[Tim Corcoran]

Originally Posted by Gach

OK I just looked at both pictures at first I only looked at the first picture. The second one doesn’t look very good. Just out of curiosity I’d like to see what the other plugs look like. There might be a clue as to what’s going on. Looking at the plug is Definitely high heat range plug I’m not saying that that’s it but I would like to see the other plugs to see what they look like.

I showed two plugs, one from number 3 and one other plug. All the other plugs look pretty much like the clean one.

[Tim Corcoran]

Originally Posted by prostreet64

I wouldn't expect this with a hydraulic roller lifter but several years ago we had a solid flat tappet cam lobe get wiped with a bad lifter. That cylinder stopped firing. Hope this is not your problem but could be checked by rotating the engine and seeing if the rocker arms on #3 are moving as they should.

I checked valve operation on number 3 looks normal just like the cylinders

[geeteeohguy]

Looks like it's getting fuel. I would try a cylinder leakdown test and a running compression test to verify the exhaust lobe of the cam on that cylinder. I ran into that one time on an SBC....dead hole, but good compression, fuel, spark, no vacuum leak, etc. Turned out to be a flat lobe on the cam, for the exhaust valve on that cylinder.

[Tim Corcoran]

Originally Posted by Schurkey

Vacuum port on the runner for #3 cylinder? A big-enough vacuum leak can make the mixture too lean to burn.

Schurkey was spot on in post number 14. I suspected a vacuum leak from the very beginning but for the life of me couldn't figure out where it could be. I even pulled the carb off and made sure the gasket was covering all the right places. I believe I did all the correct trouble shooting steps but just couldn't figure it out until I pulled the intake manifold. When I was elongating the pushrod holes so I could use 1.65 rockers I got kind of carried away and broke through in a couple places. My machinist gave me some two part putty epoxy and he said it would be fine. Maybe I sanded it too thin but obviously it didn't hold. Now I need to fix these holes with something that will stay put.

[Gach]

Yep that picture explains it all. That baby is sucking in some oil ( Big vacuum leak )

[Gach]

If you can, put a sleeve down that hole, only because the Apoxy is a hit or miss. It’ll come out again when you lease expect it

[Tim Corcoran]

Not sure how I could do that the hole is not round after I was grinding in there. It's a shame I have a lot of money in those heads, porting, valves, springs, milling.

[Gach]

In that case I would grind that all off and get a real good Apox That’s not saying that you didn’t use a good going to begin with. Hey you may have good luck. Hey I go for it

[steve25]

Tim do it right but to do that you need to pull the head(s), that’s the hardest part.

Next drill the hole with a new 1/2”
Drill bit.
Get some 1/2” OD brass tubing from a hobby shop or order it from Grainger or micro mark.

Cut it to length full coat both the hole and tubing with JB weld and install it.
Let it harden for a full day and then cartridge roll sand away what you don’t need.

Sorry for your issue, but atleast you did not harm anything in a new motor.

Here in this photo of a max ported D port 16 head you can see how I did it.

[johnta1]

If there is no rag or vacuum leak in that port on the intake, probably need more info. Hard to do this stuff over the internet.

Glad you found the problem. As said, without all the info on your engine, it's hard to determine the cause.
(nothing about head work being done)

[steve25]

Here’s another photo of that same head and on the left port you can just see the tube peaking out and how far back and flat you can get to roll back to.

If you choose to drill & sleeve you will have to drill slowly when you get to the blow out holes because the might really want to walk on you.

[Tim Corcoran]

Originally Posted by steve25

Tim do it right but to do that you need to pull the head(s), that’s the hardest part.

Next drill the hole with a new 1/2”
Drill bit.
Get some 1/2” OD brass tubing from a hobby shop or order it from Grainger or micro mark.

Cut it to length full coat both the hole and tubing with JB weld and install it.
Let it harden for a full day and then cartridge roll sand away what you don’t need.

Sorry for your issue, but at least you did not harm anything in a new motor.

Here in this photo of a max ported D port 16 head you can see how I did it.

Steve
Thanks for the great info on how to fix this. Fortunately, only one head will need to come off the other head is OK. Can this be drilled by hand or will it need to be done in a mill? I have a drill press but getting the head at the proper angle would be almost impossible.

[Gach]

Hand drilling would be tough, have to go slow and easy. But it could be done.

[b-man]

You have a lot invested in your heads.

Pay a machinist to drill the hole and install the brass sleeve, you’ll be glad you did.

[Schurkey]

Didn't we go through all of this a few months ago? Different guy, same problem?

https://forums.maxperformanceinc.com...d.php?t=866228

[Dragncar]

Originally Posted by b-man

You have a lot invested in your heads.

Pay a machinist to drill the hole and install the brass sleeve, you’ll be glad you did.

This right here. Its cheap in the long run.

[steve25]

A drill press would be the best way to do it, but you would need to cut a lenght of wood to a 14 degree angle to sit the head on.

I have always done it with a big hand held electric drill that I have which has a side bar handle .
Maybe you could brorow one or get you hands on one from a tool rental shop.

[steve25]

Here's another tip for you Tim.

Use a Qtip wetted with some light oil to coat the whole inside of the tube so that any stray epoxy you get inside it will be far easier to sand out it you should need to.

[HWYSTR455]

Is the PCV routed to that runner on the intake?

Lay the spark plug on the side of engine or other ground and crank it over, see if it sparks.

The plug could just be bad.

.

[steve25]

He found the issue gang!