Found it...
Printable View
Found it...
I've done a lot of reading on this and can't seem to find an exact answer, but cylinders within 15% of each other seemed to be the general consensus for acceptable.Quote:
Originally Posted by 36 sedan
A leak down kit has been ordered and I'm sure will give some results to consider.
TDC mark is verified. I don't understand timing enough to give you an accurate number on "what it's set at". Between the vacuum advance, mechanical advance, and just regular setting. I'm not 100% sure. My strategy largely reliant on looking at what other's did on the internet and adjusting it until I didn't hear any knock anymore. I do have a timing light, but this is why I am planning on going to a tuner since I'm not at all familiar with this.Quote:
Originally Posted by jerry clayton
15% is a pretty wide spread. I would question anything more than 10%, especially on a new motor. Did you follow with a wet test?Quote:
Originally Posted by NegativeZero
Probably irrelevant, the leak down test will tell more.
You may have just found the problem! With the engine warmed up and running at idle unhook the vacuum line to your distributor and plug the hose (pencil or golf tee work good). With the engine at idle adjust the distributor position to your base timing with your timing light - I would start at 12 degrees before TDC for your SBC, tighten the distributor hold down bolt and recheck to be sure it didn't shift with tightening. You can rev the engine a bit to see with your timing light that the mechanical advance is working, then hook up your vacuum line and you're good to go.Quote:
Originally Posted by NegativeZero
record the timing reading you get and the rpm--check for how far it advances as you add rpm and record-
Most tuning places will be tuning your car for max HP so will want higher octance fuel to run more timing advance------
if you want to tune for street performance and available fuel at your location-tell them that---------and they can work around just drivability at street RPM
Since you had a failure of the chins wall gasket and you used rtv-------maybe you have a oil leak at the corner of the heads/manifold that is running down the front cover and just appears to be leaking there--------
wish you were closer so I could help-------.
NegativeZero, Jerry's comment,made me think that you need to be sure that the tuner you're going to knows how to work with an old school carbureted engine with no computer controls. Most of the hot shot tuners today tune for max HP and Torque like Jerry says, knowing that the computer will then take care of any differences that come up, and even self learn the changes over time. Take them a new Mustang, Camaro or Challenger and they may tune it with BP 106 octane, and then when they fill the tank with 93 octane the ECU will back out a ton of timing, and may increase the signal to the injectors to keep everything good. You need an old school tuner, not a kid who only knows the modern stuff, IMO. Or tell Jerry you'll buy his gas & hamburgers for a trip to Choctaw, OK, and let him have some fun!Quote:
Originally Posted by jerry clayton
I'm with you Rodger, Jerry can fix anything he's got easily!!!! And it would be cheaper than going to a tuner, especially one that doesn't know carbs.
And beware! A trick some dyno tuners use, is he'll hold back on the first few runs so it shows improvement later no mater what (hard to collect big bucks if there's no improvement).
Alright, a lot to catch up on now that the holidays are over
In short:
I believe what happened was I washed out my piston rings from running it too rich. I wasn't aware that this was a possibility and I knew there was a danger in running too lean, so I purposefully was running fairly rich ever since I got it running (about a month ago).
Long story version:
I drove my car to a local tuner. I know people that have used him and I trust his work. We talked for about an hour, I gave him all the details and everything I've done. At this point, my car smokes a lot from the leaking oil as well as the excessive blow by. In his opinion, my ring gaps alone wouldn't cause this issue and after talking more he's confident I washed out my rings from running it too rich. I got my car back to my garage, did another compression test with about 2 weeks and about a hundred miles on the engine since the first test. 2 of the cylinders were sub 80 psi, which told me, yea, I botched the ring break in. So, next week, I'll be putting in some fresh rings.
That being said, I appreciate all the advice here. Also what are y'all's opinions on ring materials and break in procedures.
Unfortunately, the only tuner I know of doesn't even do carb tuning. I'd love to meet someone that knows what they're doing with these. The only way I've had to learn is basically from Youtube, and while easily accessible and expansive, it's not the best teacher for things that are often as unique as building an engine from a million different parts. My plan for "tuning" was basically to rent some time on a dyno and make the adjustments myself, timing and AFR and such and just see what makes power.Quote:
Originally Posted by rspears
JMHO, your AFR numbers above are not rich enough to wash the rings. And, the compression dropping severely is a good indication of there may be more trouble ahead.Quote:
Originally Posted by NegativeZero
Glad you're tearing it down, hope you get it solved.
