Speed-Talk is running on www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Was this cylinder scoring caused by previous builder not using torque plate?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Bwh998
Member
Member
Posts: 61
Joined: Tue Feb 18, 2020 5:12 pm
Location: Arkansas

Was this cylinder scoring caused by previous builder not using torque plate?

Post by Bwh998 »

20200725_203351.jpg

At the front and rear of every cylinder. Ran fine, no smoke. Disassembled and surprised to find bores look like garbage.
You do not have the required permissions to view the files attached to this post.
77cruiser
Guru
Guru
Posts: 1300
Joined: Fri Dec 29, 2006 10:32 pm
Location: I Falls MN
Contact:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by 77cruiser »

I don't see scoring but yup.
Jim
Bwh998
Member
Member
Posts: 61
Joined: Tue Feb 18, 2020 5:12 pm
Location: Arkansas

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Bwh998 »

Kinda hard to see, light vertical scoring. All up and down each of those dark wear marks at the front and rear of each bore. Pretty consistent on all 8. Maybe scoring isn't the right term but some definite rubbing/tight clearance there.
Bwh998
Member
Member
Posts: 61
Joined: Tue Feb 18, 2020 5:12 pm
Location: Arkansas

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Bwh998 »

Tried to get a better pic in daylight.
You do not have the required permissions to view the files attached to this post.
Bwh998
Member
Member
Posts: 61
Joined: Tue Feb 18, 2020 5:12 pm
Location: Arkansas

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Bwh998 »

Tried to get a better pic in daylight.
HDBD
Expert
Expert
Posts: 630
Joined: Sun Jun 01, 2008 4:32 pm
Location: Northwest

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by HDBD »

You are in the fine blades of grass there with the plates. First the guy needs to know how to size properly and develop a proper crosshatch. Plates, surface finish, crosshatch angle, sizing all important. Plates more important on some engines.
Bwh998
Member
Member
Posts: 61
Joined: Tue Feb 18, 2020 5:12 pm
Location: Arkansas

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Bwh998 »

HDBD wrote: Sun Jul 26, 2020 9:52 am You are in the fine blades of grass there with the plates. First the guy needs to know how to size properly and develop a proper crosshatch. Plates, surface finish, crosshatch angle, sizing all important. Plates more important on some engines.
And thats why I'm reluctant to drop it off at the local machine shops.
BillK
Expert
Expert
Posts: 546
Joined: Wed Aug 26, 2009 8:30 pm
Location: Beautiful Southern Maryland
Contact:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by BillK »

I would be inclined to say no. In my experience the distortion from using a torque plate is almost always in line with the head bolts and only extends down an inch or so. Think about all of the millions and millions of stock engines that were not plate honed ? They dont have wear marks like that. Its easy enough to put a bore gauge in the block and see if it is small in those areas. That will at least give you some idea as to whether the bore is causing the problem or something else like uneven piston expansion or maybe too tight of a ring gap ?
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
cpmotors
Expert
Expert
Posts: 923
Joined: Fri Feb 15, 2008 8:22 pm
Location: Janesville,Wi
Contact:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by cpmotors »

That bore finish looks like it was bored to -.001" and hit with a 3 finger Lyle on full throttle..
Pete Graves
CPMotorworks,Inc.
Custom Engine Machining
Cylinder Head Fixture for Vertical / Surfacing Mills
User avatar
modok
Guru
Guru
Posts: 2603
Joined: Sun Jun 06, 2010 1:50 am
Location:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by modok »

I've never seen anything that looks exactly like that before. And I've seen more cylinders than most humans.
My guess is the cylinders were far out of round, and it was de-glazed with a cheap hone and re-ringed.

Are the cylinder walls very thin?
gunt
Pro
Pro
Posts: 349
Joined: Sun Sep 26, 2010 2:52 pm
Location:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by gunt »

couple of questions

what was the compression reading like now v and when assembled

what mileage is on the bores and what kinda hurt they they suffer

whats the piston skirts like
bentvalves
Pro
Pro
Posts: 257
Joined: Mon Dec 12, 2016 3:37 pm
Location:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by bentvalves »

some scuffing is visible in the well lit picture, that is in-line with the wrist pin.

in line with the wrist pin can be seen in all 3 pictures.

its not happy as something isn't right.

if it were tight, scuffing or rubbing would bee seen on the major thrust side of the skirt, and bore.

show us the pistons.
Dutchman
Member
Member
Posts: 123
Joined: Sat May 11, 2013 9:15 am
Location: Bohemia ny

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Dutchman »

A local guy use to bore to the final size and ball hone the finish. Looked just like that.
He worked on a dirt floor,don't know why but he always stayed busy. Cheep I guess
Old School
Pro
Pro
Posts: 402
Joined: Sun Feb 13, 2005 11:27 am
Location:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by Old School »

I agree with BillK, this is not a torque plate issue. All the out of roundness I have seen from lack of a torque plate occurred at the bolt holes.

Looks like an engine that had piston pin buttons, but scarred up much worse than buttons would do and a much wider scar.

Show us pictures of the rods and pistons. Both the skirts and sides of the pistons and how the pins were retained. Any chance the pins were floating and the retaining locks were left out and the pins did the damage? Doubtful, the cuts should be much deeper if caused by a pin.
bigmike
Member
Member
Posts: 60
Joined: Fri Aug 05, 2011 6:57 pm
Location:

Re: Was this cylinder scoring caused by previous builder not using torque plate?

Post by bigmike »

That does not look like a torque plate issue to me. Something else is going on. Were the pistons pressed pins? Could someone have pressed piston pins on and off a couple times and distorted the pistons?

How much over are the bores now? It is interesting to note that coolant flow is not the best in that area between the cylinders. Could the water pump flow be marginal? Was a thermostat used? If so what temperature is it opening? Was this used in a boat with fresh water cooling?
Post Reply