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One head turned out to be cracked. Junkyard was able to source another one... hopefully this checks out and we'll be all good.
Crazy how common cracked heads are on 7.3. I wonder if that's due to people tuning without keeping track of combination temps?
Ayyyayay. Sorry to hear that.
I think your guess for why there are so many cracked heads is a good one. I have seen/heard so many stories of people paying attention to EGTs only after the engine has blown at least once. *raises hand guiltily*
Was the crack between the valves? My old mill had cracks on them in those places had to use another set of heads for that reason. Good luck on your engine build.
Was the crack between the valves? My old mill had cracks on them in those places had to use another set of heads for that reason. Good luck on your engine build.
The original heads both had cracks between valves and some radiating outward from the glowplug and injector holes (no doubt stress risers). The bad head on the core engine had one crack radiating from a valve (past the seat). Maybe a combination of beyond-design-limit combustion temps, thermal cycling, and a lack of adequate chamfer on those areas?
My OG heads were running fine even with the cracks so who knows how big of an issue they present in practice.
Two junkyard heads later and I still haven't found one without crack. No choice but to keep going though.
On the plus side, block machining should start next week! If I can find a second head soon the machining work should be complete in a few weeks.
When head surfaces this shop always produces a surface Ra that's friendly to MLS head gaskets. I've seen it mentioned that composite gaskets need some "seasoning" time where you need to be mindful of the cylinder pressures... if the shop is going to machine the head surface fine enough for MLS, there any downside to using Cometic gaskets for this build? I've heard they are good to go from the start and don't require the "seasoning" period.
Also is it worthwhile to cryo treat stock forged rods? Or at they proven to 800-1000 ft-lb?
Happy New Year @PriusLover !! Haven't seen you in awhile. Glad to hear things are progressing although I have to ask, have you considered a Cummins swap after finding so many cracked Powerstroke blocks?
Happy New Year @PriusLover !! Haven't seen you in awhile. Glad to hear things are progressing although I have to ask, have you considered a Cummins swap after finding so many cracked Powerstroke blocks?
Cheers. I thought about it before this all began but it seems like a lot of headache, money, and if I was going to do the work I'd rather put one in a pre-2017 6.7 superduty with an nicer body and interior. Plus I don't have a garage.
Originally Posted by FinnishStroker
Only cracked heads? One block was dropped and screwed by machine shop?
Here's the total count:
-Original block was ****ed up by shop #1, they sourced a another one and did shoddy work on it.
-Both OG heads were cracked, so I bought replacements, which they did shoddy work on.
-Shop #1 kept the engine they ****ed up and reimbursed me for a core (engine #2) I procured from a junkyard.
-Shop #2 said all the parts from engine #2 were good except one cracked head. Junkyard supplied me with another head which turned out to be cracked as well... and then another head which turned out to be cracked as well.
So next week will be about trying to find a head that isn't cracked lol. So far more common areas are the valve seats, with cracks extending below were the new seats will go. New machinist thinks this is due to Intl using the bare iron as the valve seat face.
