I was having severe oil burning issues in my turbocharged 401 nailhead. it was building all kinds of crankcase pressure when under boost. I ended up pulling it apart and found the cylinders to be glazed over. it did get hot 230 degrees once due to a thermostat and I overheated it. I thought it could cause it but the machine shop felt it was gassed washed and said it looks that the rings rounded off. I run o2 sensors and moniter my a/f so I never really thought I ever ran it to rich. I run nitrated steel rings with ross pistons and they finished the bore to a 625 finish. I will be picking up the motor tomorrow and installing it back in the car shortly once I finish the smoothing of the firewall and painting of the engine. looking into making it to the BPG nationals and hoping to get the bugs worked out of it in time. Has anyone ever gassed washed a motor where they wiped the rings out? did you have gd compression? I did have 150 psi on every cylinder. something just doesn't make sense to me like their is more wrong than what he is telling me. Paul
Wow - that's a drag...Get it back together soon! Buick Day at LVD in mid July! I've never heard of gas washing, but it seems to me you'd bend a rod from as much gas as it would take to do what you're describing, or at least find your crankcase about 4 quarts overfilled..???
Re: pulled nailhead apart again I changed the oil three times in 300 miles. once after the 20 min breakin . once at the end of the season and once this season. I never had a high oil level and I was burning and pushing out oil everywhere. building pressure in the crankcase causes all kinds of issues. I have always assembled my own engines and never had a issues with rings or cylinder washing but this is the first time I had this machine shop setup the bottom end. Was supposed to be a High end shop that deals with a lot of race engines so I left it to the pros. Not sure if I made the right decision. If it was gassed washed that means it had to be running pig rich and my fast wideband o2 sensors reading are wrong. I am picking it up tomorrow morning and i will get the heads back on it. i am hoping to have the firewall and engine painted and have it back in the car within a week to be putting the engine back in. looking to beat the hell out of it right away. no go easy on it like last time. Atleast every time it comes out the little things that need to be done get taken care off. always wanted to shave the firewall and basecoat and clearcoat the engine. I am also doing all vacuum line in steel tubing and than powdercoating after. I think it will just clean it up that much more. to bend a rod i would have to hydrolock the motor. i have seen that done when i was turning wrenches at the dealer, but i have only seen it when people suck in large amounts of water into the intake. I would love to run it at LVD and their is a chance i might be ready. Do you run a battery in the trunk? if so do you have a master shutoff?
I like the sound of the engine bay mods you're doing, hopefully I can check them out in person soon - Seems to me if it were running that rich you'd know it, you'd have to. you wouldn't be able to stand next to it when it was running, 02 sensors or not.....and yeah, my hydrolock experiences have all involved water too, except for one time someone poured a whole can of top engine cleaner in an 83 LeSabre all at once. Gotta read the directions. I've got a stock configuration with the battery up front, so no shutoff. I'd bet they'd look for one on your car though.
That's a bummer you had to tear your engine out again. I feel your pain. That's weird you got blow buy with that kind of compression. I run a battery in the trunk of my 66 gs and you have to run a master shut off switch if you are gonna run her down the track. I ran mine behind the license plate and when I race the car I just drop the license plate down.
A simple "Leak Down" test will tell you how the Rings are sealing without tearing apart the engine. My guess is the rings lost some of their temper from the overheating and no longer able to hold back the pressure. If you have alot of crankcase pressure after the rebuild something is wrong with the rings and or piston ring grooves. Standard rings should be more than capable of holding the Boost from the Turbo. The piston ring grooves can easily get scratched during ring installation if you are not very careful. Scratches will prevent a good ring seal. Remember Rings not only have to seal against the Cylinder wall but also against the piston groove bottom surface.
A cylinder leak down test only told me the problem was in the lower end and that's why I pulled it apart and found no cross hatch on the cylinder finish. I feel that under boost my rings where actually skating in the cylinder.When you overheat the engine during breakin you do not hurt the rings but actually glaze oil under the plateau of the cross hatch. I went to the machine shop today and he was installing the rings when I showed up. The rings didn't look bad compared to the new rings under the magnifying glass. A standard steel ring is not rec for a boosted application and a nitrate steel ring is highly recommend when running boost. it is similar to running a cast piston. you can run a cast piston and they will hold boost but they are not designed to handle the heat and pressure like a forged piston is. The cross hatch was wiped in the cylinder and I still believe after looking at the rings today that the cylinder hone was finished to the wrong grit. if you have time here is some great reading on ring tech.. their is a lot of misconception of what piston rings do and this does clear up some things. http://www.hotrod.com/techarticles/engine/hrdp_0910_piston_ring_tech/ .. I will be "borrowing" your license plate idea and run the switch right behind it. My garage is always open to visitors and plenty of beer in the fridge. Rhett --I will not be able to make in on july 12th because I will be camping in maine with the wife and friends but will hopefully be attending the BPG nationals at the end of July. i talked to kevin at CSU and i went over my a/f readings with him and he said he has never seen one gas wash and the settings i am at is pretty close to where i want to be. I will hopefully be priming the firewall this weekend and get some paint on Monday or tues.