Yea once I saw that big a drop in compression, I knew it was time to crack it open. Rings are fairly cheep, so I'm honestly not too bothered by it. Planning on reducing the gap to 24 on the top and 25 on the bottom. I still think that leaves plenty of room for low boost applications and will hopefully reduce blow-by. Also adding a windage tray so hopefully keep crankcase pressure down a little bit more.Quote:
Originally Posted by 36 sedan
Check the bearings as well as I believe they might be just a tad out of spec.
JMHO, I really don't think your ring gaps were causing your trouble, unless they were significantly larger than you posted. In my youth (a long, long time ago) I ran some pretty worn out motors, a few had enough blow by to lay out a smoke screen and oil slick out the tail pipes, yet not enough crankcase pressure to blow out gaskets.Quote:
Originally Posted by NegativeZero
When you tear it down look it over closely, I believe there's more to this story than what meets the eye.
Also, I think you are a little confused on what a windage tray does, it does NOT reduce blow by or crankcase pressure, generally they are good at minimizing aeration of the oil at high RPM, which helps with a speedy return of the oil to the sump. There are lots of pro's and con's (and opinions) on windage trays.
I was told when I was young (many years ago) there are two phrases that apply to motor building and troubleshooting;
MOTOR BUILDING - Check, check, check, MAKE MISTAKES less, less, less
TROUBLESHOOTING - Test, test, test, SPEND less, less, less
IMO you'll be spending, and wasting a LOT of money with your plan to rent dyno time, and you won't gain anything from it but an empty wallet or big credit card bill. The popularity of the dyno and tuning for numbers is driven by the fact that the "Tuner" can quickly make changes to the fuel & timing maps on his keyboard to affect change, then immediately make another dyno run. For you, you'll be doing a dyno pull, then to change your timing curve you'll pull the distributor, change out springs, put it back in and set timing. To change fuel you're pulling the top off the carb, changing jets, putting the top back on, all while your paying for dyno time.Quote:
Originally Posted by NegativeZero
I'd dial in the fuel by making a WOT run through the gears, shutting down to coast to a stop and reading the plugs. Check around the old mechanics shops and find one that has a distributor machine and you're done - https://horsepowersports.com/distrib...ke-a-comeback/
I hope you'll come back and let us know what you find when you get into the engine. 36 sedan gave you two good old school rules to follow....
I'll be looking everything over to the best of my ability, trust me. I don't think the extra gap was necessarily the cause either. But I'm sure reducing that gap a tad won't hurt. I want to t minimize the smoking.Quote:
Originally Posted by 36 sedan
Since I'm not incredibly knowledgeable of this stuff, I'm debating sending the crank, rods, and bearing, to a machine shop so that can measure them with the proper tools.
I know a windage tray doesn't reduce blow by, but like you said, it does reduce aeration of the oil, which from my understanding would keep pressure down. Maybe not, but still. I'm planning on revving this engine out to 7k so it seemed like a good idea.
I guess I should elaborate, I was going to do as much "tuning" as I could on the street before taking it to a dyno. My tuner guy does 75 dollars for 2 runs, and I want to do it just for my own satisfaction to know how much power I'm making, (expecting 500 crank). He won't even touch the carb, so no worries about paying for that.Quote:
Originally Posted by rspears
I have an AFR gauge installed in the car, and if I can find someone with this distributor machine like you're talking about, I feel like I should be able to get fairly close to max power.
I'll echo Rogers comments above, use the money for a good timing light instead.Quote:
Originally Posted by NegativeZero
Here's a link to an article I wrote for my car club a while back that will show you how to adjust and set your timing;
http://www.boyxunderthehood.com/wp-c...ERFORMANCE.pdf
Back to the original problem.. excessive pressure causing seal failure(s).
Back in this thread you mentioned that it only happens at 6K rpm or above. So my new theory is your probably running a high volume oil pump and at that high rpm your pumping oil up into the heads, flooding them and this causes a "trap" the pressure has no place to go. So it seeks a weakness. A loose fitted seal, or the Chinese wall ... It's called a windage tray because it "breaks" the wind shear or turbulence around the spinning crankshaft, this allows the oil to get out of the "wind" and settle to the bottom, where you can pump it back for another cycle.
My other thought is your selection for the ring end gap is excessive. If you aren't running boost, don't worry about building a motor for the added boost pressures. You said it yourself, rings are cheap. Build the motor for the duty it will perform, not for what you "want someday"...
And another thought, drop some of the bearing caps.. the ring materials went somewhere! Find it before you close the motor up.
