As the thread states. It's a 400 .040 over, Scat crank, Eagle rods, KB -18cc dished pistons with Total seal TSS gapless rings, 70cc Dart iron eagle 200cc runner heads with teflon oil seals.

It didn't have gapless rings in it when I bought the engine, but I thought the rings were "fuel washed", so I tore it down, put in all new bearings rings, had the block re-honed and re-assembled everything. The heads were just looked at since the engine only had less than 10K on it, and everything still looked new and seals looked great. I've changed intake gaskets several times and tried different styles of gaskets - still smokes. Also tried unhooking the PVC altogther, and it's done this since day one I've owned it. I've done all this work and it hasn't changed the smoking problem. It fouls plugs within 200 miles...black, wet, sooty. After awhile, it'll start missing and I have to change plugs. Thought it was a fuel rich problem for awhile, but it's using oil and I've tried every timing combination and 2 different carbs.

When I first start it, the exhaust is clear. As it warms, it'll start to smoke and it only seems to do it at idle -and it seems to get worse if I idle for a long period. If it was strictly a strip car, I wouldn't care too much but it's 95% street driven and embarrasing at a stop light. As I'm going down the road, I don't see any smoke out of the rear view. It has a pretty stable 14" of vacuum at idle, which I think should be about right with the cam I'm running. Has good power though.

Compression checks look fine. The only thing I can think of is the heads, or some weird crack in the block. But I see no antifreeze in oil or vice-versa. Doesn't overheat. The only thing I plan to do is remove the heads, take them to a machine shop and have them gone over. If they check out OK, I'm really at a loss.

I've been putting this disassembly off (been too cold out anyway) - but now it's time to do this right. Any final other things I shold look at before or during the tear down?

-A Motown block isn't out of the question either.

 

Have you eliminated all possibilities that the intake is sucking oil in?

Were the block or heads decked? If so, was the intake shaved to match?

Back in '97, I got a Weiand Action+ for the 396 when I rebuilt it. It used a quart of oil in the first 50 miles. I thought I had really messed up assembling the engine. I started by taking the intake off, discovered oil was being sucked up from the bottom of the intake gaskets - looked fine from the top side. Turns out the intake port faces were machined unsquare, leaving a gap at the bottoms of the ports. I also noticed that not all of the mount bolt holes were drilled (the "top" row), thought that was just an "aftermarket" way of mounting. I was able to return it, from what I can figure it made it's way from the scrape heap to the shipping room by mistake.

Anyway, I'd check the intake.

 

"Prof Products "Crosswind" intake (ported)"

Not that many people haven't used them successfully, but that just heightens my suspicions (I saw that after I composed the reply above, FWIW).

 

That's one real possibility, right there. And it's even quick and cheap and easy to check.

Something else you might want to check, is if you can get your hands on a known good set of heads from somewhere off of a known smoke-free engine, and put them on yours (even if they're not "ideal" for your setup), and see if the problem changes. I know it's alot of work, and all that; but it would REALLY suck if it were to turn out that your heads have something wrong with the guides or seals or the rocker studs or what have you, and you've been working on the short block instead. IMO it would be wise to break the possibilities in half somehow, and eliminate one half from consideration. Seems like you've already done that by replacing the short block. Seems like the top end would be next.

 

I have pretty much the exact setup you do, i was in the same boat you are now about 3 years ago. I totally rebuilt my 406, put reman vortec heads on it go it going smoking like crazy drove it 200 miles and pulled it back out, backs of valves totally covered with oil, so i pulled the heads and took them to my machine shop and the valve guides were shot... totally shot you could feel the play in the valve. So i got a set of dart iron eagles like yours and its been fine ever since. Where did you get your heads from? I know mine have bronze guides in them not sure if yours do or not. Also have you ever thought about running a crankcase evacuation system? (breather in valve cover, connected to header) How about the wierd end gaps on the keith black pistons, i know they take a lot larger gap than any other piston for whatever reason, could that be part of the prob

 

