F.E Drill Bit Test.....??

[MIKE SCHULZ]

Gentlemen;I have read several posts but none seem to tell me enough information about how to perform this "Drill Bit Test" - so next time I am at the junkyard on my back covered in Goop - I can be reasonably sure that the block I am looking at could have the thicker cylinder walls. I have 2 D4TE blocks with the webbing and I punched out the freeze plugs.Can anyone inform me as to how I go about doing this??.....Thanks!....Mike Schulz

[K.Wilson]

Mike,

The process is quite simple, but you will need a good drill index with all sizes down to a 64 inch and letter drills too; plus a good electronic caliper if you want to get good results.
As an example (no specific engine):
With the head off measure the distance between the bores at the most narrow point for the cylinders you will be measuring.
Then find the drill bit that most tightly fits between the cylinders ( the one that just "wiggles" in) using the drive end of the bit not the cutting end.
Take the measurement between the cylinders minus the drill bit size, divide by 2 and you have an approximate wall thickness.

Example: distance between cylinders .380 inch minus drill size 3/16 (.187) equals .193 divided by 2 equals .096 cylindar wall thickness.

Now the bad news, the walls could be shifted and one side could be less and the other side more, or they could be tapered etc. so the measurement is not exact. But for a simple evaluation of a block it is a good indicator.

Keith

[MIKE SCHULZ]

Thankyou Sir; That method makes sense!.....Now away I go to get covered in "GOOP!"