and one new std. size
were installed and the final freeplay measurement
was under +0.002"

return to Whitey's pages

return to Teglerizer's home Page©1987-2010
All material copyright© Teglerizer 1996-2008

last edited 

Hit Counter
hits since last reset

Paul's Triumph Home Page Paul's MGB Home Page Paul's MG Midget Home Page


Hit Counter