5-7: I know it's a knockoff intake, but it's made pretty well and all bolt holes are there..lol - I've changed gaskets several times, and it so happens I have a spare Weiand Action Plus lying around, and I tried that - same thing. I've laid down sealer around all the ports and snugged it down and then removed the intake right away to see where it was pressing....it SEEMS to make a good seal all around - I know it's not an exact measurement or anything...the heads, well, from what I can tell have not been shaved - but I know I ordered 72cc heads and they list them on my original build sheet as 70cc....so maybe 2cc was shaved off? Doesn't say the block was decked anywhere, so I'm assuming it's std... I was really, really hoping that was the whole problem with this thing, but it doesn't seem like it. Both mating surfaces between the block and intake seem square when I just sit the intake on without a gasket (to the eye)
That's kinda where I'm going now Sofa - I've re-sealed these stupid rocker studs silly. If the valve seals are good (and they still look new), but the guides are too loose for some reason, will oil still get by? Well, I'm taking the heads to a machine shop to get them checked anyway - measured, magnafluxed (if needed) and go from there. Only known good heads I have are the 416's I have on the 305HO on my engine stand....but I hate to crack into a good running rebuilt engine (at least till I pulled it). Besides, with 58cc chambers, wouldn't my compression be insane for pump gas? - and I don't think they'll take a .540 lift.

Anyway - if I'm going though the trouble of pulling both heads, I might as well yank the engine out. I have a small leak anyway on my oil pan behind the oil filter....the pan rail is too thin there from crank clearancing and refuses to seal with the nice one-piece gasket...time go use the old school gasket with lots of snot, so hopefully it won't leak no more!

 

You must've posted while I was answering 5-7's and Sofa's post...I don't know where the original builder of the engine got the heads at....they were SUPPOSED to be new. I'm really hoping to find something wrong like valve guides in these heads....my crankcase evacuation system is the PCV system. I don't think I'm up to the HP levels that require a vacuum pump or anything.

I have read both yours and Lil jay's posts to get a grip on what's wrong with my engine, but I have not come up with any "smoking gun" - excuse the pun....

I never heard of KB's requiring a larger gap than any other hyper. I'm using gapless rings...

 

Sorry, I re-read my previous posts and changed a couple of things.....

By the time I'm done, I'll have the most $$ 408 ever.

 

"I never heard of KB's requiring a larger gap than any other hyper. I'm using gapless rings"...

Well the instructions on the KB/UEM site and the instructions included in the box that the KB hyper pistons come in clearly state the KB hypers require a much larger top ring end gap than other brands. They give recomended ring end gap factors based on intended usage. Reason being is the special KB Hyper alloy (transfers more heat to the ring and the top ring/land position. The rings run hotter, requireing a larger ring gap then what people are used to running. When the motor is running under load the ring end gap closes up more than a other brand of piston would. Like federal Mogul hypers)
I run these pistons in my 406. Made the top ring gap extra "biggie size" for moderate Nitrous use. (.033")
If your previous build had too small a ring end gap and the rings butted, the ring lands could be distorted (destroyed) now causing the new rings to rock and or twist in the lands, creating a oil burner. Essentually, the pistons may now be junk.
Do you have the old rings? Look at the ring gap ends. Butted rings ends look shiny.

Many engine builders have trouble with and knock these pistons saying they are junk etc etc. But they refuse to follow the recomended non typical ring end gap factor.
When it comes to ring end gap with these pistons, bigger is better.

 

Do you want a last ditch effort? Proven to work.

Do the old borax trick. They had to do that back in the day when bunch of GM motors were build with to smooth cylinder wall. They smoked brand new. Fix was the dealers ran some borax down the carb while it ran. scuffed the cylinders, sealed the rings and they ran great as it only did enough damage to help, not hurt.

