6 Cylinder head - The 1947 - Present Chevrolet & GMC Truck Message Board Network

daddybullfrog · 09-03-2002, 11:14 PM

I seem to have developed a crack in the head on my 250 CI engine. I was wondering if anyone knows which head to look for in a wrecking yard. The 194-230-250-292 all look similar, but I am concerned about valve size and interchangebility. Anyone know what will work?
Thanks

**'68OrangeSunshine** · 09-04-2002, 05:24 AM

I don't know of a way to ID an L-6 head if it's separated from the block. They are all milled from the same blank but the 292s have bigger valves and stiffer springs. I have heard that it was a cheap trick for old time dragsters to increase compression by putting the smaller cid engine head on a larger displacement block and it would scream down the strip until it blew up! 292s are obviously bigger, with 1.75" taller deck height than a 230/250. How to tell a 230 from a 250 or a 194, I couldn't tell you. 250s should be the most common in any junkyard.
To be sure, I suggest you hit these sites where the folks are very well versed in inline Chevy engines:
Inliners International-- http://www.inliners.org/
and The Stovebolt Page --
http://66.221.101.248/bboard/cgi-bin/ultimatebb.cgi
I have a '68 C/10 shortbed stepside myself. Adios.

Michael A. K. G · 09-04-2002, 11:39 AM

I don't know if I'd buy a head already separated from a block. If the engine is in the truck, you can get the displacement off the VECI label. Most likely, if it's an inline-6, it's a 250. They were used in Novas, too, and those seem to be a bit easier to find in the junkyard.

The year of manufacture is cast into the engine block near the passenger side mount.

Bring some Kroil, a 1/2 inch drive impact socket to fit the head bolt (very low distortion, and 6-point edges), a long breaker bar and a few feet of cheater pipe, and the bolts should come off ok.

I wasn't aware these heads were prone to cracking (like the Ford 2.9L I have on my other truck). Are you sure it isn't just a head gasket? Are these heads repairable? Or have you already had it Magnafluxed and declared deceased?

daddybullfrog · 09-04-2002, 04:38 PM

Thanks for all the help, but I'm still a little confused.
I'm 90% sure the head is cracked since I replaced the head gasket and had the same problem. I suspect it is cracked near an intake valve as it still runs ok but loses water and turns into a Stanley Steamer in the exhaust pipe. I do not get coolant in the oil. Stop leak made the problem intermittent, but I'm looking for a head to replace it while it is still driveable. Does the 194, 230, 250 all have the same size valves? I'll check the URLs you guys gave me.

**'68OrangeSunshine** · 09-05-2002, 06:05 AM

I believe the spring sizes get progressively bigger with each larger-sized displacement, so I guess the valve diameters must increase too. A good reference is "Inline Chevy Power Manual" by Leo Santucci. Just came out, about$20. You can get 'em from the Inliners online. Mine's out in the truck or I'd look it up. You might ask a local machinist if he knows of a good 250 head, if you just want to effect a simple head transplant.

Michael A. K. G · 09-05-2002, 11:11 AM

It *could* be warped.

I'd yank the head, examine the inside for cracks and the sealing surface for warps (use a steel straightedge and a feeler gauge -- you may have to sand off that @#%$ stop leak from the cylinder edge to get a decent measurement). Examine the block, too, in the same way. If you don't see any cracks, take the head and block to a machine shop and have them Magnafluxed and then flattened if good. You can sand out SMALL warps yourself. Large ones must be machined. Not all cracks are visible to the eye.

This would be a good time to have a valve job done, also (around $100), if the head passes the Magnaflux.

White smoke out the tailpipe on a warm engine is a good indication of an internal water jacket leak, on an inline (for a V8 or V6, it could possibly be a problem with the intake manifold gasket instead). The leak doesn't have to be in the head.

PanelDeland · 09-05-2002, 10:03 PM

As near as I can tell from the previously mentioned book.The cylinder heads all interchange.The 292 has larger valves and the combustion chambers sizes are different on motors depending on their use.I just got this 6 cyl power manual and it has lots of good info on the 6.The guys over at inlinersinternational can probably give you the best casting #'s and the ones to stay away from.They can also recomend cams ect. in case you want to upgrade while you have it apart.I do know that the later model heads use a different plug than the older ones.Also remember the older heads may not have the hardened valve seats and you will need to have them installed if you want it to last.

