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Hi,
I have a 63 chevy truck with a High performance 454 in it pushing around 500hp. I have a 750 holley carb on there with a open plane manifold, and a 280 gph fuel pump.
My problem is that i moved up to the 4000ft altitude and ever since, i have been gassing out my oil pan within 20 miles of driving. I had the carb professoionally fixed and everything but i dont ever remember the gas doing this at sea level. The fuel pump is only about a year old. Any suggestions on what to check?
thanx,
david
Answer -
Hea Dave;
OK this is a first for me as I have never ever seen any motor excpt for plane engines up in the sky that had any trouble like you are having. When you say you had the carb fixed what was done to it ? I had a 454 in a 66 ss and it had 600 p+ HP and I had a 800 d.p. on it with a alum. intake , I wonder if you are just getting to much gas from that pro. fixed carb ? and you should get a psi gauge to see what psi is going to the carb> you might be getting too too much gas psi in it. get a in line gas/fuel regulator as it might do the trick for you OK as gas in the oil is super bad drain that oil a.s.a.p. I wonder what was done to that carb ? PS how are your plugs are they getting all wet and fouled too. if so you are getting too much fuel in there
check you fuel psi first OK.
Roger
HI,
Thanx for the fast response. I do have a regulator and i have the fuel at 5psi. The carb shop did a flow bench on it and flattened out the metering block. I have 73 jets and 84 jets secondary, because they said that those were what the carb performed best with those. Before i sent it in, i had 72 and 73 jets in there and same problem.
I have had people tell me that it could be the fuel pump diaphram? I dont know what that is or how to check it so i thought id seek other opinions. Anyways, thanx again for the help.
thanx,
david
Answer -
HI Dave
OK now I know what was done to the carb. and that should not be causing what you have going on, and the same for the fuel psi. as 5 lbs is low if any thing. and as far as the fuel pump diaphram the only thing that that will do is not work and you will get gas into the oil, but I thought you have a elect. fuel pump? and if you have a elect. fuel pump and a regular fuel pump that could be what is wrong you should remove the std. pump and get a block off plate as the elect pump will push the fuel into the stock pump and yes it could cause fuel to go into the oil as it might blow the pump. .
as far as the carb that should be fine as it is.
so if you have a std. pump also get rid of it. ok
Roger
Hey Roger,
Sorry, yes, it is an electric fuel pump and does not have a standard pump. Also, on the plugs, they are black within the same time as the gas gets in the oil, pretty scary. I have already changed the oil like 4 times within like 50 miles of driving trying to figure this out, but its very frusterating.
Thanx again for the help,
david
Answer -
HEA DAVE,
OK if you do have a std. pump on it than I bet that it is leaking into the engine and that is real BAD as it can/will cause some serious damage or even blow the engine up like in BOOM ! you have the gas mixing into the oil and thinning the oil out to about a 10 wt/ and it is taking a lot of miles of wear off that engine so take that pump off a.s.a.p. and get a block off plate or you can even take the pump out remove the rod from the inside than plug up the two lines comming out of the pump and put it back on till you get a block off plate but that pump is pumping gas into your oil . I used elect. pumps all the time and I would remove the std. pump . You have a fuel gauge and regulator so just run the elec. pump and watch the p.s.i. on the pump. just do not go too hi with the psi I think 6- 7 or 8lb is more than enough it will be fine but the std. pump is doing damage to your motor and you might even burn or spin a bearing or throw a rod so change the oil and filter and get the std. pump off and disconected now before you blow your engine OK DAVE I would NOT put it off for one min. The plugs are black so they are not wet fouled so the fuel is going into the oil it is fine from the carb and intake so that area should be fine . GOOD LUCK
Roger
Hey Roger,
Sorry you misunderstood me, i do have an electric, not a standard.
thanx,
david
Answer -
OK DAVE;
If you do have a elect pump fine but if you have a reg. pump and if it is hooked up that could cause the gas in the oil. so if you do have a std. fuel pump hooked up take it off and plug it up as that is what is most likely causing the fuel in the oil. Or what do you have in place of the fuel pump ?. is the old one still there and hooked up too ? and do you have a fuel filter in the carb or one in the front and one in the back if a dbbl. pumper if no filter in that is not good either. I would also put a in-line filter on the gas line before the carb. a small chrome glass one or a plastic one. let me know ok
Roger
Roger,
The there is no std fuel pump on there and there is a block off plate on instead. As far as i know and have seen there is only one fuel filter on the truck and that is between the carb and the fuel cell, and that is a big cone type of filter.
Thanx again,
david
Answer -
OK dave if there is no pump on the block than I would look at the carb. as the fuel is getting into the oil from some place and if you only have 5 lb. of fuel psi. than it is leaking in from someplace, if all plugs are good than it is from the carb. area. ok let me know , can you put a differnt carb on to see if it gets better. thats what i would do.
Roger,
Thats a good idea to try a differant carb, unfortunatly, i dont have another one or access to one. I had a holley dominator on it before when i was at sea level and then when i moved up here, i started having this problem. then got this new carb and still have the problems. Ill try to find one or something.
thanx again,
david
AnswerHea Dave;
I wish for you to keep in touch with me OK as I want to see this fixed, if you can get a differnt carb. to use or try that would help a real lot and rule out all of the other things that could be causing it, as far as buying one , and that is not that cheep/ so I would try to find one that you could use /even a quadrajet with a adpt. would work.It could also be comming threw from a blown diaphram in the carb or a seal on the carb. plate. can you get a rebuilding kit for it and rebuild it. or there could be something stuck inside the carb. so I would get a rebuilding kit and open the carb up. ok
Roger
