Griff

If one of those non adjustable rockers is out of spec that much, you've either got a bad cam lobe, bad lifter or bent pushrod.

man-of-war

Thanks for the heads up guys. I had to take the boat back to storage yesterday due to parking accommodation on my driveway.

..where do I find the stamp that says the year of this engine. it's a mercruiser 454 mag/efi 385hp

I'll also like to know what's the torque specs for the rocker bolts. I would need to torque the rocker bolts back down after checking the push rods and rockers.How do I check the lifters? Could they be removed with a magnet?
I'll have to look in on the rocker pivot kit to make them adjustable.

92nsx

40 lb. ft. (54 N·m)


Merc manual 23 pg 3A-4, Online manual 208

Also
5. Install push rods and rocker arm assemblies in their original positions. Coat threads on
rocker arm bolt with Perfect Seal. Torque to 40 lb-ft (54 Nm). page : 3A-40.

How ever it seems high ???

Budman II

iTrader: (1)

Intake manifold has to come off to pull lifters on a BBC. If you have a cam lobe going flat or a lifter dying, there may be shavings and debris in the oil filter. If it is a simple matter of a hydraulic lifter pumping down, then there will probably not be any stuff in the oil filter. I would convert to the adjustable rocker arms as I think griff suggested - stamped steel rocker arms should be just fine with a stock cam. Then if you still can't get a particular valve to stay in adjustment, you probably have a bad lifter or cam lobe. But the stock hardware should not need to be fooled with like this - GM went to the non-adjustable rockers to save assembly time and tinkering on long haul motors that are supposed to hundreds of thousands of miles. I am concerned that you have a bad lifter or two. Check for broken valve springs as well. Has this engine ever overheated?

Budman II

iTrader: (1)

I am quite intrigued that you gained 13 MPH by removing inner strakes and hooks on that hull. I had the little hooks removed on my 88 Force 235 and only gained a little more porpoising. That must have been one helluva hook!

Quick2500

I'm intrigued, too. My immediate thoughts were removing lifting strakes would increase wetted surface and drag, maybe the hook was exaggerated by poor support from the trailer?

man-of-war

I was waiting for you guys to bring up the 13 mph gain..lol
the reason the inner strakes and hooks were removed was to sink the back end to rais the bow.
I also raised the x dimension / outdrive 3'' which allowed me to run with a bigger prop.

hooks and strakes removed

92nsx

Man of war has done a TON of work/mods to his Baja Force!. Still amazes me today what he all did!

His thread was one of the first ones I went post by post threw. (most deleted). Then, threw google to find his photo's of the work when i was buying my DVX (same hull) 4 years ago.

Great job on the boat by the way.

Budman II

iTrader: (1)

Interesting! Did you do both modifications at the same time, or were they done in stages so you could know how much of the speed increase can be attributed to the strake/hook removal, and how much was due to the raised x-dim. I suspect raising the drive up higher would have a bigger effect on speed. You are right about wanting to get the bow out of the water - that's the big issue on my 235 as well. The bow is damn near glued to the water (of course, that might have something to do with all the crap in the cuddy ) I can only imagine how much of an issue it would be with 3 more feet of hull in the water and a single engine.

man-of-war

It would have been intresting to see which mod gained more mph.

before


To me raising the drive played a big roll with the speed gain.