 

F-BIRD'88: Well, I didn't know KB's needed a bigger gap or I just didn't pay attention. I'm using gapless rings now, and they fit in the lands just fine...hmmm. I tossed the old rings during the rebuld, but after reading your post, it prompted me to look at my original build sheet to see where the cheap "Enginetech" rings were set at when they were installed. It says they were set at .016 end gap. I guess that's something I'll have to look hard at if the heads check out OK. For now, I'm assuming the short block is fine since it's smoked from day one and a ring and bearing change didn't do anything to help or hurt it. I pretty much decided if I end up having to tear the shortblock down again for any reason, I'll get new pistons and a Motown block this time around.

camarokev400: I re-read your post closer, and you may have something when you said you seen oil on the backside of your valves. Once when I took my intake off, I saw a few puddles on top of my valves. I showed that to the machine shop, and I think they discounted it as a leaky intake gasket (since the heads were almost new). That's why I changed intake gaskets like 4 times since then, and no help. AFAIK, the guides are bronze like yours, and have not been looked at. The shop only looked at the seals (not guides) and said they were fine. Hmmm. It begs me to ask the same question again I had earlier...
Gumby: That really does sound "last ditch"!! I'll hold off on the borax for now, but I'll keep it in mind. I used the new "Quick Seat" powder on the cylinders when I installed the gapless rings....I think the problem is on the top end, and if it's the shortblock, well........

 

Do the holes for the rocker arm studs protrude into the intake port? Many heads do this and require sealant on the stud threads.

RBob.

 

RBob: Yep you're right. They do protrude into the ports, and I've used thread sealer on all of them. Even changed studs once, no change.

 

my heads that had worn out valve guides also had brand new seals and it still had oil all over the back sides of the valves... i would def pop some springs off and check the guides. I know what your going through with the high dollar 406 rebuilds..... mine has been done about 3 times now finally stopped smoking, i know the crankcase evac says for high horsepower or drag race only but i am running one on my car now it goes in the passenger side valve cover and it goes to the pass header, it has a check valve and the exhaust creates a vaccum.... the description in summit says that they eliminate blow by and seals rings faster dont know if it did anything for me but that is what i run..... I kinda wanna pull my valve covers off and check my rocker arm studs now that you guys are all talking about it... but i dont smoke so i think ill just leave it alone for now.

 

Thx camarokev400, good to hear from someone that can relate to this problem. I've thrown way too much $$, time etc. and have gotton zero. Still smokes.....like polishing a turd. You've convinced me. Heads are coming off.

I've read the clearnce is pretty close on the guides....like .0015 or something. So if I can feel the stem wiggle in the bore at all, it's probably worn out I'd think. Both heads will go to the shop regardless to get checked out.

-And don't pull your rocker studs if it doesn't smoke....I would'nt..... then what are you fixing? lol

 

While we're talking about oil consumption, 2 more things to think about:
1)Nobody mentions the oil control rings. They have to be assembled and oriented correctly.
2) Everybody remembers the picture of the feeler gauge stuck between 2 connecting rods to measure the gap, but it never says what to do if it is too big. This gap says how many GPH of oil is thrown on the cylinder walls. If too much oil is put on the walls it will overload even the best oil control rings.
This problem is most often found on crankshafts that have been "re-ground".
It seems that grinders can't resist cleaning up the side surfaces of the rod journals... The result: chronic oil consumption.

Your problem seems to be excessive valve guide clearance though...

 

You still have to check the gap where they overlap, and only 1 ring is probably gapless. It sounds like the valve guides to me, but I would have your machinist check your intake while you have the heads off, you never know.....I had the same problem (among others) with a warped LT1 intake sucking oil. If you have a ring problem you will probably be able to see it with the heads off.

 

Whats the story on the heads? Were they new?
One thing I've never seen good results with personally is knurling valve guides. It just creates an oil using engine. It will take up side clearance, but thats it. And yes even with good seals it can use too much oil.

 

knurling should be treated like the borax trick.

A last ditch effort to over come a lack of funds or parts.
Never do it unless you have to. Kinda like just slapping in new bearings or only fixing just the 1 cylinder that threw a rod.


In the lawnmower repair world they knurl pistons all the time but only cause having one bored out cost to much.

knurl the pistons, run a set of .10 over rigs with end gap filed down to spec and your good to go for several more seasons of mowing.

