Iron Pukes & Chebbys

["Bruce Hevner" <scramblr@xxxxxxxxxxx>]

>>" The "Chevy Marine" (they were known under several different "Marine
Brands")
>>" and "Iron Duke" are the SAME motor with a few differences. They are ALL
>>" Pontiacs actually.

>>i don't know if that's true now, but the 181" marine four came out in
>>the late '60s - looong before the iron puke was a sty in its
>>designer's eye.  and that marine head which fits the 153...

>>and yes, it did sell under lotsa names - omc and mercruiser, for the
>>most famous.

**I think THAT 181 is LONG gone. All I ever saw from the early marine chevy
were the heads. 
**The Chevy's I worked on were all 153's using the marine head (WHEN they
could find one). This was 1967-1969

>>" These engines underwent a LOT of changes over the years.
>>" I know of at LEAST five different piston changes and MANY cyl head &
head
>>" gasket changes. SOME of the heads will interchange & some will not
>>" (different head bolt pattern). They are TOTALLY different from the
earlier
>>" "Chevy" 4 cyl.

i do know this is true of the iron puke.  it would be unfortunate but
plausible if they replaced the chevy-based 181 with a poncho-based
one somewhere along the line.

** I'm not sure when they started using the Pontiac type engine in boats.
**  ALL the boat engines I worked on (in my shop) were the "Iron Puke" type.
**  This was 80's early 90's.

>" When I had my shop a local marina approached me with a problem. The
>" "Mercruiser" 181's were galling piston skirts left and right. These were
new
>" boats with just a few hours on them. The factory had assembled them
WITHOUT
>" torque plate honing the blocks. The cylinder bores were SO far out of
round
" 
>this is an almost-40-year-old engine which never sold in vast numbers.
>could be they got sloppy with worn out tooling, and the move to Mexico
>could have happened about the time of this problem...

** No, the Pontiac is not a 40 year old engine. It's COMPLETELY redesigned
from the Chevy (but NOT necessarily better). The 151 type was used ** in
LOTS of vehicles and boats. It uses a lightweight thin wall block. That's
why they were having the problems with the cylinders. The deck of the block
is also thin. They were having head gasket problems and one of the things
they did was to increase the size and torque of the head bolts. Some of them
used SAE bolts and some metric. The big bolts torque to 120 ft lbs which
warped up the cylinders pretty badly. If you put a torque plate on one of
these before honing and put a ring in the cylinder, they would be so far out
of round you could actually see light between the ring and the cylinder
wall!! BUT,,, set up the right way with the right equipment they could make
300 HP.
Bruce Hevner