Recently I found that my stock short block was going down hill, finally. At 75K she was down on compression in 1 cylinder, burning a ton of oil anytime it saw significant boost levels, and now smoking from the crank case. I knew this day would come, just didn't plan on it being NOW. So, after some shopping around, I came across a killer deal on a used/built short block. Said block has 100 CP pistons, Pauter rods, and I picked up a set of GSC 2 cams to go with it. (Thx Drew) The parts were definitely used, but didn't seem to be abused or damaged. I even took the SB to Ball Engine (where the SB was originally assembled) to have it looked over. I was a little concerned about a spot on one of the cylinder walls, and I just to be sure the job I was about to do would only have to be done once. I picked up the SB from Ball with a clean bill of health. They said pistons, rings, and cylinder walls all looked good and spec'd out. GREAT! I purchased an OEM engine gasket kit, new T-belt, and WP. Engine removal began Tuesday morning. Everything went really smoothly, with the exception of getting the valve clearance right with the new cams and also BC valve train that I installed. Some of my intake buckets were too thick to reuse, but with the help of some of the SOG techs and a drimel in 2 cases:coolugh:, I was able to achieve the correct clearance. I installed the engine yesterday evening and buttoned everything up around 10pm. Time for the moment of truth.... Cranked up and immediately, knocking, LOUD KNOCKING! I shut it down and went home with my tail between my legs. Shit sucked BAD! So today, I'm on the phone with everyone I know that knows Subaru. Tuners, Mechanics, Part Manufactures...I even called up Ball Engine just to make them aware of what I was dealing with, and to double check that the SB was good to go, which he said it was, with the exception of the rods which were not inspected because I didn't request it. It sounds like a rod knock, only faster, @ idle, like loose valves, only louder. I started it up again and let it warm up thinking, maybe it just needs to warm up, build up oil pressure, something minor...No Bueno. It never goes away or gets quieter. After scratching my head all day and rechecking the valve clearance, my phone rings...It's David, from Ball Engine asking me what head gasket I used. Come to find out the Pauter rods used to assemble the SB require a thicker HG for proper piston to head clearance.:wtc: I know it's my fault for not researching thoroughly enough. It just never occurred to me that this would be an issue...FML Soooo now the choices are, A) Remove engine and buy thicker HG's; or B) Remove engine and swap stock rods from old SB into new SB using OEM HG's I'm only running a Green right now and I don't plan on making 600hp with this car, although I do plan on upgrading the turbo. What do you guys think? Sorry for the short story that's kinda long.
make sure your valves are fucked first. then check the pistons themselves and go from there. if they are fine, then just pick up the correct headgasket.
Well, it doesn't look too bad considering... The pistons aren't damaged and I cant feel anything on the heads. Waiting on Ball to call me with the correct HG thickness I need.
While you have the heads off I'd do the sharpie check on the seats, mark the seat and rotate the valve. Pull the valve and look, it will be obvious if the wear pattern isn't even.
Looks like the valve was BARELY touching the pistons. I'd pull each valve and have it inspected for truness and straightness.
I can't see any place where the valves have been contacted. It's hitting on the flat part of the combustion chamber on the edge of the pistons. I'm gonna check them to be sure, but I'm pretty sure the valves are ok.
You can see where the carbon deposits on the valves were chipped away. Those valves should be cleaned all up anyways....that's nasty and cause hot spots. It doesn't take much at all to bend a valve when you consider how fast and how much pressure they are under when operating.
ugh, sorry aaron, i had no idea it was an aftermarket HG, i bought the block assembled from Ball Engines and didn't have to go through this stuf let me know if there's anything else you need from me, man, gl with getting it wrapped up
Pretty sure? Is there a standard measurement I can take...say X thousandths + whatever is measured above the cylinder? I really don't want to do this again... No luck on finding the invoice?
Doesn't look like the valves hit to me but the piston sure did. If it was me I would just roll the dice and put on a thicker headgasket. The only thing that gives me any hesitation at all are the bearings.
The way I look at it is what is the expense of checking everything compared to getting it all together and it scatters 5 miles down the road? Hindsight is a bitch if it's not done right the first time.
I'm not at the shop right now, but I know we didn't have a custom gasket made. Cometic offers them in two thicknesses, standard (.040) and .051
I'm crazy like that. On my own car I am willing to take risks. If I am putting a car together for someon else I would tear it down and check everything.
Looks like some contact right there in the valve reliefs. Just a tad bigger valve reliefs and it probably would have been fine
I would check the bearings... usually when the piston hits the head like that the crank still has to turn. The rod bearings can touch...
As far as the bearings, am I looking for scoring? Ball said its highly unlikely that they have been damaged...since it ran for a total of 10-15 min mostly @ idle and never saw above 3K rpm. Also, running the .051" HG, WJM told me something about the cam timing being altered. Is that something that can be tuned around? What is the downside of running one that thick?
You need to check the pin bushings, center to center rod length, ring groove thickness in the piston (especially top and second), check the heads with a machinist straight edge, and by all means replace the bearings, doug is absolutely correct about the rod bearings. Any time you have contact between a part with that much force, 10 to 15 seconds is to much time, the bearings and other components will not be "fine".
Yeah thats my brothers old motor, that motor needs 051 gaskets. It has long rods in it you can not run a standard head gasket.
Well, I'm taking it back to Ball to have everything measured and likely new bearings installed. Definitely doesn't make since to guess or assume at this point. Hopefully It'll be running next week.
Well, I took the SB back to Ball last Tues. to have everything checked out. I had him install a new set of bearings with my "stock" rods. This way I will be able to run the OE HG's and also maintain an acceptable (IMO) piston to head clearance. With the other rods and .051" HG, clearance was .010"hnoes:. Just seemed a little safer to go this route, as this is my DD and not a race car. I used my spare time during the week to clean up the heads. I removed all the carbon and re-lapped all the valves. Got all my valve clearances set with the proper sized buckets and I only had to buy 1 from SOG, so that was a win. Before After I picked the SB up on Friday around 5pm. David said that everything looked good and that there was no damage from the piston contact. I only got to work on it for about an hour before my ride came. Saturday, I had to work til 3 ssh:. After that I was finally able to finish reassembly and get the motor in around 530. Finished buttoning everything up last night around 9pm. She fired right up and idled smooth without incident. Took her for a short little cruise up the road and back.(no boost) Everything feels good so far. Gonna need to get it tuned next week sometime, so I need to see who's gonna be available. At least I can partially/mostly enjoy my weekend now.
That's what David told me... I asked him, cause you can see marks on them, but he said they were "normal" wear marks. I just got back from picking the car up from the shop. It still has blow-by coming out of the vent tube. WTF!?!?
Very similar if not identical to what I posted in that video before I found 2 broken pistons. You can see and smell a steady stream of exhaust/smoke coming out of AOS vent. Separately, you can barely see a small amount coming from each head and nothing from the crank case, but when all hoses are connected you get this.http://www.youtube.com/watch?v=5GIYbNPQ-BA
Its plumbed exactly like this. The upper left vacuum port is open to atmosphere and the PCV valve is removed.
They are multi layer steel gaskets, even if he reused them chances are they aren't leaking at idle, theres just not enough cylinder pressure.