Block rebore info?
14-05-2007, 03:31 PM
#1
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Block rebore info?
Right as im sure a few of you know im rebuilding my bottom end... again 
and i need to get the block rebored for the new pistons ive got..... The Youth off here ( steve) mentioned yesterday that when you get the block rebored they should be using a " torque plate " to rebore it to make sure the bores are perfectly round, ive just been in touch with the engine place i got my crank done and they said theyve never even heard of it? yet i rang another place who uses the torque plate, but they cant do it for 2 weeks
what exactly is it and is it neccessary?
the place that did my crank said theyve been reboring blocks for years and have never used one or have any knowledge of one
anyone shed any light for me?
cheers in advance
and i need to get the block rebored for the new pistons ive got..... The Youth off here ( steve) mentioned yesterday that when you get the block rebored they should be using a " torque plate " to rebore it to make sure the bores are perfectly round, ive just been in touch with the engine place i got my crank done and they said theyve never even heard of it? yet i rang another place who uses the torque plate, but they cant do it for 2 weekswhat exactly is it and is it neccessary?
the place that did my crank said theyve been reboring blocks for years and have never used one or have any knowledge of one
anyone shed any light for me?
cheers in advance
14-05-2007, 03:47 PM
#3
Too many posts.. I need a life!!
Join Date: May 2004
Location: in the garage fixing yet another oil leak
Posts: 925
Likes: 0
Received 0 Likes
on
0 Posts
there are more knowledgable people on here than me but heres my two penneth anyway!
the theory goes that when the head is torqued up the block will distort particularly around the areas near where the head studs screw in so if you were to bore it at operating temp and with a great fat lump of steel tightened down on top this would distort the block by a similar amount as actual real world operating conditions resulting in the bores being more accurate at that time (although of course when you take the torque plate off and it cools down they will be distorted again!)
when you put the engine together and fire it up the bores which were distorted when cold will now re-assume the conditions when they were bored and be true.
the use of a torque plate appears to be much more common in usa than here. apparently the use of long studs in a 200 block goes much of the way to reduce this effect anyway but loads of YB's have been built without the plate and worked so not sure of the siginificance of it. i guess theoretically it will reduce piston blow by which is more important on a boosted engine.
the theory goes that when the head is torqued up the block will distort particularly around the areas near where the head studs screw in so if you were to bore it at operating temp and with a great fat lump of steel tightened down on top this would distort the block by a similar amount as actual real world operating conditions resulting in the bores being more accurate at that time (although of course when you take the torque plate off and it cools down they will be distorted again!)
when you put the engine together and fire it up the bores which were distorted when cold will now re-assume the conditions when they were bored and be true.
the use of a torque plate appears to be much more common in usa than here. apparently the use of long studs in a 200 block goes much of the way to reduce this effect anyway but loads of YB's have been built without the plate and worked so not sure of the siginificance of it. i guess theoretically it will reduce piston blow by which is more important on a boosted engine.
14-05-2007, 03:53 PM
#5
PassionFord Post Whore!!
Join Date: May 2003
Location: Northants
Posts: 9,076
Likes: 0
Received 0 Likes
on
0 Posts
A torque plate is to recreate the stresses of having a head torqued down onto the block. An engineering firm will only have them for engines they see a lot of....
Some say they're not needed, and quite a few say they are - or at least they use them (e.g. GGR) but ultimately it depends on wether or not the bore can distort once the head is torqued down.
I'd probably get the work done by someone who does a lot of YB's (although personally, I leave that work to my tuner).
Some say they're not needed, and quite a few say they are - or at least they use them (e.g. GGR) but ultimately it depends on wether or not the bore can distort once the head is torqued down.
I'd probably get the work done by someone who does a lot of YB's (although personally, I leave that work to my tuner).
14-05-2007, 04:27 PM
#6
Given that you will have clearances of a couple of thou, and the torque plate is unlikely on a YB block to alter the shape by more than a couple of tenths of a thou at most, I would say its totally uneeded on a YB.
If you want to do anything to replicate the engine in use, putting hot water through it will probably alter it MORE than bolting an ally head to it after a fibrous gasket, as that really isnt going to influence the shape of a big lump of pig iron like a YB block to any great extent.
If you want to do anything to replicate the engine in use, putting hot water through it will probably alter it MORE than bolting an ally head to it after a fibrous gasket, as that really isnt going to influence the shape of a big lump of pig iron like a YB block to any great extent.
Trending Topics
14-05-2007, 04:33 PM
#8
Originally Posted by peteh
i have a 205 block bored to +.25mm for sale to save you some money and time
14-05-2007, 09:09 PM
#11
Dicko found this on the GGR website..
"
Why do GGR always use a torque plate when reboring the cylinder block?
It was an early discovery of ours that the cylinder bores distort alarmingly in the engine when the cylinder head is tightened down. The mis-shaped bores can then lead to excessive piston ring blow-by, and the piston to bore clearance is larger than necessary. Using a torque plate, we can guarantee round bores, and tighten up on piston to bore clearance, reducing piston slap, and improving piston ring seal."
was it amac that use the torque plate?
steve
"
Why do GGR always use a torque plate when reboring the cylinder block?
It was an early discovery of ours that the cylinder bores distort alarmingly in the engine when the cylinder head is tightened down. The mis-shaped bores can then lead to excessive piston ring blow-by, and the piston to bore clearance is larger than necessary. Using a torque plate, we can guarantee round bores, and tighten up on piston to bore clearance, reducing piston slap, and improving piston ring seal."
was it amac that use the torque plate?
steve
15-05-2007, 04:50 PM
#13
saff is working!!!...atm
iTrader: (1)
Join Date: May 2006
Location: fishburn sex shop...co.durham
Posts: 8,984
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Dicko&Sarah
yes ste they do but i cant afford to wait 2wks for it to be done
15-05-2007, 04:52 PM
#14
10K+ Poster!!
Thread Starter
iTrader: (3)
Join Date: Jun 2003
Location: Hartlepool
Posts: 10,956
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by pete mcrash
Originally Posted by Dicko&Sarah
yes ste they do but i cant afford to wait 2wks for it to be done
15-05-2007, 04:54 PM
#15
saff is working!!!...atm
iTrader: (1)
Join Date: May 2006
Location: fishburn sex shop...co.durham
Posts: 8,984
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by Dicko&Sarah
Originally Posted by pete mcrash
Originally Posted by Dicko&Sarah
yes ste they do but i cant afford to wait 2wks for it to be done
Thread
Thread Starter
Forum
Replies
Last Post