Paul Get the car back together then go camping(making sure to relax). When you get back from that finish any last minute little things on the car so you can make it to the BPG show. Jenn and I will be there Thursday through Sunday. Looking forward to seeing you and the car there.
picked the motor up at the machine shop today and their was a bill of zero.. He took care of all the parts and labor and said its all set. I asked for the old rings and when I got home I dropped a few rings in different cylinder and wow.. I had as tight as ..014 and over .035 for ring end gap. my thought is the number two rings had a gap of over .030. These are file fit rings so something was not right. I think maybe it was 5 oclock(miller time) somewhere when they originally installed the rings. I only check a few rings and non where the same or around .018-.022 in which I thought they should be around. I was running a tighter plug gap than I was a ring gap:spank: I will be assemble the heads and etching the motor today and tomorrow to get it rear for paint. I will post some before and afters once done. Paul turbo nailhead
Could the rings have butted under boost and wiped out the crosshatch? I know we run a lot of gap on the SC engine because of how quickly the rings and pistons expand under boost. With a 3.57" piston we are running a .025" top ring gap and a .027" second ring gap. In the original engine the tops of the forged pistons were almost pulled off when the rings butted. This is a factory SC engine, but it was boosted at almost double the factory boost and had a stretched primary timing chain on that side. Cheryl
Cheryl, I think you are right. some where even tighter than .014 top ring gap. I am checking on the cylinders after they have been rehoned so they would have been even tighter. Kind of makes sense why the motor ran alittle hotter than normal. It was literally a tight engine. I stopped by my friends shop today on the way home and he runs a machine shop and auto parts store. he took a look at the rings and right away picked up four and said they were over heated and check the ring end gap in the bore. He called it, he said that they would be too tight and picked out the ones that where. exsperiance is a great thing. .He did it by feeling the outter edge for sharpness. Paul
Atta girl,Nancy Drew would be proud because I think you just solved the mystery why the cylinders got washed out.:TU: That sure had me baffled why that would happen with the proper(or close to) A/F ratios. Thats why I don't trust the "professionals" to assemble an engine for me. The last time I did(back in the mid 80s)after the engine failed and I took it back apart I found that the rod bolts were only finger tight!!! After that I never trusted a shop to do the assembly work for me again. Hope you get back on the road soon,and goodluck,I love your build. Derek
Hello, I'm a long time lurker that appreciates the info on this forum that is particular to the Buicks... Do you think the shop verified that the top ring grooves didn't stretch from the butted rings? I guess I've never seen pistons NOT damaged from this by the time an engine runs to the point that it really slows down and labors. I would think having the pressure to scrape the 'hatch from the bores would damage more than just the rings. I went through a similar learning curve the first time using the Keith Black Claimer type pistons. It didn't take long to nearly rip the tops from those slugs. I don't mean to worry you, but my area suffers from horrible machine work also. I see the silliest things on nearly a daily basis, but that's the subject of maybe a new thread. Maybe a phone call to verify what exactly they checked, what they found, and how they corrected the problem would be in order before you run this again. I would have them fill in the blanks rather than you lead them to answers. Be polite, of course. I have a hard time believing this got by any pro the first time around. Wish you the best in getting this back in order. Tony.
pulled the heads apart today to clean them up, lap the valves and reinstall. I had four intake valves with two much valve to valve guide clearance. I went the route of installing new guides because the play was so excessive on one I did not want to knurl it. Unfortunitly they are two days out on order. Because of construction i cant bring my heads to work where i would normally do the guides and cut the seats. The nice part is the guy we buy all of our parts from has a small machine shop in the back so this morning i spent three hours on the heads in his shop. It took forever to sandblast and clean them. Their was so much carbon and burnt oil on the throat of the valve and in the chambers. i have seen heads with 80k that looked better than these. 300 miles on these heads with new valves, valve job , rocker assemble and guides. You can see where the valves where extremely hot from the discoloration. By the chambers and valves I could see which cylinders had massive oil consumption.. Hopefully monday i will get the guides and have it all back together soon. Nothing like trying to rush to get it all back together before BPG event. Paul
I hate to say, but how many red flags do you need to see? Last thing I would do is rush it back together to make an event. A couple things you could do prior to short block tear-down (or engine assembly) would be to put a feeler gauge up from the oil pan side to see how much clearance after re-honing the bores, and to check if your nice Ross pistons are all at different heights relative to the deck. Your previous post didn't indicate whether or not they replaced pistons, but regardless, I wouldn't assume that anything is OK just because they said so... I do not believe that fatal engine errors would be a result of a "5 o'clock Miller time" :beer situation, more like incompetence, apathy, or ignorance. They showed you once what they were capable of already, please check things further while it's apart, and easy to do. Sounds like you are on top of the heads anyways :TU:. I did see the post that states they took care of everything, but they did let this out the door once... Have a happy and safe holiday weekend! Tony.
well motor is back together and just finished etch priming some pieces and primed the motor. looking to 600 the firewall tonight and base and clear everything tomorrow. anyone breaking their engines in with rotella 15w 40? Found on Buick rodder website that he said not to use sealant on the head bolts. I used ARP head studs and called arp and the said to run sealant and snug them to the shoulder of the stud. anyone got any info on this ? My goal is to fire this thing up by sat.. wife just booked a whale watch on sunday so thier is one less day. Paul
Paul, I used Royal Purple Break In oil I did use sealer, some of the head bolts go into coolant, I also used the ARP studs no issues, no leaks Roger
Me too Rhett!! its about 12:30am and just finished the basecoat/clear coat on the motor and firewall. I hope the flash floods and thunderstorms are not as bad where you are as down here. Nothing like power flickering when shooting clear.. hopeing to get some pictures up tomorrow but my phone wouldn't let me upload. I am going to be having a powdercoating party at my house to finish up all the brackets in some fresh color. Rhett, Are you going to bpg nationals? Paul
