dabomb6608

iTrader: (3)

Hey guys, so today has been a pretty horrible day. Yesterday i got my ebl flash system installed and running in my car and took it out for about a 70 mile drive to start doing the VE Learns. It was running fantastic. WAY better then it was on the stock 305 automatic prom. Well this morning i started it up to head out again to do some learning on some tunes i worked on last night when i got home. It started right up fine no problems at all. I took off and got about 1/2mile down the road and it bogged like crazy and died. It acted just like it did when the external fuel pump sucked air a couple weeks ago on a test drive when i was super low on gas.

Well i pulled over and eventually got it to start back up. But it was running horribly and popping. I limped it back home and noticed it was smoking alittle bit when it was idling. Well i went back to the tune from yesterday and started it back up. It was still running badly but i took it down a back road just to see what it would do. It was still popping and everything.
I went back home and started pulling plugs. All the drivers side was fine. But the passenger side wasnt. Especially #6 and #8. The gap was closed up like something was hitting them and they were oil fouled. So i got them regapped and cleaned and put back in and started it up. Ran better so i took it for a drive and it seemed to be running alot better. Well it was running good but it still had a lot of blue smoke bellowing out of the passenger side header(its running open headers currently). So i pull it in the garage and figure it can be only a few things all of which require me to start taking the tpi and everythig off. SO to kindve make this alittle shorter i will jump to the part of me getting the passenger side head off.(sorry once i start explaining something it gets really long)
Well the #6 piston had damage on the top crown of the piston. Heres a pic.

Now for my questions, what could cause this type of damage? Ive never came into contact or read about one malfunctioning like this so I figured i would ask. I tryed doing a search online about piston damage and one link had pictures of various types with this being one of them. It was called chipped crown and was said to be caused by head gasket problems/leaks. The head gasket did look pretty bad with the skinny part between #6 and #4 being burned and basicly disinigrated(spl?). I have since got the engine pulled out and the other head pulled as well. Its the only piston with damage like that. #8, #4 and #1 looked to have some debri damage upon quick examination and there was a few pieces in the pan but not that many.

At this point i will be calling a machine shop tomorrow to see about getting the blocked checked for any damage to the cylinders. My hope is that it just needs alittle honing and new pistons/rings. But seeing how all of my hopes that i had today went to the can most likely that hope will to. Thanks for the help guys, and again i am sorry this is so long. I try and give alot of details instead of just saying HELP!! without even giving background info.

Apeiron

What was your ring gap?

grumpyvette

your piston pictures are not clear, and clear pictures sure would help. but it sure looks like you busted about 1/2 of the top ring land off, now theres several potential causes but the most common

(1)are having the ring gap too tight so the ring ends butt when the engine heats up locking the ring in the bore that easily breaks the piston land but usually also breaks the ring
(2) detonation damage this usually results in the ring land over heating and having a slightly frosted or pitted look ,the appearance is due to partly melted alloy and slightly rounded edges where the piston alloy partly melted are common and usually located near the edge. bad fuel or to much ignition advance or a vacuum leak can cause it.
(3) foreign objects in the cylinder (but that usually results in multiple clear impact damage)

http://forum.grumpysperformance.com/...+piston#p17973

http://forum.grumpysperformance.com/...php?f=53&t=509


http://forum.grumpysperformance.com/...+piston#p16848

http://forum.grumpysperformance.com/...hp?f=53&t=5454

305sbc

iTrader: (3)

The space between #4 and #6 is between two exhaust valves, and is a common area for localized overheating. I would look for blockage in the water passages or in the holes in the head-gasket in that area.
Other possible causes are a lean injector, or spark plugs that are too hot for the load range the engine is seeing.

Sometimes an overly rich tune can cover up a problem like this, and when finally tuned correctly the problem surfaces.

It could have also happened due to loading the engine too much ( 75% TPS or more ) before the PE mode was properly tuned.

Localized heat causes the top ring to butt ends which will break off part of the top ring land.

On SBC1 race engines it is common to run extra coolant lines to locations between the center cylinders to prevent localized hot-spots. You can see the line going from the water pump to an area below the #3 & #5 exhaust ports in this photo.
http://www.steveschmidtracing.com/im...-8246-2638.jpg

dabomb6608

iTrader: (3)

Thanks for the replys guys. The engine was a reman. that was in my fathers blazer for several years. It then got electrical problems followed by a bad tranny so it sat for 3ish years. We pulled it to put in my TA. I don't know what the ring gap was in it unfortunately. I will be tearing apart the motor in the morning to take it to the machine shop to get checked. I looked more closely today in-between my two jobs at the cylinders. I can say that the cylinders honestly don't have any visible scaring or Knicks. #6 was the only one that felt to have some slight damage in on spot. Felt like a vertical scar, and then on the top of the stroke it almost looked to have a small area that had tiny pits and felt alittle Rough. More pics will come tomorrow once I have the pistons out.

