7.4 454 Repower opinions needed.

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: 7.4 454 Repower opinions needed.

Did you look at the crane cam flat tappet oil change procedures ?? Comp cams i the same CHANGE AFTER 20-30 MIN
The o/p was about a flat tappet short block. You guys are trying to apply mercruiser roller cam rules to older flat tappet cams. Just saying!!;)
 

sparky774

Seaman
Joined
Oct 2, 2011
Messages
54
Re: 7.4 454 Repower opinions needed.

Doesnt change the fact that every single cylinder is scored to crap which points towards mechanical failure. If it wasnt broken in properly then it would just burn oil because the rings would seat properly. Im not talking a few scratches here it looks like the thing litterally was bored out with a grinder ive never seen anything like it.

Not to mention there were a few empty gallons of straight 40 weight conventional oil in the cabin...
 

joewithaboat

Lieutenant Junior Grade
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Jul 3, 2011
Messages
1,172
Re: 7.4 454 Repower opinions needed.

Make sure to go over fuel system, as suggested.
Also check water pump(s)!! A new engine gets extremely hot very quickly.
For flat tappet break in, rpms need to be up right away but make darn sure you can get enough water to it. Not sure I would trust just hose and muffs.
A Bad overheat can cause piston galling like you describe. Lean fuel condition usually attacks the pistons near the edges just above rings. I have never seen all 8 burned up from lean fuel usually one or two per side. Others may have different experiences.
You really should post pictures or take that stuff to a machine shop and let someone who knows what they are looking at check it out.
Good luck!
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: 7.4 454 Repower opinions needed.

Doesn't change the fact that every single cylinder is scored to crap which points towards mechanical failure. If it wasn't broken in properly then it would just burn oil because the rings would seat properly. I'm not talking a few scratches here it looks like the thing literally was bored out with a grinder Ive never seen anything like it.

Not to mention there were a few empty gallons of straight 40 weight conventional oil in the cabin...

Sounds to me like this previous owner had a really shoddy machine shop doing his work. Either the piston's weren't setup at the proper clearances or it leaked or burned oil so bad that he was running it low on oil regularly,hence all the empty oil containers. Also appears that he tried to hop it up some with the aftermarket exhaust, intake, and 850 holley carb. I bet if you get into it that it has an aftermarket cam in it too. He probably thought that was going to really make a performance improvement and ran the crap out of it.

As for replacement I don't see where you feel buying a reman somewhere is going to be any different than having your short block rebuilt. You should be able to find a reputable machine shop in your area that can supply you with good work. You would be able to work closer with them and know exactly what you have when their done. If you have any problems the shop would be right there. I couldn't imagine having to deal with some remain builder out of town somewhere especially if the engine had to be shipped back to them because of a problem, and of course at your expense.Also wouldn't have to mess with shipping and core return. Just because they might have a fancy website you have no idea of the quality of these remains on the internet. There's no way I would ever buy a reman somewhere when I could have my own done locally. Going local you would be able to check out their shop and equipment and speak with with them to form your own opinion of what you could expect.
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: 7.4 454 Repower opinions needed.

I was gonna ask the same question, as to what's been killin' these motors...
'n I agree, it's probably not the builds...

I'm thinking it may have been the tool on the end of the throttle stick.
 

sparky774

Seaman
Joined
Oct 2, 2011
Messages
54
Re: 7.4 454 Repower opinions needed.

Yeah im starting to lean towards finding a machine shop in my area and building a new motor even if i need a new block i will probably be better off.

That way i could go with a forged rotating assembly too and get some better heads.

thanks for the advice
 

sparky774

Seaman
Joined
Oct 2, 2011
Messages
54
Re: 7.4 454 Repower opinions needed.

Well i know it wasnt me the thing lasted all of an hour running at 3-4k
 

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: 7.4 454 Repower opinions needed.

I cut my teeth on small block chevy stuff so i cant give you specifics as to books titles but You should take a visit to your local book store and find one or two books on big block chevy motors. It will give you a basic understanding of how all componets relate to each other, what mistakes to look for, and where your money would be best spent.
Here are some examples you could order online but i think its better to flip thru them in person. I have several books by David Vizard for small blocks that are great.
I have heard the Dennis Moore book is good.

http://www.amazon.com/Big-Block-Che.../ref=sr_1_38?ie=UTF8&qid=1317773832&sr=8-38#_

http://www.amazon.com/Build-Max-Per...9387/ref=sr_1_5?ie=UTF8&qid=1317773941&sr=8-5

Good luck!
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: 7.4 454 Repower opinions needed.

Wasn't talking about you Sparky. Talk'n about the previous owner that had to rebuild the thing 3 times. Was probably already hurt when you got it. You can run them 330's 4500rpm all day for years with out hurting them.
 
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