>Vern Klukas responded to my question, "As you have >surmised in retrospect,
>the idea
is to measure the amount of freeplay in the crank by >pushing full forward,
measure,
pull full back, measure and subtract the two.
I finally figured that all out! As I pointed out to SOLer Lee Daniels last
night, the
Haynes manual is *really* misleading in this detail...I checked the Chilton's
manual,
and (for once) their description was infinitely superior. My confusion was
initiated,
I think, by the fact that you are indirectly measuring the clearance, as it is
not
possible to directly access the bearing. The fact that the measurement is made
between
two surfaces other than the bearing surfaces really got me off balance,
mentally.
>Where you measure from doesn't matter (as long as it's in the same axis).I
>would be
>very surprised if your end float is .018. You should reorder standard thrusts
>and then start over.
You're right, it wasn't...new measurements made like you (and Chilton)
correctly
describe indicate 0.020-0.014=6 mils clearance. I kept the standard spec
thrust
bearings which I had already installed. (FOR SALE: ONE SET +0.005 THRUST
BEARINGS.
NEVER USED. OWNED BY LITTLE OLD LADY WHO DID NOT KNOW HOW TO MEASURE THRUST IN
FIRST
PLACE)
>A measurement made with old bearings is useless,
>because you cannot know the wear on old bearing. The pros would measure
>this by installing new bearings, measuring the clearance and, if required,
>putting a different set of bearing in.
Roger that. Wish the machine shop had kept the old ones, though, so I could
have
measured them for comparison with new ones, though.
> The real pros would measure all the various components and then calculate the
>
>clearance.
I guess this means you would measure the thickness of main bearing pedestal,
subtract
the distance between the thrust surfaces, subtract the combined thickness of
the two
thrust bearings, and compare to specifications? I guess that requires inside
mic...I
only have an outside mic, but I would never have thought to do that.
>BTY, you must have all the mains installed and the caps torqued to spec for
>this
>measurement to be accurate.
Right, the manual was clear on that. One other question which came up in that
respect
was the need for spring washers on the bearing cap bolts. None were installed
in the
engine, but manual and parts catalogs clearly call for them. I considered
reassembly
without washers, since there is such a long portion of bolt free to stretch,
but I
chickened out, and put in new spring washers. Anybody else know whether spring
washers
are sometimes not fitted on the 1500 main bearing bolts? Is this a PO problem?
I
don't think that was cause of my original problem, which resulted in failure at
#4 big
end rod bearing. There was some damage, though to one main bearing; enough to
require
grinding the crank main bearings 0.010 in. Current theory is still oil
starvation, as
indirect result of major league oil leak and minor league driver. Oil pump is
in spec,
and goes back in with new bourdon tube oil pressure gage to supplement idiot
light.
>>Also, Dennis writes..."
>You must be VERY VERY careful with the thrust bearings on 1500s. The 1500s
>and 1296s are notorious for pushing con rods through the block. The thrust
>bearings wear and actually fall out so the crank has so much play that
>something
>gives. The 1500 only has half circle thrust washers ( the A series for
>example has full circle bearings) so they will wear faster than the full circle
>ones. this is confounded by the cooling capasity of this motor unit. The
>A' series motor can be tuned to over 140 hp, the 1500 can too but at high revs
>it generates local hot spots and destroys itself. Essentially the cooling
>system and oil circulation system is not as good as it could be and the
>engine suffers. One of its weak links is the thrust bearing.
My thrust bearings did not break up and fall out. The machine shop measured
everything
when they tore it down, I think. Certainly the report they gave me seemed
thorough, so
the absence of any report of problem with the thrust bearings would lead me to
conclude
that there was no evidence of damage to them. They bought the parts for me,
and they
ordered the standard thrust bearings. I don't know whether they made the
measurements
that Vern described (see above), but they probably did. They seemed a bit
surprised
when I called them back complaining that I had 0.018 mils of thrust clearance
with the
standard thrust bearings. I'll let them know today that they had it right in
the first
place. I visually inspected the thrust bearing surfaces on the crank and they
were
perfect (but I expect the crank grinder probably brushed those surfaces with
the
grinder when he ground the main bearing journals). Surely if the thrust
bearings had
worn to the extent that they could have broken up and fallen out, there would
be
serious damage to the thrust bearing surfaces, right?
>The solutions are:
>1) Have your machinist fit a full circle thrust bearing with minimal tolerance
>You can call Mark Sayer at performance engineering who wrote a fact sheet on
>this. I have not seen this sheet but I know it was published in a motoring
>mag. Shouls be not more than $130.
