Leghome Posted January 16 Share Posted January 16 I have posted about this somewhere on this forum or something similar but cannot find it so here goes again. My 72 SMB 350 has been bored 20 over with a roller can and lifters. No 2 and 7 plugs have been fouling horribly. Switched from AC R45TS to NGK UR4 6630. They still fouled but not as bad and have not affected my O2 sensor for my Holley Sniper like the AC's did. Talking to a friend today that followed me home form one of the last car shows of the season and he told me every time I accelerated from a stop it would smoke but clear up pretty quickly. He said to him it looked like a ring problem. What do our engine guru's here think? Looking for solutions that does not require and engine removal if possible Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted January 16 Share Posted January 16 Valve guides or seals. Seals usually smoke and clear up on initial start up. Rings usually smoke continuously. Fouling plugs that bad is usually guides. 4 Quote Link to comment Share on other sites More sharing options...
EVC Posted January 16 Share Posted January 16 Valve guides … possibly caused by poor rocker Geometry. How many miles on the engine ? Does it have roller rockers ? Quote Link to comment Share on other sites More sharing options...
jft69z Posted January 16 Share Posted January 16 As advised before, try a compression and leakdown test. Can't hurt. I went thru this with my Camaro motor recently, after I went thru the car to freshen up the underside last year, add a Tremec, EFI, and ARH headers & a full new exhaust with tailpipes. After that, I noticed it was burning oil occasionally, which I never noticed before as the exhaust used to end at the mufflers. I changed the valve seals from the old teflon ones to a viton seal, which helped a bit. Next did a leakdown and compression test (numbers were great, btw). I did find the intake manifold gasket was compromised on a couple cylinders, likely pulling oil in from the lifter valley. Also saw evidence of it in the intake runners, where there was signs of oil soaking (not just wet fuel). After all that, it still burned more oil than I consider acceptable. Long story short, it's out of the car and at the best machine shop in the area now. If it's fouling plugs that bad, maybe try viton valve seals, if they'll fit inside your valve springs, then maybe an intake gasket set, and most likely, a trip to the engine shop. Carlisle is coming soon.... EDIT: I found your original post, it was in the 'What did you do to your Monte' thread. I see you already did a compression test, so that leaves a leakdown test if you decide it's worthwhile. In my case all the numbers were great (around 210 psi compression & 3-5% leakdown). The popular opinion is maybe the oil rings lost tension, or other possible issues. The valve guides aren't an issue in my case, so a teardown to see what's going on and a freshen up is next. It was put together in the early 90's, so more modern parts are sure to be available and help the cylinders seal better. 3 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 17 Author Share Posted January 17 2 hours ago, jft69z said: I found your original post, it was in the 'What did you do to your Monte' thread. I see you already did a compression test, so that leaves a leakdown test if you decide it's worthwhile. In my case all the numbers were great (around 210 psi compression & 3-5% leakdown). The popular opinion is maybe the oil rings lost tension, or other possible issues. The valve guides aren't an issue in my case, so a teardown to see what's going on and a freshen up is next. It was put together in the early 90's, so more modern parts are sure to be available and help the cylinders seal better. My compression was lower but all cylinders were within 5 lbs . I did not do a leak down test but did leave the compression gauge on number seven(the worst fouler) for a couple of days and it still had a lot of pressure built up that when I broke the connection between the gauge and hose it about blew the gauge out of my hand I am ordering a bore scope to take a look inside before I tear it apart that way my mechanic (son In-law) and I will have one. Never thought about maybe the intake gasket may be leaking, that is one reason I had it rebuilt when I did because It was consuming oil and assumed the engine guy would have looked everything over when he had it apart. After getting the bore scope and looking inside the cylinders will start disassembly if needed and check that out and that may be all I need is an intake or just gaskets Thanks Joe for the info 1 Quote Link to comment Share on other sites More sharing options...
jft69z Posted January 17 Share Posted January 17 I just picked up a new borescope last week. I have a SnapOn one I got years ago that works good, but the new Milwaukee one also has a side camera on the tip, that works great. The SnapOn one used a 45 degree mirror attachment that slipped over the end, if that falls in the cylinder, that's baddddd.... The picture quality of the new one is much better too. The flex cable is smaller in diameter than the other one too, so it's able to get into tighter places as well. They can both take pics and movies to a SD card, which is good for record keeping, especially if working on someone else's car.... https://www.milwaukeetool.com/Products/3150-20 HD had the best price, when figuring in the 10% veteran discount, plus if it ever breaks, the warranty is probably going to be honored vs. a place like ebay or Amazon. They had a bunch of other models that looked similar, but none had the side camera, except the most expensive one, naturally. https://www.homedepot.com/p/Milwaukee-M12-12V-Lithium-Ion-Cordless-Auto-Technician-Borescope-Tool-Only-3150-20/326368815 In regards to your statement that it held pressure for days.... usually those hoses have a Schrader valve in the tip, at the spark plug end. I'm thinking that's why it appeared to hold pressure on that cylinder, it just trapped pressure in the hose itself. With the piston rings having an end gap, it would be impossible for the cylinder to hold pressure for more than a few seconds, let alone a day. My SnapOn compression gauge set has a little pressure relief button on the side of the fitting, to vent the hose down after taking the reading. 1 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 17 Author Share Posted January 17 Joe this gauge also has the valve on the side to relieve the pressure no shearer valve on this one Quote Link to comment Share on other sites More sharing options...