 

Thx for the replies everyone! That's why I stick around here, I learn a lot.
I can answer a few things.
Supervisor42: That was where I started. I thought my oil rings were shot possibly, so I put these gapless ringset in. It ate a cam when it was on the builder's engine dyno, and although he said he cleaned everything up, when I took it apart I noticed the lower cylinders had some light scoring. So the machine shop rehoned it which took most all the scratches out. The second ring land has the gapless ring I think. I made sure to install them right. The top ring is std gap. The crank isn't a regrind. It's a almost new Scat 4340. Rod side clearance was around .017 when I checked.

Lo-tec: Yeah, that's a good idea about taking my intake to the shop too. Can't hurt. How will I see a ring problem with the heads off? I mean aside from something obvious like screwed up walls or something...I can take pixs and post up when the heads are off.

madmax: Heads and everything else were supplied by the builder and SUPPOSEDLY new (I paid new price) for pretty much everything in it. I've heard of knurling valve guides and pistons like Gumby says. It works...for awhile. Money has never really been the big issue. Not rich by any means, but I'm willing to spend what it takes to make it run right. But I don't want to spend much more scratch on a .040 overbore block either.....so I hope the prob is the heads.

 

Look at the cylinder walls with the heads off. If the rings are butting I would think there would be a line or two in the wall. For a reference, I just pulled out the instructions for my C&A Zero gap rings. Their gapless ring (2nd ring) listed a minimum .016" gap and should not have to be filed, just checked to verify clearance. It also states in bold letters to add 40% to the minimum clearance for hypereutectic pistons (for the top ring).

Did you get a 4.040 or a 4.045 ring set?

 

I'm including this just for future searchers since the rod side clearance spec and its effect on oil consumption is often misunderstood.

 

Maybe call your local BBB and see if anyone has had problem with them.

In Toledo we got a machine / engine shop that is famous for running folks stuff. Which no one find out till to late. The other shop is town get most of the business fixing his goofs. Problem is its a real old shop and the BBB doesn't do anything as long as he refuses to respond. So he is still a BBB member.

Buddy had the guy doing an engine and he went on n on about ohh crank needs turned this much, all this that n the other.... the foolishly said come bakc and check out our 1940 equipment we use. There was buddies engine still covered in goo and had yet to be taken apart. His quick explains was he makes the guys keep the motor in one piece. Yea someone s gonna pull it all apart to check specs, then reassemble it still all cruddy.

Friend foolishly left it there and then spent double having a real shop fix it all.

 

Kinda similar but you get the same problem if you send Buick heads off to just any shop. 75% of the time they ruin the heads as they think they know everything and treat them like Chevy heads.

You want a clean machine shop with fancy equipment, nice shirts and tech books laying around being used.

Lots of guys know their stuff but aren't willing to learn or even open a book. Old-school ways don't fly for machine work anymore. Unless your in a pinch.

Then visit the shop with old equipment, and a dude named bob wearing a shirt that says jim, who looks like he just got out of jail, covered head to toe n grease.

Just a chatty kathy today but we get similar in the Yamaha Virago world.

98% of all shops even dealers won't touch one. As they don't have a clue how to fix them right. They just won't open a book. They think they know bikes already and it just doesn't work for everything. You have to be your own mechanic if you want somethings done right. I know bikes but I didn't know Virago's till I owned one and opened up a book.

 

It's not a question of old and new school. There have always been good and bad machinists, and there always will be.

 

Well, here it is a few months later but I finally got around to pulling these heads. They should be off today, and I'll post pics with my cheap camera. I can say everything looks great coming apart as it always has.

I looked closley at the area around where the intake gasket seats to the heads and intake, and both looked like they were sealing fine. And as a bonus I found no broken pushrod tips this time either. I guess I finally got the correct length!

Sticking to the original plan - taking my heads and intake to the shop to have everything checked on both. I'll also take a look in the cylinder bores too. Don't know what I'll do if the heads/intake get a clean bill of health......

 

Heads are off now. Pics as promised. Pistons are discolored, but heads sealed fine judging by what the gaskets looked like during removal. No scores in the cylinders that are obvious, and still has hone marks. I know the pics are crappy, but again, I'm no pro at this:

 

What do the intake runners and valve stems look like? Any oily crap on them?

