[mike76]

Pulled heads on my engine . Found the cylinders smooth with no cross hatch pattern left. This is on a engine w/ only 3500 street miles since rebuild. How did this happen ? And where did the cross hatch go so fast? Finally , how can I avoid this in the future? Thanks, Mike

[Tim Corcoran]

How is the ring seal? What rings are you using?

[mike76]

Originally Posted by Tim Corcoran

How is the ring seal? What rings are you using?

Well...all I can say is that my cranking comp. was where it should be . I was told by a engine shop that it was due to gas wash. I was running the UD 288/296 solid flat cam on the street with a lot of idling and low speed driving. This is a 4 speed and I like the sound of the snotty idle. Thanks

Oh! Was using Total Seal file- to- fit iron rings

[BGus16]

We had this problem on my brothers 455 also. Engine builder took one look and asked if it was a Holley carb. We were running a 800 cfm double pumper on the motor. Switched it out for a Q-jet.

Barry

[mike76]

I've heard it said somewhere that when all cross hatch disappears the cylinder begins to leak oil past the rings. Is there any truth to that?
I can have the cylinders all re-honed w/new rings but I don't want to go through this again. And so I post here to find the cause of this issue and help to prevent this in the future. Thanks again!!

[Pontirag]

Originally Posted by BGus16

We had this problem on my brothers 455 also. Engine builder took one look and asked if it was a Holley carb. We were running a 800 cfm double pumper on the motor. Switched it out for a Q-jet.

Barry

that horrible holley strikes again.....

wouldn't have anything to do with being improperly set up would it?

funny how the machinist blames the carb too

naa!

quadrajets never run rich, only holleys

[steve25]

It's time to ball hone the cylinders, install new rings if the ring to ring land clearance has not gone above .004, check the piston skirts and bore clearance" and get the excess fuel issue from the jetting of the carb delt with !
The bearings maybe suspect also due t the fuel wash ending up in the oil.

[mike76]

Originally Posted by steve25

It's time to ball hone the cylinders, install new rings if the ring to ring land clearance has not gone above .004, check the piston skirts and bore clearance" and get the excess fuel issue from the jetting of the carb delt with !
The bearings maybe suspect also due t the fuel wash ending up in the oil.

Strange thing about this is that i had sampled the oil to Blackstone Labs @ every oil change and only average levels of gas were present each time.

[BGus16]

The 800 double pumper was installed right out of the box from Summit. When we took the heads off you could see the cylinders were polished on the lower side. All 8 of them. The motor had maybe 300 miles on it, but it shredded the B & M torque converter and that wiped out the thrust bearing. Hence the motor tear down. Took the short block to a pontiac engine builder (40 years) near Chicago and that was what he said.

Ended up needed to replace the crankshaft. After having to have the motor gone through again after the initial rebuild, the trans gone through to clean all of the metal out of it, and a new Continental torque converter it was quite an expensive deal. So not to take any chances we followed the guys advice.

Just tried to relate our experience.

Barry

[steve25]

A little bit of gas over 3500 miles will do it!
Was the motors water temp below 180? If so that's no much help either if the motor is running on the rich side.

[RamAirIV28]

Originally Posted by BGus16

The 800 double pumper was installed right out of the box from Summit. When we took the heads off you could see the cylinders were polished on the lower side. All 8 of them. The motor had maybe 300 miles on it, but it shredded the B & M torque converter and that wiped out the thrust bearing. Hence the motor tear down. Took the short block to a pontiac engine builder (40 years) near Chicago and that was what he said.

Ended up needed to replace the crankshaft. After having to have the motor gone through again after the initial rebuild, the trans gone through to clean all of the metal out of it, and a new Continental torque converter it was quite an expensive deal. So not to take any chances we followed the guys advice.

Just tried to relate our experience.

Barry

interesting that the cylinders were polished only on the lower side of the bore. There are several implications based on that observation

the bore was not cut befor it was honed

it was cut improperly

there was some possibility of overheating

or the cylinder walls are a bit too thin

Maybe a machinist can chime in here

I'm curious about the quality of the hone job. because I remember doing finish hone jobs on rebuilds back in the day and not knowing or caring about the roughness of the hone back in the day. we would hone it and then wipe it down with a paper towel until it came up clean and call it good. But: since then it has become important to consider the angle of the cross hatch pattern and more recently; the roughness of the hone finish has become a key to a good ring seat. so an understanding of the evolution of the technology has come about over the last 25 plus years. Why maybe it matters? because some old school farts like my self (and others)may not know that these improvement and understandings have developed( along with complimentary ring technology)

Tough call. might want to mike the bores from top to bottom and see how the dimensions changes from top to bottom. Limited information in the OP's posts but Im betting somebody might have took a short cut somewhere. Hope I'm wrong but...

the other thing to consider with regards to over rich mixtures or gasoline washing lube off the cylinders.... its not consistant from one bore to another because just about all carbs run rich in some cylinders and leaner in others. so any wear will not be uniform in that way either

[mike76]

Originally Posted by steve25

A little bit of gas over 3500 miles will do it!
Was the motors water temp below 180? If so that's no much help either if the motor is running on the rich side.

My engine always runs cool . I'd say 180* tops. This is a 850 Holley d/p with the UD 288/296 solid flat cam and # 78's primary and # 86's secondaries w/o a rear power valve. Thinking of going to 75 front and 84 rear. My thoughts on this though is that since 95 % of the time I tool around at part throttle running off the primaries that my problem is too much part throttle operation at or under 3000 rpm on the street w/ that cam. Maybe I need to run it harder than that more often. Again... this is a 4 speed car. What do you think?
Thanks, Mike

[steve25]

Hind sight is always 20/20 right?
For the cost of what you now need to put into the motor to get it right again, a 3 hour chassis dyno session would have got the jetting and power valve set up right in the carb and been cheaper to boot.
I can not see why since your car spends most of its time running on the street crusin around that you would want the rear power valve plugged

[J.C.you]

it would be nice to see some pics of the top of the pistons and skirts. I would not automatically suspect fuel wash could have been the culprit. Sounds like you had a lot of metal floating around in the oil since the crank was trashed.

[Pontirag]

Paul,GTOFREEK is a machinist. maybe he can evaluate the nature of the wear pattern

good point on the advantages of dyno sessions as part of the rebuild process

[GRX]

At this point it might be good to discuss plateau honing and ring types.