87 351w, broken rings?? causes?
Thread Starter
|
Posting Guru
Joined: Nov 2003
Posts: 1,071
Likes: 1
From: Concord, New Hampshire
87 351w, broken rings?? causes?
well as some of you may remember i posted awhile ago about doing a motor swap, well i pulled mine apart to see what went wrong, and i am just going to fix it now but heres my question, number 5 had no compression, well 30 psi, and i have it all apart now, and the top two, (compression rings) were in about 5 or 6 peices each?? but the oil ring was perfectly fine. what would cause someting like this?? has anyone seen it before? its very odd to me, because it also took some small chunks out of the piston, but the cylinder wall is perfect? well thanks for any help i can get, i guss for now im gonna start rebuilding it, with new rings mains and rod bearings. oh yeah, by the way, 87 f-150, 4x4 351w, with 106,000 miles.
Thread Starter
|
Posting Guru
Joined: Nov 2003
Posts: 1,071
Likes: 1
From: Concord, New Hampshire
oh im going to Take the small ridge off of the top of all 8 and then hone all 8, hopefully after that, and some new main bearings and rod bearings, i should be good to go, but, for now i have to have the wrist pin pressed out of the piston, and the new piston put on the rod, but the machine shop is a week out, so im a little p'ed off about that, 
but i gots plenty to do and ill hope they get done early.
but i gots plenty to do and ill hope they get done early.
Posting Guru
Joined: Jan 2003
Posts: 1,061
Likes: 0
From: Still under the hood in O
Could be one of three things...
1)Irregular oil changes - The ring grooves get packed with sludge causing the ring to stick. After a while the stuck rings break.
2)A high mileage motor that has developed a ring groove (such as yours) that isn't driven hard for years suddenly finds a heavy foot. A high RPM blast beyond what the (high mileage) motor has not seen before can actually cause the piston(s) to travel above the ring groove. When this happens, ring breakage results. This is evident by the piston breaking in the ring lands.
3)If the piston damage was on the top, I would say it leaned out and detonated. If this is the case then the broken piston actually caused the ring breakage.
1)Irregular oil changes - The ring grooves get packed with sludge causing the ring to stick. After a while the stuck rings break.
2)A high mileage motor that has developed a ring groove (such as yours) that isn't driven hard for years suddenly finds a heavy foot. A high RPM blast beyond what the (high mileage) motor has not seen before can actually cause the piston(s) to travel above the ring groove. When this happens, ring breakage results. This is evident by the piston breaking in the ring lands.
3)If the piston damage was on the top, I would say it leaned out and detonated. If this is the case then the broken piston actually caused the ring breakage.
Thread Starter
|
Posting Guru
Joined: Nov 2003
Posts: 1,071
Likes: 1
From: Concord, New Hampshire
ok, well the head is fine, the damage is on the side, just above the top ring, not deep maby a couple of scratches are 1/64"but it was BOTH upper rings that were broken, i know i have a hard foot, but it they broke both from going over the ridge, it would have smashed dead on into the head. i alsked on one my proffesors today, he said just age was to blame, maby a lean condition,(it had a bad fuel filter durring the start of the problem) but probly just age. and 106,000 miles, high millage???
Posting Guru
Joined: Jan 2003
Posts: 1,061
Likes: 0
From: Still under the hood in O
If it were above the ring lands, then I would say it leaned out. Now if the ring lands collapsed in the opposite direction, then I would say it was the ridge..........but that's not the case. Sorry for not making that clear.
Trending Topics
Thread Starter
|
Posting Guru
Joined: Nov 2003
Posts: 1,071
Likes: 1
From: Concord, New Hampshire
well im baffeld, i think ill just fix it and hope it dosent do it again before the nex 100,000 mile mark.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
Thread
Thread Starter
Forum
Replies
Last Post
BroncoBilt
1987 - 1996 F150 & Larger F-Series Trucks
4
Jan 16, 2015 01:50 PM
mattd17
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
3
Feb 2, 2006 01:01 AM
