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Still getting the engine together in my sport coupe and have two questions relating to the front crankshaft main bearing cap, and one about the rear: Question #1: I assume the cap would get sealer on the machined front fact, that backs up to the engine front mounting plate. Since part of the cap remains outside of the oil pan, would it also get sealer where it meets the block and at the corners where the block and engine front mounting plate meet? #2: I made new main bearing cap bolt keepers in same gauge steel, using the worn out originals as patterns, for the center and rear cap bolts. The front cap bolts had no keepers on them. Do the bolts get torqued down with their heads right on the bearing cap (no keepers or lock washers)?
On the rear bearing cap, the check valve ball was missing on mine. I've come up with one that seems to be about right, and it's 1/4" diameter. I measured one from the rear cap in a friend's early Chevrolet parts, and it was larger -- so big in fact that a ball of that size would not work at all in my bearing cap. It might have been from a '32 or possibly there was a mid-year change in the drain design, to a larger orifice and ball. Since the ball is often found to have been removed, I'm hoping someone might have a spec on the size.
Many thanks in advance for any insight on these three questions. Andy in Santa Fe.
Hello Andrew Baron,
I would not assume sealer without repair manual instructions say so. I don't have access to repair manual. You may see answers to your other questions by going online to: chevy.oldcarmanualproject.com
scroll to:1929-1932 Chevrolet Master Parts Price List for Six Cylinder Models
index: Motor page 1
Crankshaft page 8
(I=1929, U=30, Ind=31, C=32)
see: U, Ind CAP with Dowel, Crankshaft Rear Bearing (with Ball Check)
see: I, U, Ind, C LOCK, Crankshaft Front Bearing Cap Screw
I believe that the word (Screw) refers to the crankshaft bearing cap (Bolt)
The only sealer needed on the front main cap would be where the cork seal meets the oil pan side gaskets. I use a little dab of Permatex #2 both front and back caps. You could put sealer on the front engine (timing gear) cover gasket if you wish.
There is a special front main cap bolt retainer. It has 12 sided holes for the bolt heads. It is in an arc shape with a tab for the center bolt on the timing cover in the center of the arc.
I am not home were I could measure a ball. They are of the size to seal at the top of the taper and small enough to have an open area greater than the hole in the cap at the bearing. That way they don't inhibit the oil draining flow while preventing draining the oil pan when parked with the front of the car on a upslope.
How sweet the roar of a Chevy four
Participant on Chatter since 11/22/2001
19758 posts on the former Chatter site
@harry-truppner Thank you, Harry. Much appreciated. I have an original parts book and will search where you've shown me.
I reverse-engineered a front main bearing bolt retainer, which without seeing what an original looks like, I'm reasonably sure doesn't follow the original form, but it should work. I did first take in paper, then gray board from the back of a note pad, then hard clockmakers brass, which should do the job nicely and hold its form effectively, after bending the tabs. Replicas of the other retainers were made in half-hard steel. Photos attached.
The retainer is impressive and should work as long as you solder, braze or epoxy a nut for the center of three bolts holding the bottom of the timing gear cover.
How sweet the roar of a Chevy four
Participant on Chatter since 11/22/2001
19758 posts on the former Chatter site
Thanks for the advice Chip. I'll add a split type lock washer and nut to the front facing end of the center bolt of the three that secure the bottom of the timing cover.
My '29 still has all of its original main bolt retainers. Your home built retainer is close to what is on my block. The front ones actually slipped down over the bolt heads after they were tightened and had notches that kept the bolt from turning. It was much more delicate looking than the other main bearing cap retainers, and is probably why not many of them survived.
@arthur-p-sell Your description in combination with Chip's comment paints a complete picture for me and is greatly appreciated. I wouldn't otherwise have been able to make sense of the 12-sided holes, since the other keepers have folded tabs. I just failed to make the leap. Thanks again, Andrew
Just to put a picture on the earlier description of the front main bearing retainer, here's a photo of a set of mains, with the front bearing retainer at the top right.
All the Best,
The other Chip.
W. L. "Chip" Boyd
VCCA Number 43428
Asheville, NC
'29 Fire Engine, '29 and '30 Phaetons, '32 Deluxe Sport Coupe
That is it. The 12 sided retainers will twist a little to fit down over the bolt heads.
@w-l-chip-boyd Many thanks, Chip Boyd for posting this photo. I've added it to my file. One of the four tabs broke on my hard brass keeper (too brittle), so your image may well come in handy. I had no problems with the steel replicas I made but found that when I torqued down the bolts on the brass keeper, the ends wanted to twist several degrees at the end of the final turn. This crammed one of the tabs, which I then tapped down lower so as to block the turning. This proved a bit too much for it, so that when I tapped it back up to hug the edge of the bolt, the formerly purposely impinged tab broke off.
@arthur-p-sell Thanks Arthur for letting me know about the twist. This makes total sense with that original design.
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