What is this guard around the valve spring?

[CLi87]

I'm rebuilding the cylinder head on a Merc 7.4 and was wondering if anyone knows what these metal guard things are around the valve spring? I don't see them in the parts diagram either.

 

[Bondo]

Ayuh,.... No idea what yer lookin' at,.....

 

[CLi87]

Ayuh,.... No idea what yer lookin' at,.....

Oops, sorry, forgot to attach the pic

 

[Bondo]

Ayuh,.... I believe those are dampeners, kinda like the inside dampeners on most chevy heads, which I don't see inside yer valve springs,....

 

[CLi87]

Ayuh,.... I believe those are dampeners, kinda like the inside dampeners on most chevy heads, which I don't see inside yer valve springs,....

Do I need to have these? It was a pain to remove and looking like a worse pain to reinstall and it's not on the parts diagram breakdown for my engine

 

[Scott Danforth]

Do I need to have these? It was a pain to remove and looking like a worse pain to reinstall and it's not on the parts diagram breakdown for my engine

Your motor may have been changed.

Depending on original application, they are most likely in the GM manual

 

[Scott Danforth]

Google 1 ton oil control sleeves and valve rotators.

Common on Mark IV big truck motors such as RV

Run the casting numbers

 

[dubs283]

Common on Mark IV

Donna mean a hijack a thread, but...

Can you visually decipher between Gen 4, 5, and 6/ls 454,s

 

[Scott Danforth]

Donna mean a hijack a thread, but...

Can you visually decipher between Gen 4, 5, and 6/ls 454,s

Yes.
2-piece RMS for a Mark IV, tin valve covers, Hi PO Pass and 454 cast on block

1-piece RMS for Gen V and VI

Thin deck, 10 bolt timing cover, ribbed valve covers on Gen V. Unmachined fuel pump boss

Thicker deck and 6 bolt timing cover, smooth valve covers on Gen VI. No fuel pump boss, 7.4 cast on the block

Gen VII had no distributor, cathedral intake ports, 8.1 liter cast on the block

Casting numbers help

 

[CLi87]

Google 1 ton oil control sleeves and valve rotators.

Common on Mark IV big truck motors such as RV

Run the casting numbers

Very interesting, I've never seen them before, is it a big deal to leave the rotators off?

 

[Bondo]

Very interesting, I've never seen them before, is it a big deal to leave the rotators off?

Ayuh,.... If the valves don't rotate, you'll be replacin' the heads in short order,....

 

[dubs283]

Yes.
.....
Casting numbers help

Thank you, Scott!

Many people who regular this forum know my extreme love of the GM 454/7.4 L engine. Fantastic torque output works wonderfully in the right hull/drive application.

I do not own a boat but drive many on an almost daily basis and when the opportunity arises for me to control a 454 I'm all in.

Dream is to create a sleeper with a 454 and bravo one, 22ish length. Currently drooling over a cobia that has a 454/king cobra, owner won't let it go though

FYI I would ditch the omc stuff and donor/purchase required merc parts....

 

[Scott Danforth]

Thank you, Scott!

Many people who regular this forum know my extreme love of the GM 454/7.4 L engine. Fantastic torque output works wonderfully in the right hull/drive application.

I do not own a boat but drive many on an almost daily basis and when the opportunity arises for me to control a 454 I'm all in.

Dream is to create a sleeper with a 454 and bravo one, 22ish length. Currently drooling over a cobia that has a 454/king cobra, owner won't let it go though

FYI I would ditch the omc stuff and donor/purchase required merc parts....

for a 22 foot boat, not sure you need a pork chop motor. a 6.2/bravo would be a good mid 50's boat.

 

[dubs283]

for a 22 foot boat, not sure you need a pork chop motor. a 6.2/bravo would be a good mid 50's boat.

Yeah, but I wanna do a sleeper. The cobia I referenced earlier has a hard, i.e. upwards towards keel, chine. Would handle 454 torque/speed fine, trimmed properly of course

And I have nothing against any sbc, great motors. They just don't have enough power to "hurt" themselves. This is why I believe they are so prominent in boats, availability aside.....

 

[Scott Danforth]

Yeah, but I wanna do a sleeper. The cobia I referenced earlier has a hard, i.e. upwards towards keel, chine. Would handle 454 torque/speed fine, trimmed properly of course

And I have nothing against any sbc, great motors. They just don't have enough power to "hurt" themselves. This is why I believe they are so prominent in boats, availability aside.....

as soon as you migrate away from wet exhaust, there is about another 50% more power in motors available without getting crazy

 

[dubs283]

But a sea water pump with a sound exhaust ought to produce enough flow to maintain manifold temp allowing a bbc to breath enough? Especially with a short freeboard/transom

 

[dubs283]

 

[dubs283]

This is boat I refer to....

 

[jimmbo]

Is that boat sitting directly on the Trailer Frames, as in no Bunks?

 

[dubs283]

Is that boat sitting directly on the Trailer Frames, as in no Bunks?

Is an a frame. Mann made product, solid and easily road transportable with one person capability of blocking on stands