dabomb6608

iTrader: (3)

Here are pictures of the tear down. The pictures showing the cyclinders arent the best quality and the one kinda makes it worse then it is in person.

dabomb6608

iTrader: (3)

dabomb6608

iTrader: (3)

grumpyvette

the transfer of micro bits of molten aluminum are a strong indicator of detonation

the pitted sharp edges and general over heat and appearance indicates detonation also

305sbc

iTrader: (3)

This makes it sound more likely that coolant passages may have become blocked while sitting for so long. That will cause a localized hot-spot and detonation. Loading the engine hard with a hot-spot will cause detonation.

My experience has been that coolant passages develop a lot of internal build-up of corrosion/residue from sitting for prolonged periods, especially if Dexcool (orange) coolant is used.

dabomb6608

iTrader: (3)

Well that would explain alot of things. So it appears detination was the cause. It had shown it was detinating on the EBL software so I had been lowering my SA table Weds when i was tuning it. I had started to think it was false det. since me lowering the SA didnt seem to be helping any.

The block is now at the machine shop getting cleaned/magnafluxed/checked. I will hear back from them sometime this week on whether or not the block can be bored or honed out and reused. Thanks alot for the info guys.

dabomb6608

iTrader: (3)

I just finished talking to the machine shop. The cylinders only have .006 thousandth wear. So they are going to be able to just hone it. It was already .03 over. Unfortunately the crank journals need to be takin to .02 under. Both the main and the rod journals. They were already .01
So at this point I told them to go ahead and do all of that. I'm now in the process I'd deciding what I want to order in terms of rebuild kits. I've found one that I'm interested in on summit. It has the hyper pistons. There isn't a complete rebuild kit available with forged and even if there was it would be out of my price range. One of those things where I would like to get them but just can't. Anyways here the link to the kit. http://www.summitracing.com/parts/FEM-MHP139-322/
This look like it's a good kit for the rebuild?

Steel Armadillo

Well, at first, it sounded like detonation. But it also looks like the ring shattered
(which I suspect would happen either way). It does look like you had some molten bits moving around like grumpy said. Where are all the bits of ring and piston?

I'm not familiar with your build, so forgive me, but you're 100 percent sure you're using the correct fuel and that it isn't old/bad?

What is your compression ratio?

Strange that it's just two, and that they are right next to one another.
I'm no expert, but that would suggest, to me, a localized overheat. But I don't think it will cause that "molten transfer" as the smart guys call it.

I doubt a lean injector.

You said you found debris in the other cylinders?

Sorry for the long, rambling post.

dabomb6608

iTrader: (3)

It was a remanufactured sbc 400. It has the stock heads that were found on 400s of that time with the 76cc heads. So the comp. Ratio was in the 9:1 area. It had a full tank of new gas in it. I think the cause was from a combination of things all caused from the motor sitting for so long. Any thoughts/comments on my last post guys?

305sbc

iTrader: (3)

400 blocks need to have steam holes drilled between the #3/5 and #4/6 cylinders to allow air pockets to move from the lower side of the water jacket to the upper-side and on up into the heads. Otherwise a large steam pocket will form in that corner, and steam gets much hotter than the coolant and will not remove heat from the metal there. Have your machine shop drill the block for you.

dabomb6608

iTrader: (3)

Ok, I will call the machine shop about that tomorrow morning. I also need to take them the rod caps and nuts so they can check the rods.

Apeiron

The block doesn't need to be drilled, all 400 blocks come with those holes. The heads need them drilled if they weren't originally from a 400.

dabomb6608

iTrader: (3)

Thats what I had thought. I knew what he meant.Well I took my rod caps over to the machine shop. They said they would have it done by next week. Im ordering my rebuild kit today off of summit.

Steel Armadillo

Machine shops say next week, but that's really when they want you to call and remind them.lol

One more question and I'll just be quiet and read. I know you said it was sitting; after it sat, did you ever disassemble it? I assume the answer is no.

dabomb6608

iTrader: (3)

No, unfortunitely I didnt disassemble the motor. I wish I would have now. Lesson learned i guess. BTW: I looked at the heads that were on the motor. They did have the steam holes drilled. They are the crappy stock heads though. There is a swap meet this Sunday that I am going to go here in town. Im hoping maybe I can find a decent set of heads for a good price. The shop said they can drill the holes if I do find another set of heads.

dabomb6608

iTrader: (3)

Well ive got the motor back from the machine shop and got the crank, rods and pistons in tonight. Heres a picture of the product of tonights work.

Brando5641

iTrader: (-1)

I love the look of a new short block.