[1980 TA]

I pulled my 455 due to a knock and a lot of oil leaks. I have everything disassembled and ready to post pics to get some help in diagnosing the problems. What is the easiest to use site for posting pics?

Thanks.

[tooski]

Post pics direct from your device. When posting, scroll to the bottom where you will find 'Manage Attachments'. (If you use a regular digital camera you have to download the pics to an internet capable device)

[tom s]

Real EZ from a cell phone IF you are on the site on your phone.Tom

[steve25]

First off even before posting up any pictures, what year is the motor and what casting number heads are on it.

Your very lucky to have had the time to shut the motor off before something let go all the way!

One of my street 455 motors that was perfectly quite went into having a light knock and then a very loud hammering in just 5 to like 7 seconds!

I was lucky also that I was just cruising with light throttle at 2200 rpm, and you would have never known that anything was amuck by looking at the oil pressure gauge!

[1980 TA]

It is an original 455 block. I'll look for a date code the next time I'm in the shop.

The heads are 6x-8.

I was running though the gears this summer and at the top of 3rd gear the oil pressure gauge dropped from 80 ish to 40 and came right back. I let off the accelerator and when I got home I could hear a faint tick. Checked the oil when I got home and it was a quart plus low. I had lost track of the last time I checked it and I apparently mis judged how much had leaked from the main. The tick got a little louder over the next month and I decided it was time to pull it and see what was going on.

While tearing it down this is what I can tell so far. The bores look great. The main bearings look new. The rod journals on the crank look un harmed. Cam and lifters look like they have a good pattern on them.

The only signs of damage I have found are several rod bearings that are not like the others. On the quick inspection of the rods while removing them and bagging them, none of the bearings look like they spun. Maybe I got lucky and the bearings took all of the damage. I'll lay them out today and post pics.

[steve25]

Well those 6X heads are not original to the motor since all 455's got the huge 124 CC chambered 6H casting heads starting in mid 75 or so.

The last year for the 455 was 1976 and fortunately the 455 never got a weaker down graded block like the late 400 motors did!

In 76 the TA 455 was called the HO option, but there was nothing HO about it, it was the same Bread & Butter 455 you could get in the B body cars.

If you where that low on oil and rumping thru the gears then my money's on the the number 2 or 1 Rod Bearing going starting to go south on you since they get oiled last out of all the Rod Bearings.

[1980 TA]

The motor is not original. It was a combination put together by an engine builder.

Here's some pics of the bearings.

[FrankieT/A]

I'd pitch that crank....

[74Grandville]

Originally Posted by FrankieT/A

I'd pitch that crank....

I would think you could get it cut down.

[FrankieT/A]

Why bother? New crank from Ohio Crankshaft $400.00

[Will]

Originally Posted by FrankieT/A

Why bother? New crank from Ohio Crankshaft $400.00

Because I trust GM stuff more than I trust aftermarket made in China stuff?

[steve25]

Well it does not look all too bad since none seem to have spun, but the good thing is that the ware pattern shows that the block line Bore is straight.

Xs 2 on that reusing the factory Crank if it mags out good!



Cut down the mains to .020" even if a cut of .010" would clean it up and have the Crank grinder put a radius in from the main Jurnal to each cheek which will add strength to the Crank.

China crap is what got us into the situation we are in now!
With every Dollor we have saved from using such we have lost 20 Dollors a day of of our freedom over the years!!!!

As a example of such look at my last comment I am typing out real fast because those folks who own this site will take it down real fast due to its political nature just like only a few Months ago when they made me change my last signature that I had up for years!

[FrankieT/A]

Originally Posted by steve25

China crap is what got us into the situation we are in now!
With every Dollor we have saved from using such we have lost 20 Dollors a day of of our freedom over the years!!!!

The way things look right now if you're younger than 40 you might want to brush up on your Chinese.

