My father-in-law has a 81 Caprice diesel, and being a diesel mechanic
on Cat and other heavy stuff, he has redbuilt the diesel after 100k,
but then after a while the wrist pins on the pistons wore out and he
has parked the car under a cover for a few years.
He mentioned that someone told him only one Olds v8 motor would fit in
the car for that year, and it was tough to find. I was wondering if
anyone knew accurate information on this. I know those old caprices
were great cars, and popular as police cars, and that I would guess
nearly any small block of that era would fit.
Because of the diesel powerband, I imagine the transmission would also
have to be swapped.
Any advice? He is a country mechanic w/o a lot of funds, but a hell of
a shop and connections with a lot of folks for parts.
We had a lot of early 80s diesel Oldsmobile company cars which were hard to
Some people bought theirs from the company and drove them as long as they
A few converted them to gasoline when the engines wore out.
I dont believe they replaced the transmissions. They just swapped in the
engine and made the peripheral changes needed. I suspect your application
be much different, BUT if you cant do it yourself, it will be far more
it is worth. Even if you can do it yourself, it is probably not worthwhile
on a car
The reason for that is attachment of the transmission bellhousing to
the engine: Oldsmobile and Chevrolet V-8s use a different bolt
pattern. If you want to keep the existing transmission, the only gas
V-8 of that model year you could use would be an Olds 307.
You could use the complete drivetrain (engine, transmission,
driveshaft and rear crossmember) from nearly any Caprice from 1977 to
1987, possibly later. However, you will run into issues with engine
computers. carbs and such AND, if you live in certain states, issues
of being "smog legal". Would be best to find a 1981 Caprice that has a
gas drive train as a "doner car".
Scott, to my way of thinking the first decision is "is that old Chevy
worth all that work"? If the car is a creampuff except for the bad
diesel engine, then go for it. Otherwise, I'd send it off to the
boneyard. I know that is a painful decision (I've been there and done
that on an '87 Olds 98 I used to own) but sometimes just "moving on"
is better and less expensive.
Thanks will relay the info. The car is straight clean and no rust, but
has been sitting a bit. I imagine some chevy nut would like it if he
decided not to mess with it. It would be a neat car to put a crate
engine in and a decent transmission, a sleeper.
He's also got a older Ford Escort Diesel he got free from someone and
rebuilt the motor on it, it was running good and got super milage. The
guy has a lot of big projects for someone over 70, but he's a diesel
mechanic and used to some unbeliveable large projects like taking the
rear end and trans out of big Cat bulldozer, and these things are so
big he has to do it outside his shed, but at least he has a old bomb
loader thing with a crane on it to lift some of the heavy stuff. Well,
nearly everything on a bulldozer is heavy, even the pan under the
engine! One time he rebuilt a D8 Cat bulldozer, it was freakin huge.
the engine was enormous and even the connecting rods were so heavy you
could hardly lift them. I respect his country ingenuity on stuff like
That trans has the BOP pattern on it That is Buick/Olds/Pontiac style.
The Olds 307 or a Pontiac 455 should bolt to it. Or just do the easy
thing and grab a complete small block and 700R4 trans and drop that in.
Would give you the ability to use it and still get a bit of mileage on
I managed a parts store, machine shop and service center between 1978 and
1986. We replaced a lot of the olds diesel motors with Olds 350 cubic inch
gas motors. We were getting them from salvage yards out of late model wrecks
and installing them. We probably did one a month at least (6 bay shop) for
If smog legality is an issue, don't bother. If not, as previously
posted, you are stuck with BOP motors as options unless the trans is
replaced (some had dual-pattern bellhousings, but I don't think in the
diesels??? Some late-70s th400s???). Trans issues not withstanding, a
pre-1981 (non electronic) qjet and a 4-pin HEI appropriate for the
engine used should be the only components necessary to acquire (in
addition to the obvious engine assembly). Perhaps someone that has
pulled this off will know if the exhaust head pipes will match the
manifolds on a gas engine? It is worth noting that use of a non-Olds
replacement motor will pretty much, I expect, make all the existing
accessory brackets useless. So get a whole friggin' motor/trans, air
cleaner to pan, fan to tailshaft, to make it easier. Easy-wise, I
would think a 307 Y-code motor would fall right in, and those are about
as common as dirt, although mostly all high-mileage by now. I don't
know why only one year would 'fit.' Stick the aforementioned old-tech
carb and dizzy on any old 307 and take the bulb out of the ck engine
lite. Not exactly technically legal, but hell, anything gas with a
proper tune is probably cleaner than a 1981 diesel olds.
I owned an '81 Impala that started life as a 267 gas car. I spent
obscene amounts of money on it, changed displacements to 305, 350 and
383 along the way, and cried when it went to the scrapyard. It was a
cushy, smooth, comfortable car, if a bit rusty. I can understand
wanting to keep one.
Thanks everyone for advice. Will relay. As far as smog regs, diesel
titled vehicles don't have to go in for emission testing. I understand
those big, cushy rear wheel drive caprice's were decent cars, would be
fun to have a nice v8 in it. good point about the accessory brackets
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