Bad mech. fuel pump from crankcase pressure?? [Archive] - Team Camaro Tech

: Bad mech. fuel pump from crankcase pressure??


Erik Beckett
Apr 22nd, 08, 05:04 PM
So if its not one thing its another! Today was a beautiful day to drive the new camaro 18 miles to work. I made it about 14 miles then I noticed small puffs of smoke in my rear view mirror. So I stopped at a light and got on it some and noticed a lot more smoke coming out the passenger side of the camaro. I pull over and pop the hood to find oil all over the front passenger of the engine down low. The top of the Edelbrock fuel pump was covered with oil and as I would rev the motor the fan would splash the oil on the headers and you get the smoke.

After a little digging around the only leaking was on the fuel pump itself. I guess there are weep or seep holes on the top of it and oil was coming from these holes. I called Edelbrock and they said that when a motor has excessive crankcase pressure the seal in the fuel pump will blow and oil will shoot out the seep holes.

So then I call Bill Mitchell and they said thats BS. They have never heard of that and the fact that I have a PCV valve connected to the back of the carb and a Billet Specialties breather in the other valve cover that I am good to go.

So was this a coincidence that the first time I drive the car for more then 10 miles at around 2800 rpms the whole way and the fuel pump blows the seal?

Any input would be great!!!!

Thanks, Erik

Everett#2390
Apr 22nd, 08, 05:45 PM
Fuel pumps are cheap enought o buy one and swap it out to see if the f/pump is the problem.

You could hook up (Tee) a vacuum/fuel pressure gauge to the PCV line to see how much blow-by is generated at 3K rpm's. A sealed engine should have minimal amount of blow-by. You may have to seal the breather.

Any oil film from the breather? If there is, evidence of too much blow-by.

BillK
Apr 22nd, 08, 05:50 PM
Erik,
I have never heard of a fuel pump diaphram breaking because of crankcase pressure. I would just figure it broke, things do get old and break :) Replace it and get on with driving.

Erik Beckett
Apr 22nd, 08, 06:07 PM
I did replace it, it was the only way I was getting home. Thankfully a friend who is a camaro god and drag racer lives within a mile of my work. He wasn't home but his wife gave me access to his tools. I borrowed her truck, ran to Jegs and bought the same pump and installed it and drove 17 miles home with no issues. I took the brathers apart and there was some small oil residue but not enough that I would get alarmed.

Hopefully all this is a coincidence. We'll see and time will tell.

Two engine builders told me that it is not crankcase pressure as well.

Thanks, Erik

lluciano77
Apr 22nd, 08, 08:13 PM
This just happened to me this weekend. I am trying a new baffling system for my valve covers that don't have the room. They are tall valve cover but still don't have room for baffles because of the stud girdles. Anyway, the PCV pops off the hose at WOT and I get the cloud behind me.

I have been through 3 Edelbrock and Holley pumps. They all have the same flaw. The oil seal in them slides off the diagphram shaft easily. The 6 vane pumps like this are notorious leakers and it is very common for that seal to slide down. You have to unbolt the bottom of the pump, unhook the diaphragm and slide the rubber oil seal back in place.

I am researching what kind of mechanical style pump I am going to run next. I am tired of these production flawed units that are destined for failure. Holley and Edelbrock can send me as many replacement oil seals for free as they want, but they aren't the ones having to unbolt the pump (that should work) and hoping the cheapo cast housing isn't going to strip out this time when I put it back together.

lluciano77
Apr 22nd, 08, 08:15 PM
I did replace it, it was the only way I was getting home. Thankfully a friend who is a camaro god and drag racer lives within a mile of my work. He wasn't home but his wife gave me access to his tools. I borrowed her truck, ran to Jegs and bought the same pump and installed it and drove 17 miles home with no issues. I took the brathers apart and there was some small oil residue but not enough that I would get alarmed.

Hopefully all this is a coincidence. We'll see and time will tell.

Two engine builders told me that it is not crankcase pressure as well.

Thanks, Erik

It is crankcase pressure. But that shouldn't be enough to knock a properly functioning oil seal off. Do a search here and on other boards. You will see a lot others running into this problem. There would be a lot more people complaining if they knew the real reason their pumps failed. I think most people just throw them away and buy a new one or get a different style.