[1980 TA]

Be glad to post pics of the crank. I did not see anything during tear down that looked bad on the rod journals as far as scratches or hot spots. The rod journals looked very uniform.

Keep in mind I don't claim to know much about internal machining but the two options I was hoping for was putting in new bearings or grinding the crank to match new bearings.

While I have it apart, anything to take pics of on the cam and or lifters? Each lifter was bagged and labeled so that they could all go back into the same hole.

Motor has 7000 miles on it since the last rebuild by the previous builder.

[steve25]

The push Rods and rocker / ball package need to go back where they came from also.

You should look very close at the base circle of each Cam lobe for the signs that the shinny ware pattern is progressing to over 1/2 the with of the lobe.

If so then that lobe is on its way out, it may not be making for a ticking valve noise yet, but it's in route to do so!

While your in there if the timing chain is flapping a bit then I would get a 2 degree Cam advance key and install to make up for that slack.

Also check that the line on your balancer accurately reflects TDC.

Confirm that the oil pump pick up is tack welded or has been moded for a small set screw to keep it on the body, also check that the pickup is seated close to the pumps casting nub which guarantees that the pickup is at the right height off of the pan bottom.

If the pass thru in the block of the oil dip stick tube looks to close to rotting thru then now is the time to replace it.

Before you go to bolt the main caps and the heads Bank on be sure to check that a bolt will thread in with easy finger force and will bottom out in its hole.

If not then get a bottom tap and clean out the treads until all the bolts go in easy.

[1980 TA]

After having time to look through everything and start cleaning parts, I found some obvious damage. One of the cam lobes was almost round and the #3 cylinder Intake lifter was severely concave on the bottom.

I looked up the recipe from the original builder and it has 6x-8 heads with 1.66 exhaust valves. Compression ratio is 9.25:1. Valve springs are supposed to be Comp Cams with 120 pounds seat pressure. The cam is an 041 with rhodes lifters. 1.5:1 rockers.

I was looking at going slightly smaller with the cam due to the 3.08 rear gears and overdrive. The combo worked well enough getting into 5th gear at 1500 rpms or so but since I will never track the car and usually shift at or under 3000 rpms , I figured the car might be more fun with a little less cam. I kinda felt like I was lugging the engine and it would be happier at higher rpms but with the gearing and speed limits I spend the majority of time between idle and 2500. Whatever I give up above 4500 I'd like to make up in cruising in 4th/5th gears.

I was looking at the crower 60916. The current cam has .470 inches of lift and the lift on the crower is the same. I'm hoping to not have to modify the heads to work with the 60916??

Is this too small or too big still for my desired goals. Besides a stout cruiser, I'd like to clean up the exhaust smell a little bit with the smaller cam. It's not horrible, but pulling into the garage and walking into the house, I'll smell like old car. If the wind is just right, even outside, the exhaust smell will be in my clothes for up to 30 minutes. I can live with it but my wife only barely tolerates. it She would be happy to not have the smell of exhaust in her clothes or hair. I plan to drive the car a lot in the next 10 years and its a small thing but happy wife means more seat time.

[mgarblik]

I too see no reason to fill the engine with a bunch of Chinese parts if this essentially a stock/mild rebuild. Unless the crank is already undersize from the previous rebuild, I would check it, grind it, and reuse it. Connecting rods have not been mentioned yet. With the heat generated to "get into the copper" of the rod bearings, the rods will need to be reconditioned or replaced. I have no idea what's in the engine now but if stock PMD rods, properly reconditioned with new hardware, I have no issue reusing them if you limit your RPM's to 5500 in a 455. If it already has aftermarket rods, they will need to be reconditioned as well. Some will chime in and insist all OE Pontiac rods need to go in the trash. If you respect the red line, I am not in that camp. If money is no object, than by all means buy a new forged crank and quality aftermarket rods. IMO all the stock internal rotating parts are plenty safe to 450 HP @ 5500 RPM's.