PDA

View Full Version : Dropped a valve seat, head trashed?



insanity
11-11-2009, 10:08 PM
Dropped an exhaust valve seat out of the head in the number 7 cylinder last time out. Had a head gasket leak earlier in the year in the same cylinder, we fixed that but I'm assuming the leaky head-gasket was the precursor to the valve seat falling out. The head cracked between the valve seats, I'm assuming this head is junk? Not to mention the valve seat pieces beating the chit out ot it...

Blue Oval
11-11-2009, 10:41 PM
I have a picture of my #7 cyl. on my 99 Powerquest, lost the valve seat and took out my piston, 4 days before our Boyne Thunder Poker Run 2008. I now have a new engine on the starboard side. When I find the pic I'll post it.

Pismo10
11-12-2009, 07:50 AM
Dropped an exhaust valve seat out of the head in the number 7 cylinder last time out. Had a head gasket leak earlier in the year in the same cylinder, we fixed that but I'm assuming the leaky head-gasket was the precursor to the valve seat falling out. The head cracked between the valve seats, I'm assuming this head is junk? Not to mention the valve seat pieces beating the chit out ot it...

What kind of engine is it? What head? is it a 454or502 Mag?

insanity
11-12-2009, 08:47 AM
HP500 Carb. Square port, 088 casting.

Blue Oval
11-12-2009, 09:00 AM
Found the picture of my sick 454

Trim'd Up
11-12-2009, 09:11 AM
Damn near anything can be fixed, but why bother? Those heads are easy to find and are pretty cheap. If it was out of a numbers matching L-88 67 vette I would say take it to the machine shop but not a boat.

insanity
11-12-2009, 10:09 AM
Found the picture of my sick 454

Funny how similar the same issues look :D

Geronimo36
11-12-2009, 10:42 AM
cast steel head, throw it out... they're cheap!

At least it didn't get the block!

Blue Oval
11-12-2009, 12:40 PM
I've been around motors all my life, the valve seat dropping out was odd. Then again most of the engines I've been around were Ford engines. Not that we have not had problems, I just have not seen this before.

Pismo10
11-12-2009, 04:03 PM
I've been around motors all my life, the valve seat dropping out was odd. Then again most of the engines I've been around were Ford engines. Not that we have not had problems, I just have not seen this before.

The 502 with the GM steel heads seems to have a reputation for dropping valve seats. I don't know why. Reversion? Was it an exhaust seat?

kidapache
11-12-2009, 05:43 PM
I can put new ones in for you we have the tools

LAKE EFFECT
11-13-2009, 07:45 AM
If you need a piston let me know, I have a view spares that I can sell.

LE

Tyler Crockett
11-13-2009, 09:19 AM
If you need a piston let me know, I have a view spares that I can sell.

LE

He will need to go with a oversize piston in that hole. I can see the scratches I have some .005 over pistons. Tyler 8103242720

Warlock28SXT
11-13-2009, 09:52 AM
I dropped a valve seat in mine a couple years ago. Gen VI 502MPI, #8. LWP got plugged and the motor got hot, next time out dropped the seat. Mine also cracked between the seats. Now it's 509" with SRP pistons and Brodix heads.

insanity
11-13-2009, 10:29 AM
I took a bore gauge to it the other night, the bores seemed virgin, most of them were around 4.468 give or take .002. We are waiting on the engine stand to show up to finish tearing it down. But I'm getting close to being out of my wheelhouse as far as where to go next...So any suggestions would be great. Is it possible to just hone/bore one cylinder and put a slightly oversize piston and new rings in that cylinder only? From looking at the other cylinders, I'm leaning more towards tearing it all the way down, having every cylinder honed and putting in new rings (and obviously at least one new piston), new main/rod bearings, etc. What's a ballpark price for hone/reassembly?

Rookie
11-13-2009, 02:46 PM
"088 head cracked between the valve seats and dropped the seat" Been there done that.

http://i43.photobucket.com/albums/e395/jay2one/DSCF0149.jpg