I have been gone form this forum for about 2 years and its good to be back.I will explain my problem. Some may recall that I rebuilt a 351m. Everything was new except the block. I had the block bored 30 over,crank cut, new bearings,cam,etc,Yes I plastic guaged them! Well I was stupid enought to put the pass side head gasket on backwards but I caught it in time before there was any damage. The engine had 400 miles on it when I lost oil pressure and it started to knock.. It sat for about a year and last weekend I pulled the engine and crank/pistons etc I found the following:

The front piston bearings on 1,2,5 and 6 looked ok, the rest was worn down to the copper. The front mains looked ok, but the back 2 were worn down to copper. The rear main was the worst, copper and a ridge worn in the crank. Also the cam was perfect.

It looks like I lost oil pressure to the back of the engine. The engine was cleaned and so was the crank. I noticed a lot of grit on the bearings.

If you need more in for on the eng check my gallery

Anyone got any Ideas?

Thanks Art Gillings

 

Sounds like you had excessive bearing clearances or a massive internal oil leak so that there was not enuf oil flowing thru the system to keep up with the leaks and lubricate the back of the engine. This should have shown up as no oil pressure on your oil pressure gage since the sender is in the back of the block. If you put the engine together in a dirty environment then the engine bearings would have worn rapidly producing excessive clearances.

 

check for the oil galley plugs in the area behind the cam timing sprocket. and make sure that the oil pick-up tube is tight in the oil pump, meaning that it can not go another turn in.

 

When I started the engine it had great oil pressure. I am just wondering if there was an internal oil blockage and when I pulled the pan there was a lot of junk in the pan dirt and grit. I am gonna take the block get it diped again. I have a new 400 crank and new flat top pistons I think i will turn it into a stroker.

 

your first post is titled " what did i do wrong!", and by the end of your second post you are on the road to rebuild it without finding the cause of failure. for your $ake i hope you determine what happened to the first engine, or you may be doomed to repeat?

 

It sounds to me like there was a significant amount of dirt left in the motor after the block machining was done. Once you get a block back from the machine shop it needs to be thoroughly cleaned. Actually that goes for any part. You can get a set of engine brushes specifically designed for this for a few bux.

I put my engines on a stand and take them outside with a big bucket of soapy water (dish soap works great), a garden hose with a high pressure nozzle and my brushes and go to town. Run the brushes through all of the oil passages and try to pump as much water through as you can.

When you're done with the oil passages then you have to clean the cylinder bores out. When you're done you should be able to take a clean white rag and wipe it in the bore and have it come out as clean as it went in. It usually takes a few scrubbings to get all of the grit out of the honing pattern.

 

Tide works well and has some chemicals that help clean the block.

 

I think I agree with you guys about cleaning the block and crank. There is an alful lot of grit in the pan and the bearings. Well i learned my lesson. I wll post some pictures of what not to do.Thanks Art

 

Glad to see you're back dsc.

Have you read the article about reducing the size of the one oil passage to increase the oil pressure when re-building a 400 ?