67CamaroRS/SS
Apr 23rd, 08, 05:44 AM
I had the same thing happen to my Edelbrock pump and they told me the seal was bad, but they never told me it had anything to do with crankcase pressure. They just said the internal seal was bad and they would replace the pump for me(free).

onovakind67
Apr 23rd, 08, 05:54 AM
https://publish.comcast.net/rpath/zzf3YxeJK3_LVn4DOklW0Tr_RvH824DPomIF_T9PFBMl_A9ImD B7N14uhOUA8DZABHUn0-QlAoX1-cDewnmVCndydS0CEXbS3X47yN_xWlo/

Got this bolt installed?

67CamaroRS/SS
Apr 23rd, 08, 06:04 AM
Nova, he said he had oil on the top of the pump. If that bolt wasn't installed, would he get oil on top of the pump? I am asking because I honestly don't know.

onovakind67
Apr 23rd, 08, 06:37 AM
I pull over and pop the hood to find oil all over the front passenger of the engine down low.

Nova, he said he had oil on the top of the pump. If that bolt wasn't installed, would he get oil on top of the pump? I am asking because I honestly don't know.

I must have misread the symptoms....

67CamaroRS/SS
Apr 23rd, 08, 06:49 AM
"The top of the Edelbrock fuel pump was covered with oil and as I would rev the motor the fan would splash the oil on the headers."

You are right about the front of the engine, but he also said he had oil on the top of the pump.

onovakind67
Apr 23rd, 08, 06:57 AM
Oil tends to collect much more on the top of things than the bottom.

ace's68
Apr 23rd, 08, 07:44 AM
Why not just do an electric fuel pump?
If I were to burn through 3 mechs i would switch to electric...

Everett#2390
Apr 23rd, 08, 08:56 AM
Oil tends to collect much more on the top of things than the bottom.Damn that gravity!

camjoe63
Apr 23rd, 08, 11:11 AM
Curious on this condition. Is anyone running a high volume oil pump ?? and if so could the high volume pump push to much oil behind the fuel pump causing the seal to fail ????

lluciano77
Apr 23rd, 08, 04:40 PM
Why not just do an electric fuel pump?
If I were to burn through 3 mechs i would switch to electric...

I have done that in the past. I am still running one on my Ford. I just don't like the cheapo noisy DC motors they are plagued with. Not only that, but I like the fact that my mechanical pump will shut off if the engine dies. You can run an oil pump shutoff switch with an electrical pump, but what if that fails???

lluciano77
Apr 23rd, 08, 04:41 PM
Curious on this condition. Is anyone running a high volume oil pump ?? and if so could the high volume pump push to much oil behind the fuel pump causing the seal to fail ????

I have a high pressure/volume pump. The pump cavity should only get splash back oiling.

Erik Beckett
Apr 23rd, 08, 07:48 PM
I am not sure if the motor has a high volume oil pump or not. I can say the oil pressure was pretty high like 70lbs while cruising 2800 rpms for 15 miles. I just took the oil fuel pump apart and I assume there should be oil in the top portion of the fuel pump. That is actually above the oil seal. So I guess I am confused on why oil wouldn't leak out of those weep holes all the time? I even downloaded the exploded view from Edelbrocks website and the holes are above the seal.

i guess I just don't understand.

Erik

lluciano77
Apr 23rd, 08, 07:55 PM
I am not sure if the motor has a high volume oil pump or not. I can say the oil pressure was pretty high like 70lbs while cruising 2800 rpms for 15 miles. I just took the oil fuel pump apart and I assume there should be oil in the top portion of the fuel pump. That is actually above the oil seal. So I guess I am confused on why oil wouldn't leak out of those weep holes all the time? I even downloaded the exploded view from Edelbrocks website and the holes are above the seal.

i guess I just don't understand.

Erik

Thank you for helping to illustrate my point on how these are poorly designed.

Like I was saying also, this is not an area that is under fuel pressure. The high volume/pressure pumps should have no bearing on this problem.

With the pump apart you can push the seal back up. There is a cast in area it will slide into at the top.

RickD
Apr 24th, 08, 04:20 AM
As a side note, I have run Carter fuel pumps with zero issues.

onovakind67
Apr 24th, 08, 04:51 AM
I am not sure if the motor has a high volume oil pump or not. I can say the oil pressure was pretty high like 70lbs while cruising 2800 rpms for 15 miles. I just took the oil fuel pump apart and I assume there should be oil in the top portion of the fuel pump. That is actually above the oil seal. So I guess I am confused on why oil wouldn't leak out of those weep holes all the time? I even downloaded the exploded view from Edelbrocks website and the holes are above the seal.

i guess I just don't understand.

