DIY converting -86 block to 87+ tensioner??
#1
Rainman
Rennlist Member
Rennlist Member
Thread Starter
DIY converting -86 block to 87+ tensioner??
Anybody have tips or a template or anything regarding drilling the holes for the 87+ belt tensioner onto an 86 block, to make sure its exactly in the right place?
Just use a drill-stop for the depth or what?
Or is it as simple as "center the tensioner plate over the block bosses and drill through the holes to match"
Just use a drill-stop for the depth or what?
Or is it as simple as "center the tensioner plate over the block bosses and drill through the holes to match"
#2
Rennlist Member
DIY converting -86 block to 87+ tensioner??
Anybody have tips or a template or anything regarding drilling the holes for the 87+ belt tensioner onto an 86 block, to make sure its exactly in the right place?
Just use a drill-stop for the depth or what?
Or is it as simple as "center the tensioner plate over the block bosses and drill through the holes to match"
Just use a drill-stop for the depth or what?
Or is it as simple as "center the tensioner plate over the block bosses and drill through the holes to match"
#4
Rennlist Member
#6
Rainman
Rennlist Member
Rennlist Member
Thread Starter
I did get a referral by someone to a semi-local shop that can do this but glancing over their site they appear to be quite pricey, at least for parts...no idea on services.
That said, I do have a drill press tall enough to fit the block on the deck and go to town. Looking at another block I have (S2) the tensioner studs are more or less centered on the bosses, so "how hard can it be"
That said, I do have a drill press tall enough to fit the block on the deck and go to town. Looking at another block I have (S2) the tensioner studs are more or less centered on the bosses, so "how hard can it be"
Trending Topics
#8
Rennlist Member
I say go for it on your drill press. It will get your holes square enough for sure. Drill smaller pilot holes, perhaps 1/8 or 3/16, first and your final holes won't have wandered. Then chuck up the 8mm tap and hand turn the drill press to start the threading so the tap stays square. Use a new (sharp) decent quality tap. The tapped bosses are only securing the tensioner, so absolute precision is not necessary.
#11
Rainman
Rennlist Member
Rennlist Member
Thread Starter
revisiting this...
anyone know how long overall the 3x tensioner studs are, and how much thread is engaged in the block?
PET doesn't appear to list the studs as separate parts from the block, and im all out of late blocks to compare with.
i would guess ~12mm into the block would be sufficient for an 8mm stud.
anyone know how long overall the 3x tensioner studs are, and how much thread is engaged in the block?
PET doesn't appear to list the studs as separate parts from the block, and im all out of late blocks to compare with.
i would guess ~12mm into the block would be sufficient for an 8mm stud.
#14
Race Car
Just picked up my block from bore/hone today and had all studs removed because I was highly considering nikasil.
Will ping you dimensions of studs.
Against the norm here, I would set the tensioner and use a bit same size as the holes in tensioner.
Just kiss the aluminum boss with that size bit to mark it for all three holes then remove tensioner and proceed from there.
The bit of mounting hole size will self center your holes and will have created a divot that will keep your 1st drill size from walking when you proceed up in bit sizes to reach the recommended 8mm thread tap size.
T
Will ping you dimensions of studs.
Against the norm here, I would set the tensioner and use a bit same size as the holes in tensioner.
Just kiss the aluminum boss with that size bit to mark it for all three holes then remove tensioner and proceed from there.
The bit of mounting hole size will self center your holes and will have created a divot that will keep your 1st drill size from walking when you proceed up in bit sizes to reach the recommended 8mm thread tap size.
T