I read a lot about 430 heads are prone for cracks. Is there a common spot where they mostly crack? This happens after engine ran too hot or it just happens? Thanks.
Between the spring pads. Yeah, it just happens. Hot running doesn't help. http://www.v8buick.com/showthread.php?309759-67-430-Heads&highlight=430+head+cracks
I added a linked thread to my post, here it is again, http://www.v8buick.com/showthread.php?309759-67-430-Heads&highlight=430+head+cracks
Are the 67 heads more prone to cracks then 68/69 or is there no difference? Same thickness near the water jackets?
I think they mention casting numbers in that thread. Some of those heads had bigger intake ports which made them desirable. That may have also made them more prone to cracks. Research the V8 site, it's been talked about many times.
It's not so much over heating that makes for those type of cracks and others, its this! It stems from a over heating / loosing coolant session and then adding far cooler water or coolant and then starting the motor up near right away and making a thermal shock take place!
I still have the stock big-port heads on my 430, and I bought a spare set a few years ago. The heads on the engine now were re-built with SS valves, bronze guides and hardened seats. I've heard of cracks around the spring seat/valve guide, but I haven't had any cracks occur in my heads to date, and that's with about 40k miles on them since the rebuild.
My '67 Buick sported the "large port" heads. No problem with them for the first 30 years! The cracks appeared after I increased valve spring pressure for a custom ground cam around 1987. I spent days porting the heads, changing the combustion chambers, all the good stuff. Did the Stage 1 valve conversion. First I had the cracks brazed, that failed. Then finally welded. They held up well after that but all this stuff was too expensive. All that work is sitting on the floor, it was a learning experience, for sure! The replacement? TA aluminum heads, Gessler's finesse. The verdict, or lesson or moral of the story? Leave the 430 heads as they are. If you ask too much out of them, it'll hurt. It did me. Devon
I am not going to do any modifications to the heads just wanted to know the story behind the cracks. Thanks.
Broken link. When the board was upgraded, the linked threads from the old board no longer work. https://www.v8buick.com/index.php?t...ads-where-have-they-gone.333372/#post-2804614 https://www.v8buick.com/index.php?t...fix-all-the-broken-links-on-the-board.357075/ Never did figure out how to fix that problem. Just have to do a new search. Was there a specific question you need answered? Here is a thread on the 430 head cracks, https://v8buick.com/index.php?threads/67-430-heads.309759/#post-2574516
Just would like to see some good pics of where the typical cracks would be. Picked up a pair of 1382901 heads that have Stg1 valves. Would like to know a bit about what to look for and to ask the machine shop that I'll have check them to see if they know(they should). Thanks.
Hi Jim, the cracks show between intake and exhaust valve spring pockets topside. Magnaflux will show even if not visible. Can be repaired if found, but then more $. Devon
Devon, can you post the pictures you linked in post #5 of this thread? https://www.v8buick.com/index.php?threads/430-head-question.154759/ The links no longer work.
I got it, its the Buick GS/GN Performance Torque Sheet. Had to find it in my Buick Library. I can scan and post it. Stand by.
