Compression woes 429 Ford

[blacksheep]

Ok, here's my situation. I bought a used 429 from a friend who pulled it out of a 72 Torino with 65k miles. I brought the nSty beast back to my place, and went to work on it. First thing I did was to do a simple compression check on all cylinders. All seemed to be good enough to run it for a while. I averaged about 165 psi on all cylinders. Well, I put rebuilt C8 heads on it, along with Edlebrock performer intake ,straight up timing chain, and HEI distributor. We cranked the motor up and noticed when I hit the throttle it smoked. White smoke , and smells like gas. The biggest thing is that I have blow by out of where the PCV valve plugs into the valve cover. The crazy thing is, this engine pops off at the slightest turn of the starter. But the exhaust smells like gas. Fast forward to tonight. I cranked her up and let her warm up , then shut it down and pulled all the plugs. Below is what I got checking the compression. The first number is the first puff of that cylinder, the next is after 5 hits on that cylinder.
1 -95-170
2-110-165
3-90-170
4-90-160
5-95-160
6-110-165
7-100-170
8-110-160

Now, I know that blow by means rings , but what should I do next ? Leak down? Before I yank the motor back out of it.

 

[ssimpala]

Yes, leakdown and then maybe 20/50 Valvoline for a little while. I don't know, maybe it will get better with a little driving. Good luck, Bill.

 

[LOWANDRATY]

White smoke

Did you run this motor at all in your car ?, your compression #'s are good 165 to 170 across the board, way lees than the normal 10%
If you never had it running in the car then the engine had to have problems before, if you did run it and had no issues until the head work, then you have a problem in the heads or the head gaskets. Sound like 2 problems to me, the head gaskets did not seal up and this is the white smoke, antifreeze and water burn white, antifreeze has a very sweet smell also, and the second problem is it may just be a little rich, giving you the gas smell.
How long did it run after you worked on it ? did it start to overheat or was it normal temp. ? you may have just gotten antifreeze or water into the exhaust pipes when taking it apart or it just was setting, and this may just be burning out of the pipes and mufflers. You need to run it out if there is no overheating issues, oil pressure issues, and no coolant/oil mixing in the radiator or oil.
I hope this helps just a little, Ken.

 

[blacksheep]

Did you run this motor at all in your car ?, your compression #'s are good 165 to 170 across the board, way lees than the normal 10%
If you never had it running in the car then the engine had to have problems before, if you did run it and had no issues until the head work, then you have a problem in the heads or the head gaskets. Sound like 2 problems to me, the head gaskets did not seal up and this is the white smoke, antifreeze and water burn white, antifreeze has a very sweet smell also, and the second problem is it may just be a little rich, giving you the gas smell.
How long did it run after you worked on it ? did it start to overheat or was it normal temp. ? you may have just gotten antifreeze or water into the exhaust pipes when taking it apart or it just was setting, and this may just be burning out of the pipes and mufflers. You need to run it out if there is no overheating issues, oil pressure issues, and no coolant/oil mixing in the radiator or oil.
I hope this helps just a little, Ken.

Hey Ken, no water in the oil or any steam blowing out, radiator stays consistent . We test ran the engine before the install, and it ran fine. I thought at first that it might be old oil left in the exhausts from the old worn out 351 we pulled from the car. I believe now that my carb has dumped fuel on top of the pistons , and not letting oil seal up around the rings. My oil smells real bad like raw gas. I pulled the carb last night I and found fuel laying in the intake ports from two days ago. My theory is that the fuel has washed the oil from the cylinder walls, thus allowing oil to pass by the rings, and gas has got my oil thinned out. My oil level actually went up . Haha. That's from running the motor 3 times for very short periods of time. Gonna get the carb right , change the oil and see what happens. This motor starts and runs perfect with just a touch of the key, so I'm hoping it is something to do with the carb. I'll keep you guys informed.

 

[LOWANDRATY]

Too much gas

Yep, get that carb. under control and let us know, sounds like you are heading in the right direction.

 

[blacksheep]

Ok, so Saturday I installed the newly tuned carb. I also decided to replace the intake gasket with the one recommended by Edlebrock ,using their manifold. I still have smoke , but now at idle and when you rev the motor, my PCV valve sounds like a locust when the engine warms up . When I pull it off the valve cover it is pulling mucho vacuum. I have a little blow by coming out of the valve cover. I still cannot adjust the air /fuel screws to make the engine stumbled . I did notice that the old intake gasket was wet from oil around the bottom loops of the gasket, and between the head and gasket. I did some checking and found that Edlebrock recommends a gasket that has the windage tray built in. I just knew I had solved my problem when I saw the old gasket, but I guess I was wrong. My first thought last week was to just pull the motor , and rebuild it. I just don't want to find out later that it was a warped intake or something silly like that causing the oil to be sucked up from the oil galley thru the intake. No more fuel getting to the oil , but I still am stumped as to how there is no adjustment on the carb. The guy who went thru it is very good with carbs. He's thinking vacuum leak, but I just can't find one.

