Weekend Update
Yesterday i started doing something i wanted to do for a while, that was checking the block / main bearing caps were round & true etc.... there's plenty of people who say after fitting ARP main studs the bores should be line bored / honed.
So i started off building up the bore gauge i got offof ebay (£75 delivered)
I then cleaned up all the main bearing caps and put all the ARP main studs back in to the block.
Torqued them down to 60lb/ft and started checking the clearances of the Main Bearing caps.
So the main bearing cap diameter is 59.00mm - i searched high and low for this figure online, as i wanted to check everything was in order before testing the main bearings.
I started by zero'ing the DTI @ 59.00 perfectly so that it would be easier to measure the +/-
I then decided to check each bore in 5 planes.... this was to check for any misalignment of the bearing caps... on some caps there was a slight step at the mating face even before being torqued up, it seems these blocks must "settle" a bit.
I was worried that too much of a step would cause the clearance to be too small and pinch the crank - this wouldn't be picked up with plastigauge.
The figures are below -
As you can see some of the figures are a little off..... namely across the joining lines but before i started "adjusting" the main bearing cap sides to correct them i decided that the real test is what the clearance is like with the bearings in place.
I then measured the thickness of the shells to see if there was any variation between them.... the answer was no they were all exactly the same. With the joining edges being thinner. This is normal for bearing shells as this is how the oil film is generated - by creating a wedge of oil that then gets transported round the bearing by the journal.
I checked the shells and found a couple of tiny marks on the backs of them so i ran a small flat needle file over the back of the shells to remove any tiny high spots from storage / manufacturing....
With everything re-fitted and re-torqued i then checked the sizes again -
I also measured up the main journals of the crankshaft and put them in the table, along with the calculated minimum clearance (based on dimension A only - 90 degrees to joining face)
So the clearances look good between 0.03mm and 0.06mm - The Haynes manual states for new bearings between 0.01mm and 0.04mm with a wear limit of 0.15mm.
The clearances across the joining line is quite a bit larger but i really struggled to find any limit's for these.... apparently if the 90 degree clearance is correct the joining line is not very important due to the extra clearances already machined into the bearings.
I wanted to check all these dimensions before i fitted the girdle to see if it changed anything
So the next day i started playing with my Girdle.... of course the wife thought this was hilarious !!!
Started off removing the original ARP main studs i bought -
Quick shot to show the extra length of the Girdley Studs -
First of all i cleaned the threads out in the block, using a M10 coarse plug tap -
Then fitted all by hand until they bottomed out, then put the caps back on -
Next up i popped on the spacer rings, before i tried the girdle plate on -
I noticed that the plate was rocking so in the absence of a surface plate i thought i'd check the lengths of the spacers prior to torquing the plate down.
I was quite surprised to find the spacers quite different in length (i know the spacers are to be machined down.... but if they are uneven when the plate is bolted down we will give me inaccurate dimensions to machine them down by)
I then checked them and noticed the machining marks..... really hard to photo but the middle was quite pronounced.
After a quick rub of them against a file mounted in the vice they were much better....to within 0.05mm so good enough to start.
Unfortunately i didn't have a straight edge in the garage ( i'll bring one home from work this week) so i used the bar of some manual vernier callipers - all the caps were nicely inline so happy days.
I then dropped the girdle back on and it was sitting a little better. When i turned over the girdle it was still a bit rocky..... after measuring it with feeler gauges it appears to have a slight bend in the plate (0.5mm). Not worried about the bend as it'll flatten down easy once the bolts are torqued up.
That was all i got done, next time i get in the garage i'll torque the mains up and measure the bearings again to see if the girdle alters the clearances at all. And then measure how much the spacers need to have removed to finalise the girdle position.
Thanks for reading,
Graham.