torque plate hone or not?

kawi600

kawi600

got Coal for Christmas
Joined
Jun 9, 2008
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Anyone done a hone or bore on a block, compared to a similar setup but with a torque plate on the block for the hone or bore operation.. and have a comparison for compression, blowby or lack of wear on certain areas of the cyinders that might indicate theres enough distortion to lose some compression?
trying to make sense of an otherwise healthy motor thats showing a fair bit of blowby without a lot of abuse.
Dunno if distortion is an issue with 12mm studs as well as 14mm or not? running the unobtanium 625s on there since I had plans for more air and fuel in the future.
 
Torque plate honing definatly helps rings seat , I've had both apart after low miles and ones that weren't torque plate honed had shiny spots in the cylinder where the studs are
 
Interested also..local machine shop said they NEVER use a torque plate because it pointless and not needed on a 5.9..
 
I've never used a tq plate and I've never see any signs in the cylinders that would concern me
 
turboram said:
Torque plate honing definatly helps rings seat , I've had both apart after low miles and ones that weren't torque plate honed had shiny spots in the cylinder where the studs are
Click to expand...

I'd like to see it because we never use a torque plate and have yet to see any markings due to distortion yet.
 
quick search popped up a video from industrial, I think this is what I remember seeing.
[ame="http://www.youtube.com/watch?v=6cLjdr2GSwU"]http://www.youtube.com/watch?v=6cLjdr2GSwU[/ame]

As to whether that small distortion is enough to actually DO anything, thats what Im hoping to find out. Blowing oil all over the place on the motor, despite low EGT temps and good oil. All cylinders ~360psi which is kinda low, but I dunno how much the cam overlap messes with static compression.
 
just asked my builder for the heck of it, what his take was on lowering the stud torque to OEM levels since the studs dont stretch much compared to bolts but he said it was a bad idea. guess Im stuck with this till I do a rebuild or swap.
If I had the coin (and a heated garage) Id buy another motor and build it up nice over the winter.
 
If you're not wanting the clamp loads that the studs provide, don't use the studs. You'll be better off with bolts at specified stretch than studs understretched.
 
Don't know what's going on with your engine on the limited info but its not the lack of a deck plate during honing and don't bother loosening of the studs!

Was this bored and final honed for oversize pistons? How loose?
 
When I was an engine machinist, customers would occasionally request a finish hone with a deck plate. I would do it of course, but I never had it make more than a .0005" difference in the cylinder being round. And that was on later casting small block chevys. It didn't change even that much on a nice casting like the 5.9 cummins.
 
I was trying to think of a way to test whether its responsible for any compression loss or blowby. I dont have the funds to replace another head gasket right now, and 45-50psi is pretty close to borderline on a head gasket.
If anyone is doing a head stud install only, Id be curious in a compression test before and after
 
Runninlean said:
I would be more interested in PTW clearance and ring gaps.
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Yup, wall clearance was the ticket. They seem to be too tight out of the box. I'd usually take a couple thousandths out of the cylinder and it was good to go; never scuffed again.
 
When I built my small block chevy in college they told us to always use a torque plate because it keeps the cylinder true. Simulates the head being on it. Just my .02 I'd always use one.
 
Very interesting. Always figured my blowby was from my over torqued studs and not being honed with a torque plate when i had my motor built. Maybe there is another issue going on. I well i am gonna run it til it stops or burns more oil than diesel. Looking forward to more opinions
 
The torque plate is about being able to put a clamping load on the block like the studs would. So any distortion would be accounted for in the machining.
Is it all hype? The amount of force these studs produce, I cant imagine theres not some distortion in the cylinder. It wouldnt take much. And what does this do to the ring and land over time? If I ever get a chance to tear this motor down Ill take some pics and compare to the shiny spots in the II video.
motor still runs strong, but shows about 360psi cold and blows oil through the valve cover bolts and breathers. Gotta be something going bad.
 
kawi600 said:
The torque plate is about being able to put a clamping load on the block like the studs would. So any distortion would be accounted for in the machining.
Is it all hype? The amount of force these studs produce, I cant imagine theres not some distortion in the cylinder. It wouldnt take much. And what does this do to the ring and land over time? If I ever get a chance to tear this motor down Ill take some pics and compare to the shiny spots in the II video.
motor still runs strong, but shows about 360psi cold and blows oil through the valve cover bolts and breathers. Gotta be something going bad.
Click to expand...

Like I said earlier, it does make a measureable difference, but it's only about .0005" depending on the strength and design of the block.
 
After seeing first hand in 2002 what boring and honing without a torque plate will do I would suggest to everyone to have it done with one. When the head was bolted onto the block the cyl walls were distorted. I would have to give the shop a call and find out how much it was out of round.
 
depends on how tight/loose your engine is on PWTC. DMAX is .0015" PWTC from the factory.. HS properly tightened and everything get a nice heat soaked, very good chance of piston getting grabbed..
wouldn't surprise me if CTD was the same way
 
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