 

[JBailey]

Are you re-torqueing the intake after it sits a day or after the first run? Just trying to help lol.

 

[blacksheep]

Are you re-torqueing the intake after it sits a day or after the first run? Just trying to help lol.

I torqued it to 25flbs first,then went back over it to 30 ft lbs.

 

[junker39]

How is the timing set? By the marks on the damper or just by ear? I'm asking because on my 429, it seems either the damper has spun a little on the rubber mounting and threw the marks off or the springs on the HEI mechanical advance are way too light. I had the same problem with my newly rebuilt 750 Holley. No adjustment with the idle screws. I got to playing with it and retarded the timing quite a bit, screwed the idle up a bit and now the idle screws work for rich/lean. I got the idle down from about 1500 to 1000rpm. It just doesn't sound "right" but, I'm getting used to it. I've got way too much cam for this thing but I like the way it sounds. You may want to play with the timing and idle speed. It worked for mine. Good luck.

 

[blacksheep]

Well, it is set at 10btdc . New dampner because the old on had spun like yours did. I still believe I will have to pull the motor because of oil burning issue. I have exhausted ( pardon the pun) most of the possibilities other than rings. What throws me is the compression is so high ,even on the first puff of each cylinder( over 90 psi). Not unless compression can be getting by the head gasket.

 

[blacksheep]

So, I got home yesterday from work and decided to mess with the car a bit. I retarded the timing some, and she fired right up like it always has. I retarted it a little more , and got the same results. No smoke at idle, and just a very little when I throttle up at WOT. Not sure if a ring popped back into place or if is just a fluke. Had some folks come over ,so I couldn't check into it further. Who knows. Even with the timing retarted, it fires right up with just a touch of the key. Weird.

 

[ssimpala]

Put some 20w50 and half a quart of Marvel Mystery Oil in that sucker and drive it a while. Sometimes after sitting for a while this helps get everything seated back like it should be.

 

[blacksheep]

Put some 20w50 and half a quart of Marvel Mystery Oil in that sucker and drive it a while. Sometimes after sitting for a while this helps get everything seated back like it should be.

Yep, last week I ran some tranny fluid throu the carb, and changed the oil again. I used castrol 20/50 with a pint of STP just for grins. Been using STP for years.

 

[junker39]

Does the carb adjust better when the timing is turned back? One other thing, check the vacuum advance hose and make sure there's no vac at idle. It shouldn't start to pull a vacuum til the throttle is opened up a little and it goes from the idle circuit into the main circuit. There's a hundred different ways the timing and carb idle affect each other. One other thing to check. The vacuum line to the transmission modulator. Take it off and blow thru it to see if there's any tranny fluid being sucked into the intake. Bad vacuum modulators can be a PIA. And my 429 scares me how easy it starts. Most times, not even a full revolution of the crank. I like it.[cl Good luck.

 

[blacksheep]

Does the carb adjust better when the timing is turned back? One other thing, check the vacuum advance hose and make sure there's no vac at idle. It shouldn't start to pull a vacuum til the throttle is opened up a little and it goes from the idle circuit into the main circuit. There's a hundred different ways the timing and carb idle affect each other. One other thing to check. The vacuum line to the transmission modulator. Take it off and blow thru it to see if there's any tranny fluid being sucked into the intake. Bad vacuum modulators can be a PIA. And my 429 scares me how easy it starts. Most times, not even a full revolution of the crank. I like it.[cl Good luck.

You know, I probably need to check that modulator for tranny fluid . When I I get home, I think I'll pull the modulator hose and plug the intake port to see what happens. And, no the carb still won't adjust. I can put my hands over the carb and the engine will die. The thing is , that I have the idle screw all the way out and the motor still idles around 700 rpm. You would think adjusting it all the out the motor would just die, but it does not.

 

[Dr Crankenstein]

The thing is , that I have the idle screw all the way out and the motor still idles around 700 rpm. You would think adjusting it all the out the motor would just die, but it does not.

I could be mistaken (it happens regularly) but turn the screw IN to make it stumble and/or die...

.

 

[blacksheep]

I could be mistaken (it happens regularly) but turn the screw IN to make it stumble and/or die...

.

You're not mistaken. But, I was actually talking about the engine idle screw and not the air/fuel screws. My carb guy is very good at what he does , so it just about has to be timing in relation to the amount of vacuum . But, I will keep looking. Thanks for the help.

 

[BlueNorther]

take the carb off and drain out the gas, hold carb up to light and see if primary plates and secondary plates are closing off all air flow when screws are backed out all the way.

if you can see light around the throttle plates the screws attaching them to the throttle shafts may be loose or the plates were not centered properly when the screws were tightened.