09-03-2002, 11:14 PM	#1
daddybullfrog Active Member Join Date: Dec 2000 Location: Bosque Farms, NM, USA Posts: 184	6 Cylinder head I seem to have developed a crack in the head on my 250 CI engine. I was wondering if anyone knows which head to look for in a wrecking yard. The 194-230-250-292 all look similar, but I am concerned about valve size and interchangebility. Anyone know what will work? Thanks __________________ '67 C-10 short stepside '72 K-10 Cheyenne Super under construction

09-04-2002, 05:24 AM	#2
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	I don't know of a way to ID an L-6 head if it's separated from the block. They are all milled from the same blank but the 292s have bigger valves and stiffer springs. I have heard that it was a cheap trick for old time dragsters to increase compression by putting the smaller cid engine head on a larger displacement block and it would scream down the strip until it blew up! 292s are obviously bigger, with 1.75" taller deck height than a 230/250. How to tell a 230 from a 250 or a 194, I couldn't tell you. 250s should be the most common in any junkyard. To be sure, I suggest you hit these sites where the folks are very well versed in inline Chevy engines: Inliners International-- http://www.inliners.org/ and The Stovebolt Page -- http://66.221.101.248/bboard/cgi-bin/ultimatebb.cgi I have a '68 C/10 shortbed stepside myself. Adios. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not. Last edited by '68OrangeSunshine; 09-04-2002 at 05:29 AM.

09-04-2002, 04:38 PM	#4
daddybullfrog Active Member Join Date: Dec 2000 Location: Bosque Farms, NM, USA Posts: 184	Thanks for all the help, but I'm still a little confused. I'm 90% sure the head is cracked since I replaced the head gasket and had the same problem. I suspect it is cracked near an intake valve as it still runs ok but loses water and turns into a Stanley Steamer in the exhaust pipe. I do not get coolant in the oil. Stop leak made the problem intermittent, but I'm looking for a head to replace it while it is still driveable. Does the 194, 230, 250 all have the same size valves? I'll check the URLs you guys gave me. __________________ '67 C-10 short stepside '72 K-10 Cheyenne Super under construction

09-05-2002, 06:05 AM	#5
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,504	I believe the spring sizes get progressively bigger with each larger-sized displacement, so I guess the valve diameters must increase too. A good reference is "Inline Chevy Power Manual" by Leo Santucci. Just came out, about$20. You can get 'em from the Inliners online. Mine's out in the truck or I'd look it up. You might ask a local machinist if he knows of a good 250 head, if you just want to effect a simple head transplant. __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

09-05-2002, 10:03 PM	#7
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	As near as I can tell from the previously mentioned book.The cylinder heads all interchange.The 292 has larger valves and the combustion chambers sizes are different on motors depending on their use.I just got this 6 cyl power manual and it has lots of good info on the 6.The guys over at inlinersinternational can probably give you the best casting #'s and the ones to stay away from.They can also recomend cams ect. in case you want to upgrade while you have it apart.I do know that the later model heads use a different plug than the older ones.Also remember the older heads may not have the hardened valve seats and you will need to have them installed if you want it to last. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

09-04-2002, 11:39 AM	#3
Michael A. K. G Registered User Join Date: Jul 2002 Location: California central coast Posts: 126	I don't know if I'd buy a head already separated from a block. If the engine is in the truck, you can get the displacement off the VECI label. Most likely, if it's an inline-6, it's a 250. They were used in Novas, too, and those seem to be a bit easier to find in the junkyard. The year of manufacture is cast into the engine block near the passenger side mount. Bring some Kroil, a 1/2 inch drive impact socket to fit the head bolt (very low distortion, and 6-point edges), a long breaker bar and a few feet of cheater pipe, and the bolts should come off ok. I wasn't aware these heads were prone to cracking (like the Ford 2.9L I have on my other truck). Are you sure it isn't just a head gasket? Are these heads repairable? Or have you already had it Magnafluxed and declared deceased?

09-05-2002, 11:11 AM	#6
Michael A. K. G Registered User Join Date: Jul 2002 Location: California central coast Posts: 126	It could be warped. I'd yank the head, examine the inside for cracks and the sealing surface for warps (use a steel straightedge and a feeler gauge -- you may have to sand off that @#%$ stop leak from the cylinder edge to get a decent measurement). Examine the block, too, in the same way. If you don't see any cracks, take the head and block to a machine shop and have them Magnafluxed and then flattened if good. You can sand out SMALL warps yourself. Large ones must be machined. Not all cracks are visible to the eye. This would be a good time to have a valve job done, also (around $100), if the head passes the Magnaflux. White smoke out the tailpipe on a warm engine is a good indication of an internal water jacket leak, on an inline (for a V8 or V6, it could possibly be a problem with the intake manifold gasket instead). The leak doesn't have to be in the head.



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