Erik

You never did answer the question about the missing bolt.

Erik Beckett
Apr 24th, 08, 05:34 AM
I never checked for the missing bolt yet. I guess I should. This is an aftermarket Merlin block so I am not sure if the bolt hole is even there.

Like I said, I downloaded the exploded view of the rebuild kit and I do not even see another seal in the upper portion of the fuel pump. Just a big diaphram seal seperating the top and bottom of the pump.

Thanks, Erik

onovakind67
Apr 24th, 08, 05:51 AM
http://www.worldcastings.com/prods_pages/images/MerlinX.jpg

Is this the block? It looks like there is a hole directly in front of the fuel pump pushrod. Maybe it goes through.

Erik Beckett
Apr 24th, 08, 05:56 AM
That might be the block but I can assure you there is not oil at all on the front of my motor. Also, since I installed the new fuel pump I drove it home with no issues at all.

My concern now is what why there was so much oil in the pump to come out the weep holes. I tore it apart and didn't really see any gaskets or seals above the diaphram but I will check again tonight.

Thanks, Erik

lluciano77
Apr 24th, 08, 06:05 AM
That might be the block but I can assure you there is not oil at all on the front of my motor. Also, since I installed the new fuel pump I drove it home with no issues at all.

My concern now is what why there was so much oil in the pump to come out the weep holes. I tore it apart and didn't really see any gaskets or seals above the diaphram but I will check again tonight.

Thanks, Erik


Because it is more based of splash back oiling. I think making sure your PCV system is working okay would be a good idea. I got a valve for the old SBC 302. It was the closest thing I could find to matching my vacuum numbers.

Erik Beckett
Apr 24th, 08, 06:12 AM
How can I research different PCV valves and match them up with my vacuum numbers? Is there a chart somewhere or something for me to look at? The PCV valve rattles like it should. The one thing I did notice is the it connects to a T in back and tranny modulator is connected to the other end of the T and the to the carb.

Erik

lluciano77
Apr 24th, 08, 05:21 PM
I wish there was a chart that told what to use for sure. The best I have come up with is going to the local parts store and ordering a PCV from the closest stock engine I can find.

Everett#2390
Apr 24th, 08, 06:24 PM
Stock engines took one part number, 15 in./Hg. or better. Z/28's and L88's took another, 9 in./Hg. or less.

Erik Beckett
Apr 24th, 08, 07:19 PM
i just spent some time looking a the old fuel pump and there is definetely a rubber seal a bronze guide or something that slide down the shaft. I was able to take a small screwdriver and slide it back up the shaft. Kinda of like umbrella seals.

I replaced the fuel pump already so I am not sure if this part is fixable or not?

Erik

lluciano77
Apr 24th, 08, 08:13 PM
i just spent some time looking a the old fuel pump and there is definetely a rubber seal a bronze guide or something that slide down the shaft. I was able to take a small screwdriver and slide it back up the shaft. Kinda of like umbrella seals.

I replaced the fuel pump already so I am not sure if this part is fixable or not?

Erik

That is the beloved seal. The pump is fixed for now. They will all eventually slide back down. Next thing you should do is give it to someone that you really don't like. Or keep it as a back up pump in case of emergency.

Erik Beckett
Apr 25th, 08, 05:31 AM
So what causes that seal to slid down the shaft and are there any other pumps out there that don't have this seal or atleast no weep holes? I assume if it was really crankcase pressure I would have more oil out the breathers and my dipstick tube would of popped off. How can there be so much pressure in a motor when you have breathers and such on a motor?

Erik

lluciano77
Apr 25th, 08, 05:34 AM
So what causes that seal to slid down the shaft and are there any other pumps out there that don't have this seal or atleast no weep holes? I assume if it was really crankcase pressure I would have more oil out the breathers and my dipstick tube would of popped off. How can there be so much pressure in a motor when you have breathers and such on a motor?

Erik

The tolerances of the rubber seal to shaft are bad. If they had a more positive lock holding the seal in place it would fix the problem. Like I said, there is just enough crankcase pressure to force the seal down. The seal does not completely fall off, it slides down. It is still sealing a little, but in the lower spot it lets enough oil by to show up at the weep hole.