My last thought.. a "guy" with a dyno, who can't handle a carb.?.? He is NO tuner! But that's my opinion I guess. You know a carb has like 2 moving parts right?? 36Sedan has a couple of great write-ups posted around here.. The link above from him is a keeper! Hint /Hint... PRINT IT! LOL.
Mr. Spears. At the bottom of your linked page it says this ...
quote;
"UPDATE: Looks like they’re out of business.
Link: King Electronics out of business
King Electronics has them for sale on eBay No longer available
Posted on October 12, 2011
Filed Under: Garage workshop, Made in America, Shop tools"
Fair points. I am reducing the gap this time around. Every piece will be removed from the block and cleaned well before placed back. As for the oil pump, it's an brand new OEM style pump. I still think excessive blow by was the main culprit here.Quote:
Originally Posted by 34_40
As for my tuner, I'm sure he's fully capable of messing with carbs, he just gets enough business with fuel injection he doesn't have to mess with carbs. It's not worth his time and I understandQuote:
Originally Posted by 34_40
I wasn't pushing to look for that specific machine, but more to look for a good shop that has a distributor machine, like a Sun. I was more intrigued by the headline, touting that Distributor machines are making a comeback, and that guys are seeing the value in customizing their timing curve, old school.Quote:
Originally Posted by 34_40
which two cylinders had the low pressure??????? Please post a list of all 8 cylinders--------
WOW Jerry, I totally misread two cylinders! If they are adjacent each other you are correct, it would most likely be a blown head gasket, GREAT CATCH!! It would explain everything, and SBC are especially prone to the center two cylinders with their exhaust ports so close.Quote:
Originally Posted by jerry clayton
Might be an easy fix after all..
cyl.....1st test......2nd testQuote:
Originally Posted by jerry clayton
1.......135............didnt test
2.......130............100
3.......139............70
4.......132............133
5.......133............didnt test
6.......137............didnt test
7.......125............didnt test
8.......144............134
Once I saw 2 of the 8 cylinders as low as they were, I was cracking this open and didn't even bother with the rest of the cylinders. The engine bay has already been torn down, I just have to lift it out of the car tomorrow.
oil was completely clean when I drained it, and smoke was oil smoke. I'd be surprised of a bad gasket
you need to do a cylinder leakage test!!!!!!!!!!!!!!!!!!!!
why did you just check #3 on the left side and when it was 70 didn't check the others????????
You can blow a head gasket between cylinders but not compromise the coolant passages. What 36 sedan and Jerry are telling you is that by not checking all cylinders and also doing the leakdown test you may be overlooking an easy fix that saves you money. Remember 36's second rule?Quote:
Originally Posted by NegativeZero
Of course you may have already pulled the engine by now..... Hope you find your problem, and that you share what you find.Quote:
Originally Posted by 36 sedan
400 sbc have siameze cylinder walls--with very small space between cylinders they use special head gaskets
Cylinders crack often to the coolant holes---
oil smoke mostly will be from bad seal between cylinder head and intake manifold allowing oil to being sucked into intake port
with extra vents on valve covers he has killed possibility of any vacume in the crankcase
seals and gaskets leaking are most likely from poor installation
what head and manifold gaskets did you use?
what sealant/adhesive ?
Here's some advice I can offer on boost and rings from the school of hard knocks. Most of my boost experience is from diesels. But the same principles apply when it comes to the ring gap. First of all, don't use cheap rings when you want to run larger gaps. The cheap rings aren't "round" anymore when you gap them wide and then they don't seal properly. Also when the cheaper rings get heat soaked they loose their tension. Not really cool in a diesel. Haha. In my case the cheaper brand was perfect circle/sealed power and in the gas world those seem to be a good choice. But in my scenario they were the wrong choice. 2nd, have you checked your piston to wall clearance? I don't remember if you did or not. But if your PTW is excessive and your piston isn't growing when boost/heat is added then your bigger ring gap hurts you. Years ago I didn't realize how much a piston would grow under boost and higher cylinder temps. 3rd On any high boosted engine you're going to have to have some sort of crankcase breather evac or catch can system. It's just the nature of the beast.
Also, is your crankshaft end play within specs? Did you plastigauge any of the bearings when you assembled it? If you don't have all the measuring tools, plastigauge is a great way to check clearances.
.