I didn't know about this...If I had observed thrust bearing damage, I think I
would
pull the crank back out and have that done now. I would like to get the fact
sheet you
mention...how do I get one?
>2) Have the engine balanced. About $75-110
I notice that the crankshaft was balanced (I assume that the corner ground out
of one
of the webs is evidence of balancing) by the shop that reground the crank.
What else
is done to balance the engine? I used the same rods, in same holes,... I did
add the
spring washers as mentioned earlier, and used new pistons. I didn't weigh the
new
pistons. I now wish I had, just for the record. They were AE brand, same as
the ones
I took out, but 0.020 oversize.
>3) Fit an oil cooler. 1500s badly need one. About $80 for a 16 row cooler,
>stainless steel braided hoses and a thermostatically contriolled adaptor.
I think I'll go get one. I have not had this car very long. I did put a new
radiator
core in first thing, as the old one had a couple of tubes pinched off to stop
leaks.
Even with the old one, there was no evidence of overheating, though. This
engine was
fitted with a Weber downdraft carb, and while I have no basis for comparison,
except to
the 1965 1098 cc I drove many years ago, it does seem to have a lot of power.
Now it
has a hotter camshaft, too...
>Several other cautions if you are doing this engine yourself:
>a) Make sure the screw holes in the small alloy bar located at the front of
>the engine by the front main bearing cap are all in good shape. Sometimes the
>threads get stripped.
This was in fact true. Last time I pulled the pan off, the threads in the
aluminum
front and rear aluminum components came out with the bolts. I drilled and
tapped the
four holes in question for next size...3/8-24, I think. This time, with the
aforementioned aluminum bar off the engine, I could see that the bottom surface
was
badly distorted. A bit of attitude adjustment with a vise and some resurfacing
with
sandpaper over a flat surface restored it to an acceptably (in my opinion) flat
surface.
I learned from the manual that the sequence of installation of these components
is
apparently critical...install the front aluminum bar first (over the two
gaskets),
lightly snug the two 5/16 screws securing it, then fit the front plate to the
engine,
tightening the screws from the front plate to the aluminum bar first. At some
point (I
don't remember the sequence) put in the two wooden wedge seals (is this common,
do
*real* car engines have wooden parts?) In my engine, both the front plate and
the
aluminum bar were distorted, although, maybe not so much that they could be
responsible
for the leaks I experienced. (Remember, this is the car that was spitting oil
out the
dipstick tube, and every other orifice.) I straightened these two components
as best
as I could. Machine shop did not think the front plate needed anything else,
and I
felt competent to assess the aluminum bar condition.
>b) Be economical with silicon gasket behind the front engine plate. Typically
>this is fitted one day, then the timming plate another day. However the
>screws and bolts which hold the timming cover on also hold the front plate on
>and make sure it is squeezed against the front of the engine. If the silicon
>stuff is applied too thick it will set without being squeezed into the joint
>by the timming cover bolts. The result is a very hard to fix oil leak.
>Another result is that the cam locking plate can bend when you tightening down
>if there is excess dried silicon under the front plate in that area.
As was discussed earlier, the Hylomar product I am going to use in these areas
does not
harden (it does seem to toughen a bit, to a pliable plastic state, based on a
short
term observation). I guess the advice to use the sealant sparingly might be
sound, but
my other worry is another leak if not enough is used... Will the use of the
Hylomar
reduce the concern you expressed? Should I wait to put the compound on the
front plate
until I can complete the assembly of the timing cover? Should I install the
timing
cover with the front plate to uniformly compress the gasket/compound, and
remove it
later to install the wheels and chain? How can you describe the right amount
of
sealant. Maybe it should be installed and troweled off with a grooved tool
(putty
knife?) for a controlled installation like you would lay floor tile? Guidance
for
tomorrow?
>You can do yourself several other favours: counter sink the head stud holes in
>the block and use grade 8 bolts instead of the head studs and all the other
>studs and critical bolts for that matter.
>Get hold of a dremlel tool and smooth off all sharp edges in the combustion
>chambers to prevent hot spots which can lead to ping.
Many thanks to both Vern and Dennis.
..Pressing on thru the fog,
Ray
-------------------------------------
Name: Ray W. James
Texas Transportation Institute
Civil Engineering Department, Texas A&M University
E-mail: Ray James <rwj4123@sigma.tamu.edu>
Date: 08/25/94
Time: 13:21:04
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