When fitting the wristpin into the rod, it felt a little tight. The pin fit into the rod but it just felt too snug, holding the rod sideways with the pin inserted the pin would not want to drop out of the rod. The experienced engine builder lending a hand suggested that I have the rods opened up. So I took the rods back to the machine shop and they opened the rods up a half a thousandth.
Now with the rods opened just a bit the wrist pin feels much better, it slides freely in the bushing but still does not have any play, if that makes sense.
While the rods were at the machine shop it was a good time to get the rings gapped.
So I Cleaned the blocks bore again with dawn, dried it off and did a light coat of WD-40 to keep from rusting.
Then went ahead and calculated the ring gaps. White paper is for my Talon. : orange paper is for my brother’s mr2 engine build :
BTW my engine builder stopped me and said there is nothing mild about a DSMs, go with bigger gaps. Who cares if you have to re-ring in 50 thousand miles, it won’t do much good if the gaps are too tight because you won’t make it that far anyhow.
Basically its better error on the large side.
Now this is where I used the summit ring squaring tool to get the rings squared in the block for getting the feeler gauges in the gaps. You could use piston to do this, but I guess this lessens the chances of dropping an expensive forged piston. It’s just garage bling really; I think you could do this with an old piston if you needed.
Using a summit ring squaring tool vs. using a piston.
Once the rings are squared you can measure the gap, and file accordingly to get the correct gap obviously taking baby steps. There is a lot of back and forth between the block and the ring file.
To get the correct gap I used summits tool.
The file, in use.
Once I was done I came up with these numbers. Where the 2nd rings were a little larger they came that way from out of the box, there was no filing done on those. And where the last ring is a little bigger we are probably going to move that to one of the hotter cylinders.
It was time to start again on the block. Having already re-taped the mains before any of the machining or hot tanking, all I had to do was make sure that the holes were totally free of any fluid that would keep the ARP studs from seating all the way and used lint free rags to suck up anything in the holes.
I installed the ARP rod studs with blue loctite on the block side; I used an allen on a ratchet to hand snug the studs. I let them sit like this for twenty four hours allowing the loctite to set up, I’m not worried about having the full torque on the stud while doing this because the final torque on the nut will stretch only along the vertical axis of the stud. The picture is while molly lube is on studs but is for illustration of how I left them set up:
Then placed the main caps on the block and got my washers, molly lube, and nuts set up so I could seat the nuts properly to the individual stud.
There will be three times with full torque on the mains. Once with the caps on to cut/seat, once to check the clearances with plastigauge and then the final time were the bearings and crank stays in place. The reason for this is to help cut the nut for the thread of the stud, making sure that the final torque is accurately reached. So, I got a piece of paper to keep track of the where the nuts came from and where they go when I’m taking on and off.
Just like head studs you must bring them up to the final torque in stages. The engine builder I was with told me three stages. IIRC, I think we used twenty, thirty five then fifty. Keep in mind you want a decent gap to your second target and your final torque so that the nut has to turn, for instance you don’t want a second torque value of forty five if your final is fifty. That’s too close to the final value and won’t allow the nut to spin; that was according to him. He has many motors under his belt; his own collection of built dsm’s and has had formal training in engine building.
I did wonder about the actual torque value. Take a look at these two manuals, exactly the same except for this. Feel free to chime in. Is it eighteen plus ninety degrees, or forty-seven to fifty-one? Notice the difference in the two books.
It was time to check the oil clearances; I put the bearings in dry.
Then carefully placed the crank on the bearings making sure it didn’t rotate, so that I could place the plastigauge on top of the crank.
Cranked the caps down the whole way in the three stages, with molly lube.
Pulled the caps to check clearances.
They all checked out well.
So now it’s time to put the crank in with healthy coat of assembly lube on the bearings, before cranking it down that final time, again going from 20 to 35 then 50ft/lbs.
Next are rods and pistons