Alright, it's been a long week. On the plus side, I found the problem. On the downside, the problem is a few cracked pistons.
https://cdn.discordapp.com/attachmen...976/image0.jpg
Got the motor out and torn apart Monday. Tapped out piston number 5 and a chunk fell off. At that point, I gave everything to a machine shop I trust to look over and make sure I didn't destroy anything else. I noticed a few of the rod bearings had some spots and sure enough, those are no good. Soooo, machine shop got back to me the following day and thankfully, I didn't destroy my crank or camshaft and the block is okay too. I've asked if they will reassemble the complete bottom end, since that's what I botched the first time. This way I'll know everything to the exact thousandth. This is the same place that conditioned my block in the first place. Talked with him for some time about my plans for the motor and he's selected a new piston head and we're moving forward. I've asked if I could be there as the block is assembled just so I get a chance to see how these are professionally put together and he's agreed.
Now, I've been doing a ton of reading since throughout the week, and either my type of piston damage is a result of either hydro locking or detonation. Detonation being the most likely since a few of my rods are bent as well. Luckily, it appears the only thing I've completely done in are the pushrods and bearings and pistons heads. However, I now know that you're not supposed to use a liquid based assembly lube when putting in pistons, which I did. And because I am a certified moron, I installed the distributer in backwards my first time I tried firing it. So I'm sure that didn't help either.
Now, how to avoid this happening again. I wasn't aware detonation was so destructive as it was or I would've taken more precautions. I've double checked my compression ratio calculations and it is definitely 10:1, so I don't think my gas is the problem. This is likely a result of my lack of experience with timing, but I just don't ever remember hearing much detonation. Not sure what it sounds like at high rpm however, but I am familiar with the knocking sound at lower rpms and idle. I'm debating on bringing my engine to a place with an engine dyno to have the break in done out of the car by someone who knows what they're doing, but finding someone who will work with carburetors and edelbrocks at that are few and far between here. I've heard of machines that you can put your distributor on and get a resulting timing curve per rpm back. Currently looking for a place that can do that so I can use this distributor. I'm trying to avoid buying a new fancy one just because I'm planning on switching to fuel injection in a year or hopefully less.
So that's basically where I'm at. Thanks for the help here and encouraging me to crack it open lol.
Honestly, I'm not even that mad just because I know what the problem is and I didn't ruin too much it seems. Only way is forward from here. Will continue to update and answer questions.
EDIT: also to answer a few of the other questions, head gaskets are fel pro steel core laminates and were fine. I may end up buying new ones that have a higher compressed thickness just because these new piston heads raised static compression just a hair, and I want to remain as close to 10:1 as I can.
Ring gapped will be reduced with better quality rings this time around and I've also got some dry powder lubricant for ring break in.
Good to hear your on the road to repair.. pun intended!
Discuss the ring break in with the engine builder. In the event you ask him to warranty it, be up front and honest with what you're thinking of doing. I'd agree with your thought on the thicker head gaskets, and I'm curious as to how much boost you intend to apply, starting with 10 to 1 just seems steep to me.
With you having a 400 block it is vital that you have gaskets for the 400 cast iron block and aluminum heads-----If I was doing it I also would o-ring the cylinders----
are those cast pistons??????? for your desires you need a good forged piston
I suppose I should give the full roadmap for the engine. I want to switch to fuel injection and be running e85 before adding boost to help keep things cool. I'm doing this all one step at a time however. Adding fuel injection is the next step, then switching to running on e85, then adding a supercharger with intercooler setup. I'm hoping that will keep things cool enough since 10:1 is a tad high for boost. Planning on running around 7lbs of boost, no more then 10 for sure. Goal is just to reach 700 hp. What I'll probably do is have a <600ish hp setup for street driving with a 700hp set up for the track. My builder knows my plans for the engine. I'll have to ask about a warranty, but given my track record with breaking in engines, he may not want that lol
I do have 400 specific gaskets, they include the stream holes. My heads have the holes in them as well. I've read about o-ring style gaskets but I never found any for gen 1 small block chevys, only LSs
Here are the pistons I'm going with this time around. They are forged.
https://www.summitracing.com/nv/parts/wis-pts510a4
I'd suggest that you add oilers for the bottom of the pistons for cooling---they are drilled/tapped up thru the mains and have nozzles for controled flow-If need be I can maybe do a picture of the tools so you get a better feeling for the results
I am very interested in this. I've not heard of this before and I'm all for keeping things as cool as possible.
Later today I will look for the tools needed and try to remember the contact for where you can get the jets--------I seem to remember maybe it was from a guy in Alabama
I appreciate it
https://www.pro-touring.com/threads/...-421-quot-SBC?
Hope this works-------
roll dowm thru it till you get to the BLP artical about the install of the squirters