intake/oil leaking problem

J

jggianna

New Member

Apr 11, 2011

10

0

0

Apr 11, 2011

#1

• Apr 11, 2011

• #1

I have a 66 coupe. I currently have a 302 that was rebuilt a couple of years ago and it sat. While being rebuilt we put brand new heads (351). Now we kept the intake (289). Runs pretty good, however it is smoking bad from the passenger side exhaust. We pulled the plugs and 2 are fouled. I believe (hopefully) that the rings may be stuck, but can oil back up into the intake causing the oil in the exhaust? Please HELP!

 

mustangmutt

Member

Aug 2, 2010

339

6

18

El Paso, TX

Apr 11, 2011

#2

• Apr 11, 2011

• #2

If the valve guide seals are bad it will suck oil through the intake valve guide. Can you take the car to someoine who can do a cylinder leak down test?

 

J

jggianna

New Member

Apr 11, 2011

10

0

0

Apr 11, 2011

#3

• Apr 11, 2011

• #3

We did take it to our body shop guy but he was questioning the 289 intake on 351 heads, because at first we did have a problem with the gasket on the intake not lining up properly so oil got into the water, we fixed that. He doesn't seem to think they are bad after all they are new, but again it sat. I guess I just don't want to tear it down!!

 

M

MitchGT

Member

Apr 1, 2005

204

0

17

Apr 11, 2011

#4

• Apr 11, 2011

• #4

my question is when does it smoke? If it smokes when you hit the gas, it's probably the rings, if it smokes when you let off the gas suddenly, then it's likely the valve seals. If you have a pvc system, plug it for now to make sure you aren't sucking oil through it.

 

mustangmutt

Member

Aug 2, 2010

339

6

18

El Paso, TX

Apr 11, 2011

#5

• Apr 11, 2011

• #5

289, 302 and 351W all share the same head dimensions. If it idles good then you probably do not have a problem with the intake gaskets. It is critical to follow the proper tightening sequence when bolting on the intake to avoid leaks.
Do a compression test first. It you do not have low compression, especially on the two cylinders that fouled the plugs, the rings and valves are okay. If they are low, then do the leakdown test to determine whether its the rings or valves.
How bad does it smoke?

 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Admin Dude

Jan 4, 1985

42,890

21,068

234

Box behind Walmart

Apr 11, 2011

#6

• Apr 11, 2011

• #6

mustangmutt said:

289, 302 and 351W all share the same head dimensions. If it idles good then you probably do not have a problem with the intake gaskets. It is critical to follow the proper tightening sequence when bolting on the intake to avoid leaks.
Do a compression test first. It you do not have low compression, especially on the two cylinders that fouled the plugs, the rings and valves are okay. If they are low, then do the leakdown test to determine whether its the rings or valves.
How bad does it smoke?

Click to expand...

Aren't the deck heights different though? If so, then I could see how maybe a 289 intake, 351 heads, on a 302 block might create problems.

I could also see where installing the heads on a 302 block would give the correct dimensions for the intake too. Ah dunno... thinking out loud.


Edit: Another Thought...


Did you seal the little gap between the heads and deck surface at the rear of the block? There should be a little gap there (you can fit a credit card into the gap). It will allow oil to drip down the back of the block onto the exhaust manifold.

 

mustangmutt

Member

Aug 2, 2010

339

6

18

El Paso, TX

Apr 11, 2011

#7

• Apr 11, 2011

• #7

Sorry for any confusion, the 351 blocks have a higher deck height than the 289, 302's, but the heads are dimensionally the same. There are some differences in the size of ports and water passages, but if you use the right gaskets it is not a problem.
A leak on the back of the engine might drip oil on the exhaust, but it wont foul plugs.

 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor

Admin Dude

Jan 4, 1985

42,890

21,068

234

Box behind Walmart

Apr 11, 2011

#8

• Apr 11, 2011

• #8

Tru-dat... forgot about the plugs.

 

J

jggianna

New Member

Apr 11, 2011

10

0

0

Apr 11, 2011

#9

• Apr 11, 2011

• #9

MitchGT said:

my question is when does it smoke? If it smokes when you hit the gas, it's probably the rings, if it smokes when you let off the gas suddenly, then it's likely the valve seals. If you have a pvc system, plug it for now to make sure you aren't sucking oil through it.

Click to expand...

It smokes when you hit the gas and ideling though not as bad. I do have a PVC system that we just changed the valve.

 

J

jggianna

New Member

Apr 11, 2011

10

0

0

Apr 11, 2011

#10

• Apr 11, 2011

• #10

We did seal the gap on the block and intake, but even still it's not smoking in the engine bay, only on the passenger side out of the exhaust. We are currently having clearance issues on the wires and headers, so we are looking at upgrading to the ceramic wires with a 130ish degree, because the wires are arcing off the headers and it's missing. We also got rislone in hopes that if it is a stuck ring, that will un-stick it! I want to be sure that having this intake is ok because I don't want to buy one if I don't have too! Anyone have any luck w/ the ceramic wires? Our body shop guy told us to wrap the headers but with what I have read on that...I think that's a NO GO!