Fox T-Bird/Cougar Forums

Technical => Engine Tech => Topic started by: dw85745 on March 05, 2009, 10:03:27 AM

Title: Heads - Porisity Problems
Post by: dw85745 on March 05, 2009, 10:03:27 AM
1984, 3.8L, Cougar
Driver Side heads

Engine rebuilt. 

After rebuild, coolant still appeared to be leaking from head gasket. 
Heads pulled again (Felpro MLS head gaskets used this time along with new bolts
 -- note block and head both have RA < 30)

Coolant now appears to be leaking (seeping) from behind lower head bolts.

Anyone had any problems with Porosity or cracks with 3.8L heads?
If so where?
Title: Heads - Porisity Problems
Post by: Haystack on March 05, 2009, 10:18:56 AM
those heads are famous for warping. Did you also replace the lower intake gasket?
Title: Heads - Porisity Problems
Post by: 86XR7project on March 05, 2009, 10:22:52 AM
Hey porosity DOES happen sometimes. I used to have problems when I machined knuckles for John Deere tractors. Their foundry sucks!
Title: Heads - Porisity Problems
Post by: dw85745 on March 05, 2009, 03:12:19 PM
Haystack -- Yes

86XR7Project - I know it can, the question is did Ford have a foundry problem with these head in the early years since that was when the switchover to alumium first occurred -- as I recall.

=============== 

This seems to show up shortly after rebuilt (<500 miles).  Pressure testing cooling system cold, with leak evidence showing, system holds pressure, and no leaks.

What I can put together Seems to be during the run (heat cycle) that it is leaking.  Head both pressure tested and magfluxed so only thing left (???) is porosity?
Title: Heads - Porisity Problems
Post by: 86XR7project on March 05, 2009, 03:22:53 PM
Well all Foundry's have porosity problems. The real question is, is that whats wrong with your head. It doesn't sound like porosity to me. Thats my 2 cents.
Title: Heads - Porisity Problems
Post by: Kitz Kat on March 05, 2009, 03:34:43 PM
I'm not sure what you mean bye leaking behind at the lower head bolts? Behind the the bolt heads? Did you use sealer on the head bolts?
Title: Heads - Porisity Problems
Post by: dw85745 on March 05, 2009, 03:51:07 PM
86XR7Pproject

Quote
Well all Foundry's have porosity problems. The real question is, is that whats wrong with your head. It doesn't sound like porosity to me. Thats my 2 cents.

I know from reading that getting all hydrogen out during casting is critical.
Thanks for your 2 cents

========================
Kitz Kat

Quote
I'm not sure what you mean bye leaking behind at the lower head bolts? Behind the the bolt heads? Did you use sealer on the head bolts?

Yes, it appears to be coming from behind the lower bolt heads, and yes sealer was used.