Cracked valve seats in the heads?

[kjhansen]

We have the engine from my '87 TR torn down. Took the heads to a machinist and he magnafluxed them for me. Said the area around the valve seats is cracked on cylinders in both heads. Claims he can install inserts. I've heard bad things about inserts on boosted cars (like they come off and destroy pistons/cylinders/valves etc.). So, several questions:
1. Has anyone even heard of cracked valve seats? I never had before.
2. Are inserts bad or is that just rumor?
3. Are the turbo engine heads basically just stock '86-'87 3.8 heads? If not,
4. What heads interchange? How about hot air ('84-85) heads?
5. What's an 8445 head?
Keith

 

[750H.P.V6]

Keith,

Cracks in the heads between the valves are common. From the factory there are no seat inserts in the head. Installing seat inserts in the head if done properly shouldn't cause you a problem. BTW, turbo heads are nothing more than garden variety 86/87 3.8 liter RWD heads. Earlier 84/85 heads are essentially the same without the bridged water passage at the end of the head. 8445 is the last 4 digits of the casting #.

Neal

We have the engine from my '87 TR torn down. Took the heads to a machinist and he magnafluxed them for me. Said the area around the valve seats is cracked on cylinders in both heads. Claims he can install inserts. I've heard bad things about inserts on boosted cars (like they come off and destroy pistons/cylinders/valves etc.). So, several questions:
1. Has anyone even heard of cracked valve seats? I never had before.
2. Are inserts bad or is that just rumor?
3. Are the turbo engine heads basically just stock '86-'87 3.8 heads? If not,
4. What heads interchange? How about hot air ('84-85) heads?
5. What's an 8445 head?
Keith

 

[kjhansen]

Neal,
Quick reply, thanks. I did look in gnttype.org and saw the pictures. They say the valve cover bolt holes are different on the FWD and RWD heads; true?
Keith

 

[750H.P.V6]

Keith,

Sorry for the confusion. I meant RWD but typed FWD. I need to engage my brain before responding. I edited my original post to read correctly.

Neal

Neal,
Quick reply, thanks. I did look in gnttype.org and saw the pictures. They say the valve cover bolt holes are different on the FWD and RWD heads; true?
Keith

 

[kjhansen]

I think I'll get some replacement heads. Seems to me that inserts are a bandaid, since the cracks are still there--just covered. Unless they're not deep of course, but then they're not really cracks? Anyway, wish me luck finding Buick stuff here in the Missouri boondocks.
Keith

 

[Ormand]

Unless they're not deep of course, but then they're not really cracks?

Well, yeah, they are still cracks. Once they get big enough to see, what else would you call them? Maybe if you were a tech in non-destructive examination, you might call them "rejectable indications", but they're still cracks, and will most likely continue to grow. Repair should remove all the crack, though, and then install the inserts. Many, many cars came with inserts stock, especially right after leaded gas went away. The inserts were used to keep the valves from wearing into the heads without the lead to lubricate them. Never heard of one coming loose, and causing problems, but it does seem like it would happen sometimes.