 

if the heads are off, pull off a valve spring or 2 (or 16) and check to see how much rock you have on the valves pulled open just enough to get your fingers around the head of the valve. I bet the guides are shot.

one other item I have seen with gapless rings. Most of the time they sell them with the 'low tension' oil rings. We had an engine that huffed a little, and it was due to the 'low tension' oil rings. and interestingly, it was a 406.

 

Lo-tec - Just got done dropping the heads off at the local machine shop. The owner (Tony) took a look and pulled a couple of valves. This time around, the intake runners were pretty dry. I only put maybe 200 miles on it since it was last apart though...

It has bronze valve guides, which appear to be OK. The stems were awfully hard to remove though, almost like the stems are mushroomed a tiny bit on top.
But overall - not hearing anything bad. Tony says he'll clean the heads up, check all the guides and replace the teflon seals with viton seals.

I told Tony about all the different things I've tried to get rid of the smoking problem, and he threw in a couple of different twists I hadn't thought of... he'd like to see one of the pistons. He says he's seen a few engines that seal fine with good compression rings, but the oil control rings didn't seal. I suppose that's a possibility, (if the cylinders are tapered) but I did have the block at his shop in the past and the bores were measured and rehoned.

But I suppose it's possible - as you can kinda see from the pics, the pistons are discolored. Not what you'd see from a normal firing engine for sure. But if it comes to tearing this whole thing down again, then it takes me to a crossroads per se. I.E. - How much more money should I throw at this block? Can I just get a new Mighty Motown block and it'll solve all my problems? -I just don't know that yet....and that's my dilemma. For now, I can only hope he'll find something wrong with those heads...

Oh yeah, the other thing he mentioned (and maybe more likely) is that I've fixed whatever oil burning problem I had in the engine, but the exhaust (CAT,muffler) has oil in it still that has to burn out. I never tried pulling the exhaust and running open headers (or Y-pipe) to see if it smokes still...but that doesn't explain the discoloration in the cylinders. I may have a change of plans...

 

jwscab - We pulled two valves on one cylinder, and you could feel a tiny bit of movement if you tried to rock them,but not much at all. I made the comment outloud that I think the clearance is .0015 which ain't much so I wanted them checked. Tony thought it was normal, but I told him to give them a total clean bill of health so to speak to elimate them as a cause.

I hope my oil rings aren't low tension. They're Total Seal gapless TSS rings. My part #for my rings is 0901-019004091-06 (H130) which doesn't translate into anything I've found.

EDIT: They do list them as standard tension oil rings though..

 

I went to total seal's website and summit, and your ring part# isn't close to what they list.

Where did you get the rings and where are you coming up with that part#?

 

I'm going to throw something in here becuase I've had a few "smokers" with Dart heads- one with Iron Eagles, one with Pro1 heads. Something about the guides.... could never get them to seal up. If the backs of the intake valves are badly carboned you KNOW the oil consumption is coming in through with the intake mix- that was the case with my heads. Like you, I tried everything. I came to the conclusion that oil was coming past the guides, despite the fact they were tight enough it should never have been an issue (I had replaced vavle guide seals several times with different types of seals, amongst the many things I tried). I had the factory bronze guides knocked out and completely replaced- smoke gone. I have no proof, but I still think that the oil was coming down the OUTSIDE of the valve guide insert. Like it wasn't sealed up in the head casting- just a little passage for the oil to squeeze past.

I know FOR SURE the oil was coming from somewhere in the heads becuase at one point I had replaced the heads with a set of AFRs on the exact same untouched short block and it ran squeaky-clean with the AFRs after that- no oil consumption or smoke.

It was only later that I decided to have the guides completely redone in the Darts and then bolted them to a different short block- and never an issue with that motor after that.

It's not PROOF, mind you, but I feel like maybe I've been where you are now and it was certainly a head-scratcher for me when I was in the middle of it. I have only partial confidence that I ever truly indentified the source of the oil consumption problem, but it's definitely not the first time I've run into "smoky" Dart heads.

 

Lo-tec - It's a white label after the words "part number" on the box, which I still have. The only other numbers on the box are on another white label on the box end (019004091-08) - I believe I got them at Jeg's.

