Recently purchased a 73 base motor 4 spd 93k miles eldebrock 600 cfm carb, dual plane intake, HEI distributor, long tube headers installed about 200 miles ago along with new plugs. At around 2000 rpm had a slight miss, replaced plugs which 6 out of 8 had oil on them. Put 80 miles on it, runs good no smoke. On startup before plug change had black smoke and soot just on warm up. Checked PCV system and it has good draw
To it, doesnt appear to have excessive blow by and no smoke on start up. Oil on plugs going to show up again or just an anomaly?
thoughts?

 

At the least, with 93K miles, I would do a compression and leak down test. Jerry

 

 

Replace the valve stem seals

 

potentially, Valve stem seals seem to go bad about every 10 years or so.

 

I have bad valve stem seals and it does this and occasionally one will lift and I get smoke on the passengers side and when it sits back down it goes away....If you are not burning it and you do not have a large consumption issue then its not and issue.....right now. Pulkl your dipstick and sniff the oil and see if you can small any fuel in it....if oil is coming up then when you shut it off fuel can go down.

Something to consider......IF its concerning then do a leak down test to see how much you are losing pas the rings and valves. If you dont have the tools then thats money out of your pocket, then the valve job to see if that helps is more money and time out of your pocket. Then if its the rings....its more money out of your pocket.... What Im trying to tell you is either dont get to involved in it if its not a big deal yet and put money aside for when the horse power bug bites you and you want to swap heads and a cam or do a crate motor......the key is you say its fine now and you arent showing smoke out the pipes. A valve job and head work isnt cheap like it used to be and can be almost the cost of a good set of aluminum heads. Fortunately there are a lot of good SBC heads on the market so there is a lot in the resale market. Also when I was a kid chevy motors tended to last longer than their counter parts on ring wear but all of them tended to start smoking past the 100,000 mile mark. You are getting close and mileage is wear but again, you are better off making a plan, saving up some money and getting it done for the goal you want.Right now just drive and enjoy...

 

Sound advice all thank you. Didnt mention it has a healthy oil leak which I beleve is a contributor to oil usage. Trying to get someone to run
that down for me as Im getting a little long in the tooth (65) to be crawling around under the car. Not a lot of luck finding someone to check
it out, seems they like working on cars that in alot of cases is smarter then they are. Anyway, have a chunk saved for a crate motor again think the bigger problem will be getting a tech to do the work. Recommendations on crate applications that work well in my 73?
thanks again

 

bad intake install

 

73

 

What makes you say bad intake install?

 

your first post and your issues

sounds like classic leak at bottom of runnere.

no problem pre work.

your money but sealing ain't always easy

 

Thanks for that, how to go about checking please?

 

remove mani and look

 

I would be willing to bet a Chili Dog, Fries & Shake that 60% of Intake manifold gaskets are installed incorrectly.
And the oil rings, valve stem seals will get blamed every time for "oily plugs".

 

Go for the low hanging fruit if problem continues, replace intake gaskets using Gasgacinch gasket sealer.

Edelbrock Gasgacinch
https://www.summitracing.com/parts/edl-9300

Read Post #5
https://www.corvetteforum.com/forums...practices.html

 

My choice also...

 

Wow brilliant! Serious bets out there with one of my favorite meals of all time. Thankyou all for the intake issue, would not have occurred
to me. Makes sense though, all the bolt on updates were completed not to long before i purchased the car (100 miles) and why would the previous owner have someone do
updates to an engine that may not be worth putting money in.

 

Intake gaskets are frequently installed incorrectly and the "China Wall" especially likes to leak oil if not sealed well. Most bad oil leaks from Intakes is likely from the china wall. I had installed an intake and was getting strange vacuum numbers until we discovered the china wall gasket was not holding. I had my mechanic replace it for me (post-Surgery for me) and it has never leaked a drop of oil since. I had to swap out the relief spring in an oil pump after a fresh rebuild, again a mechanic did it and there is nothing dripping anywhere on my 427. Oil pan gaskets have always been a challenge for me...

What kind of vacuum is your engine pulling and is it nice and smooth?

A Leak Down Test is my favorite in situations like what you are describing. They are a bit more involved than a compression test but show you where the leak is in a batter fashion. To do a leak down test you need to have a good source of compressed air to perform the test. The test rig is readily available and not too expensive. After watching my A&P Mechanic do the leak down test on my Cessna every year, it is a very useful test and point to the problem pretty clearly.

I am not sure which Dual Plane intake manifold you have but I have been using Edelbrock's Air Gap on my 427 and it makes a big difference having the air space below the carburetor. The ONLY negative is that the Air Gap Intakes are a bit tall for some Corvette hoods. The power curve is clearly better on the Edelbrock over a stock intake manifold. It is one of the first things I install.

 

Would the intake have to be leaking oil to be seated incorrectly? Appears not to be leaking oil that I can see.

 

leaking oil does not get on plugs