It's already been repaired Rebuilt and being installed in the car right now Next video will be running in the car. If you wanna see the engine running click on the links below in the video.
Ford Valves - two piece. Known for breaking in Boss 302 motors. Typically its the intake that breaks the head off instead of the exhaust like yours. Replace all valves with once piece high quality valves like Manley or Ferrea.
That's in remarkably good condition for what it's been through. I've seen valve heads punched through the top of the combustion chamber, dumping water into the cylinder, resulting in the side of the block being blown out. I'd be concerned about cracking above the main webs, and personally, I'd replace the crankshaft regardless, but I'd say that the owner has been very fortunate, given the unfortunate situation.
I haven’t taken the short block apart yet ,if it bent a rod then I will have the crankshaft checked. If the rods are still straight I’m not worried about it it’s an original factory, steel crank .
That valve shows textbook Cleveland 2 piece valve failure. Not common but becomes so on high valve spring tension, high revving engines. All hipo Clevelands should always be fitted with one piece valves. The valve stem is supposedly too small for the large valve sizes coupled with heavy springs and high revs. They break where the stem is fused to the head, exactly where yours has broken. They do this because the stem is liquid filled for cooling I believe - it is hollow. They fuse this stem to the head. Ford were cutting loose when they designed the Cleveland heads and I believe they have used every known technical feature. Cooled stems ✅ Big valves✅ Smallish stems - theoretically good due to lower friction, but they just pushed it a bit too far, I reckon. They are otherwise fantastic heads and any hot rodder would normally replace valves anyway.
You are right if you click on the link in the video, you can see the repaired cylinder heads we used stainless steel valve’s should be better this time around
If it's a real deal boss 302 from the factory then it's worth saving very rare and the combustion chamber size on those heads are smaller than on a 351c boss which means they're even better
I had a 1970 Boss 302 drag engine I bought in 1980 and sold in about 2001 on eBay .....and I bought a 1964 Cyclone in 1995 that had a HiPo 289 and I still have the engine along with the top loader trans. Wish I would have held on to the Boss. Sold it for $4k and I bet it’s worth way more today....
Nice!! Those cleveland heads will make anything scream. 351 boss was fords most underated engine but the best performer out of all the factory installed engines.
@@pyleup they couldn't because of the 5L displacement rule, it would've been badass if they were able to though, a 69/70 fastback with a Boss 351 engine would've been untouchable
We were able to find a 1970 boss 302 block that was a fresh 30 overboard already have it so we don’t have to worry about the damage on the service block and the machine shop says the heads can be repaired no problem so sooner or later, I’ll have all the parts back and start putting it back together.
That is true about the rev limiter the fun thing about a boss 302 is the higher the RPM the better they run they really pull hard up to 7500 but it’s dangerous without and not properly set up engine.
@@pyleup I build ford engines, the problem is from the factory they're 9k heads on a 5k block and the factory TRW pistons are heavy and prone to failure. The bottom ends need to be reworked so that they can take advantage of the bigger ports and higher RPMs. They make hardly any power till after 3k.
@@JOHNKESSLER88fellow engine builder here. What you said is so true. The cure I found was a 5.4 inch rod and a different piston. It's not a custom piston either, but the reciprocating assembly is rebalanced. And of course some oiling upgrades and studs.
Don't get your hopes up on that head. It's likely gonna have cracks in that damaged chamber. It always is a loss and a sad day when those kind of parts get destroyed. I hope it's recoverable but I've not seen many that come back from that kind of damage.
@@pyleup I truly hope so but... Many times in that case cracks will begin on the water side(the one you can't check) and will travel through after repair and being run a while. Keep the head even if the local shop can't fix it, there are specialty head shops that may be able to work with it. Costa Mesa R&D is one that comes to mind.
since you have it torn down that much you should check all of the piston skirts. I owned a 1970 Boss 302 many years ago and as I remember some of the Ford manufactured piston for that engine would crack the skirts. If I remember correctly TRW mad the original pistons and then Ford thought, they could do just as well and started making them. The Ford pistons had some problems. In my Boss 302 I had a piston skirt that cracked and had to be replaced. The other problem I had with that engine was the front oil sump. When you would get on it hard the oil would flow to the back of the pan and the pump would start sucking air. I cured that by lengthening the pan sump and running 8 qt. of oil. I must say however that that car was a good one It had a better body and the interior was much better that the 1969 Z28 that I owned. I do favor the 302 Chevy engine over the Ford however the ford was a better car over all.
This engine is already bored 30 over and there’s a little bit of damage in the cylinder walls. What happened? I’m gonna try to see if 40 over will clean it up but it might have to go 060 over to clean up all the damage from the drop valve so we will be using new pistons in this boss 302 you are correct a bigger oil pan would be better if you’re running it hard.
It's common knowledge for anyone that owns one of these engines that the original piston skirts would crack. Most of the pistons back in the day were changed out by the Ford dealers. So it'd be rare to see an original piston.
That’s the reason the engine broke the valve. The heads are already being rebuilt with new Fiera stainless steel valves. This is not my engine. I am repairing it for a friend. It was in his boss 302 when he bought it. no one knows when it was last rebuilt.
who in the world would put OEM ford valves in this engine? a rare engine and it has stock ford valves. SMH. i have built a lot of engines, and anything even slightly rare gets stainless valves.this came apart at high RPM, hope this is a lesson.
The answer to your question is Ford Motor Company put the oem valves in it in 1970. Unless the engine has been apart that's what it's going to have. I've dropped a valve at 2,200 rpm before. I doesn't take alot of rpm to drop a bad valve.
@@bradleynelson5915 it is painfully obvious that if the engine had never been apart yes these are the original valves. I would be very surprised if this engine had never been apart as these were really abused back in the day and it was not disclosed whether or not this engine had been opend previously. So it does not take a rocket scientist to know if this engine had never been apart it would have the original valves I'm sure we all know that, the chances of it being all original is relatively slim but if it is then I guess everybody knows these are the valves it would have in it. If someone has been into this engine at anytime and used OEM valve and other parts then it shows a lack of understanding when it comes to performance engines as I have never used OEM valve in anything but a grocery getter engine build, and I have over 650 engines under my belt. If its original, chalk it up to fatigue and age, if it has been built in the past, shame on whoever went this route as it could have been catastrophic for a very rare engine.
@@bradleynelson5915 This was a weak spot known back in the late 60's. No excuse not to pull that engine and have them changed out to a superior grade metal as well as junk factory valve springs. That stuff is OLD as hell, and needs to be changed out. That engine is an RPM magnet, needs to be built like it.