jft69z Posted January 17 Share Posted January 17 18 minutes ago, Leghome said: Joe this gauge also has the valve on the side to relieve the pressure no shearer valve on this one There should be one in there somewhere, I'm pretty sure. On mine, it's screwed right into the end of the hose tip. The hose for the leak-down tester doesn't have one, but another extra hose I have also has a valve in it too. 2 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 17 Author Share Posted January 17 Ahh I never looked in that part. Well there is one there was an adapter on that end of the hose. 1 Quote Link to comment Share on other sites More sharing options...
cbolt Posted January 17 Share Posted January 17 The easiest way I have found to check if the rings are bad or the valves are bad is to do a wet/dry compression test. Since the compression test has been done and seems to be within tolerance I would say the valve seals or guides are the issue, not the rings. Check compression on each cylinder, then put a bit of oil in the spark plug hole and recheck. If the rings are leaking the compression will rise as the oil will form a temporary seal. If the reading stays the same the head is the culprit. Easy-peasy shade tree engineering and way less time consuming than waiting on leak-down results. 2 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 19 Author Share Posted January 19 On 1/16/2024 at 4:36 PM, EVC said: Valve guides … possibly caused by poor rocker Geometry. How many miles on the engine ? Does it have roller rockers ? 8000 miles since the rebuild with roller lifters and rockers Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted January 19 Share Posted January 19 Did they do the heads with the rebuild? How are or were the guides? Some I have heard put the o ring and the cup type seals both. 1 Quote Link to comment Share on other sites More sharing options...
Dtret Posted January 19 Share Posted January 19 Just curious it they used hardened valves seats. 1 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 20 Author Share Posted January 20 14 hours ago, cny first gen 71 said: Did they do the heads with the rebuild? How are or were the guides? Some I have heard put the o ring and the cup type seals both. I really do not know if they did. I had the same problem before the rebuild oil consumption and that is the reason for the rebuild along with putting in the roller rockers and lifters 14 hours ago, Dtret said: Just curious it they used hardened valves seats. that I do not know Quote Link to comment Share on other sites More sharing options...
TheBMan Posted January 20 Share Posted January 20 I agree with @MC1of80 and @cbolt, sounds like valve stem seals or guides. Rings would smoke continuously. A wet/dry compression test will tell you a lot. 2 Quote Link to comment Share on other sites More sharing options...
Leghome Posted January 24 Author Share Posted January 24 t my endoscope today and played with it a little so the pix aren't the greatest but you gotta start some wheres. Looks to be some rubbish around the one valve and on top of the piston. I need to play some more to get better quality photos but that wire is pretty stiff and I need to figure out how to maneuver it. After looking at the enlarged image I don't think that is the top of the piston 2 Quote Link to comment Share on other sites More sharing options...
Searsman Posted January 25 Share Posted January 25 Similar problem here 3-4 years ago. Mine was valve seals, used the viton seal. No more smoke or fouled plugs. Teflon seals had disintegrated.. just hoping yours is that easy too Larry.. 1 Quote Link to comment Share on other sites More sharing options...
Leghome Posted February 3 Author Share Posted February 3 Jamey(son in-law Mechanic) and his dad are coming over tomorrow and we are going to delve further into it. I have the EFI moved out of the road so we can run the endoscope over to the valve area to have a look see. Also looked for model number on the intake and it is an Eldebrock Performer 2101. Also found the invoice when the engine was rebuilt and they did do a valve job and resurface the heads, polished the crank, recondition the rods, new cam bearings, bored twenty thousandths and fit and pressed the pins 2 Quote Link to comment Share on other sites More sharing options...
Leghome Posted February 5 Author Share Posted February 5 Pulled the intake off Saturday and everything looks good as far as the gasket goes good seal all around. Now to start checking the valve seals but need to get a valve spring keeper remover. If the guides are worn new heads may be coming and if the seals are all that looks bad then replacing them will be done. Been pricing different heads and they run from $1338 a pair for Brodix to $1192.50 each for Edelbrock. I had never heard of Brodix until a few days ago talking to Joe T, we have talked about this problem and solved most of the worlds problems in our over 90 minutes worth of discussion. Talked to Brodix part number 1021005 and Edelbock part number 60895 on the phone today was their best recommendations for the way my engine is setup. Waiting to hear from AFR and Dart. 4 Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted February 5 Share Posted February 5 With the intake off, look down the intake ports at the valve and stem. If the seals/guides are leaking you should see signs. Quote Link to comment Share on other sites More sharing options...
Leghome Posted February 6 Author Share Posted February 6 2 and 7 were golden colored a couple of others were slightly but the first two mentioned especially 7 was the worst by far. So now to check the valve seals and hoped for the best but expect the worst Quote Link to comment Share on other sites More sharing options...
cbolt Posted February 6 Share Posted February 6 pics would help if you can take them Quote Link to comment Share on other sites More sharing options...
Leghome Posted February 6 Author Share Posted February 6 the first photo is No 7 stem, the fifth one number 2 stem I think. I am still learning how this endoscope works So I have mixed them up. Number seven is fouling the plugs the worst. pic taken in this order 7,5,3,1,2,4,6,8 Intake valves Actually wit the way the pic ended up in a line number 7 is actually the fifth photo. When I uploaded they were in order but it is what it is 1 Quote Link to comment Share on other sites More sharing options...
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