Knockin' On Heaven's Door, what to do for a rod knock?

[Bar50]

Pics of the black marks in the cylinders?

You can drill the oil galley pickup in the block to 5/8 with a long drill bit and it's best with a drill press. From the timing cover in the block to the pickup tube(along the oil pan rail on the passenger side of the block).

The Turbo Buick V6 cam bearing up front(B12B I think). Drill a small hole (0.060) in one of those plugs that got left out (in your original build) to spray oil on the distributor and fuel pump drive.

I don't recall the specific year, but, Buick did transition to cap screw style rod bolts. They seem to be preferred by some Buick builders.

 

[online170]

Read his post (Regal has died for the third time) and 7&8 are last on the food chain.

This thread is painful to read.

lilbowtie hit the nail on the head. Your issue is oiling, and buicks have the absolute worst oiling system. You can have all the fancy stuff like regulators and whatnot, but if the clearance isnt right you arent getting the volume. Pump gear end clearance is cruicial. Excessive wear in the aluminum housing is bad. An oil pressure gauge at the end of the run (back of the block) is essential.

For starters, the components are not as weak as you think they are. But 40ftlbs isnt alot of torque for a rod bearing spinning to 6k. 6K is ambitious, but i had my bone stock 350 up to 5500rpm regularly. When i changed the rear main seal, i noticed my bearings were down to copper, and i didnt have the money to replace them, so i put them back in. I removed my oil pressure gauge, cuz i didnt need that stress in my life, and i drove the car for 2 years like that. I would lift when i heard lifters clattering cuz it had no oil pressure at the high revs. I had a 430 to replace the 350 after it blew up which i scored for $300, but that 350 never quit on me. In any case, you can upgrade to different rod bolts too and get higher torque. But you need to resize the rods to do that (standard operation when doing a rebuild, even if it didnt spin the bearings).

What you have is from sustained RPMs. Buzzing up to 5500 is not big deal, but if you stay there too long you're gonna burn it up.


To give you an idea, when im built my caddy , i had to calculate how much oil to put into my oil pan. I came up with 6qts that fit in the sump. While the engine was running, it had 1qt circulating through the engine AT IDLE! So i just put in 7qts now and dont think about.

So 1qt circulating at idle (1000rpm), how many qts circulating at 5000rpm? 6000rpm? I know you put 5qts in the pan, so how long till it goes dry?


This failure is very common, and usually starts by the #5 cam bearing getting starved, which then either lodges some debris into the #5 main or staves it. Then the main starts to chokes up and starves #7 road. This is why the grooved cam bearings are now used for performance applications.

Take a look at your rear main bearing, and rear cam bearing, i bet they are burned up too.

 

[MrSony]

I realize he said that the other bearings look new. It looks like #8 rod is bent with the wear on one side of the bearing. When I check the clearance on bearings I check from edge to edge. Also it's hard to tell but it looks like the #7 rod is wearing a mark on the crank face beside the #7 rod. I wonder what the side clearance was on the #7 and #8 rods

If by the rod looking bent you mean the rod in the picture, no, it's not. I just pushed the rod down by hand to get the bearing out of it without having to rotate the crank. Spark plugs were out so it was easy. They also twisted in the bore a little, also can do that by hand. And the it does look a bit like the inside edge of #8 was wearing more than the outer edge, but maybe that was caused by #7 spinning and the bearing shifting over to 8? I put the bearings back in the motor, so I wouldn't lose them, and they would not "snap" into the cap or rod. They were way loose and would fall out. When I put it back together, the bearings were off to one side of the rod on the journal.

 

[pontiacgp]

If by the rod looking bent you mean the rod in the picture, no, it's not. I just pushed the rod down by hand to get the bearing out of it without having to rotate the crank. Spark plugs were out so it was easy. They also twisted in the bore a little, also can do that by hand. And the it does look a bit like the inside edge of #8 was wearing more than the outer edge, but maybe that was caused by #7 spinning and the bearing shifting over to 8? I put the bearings back in the motor, so I wouldn't lose them, and they would not "snap" into the cap or rod. They were way loose and would fall out. When I put it back together, the bearings were off to one side of the rod on the journal.

The only way to wear the bearing unevenly on one side is a bent rod. If you check the bearing clearance from one side to the other a bent rod will be noticed. What was the side clearance for #7 and #8.

http://www.speedperf6rmanc3.com/content/Engine Bearings.pdf

 

[MrSony]

This thread is painful to read.

lilbowtie hit the nail on the head. Your issue is oiling, and buicks have the absolute worst oiling system. You can have all the fancy stuff like regulators and whatnot, but if the clearance isnt right you arent getting the volume. Pump gear end clearance is cruicial. Excessive wear in the aluminum housing is bad. An oil pressure gauge at the end of the run (back of the block) is essential.