-Theres also another number (H130), and it gives the size of the rings themselves: 4.165 5/64 5/64 3/16 TSS 8CYL. It came with a piece of hard candy that says "Total Seal" on it if you can believe it!

Damon - That's a good thought!! It seems feasible to me, so I called the shop after reading your post. They don't think that it's possible since the guides are press fit into the heads, but they said they'd look close at them anyway....I told them not to hesitate changing all of them out if needed.

It's beyond frustrating because the problem is well-defined. It's burning oil. What's not clear at all is how. Keep the thoughts coming! I appreciate it.

 

please dont tell me you (or machinist) just forcibly pulled them out of the guide....

 

It's actually the valve lock groove of the valve stem where the locks engage that gets distorted. A light fileing removes the slight ridge, allowing the stems to go thru the guides effortlessly on dissassembley.
Does this motor have a mechanical fuel pump?

 

Yeah, you're probably right - it may be the valve lock grooves binding things up. He was just doing a quick check on the guides while I was there. - I'm assuming he'll be replacing that one and most, if not all of them anyway. I think I made it clear that I wanted him to scrutinize the h*ll out of the heads, and do them right.

And yes, I do have a mech. fuel pump. But it was replaced after I put new rings in it....it smoked with the old set of rings with the old fuel pump too. So I don't think I'm pumping oil in the fuel -or vice-versa if that's where you're going..(I'm guessin)

Oh, BTW F-bird, You've tried helping me in the past with timing issues, which I could never get right. -But Thx!!

Just wanted to get your thoughts on this. Would burning oil in an engine effect the timing curve and/or the way you need to set the timing, or would it be almost impossible to dial it in due to plugs fouling etc..?

 

Yes I was wondering if the fuel pump had a ruptured diaphram and weas allowing oil to mix with the fuel.

Yes oil contamination in the combustion process will play havoc with the engine.
It will cause the motor to want to knock with seeemingly normal timing ( raise the octane requirement) and kill the throttle responce eventulaly fouling the spark plugs.

 

I think if your machinist pulled out your valves without filing them down first, you should seriously seek a new machinist. Even if he was going to replace the valve guides anyway - that is just a ridiculous move IMO

 

Well, here’s the news everyone and it’s not good. The shop found essentially NOTHING wrong with the heads. They’re just going to clean them up and install the new seals – not that it needed those either, but I requested they change them.

Now I can only turn my attention to the short block that’s left.

After going through this thread a bit more (there’s good info in here) – and also after eliminating things I have double checked to no avail, there’s still a couple of items brought up by others I might check.

The machine shop posed one possibility – that I had already repaired the problem and I still have residual oil in my CAT and muffler that has not entirely burnt out. It’s feasible because it matches at least one of the symptoms – the tailpipe is clear until the engine warms up. This means I’m just causing myself a lot of work for nothing. He only way I know how to test it is to put the heads back on, disconnect the exhaust after the Y-pipe and run it till it warms up to see if the exhaust stays clear.

Another possibility as mentioned above could be the rod journal side clearance. I don’t recall checking that when I installed new bearings and rings, so if it’s excessive it might be that I’m overwhelming the oil rings. Of course, this involves an engine teardown, and as I’ve mentioned earlier in this post, I’m not gonna break the bank on a block that’s already been bored .040 over. I’d just assume get a known good block and start over.

So if this were a problem on your engine, what would you do??

BTW, I appreciate the concern over the practices of my machine shop, but it just isn’t helping me solve this problem. –But I’m interested in any further input anyone has that might solve the oil burning problem. Thanks to all on the board that’s helped so far…

 

This is the best type of ring your money can buy right now, they are a Total Seal Gapless Gasported piston ring. They are a file fit 2 piece ring, too many reasons to list why I switched to them. They are not custom they are off the shelf and about 600 bucks. Just watch some test videos on these and you will be sold unless your budget doesn’t allow it. But you can spend less on pistons and more on rings which will definitely get you more power. There is power in rings!

 

also 0.060 over isn’t bad in a 350, I definitely wouldn’t do 0.060 over in a 400 though