loss of power, increase in RPM

[Bondo]

Re: loss of power, increase in RPM

Still researching all of this. I believe the heads are incorrect for a marine engine. Comparing the block and head numbers shows that most likely this engine was intended for a truck. It gave several different makes and year models but all trucks.

Ayuh,.... There's No such thing as a Marine block, nor head....

The casting numbers determine the original castings, but what makes a motor Marine is what's put in/ on it....

Marine SBCs, All start out as plain ole Chevy castings...

 

[Ciera2450]

Re: loss of power, increase in RPM

Ok guys... just trying to cover my bases here....

I have just the shortblock sitting in the boat now. I'm hoping to pull it out tomorrow to prepare for the new long block's arrival.
I have to remove the top part of the drive(transmission and drive shaft) and remove all the flywheel housing bolts...of course motor mount bolts also. The motor should slide forward slightly and be ready to lift out.... Correct???? Am I missing anything?

Whats the best things to attach to for lifting the shortblcok out? Just chains wrapped around it?

I plan to replace the PDS bearings while the engine is out and rebuild the motor mounts if needed.

 

[captmello]

Re: loss of power, increase in RPM

Sounds about right.

You can hook the chain to a couple of head bolts in opposite corners of the short block.

Pics are always appreciated for our entertainment...:joyous:

 

[RogersJetboat454]

Re: loss of power, increase in RPM

new long block is ordered and paid for. Should arrive in two weeks. I just decided to replace the long block with the proper 64CC chamber heads. I hope to pull the old block out this weekend and begin rebulding the motor mounts. I'm pretty sure they are rotted out.

Uhh... What's the compression ratio going to be with the 64cc heads? Is it a Vortec long block you ordered?
Combustion chambers in the 70cc range are correct for truck/marine applications with the old school heads (your old heads should have been fine).
Newer Vortec headed engines can have 64cc chambers. The compression ratios are usually tamed with selecting the correct pistons, and head gasket thickness.

 

[Ciera2450]

Re: loss of power, increase in RPM

I hi should end up about 9:1 compression ratio with the 64cc heads. The engine builders claimed with the proper head gasket that it would provide a slight increase in power compared to the original 72cc heads. I was told the 72cc heads were a "light casting" and not ideal for marine applications. I hope thats correct because the motor is paid for already! The boat is 5,000lbs so I was thinking the increased compression might help out a bit getting it out of the hole.

ave the hoist rigged up on a tree... ready to pull the short block in the morning. I'll post plenty of pics! Thanks guys

 

[Ciera2450]

Re: loss of power, increase in RPM

Well the engine is out!!! It went much smoother than I anticipated. No issues at all.... unbolted the flywheel housing, pulled the top of the drive off, removed motor mount lag bolts and slid the engine forward and lifted it out.

My helpers... Thanks a ton guys!!!!

 

[bruceb58]

Re: loss of power, increase in RPM

Someone correct me if I am wrong but aren't you able to pull the engine out with the bell housing attached to the engine.

 

[captmello]

Re: loss of power, increase in RPM

Someone correct me if I am wrong but aren't you able to pull the engine out with the bell housing attached to the engine.

Yes, typically. but this way works. I would recommend pulling the flywheel cover, and, following the bearing replacement, bolt it to the new motor and install them together.

Bruce, you need to pick up an older VP project boat. It will refresh your memory and provide loads of frustration and cursing. Mine's always for sale...

 

[bruceb58]

Re: loss of power, increase in RPM

Bruce, you need to pick up an older VP project boat. It will refresh your memory and provide loads of frustration and cursing. Mine's always for sale...

No thanks. My newer Volvo SX/DP style keeps me plenty busy with just maintenance.

 

[Ciera2450]

Re: loss of power, increase in RPM

I was hoping to leave the flywheel housing in place.... is there a reason i'd have to remove it? I'm pretty sure I can change the pds bearings with the housing still in place....

New long block should be here soon. I'm stripping all the parts off the old one today and blasting and painting the tin parts (oil pan, timing cover, etc)

 

[Ciera2450]

Re: loss of power, increase in RPM

btw... if i removed the flywheel housing I'd have to replace the seal there correct? I think its a rubber ring.

 

[captmello]

Re: loss of power, increase in RPM

I've heard you can reuse the two seals, But I would replace them if it were mine.
#40
Connecting Components Aq Drive 280 AQ225D - 7743320 - Volvo Penta

The bearings can be done with the housing in the boat, but since your replacing the engine you will want to adjust the height and alignment of the flywheel housing to the inner transom shield. The flywheel housing needs to be loosened for this anyway.

Alignment is nothing like a merc or newer style volvo.
http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/steps-install-engine-outdrive-303248.html

Nice pics BTW. Good lookin' crew!

 

[Ciera2450]

Re: loss of power, increase in RPM

I may as well go all the way.... I'll pull the flywheel housing out. That should make changing the pds bearings easier also. Thanks for the replies captmello.