For starters, the components are not as weak as you think they are. But 40ftlbs isnt alot of torque for a rod bearing spinning to 6k. 6K is ambitious, but i had my bone stock 350 up to 5500rpm regularly. When i changed the rear main seal, i noticed my bearings were down to copper, and i didnt have the money to replace them, so i put them back in. I removed my oil pressure gauge, cuz i didnt need that stress in my life, and i drove the car for 2 years like that. I would lift when i heard lifters clattering cuz it had no oil pressure at the high revs. I had a 430 to replace the 350 after it blew up which i scored for $300, but that 350 never quit on me. In any case, you can upgrade to different rod bolts too and get higher torque. But you need to resize the rods to do that (standard operation when doing a rebuild, even if it didnt spin the bearings).

What you have is from sustained RPMs. Buzzing up to 5500 is not big deal, but if you stay there too long you're gonna burn it up.


To give you an idea, when im built my caddy , i had to calculate how much oil to put into my oil pan. I came up with 6qts that fit in the sump. While the engine was running, it had 1qt circulating through the engine AT IDLE! So i just put in 7qts now and dont think about.

So 1qt circulating at idle (1000rpm), how many qts circulating at 5000rpm? 6000rpm? I know you put 5qts in the pan, so how long till it goes dry?


This failure is very common, and usually starts by the #5 cam bearing getting starved, which then either lodges some debris into the #5 main or staves it. Then the main starts to chokes up and starves #7 road. This is why the grooved cam bearings are now used for performance applications.

Take a look at your rear main bearing, and rear cam bearing, i bet they are burned up too.

Didn't get a chance to look at my cam bearings, but I found chunks of bearing that wasn't from the mains or rods. And I'm positive that sustained high rpm was the final nail in the coffin. I'm seriously thinking about adding an oil pressure equalizer line from the front left oil fitting to a port in the back of the block you drill and tap, and running my oil pressure gauge off of that. Along with those grooved bearings. After I installed the damn oil galley plugs, I always had great oil pressure, even with the knock. Didn't even lose a single PSI. But that was the pressure at the front of the block, not at the back where it's more crucial.

 

[MrSony]

The only way to wear the bearing unevenly on one side is a bent rod. If you check the bearing clearance from one side to the other a bent rod will be noticed. What was the side clearance for #7 and #8.

http://www.speedperf6rmanc3.com/content/Engine Bearings.pdf

Don't remember the side clearance. I just did that feeler gauge trick where you put the biggest one that will fit without any force inbetween the rods on both sides (two feeler gauges) and tighten the rods down. The rods weren't hitting the crank from what I can/could tell. The rotating assembly spun over like butter and even now it still does.

 

[joesregalproject]

If you don't already have it, it'd be a great idea to add the TA Performance adjustable oil PSI regulator when you get this motor rebuilt. It's like $20 and can save you from having this happen again.

 

[joesregalproject]

Also, do you remember your oil pump gear end clearance? Buick says no more than .005 but TA Performance has said between .002 and .003.

What oil pump rebuild kit did you use?

TA recommends against using the high volume, high pressure oil rebuild kit for most applications. They say it can cause cam bearing failure and I saw you had said you haven't seen the cam bearings yet.

 

[MrSony]

Pics of the black marks in the cylinders?

You can drill the oil galley pickup in the block to 5/8 with a long drill bit and it's best with a drill press. From the timing cover in the block to the pickup tube(along the oil pan rail on the passenger side of the block).

The Turbo Buick V6 cam bearing up front(B12B I think). Drill a small hole (0.060) in one of those plugs that got left out (in your original build) to spray oil on the distributor and fuel pump drive.

I don't recall the specific year, but, Buick did transition to cap screw style rod bolts. They seem to be preferred by some Buick builders.

The cap screw rods went from 74-80. 68-73 had studs and nuts. I have the cap screw rods as my engine is a '76. I forgot about that turbo cam bearing until someone (pontiacgp?) brought it up. Which plug should I drill? Passenger or driver's side? I'll consider drilling the pickup

 

[MrSony]

Also, do you remember your oil pump gear end clearance? Buick says no more than .005 but TA Performance has said between .002 and .003.

What oil pump rebuild kit did you use?

TA recommends against using the high volume, high pressure oil rebuild kit for most applications. They say it can cause cam bearing failure and I saw you had said you haven't seen the cam bearings yet.

I used the standard volume oil pump kit with the booster plate. I also have the adjustable regulator. Side gear clearance was .0025 if I recall. I've ALWAYS had great oil pressure, since I installed the plugs. I don't think a lack of oil pressure was the issue. I think it was just beating the piss out of a mostly stock motor with a stock bottom end, just had new bearings. Multiple times I'd be at WOT, and I mean WOT, straight to the floor, for MINUTES at a time. 4800rpm and climbing, albeit slowly. My math tells me I was doing 130ish. The car pooted out some blue smoke so I think that was related to the black scuff/combustion marks on #8 (pictured up there).