stocki26

Hi, my 69 Corvette L46 starts showing too much burnt oil on 2 spark plugs. One on each side.

I bought her in 2011 from CA and took her to Austria, where I love to drive her up the mountains.

So I am thinking about replacing the cylinder heads or let them repair .

Actually there are most parts matching # but I bought my Vette on 62.ooo mls in 2011 and the actual 92.ooo mls show that I love to drive her.

I do not want to lose power, so new heads should deliver ~ 350hp again

Also I do not want cheap scrap parts that are built somewhere in China.

So please do some steps in my shoes and tell me what you would do, maybe some of you already have experience and can describe the way ...


Maybe I can also keep that beautiful valve covers .....

terrys6t8roadster

There are a lot of head manufactures out there to choose from and new heads have better design to them, hence better performance. Keep in mind that your pistons and rings have just as much wear on them as your heads so any head work that you do that causes more compression will cause more blow-by past the rings. 92,000 miles is just about the end of the usefull life of SBC engines. My 69 got a new engine a 93,000. T
P.S. Your can keep your beautiful valve covers.

jackson

Cylinder Heads

brand: EngineQuest a.k.a. EQ

country of origin: New Zealand

material: cast iron

chamber: modern 64cc fastburn vortec style

* noted expert David Vizard has measured - tested EQ heads and found them among the best

primary EQ source in USA is AAMIDWEST https://www.aamidwest.com/enginequest/eq-catalog/ and they advertise them on eBay too ...
... aamidwest has complete pairs with new headbolts & studs on eBay for under $850 USD

rings: a proper compression test sequence can help determine if rings or valves or (or both) are leaking.

stocki26

Which engine did you choose ? Satisfied until now ?

kossuth

Like others I would want to know the health of the rest of the motor with that many potential miles. I would run a compression test and I would leak down the motor. Valvetrain leaks would be dealt with via the new heads. Crank case leaks aren’t going to be fixed with heads.

If it needs rings/pistons I would strongly consider a crate motor given your overseas. Maybe I’m wrong but my initial thought was that finding a local machinist that knew anything about a small block Chevy overseas wouldn’t be the easiest or cheapest to source.

c3_dk

Maybe your heads just need new seals for the valves, that is a low price part.
And it is a easy fix.

stocki26

can this be done without taking the heads off ?

What special tool would I need ?

c3_dk

Yes

https://www.summitracing.com/int/par...6784/overview/

https://www.summitracing.com/int/par...9700/overview/

c3_dk

jackson

If those heads have Not been rebuilt in ~92K miles, it's likely the valve guides and / or stems are worn ...
... if guides / stems are heavily worn, seals may help but not fix.

If you do have a capable shop; very good guide repair is install of "guide-liners" ... common brand in USA is "K-Line" ...
... those can restore to like-new and are very durable. They are Not guides ... they are thin-wall guide-Liners made of a bronze alloy.
NOT a DIY job. Also, liners make obsolete the practice of knurling old guides.
https://klineind.com/k-line-service-...e-liner-system

https://www.youtube.com/watch?v=MJ8A...ature=youtu.be

http://www.sbintl.com/KLine.html

PGPierce

Also agree,it could be that $10.00 valve o ring there’s 2 per valve,if your compression is good except the 2 oil soaked cyl then it’s a afternoon job

cv67

tfs 175 aluminum double humps...then you can have an honest 350hp...why spend money on old stuff that will feel the same?
They make one with a smaller combustion chamber and are members of this board

https://www.summitracing.com/parts/tfs-30210002

derekderek

unless orig numbers-matching, guide and seat work is not justified on old heads. new aluminum is not much more and 50 years if flowbench work better.

CheezMoe

Leak down and compression tests are in order here. With that many mile on the engine you need to make sure all the cylinders are tight before spending any money, imho! Good luck!

terrys6t8roadster

I custom built a SBC 434, Dart heads, all internals forged, full roller valve train. The engine design was for low RPM high torque as my 69 has 3.08 rear gears and a overdrive auto trans. It gets over 20 MPG combined driving as long as I keep my foot out of it and am very satisfied with it. T

derekderek

what do you do with this car? if not daily driver and very few are, do the valve seals to stop the smoke. you need a piece of clothesline and a lever type spring compressor. wiggle stems to check guides while springs are off. this is vette driving season. not vette motor building season...

stocki26

Not my daily driver, but as you said now is the driving season.

I was planning to do some miles this summer and now have to check everything and replace the valve seals and rings.

After this I will see if it works to drive until this autumn when I will have a deeper look inside

Btw, I didnt notice that much smoke, but I checked the spark plugs and saw 2 of them having oilcoal on it after putting them new ~ 800 miles earlier

She does not drop oil when parking but I had to refill more than I had to last year - about 2 ltrs in 800 miles.

jackson

OP
So ... again, it's numbers matching and burning about 1 quart per 375 miles.

perhaps the intake manifold gasket(s) is leaking; sucking oil from lifter valley into intake port(s) ... Not uncommon.

try gently tightening intake manifold bolts or replace intake gaskets.

again, a proper compression test sequence can help determine what's at fault; and what's not.

derekderek

not rings. not now. just valve seals.

stocki26

I meant those rings below on the pic