Tap aluminum front seal plate?

Discuss fixes, upgrades and modifications to your M37

Moderators: Cal_Gary, T. Highway, Monkey Man, robi

Post Reply
NAM VET
1SG
1SG
Posts: 1118
Joined: Mon Aug 22, 2016 6:27 am

Tap aluminum front seal plate?

Post by NAM VET »

In the past year, and more so recently, I have read uncounted posts on this and some other forums, searching for helpful information about this or that step in my motor's rebuild.

I have only installed the crank, but can really make progress now. But reading about the "front oil slinger" and the several oil seals that go into the timing cover, I understand the suggestion to use the newer National Seal # 6636s, which does not use the slinger which my motor did not have. I just had the machine shop install with the gasket a National seal from VPW which has a different number and may have been an NOS seal. So I think I will just get a 6636s seal, and ask my machine shop to pull the just installed seal, and use this more modern and suggested seal. I am sorely tempted to just put my timing cover on and get on with my rebuild and not further delay getting rolling. But when I read and see what it takes to pull all this off the front of the engine, I just can't imagine doing it all over again soon, because I used an older seal.

To remove the front plate, there is one single bolt fastener which goes from inside the block and threads into the plate. So the sump has to come off to replace the gasket between the block and the plate. The half-moon aluminum seal that attaches to the front block cap has three holes, two are threaded and thus bolted from out to in, but one has the threads on the plate, hence the bolt/screw goes from inside to out. This single fastener is the reason the sump has to come off.

This misery is mentioned in several threads. So I was out to my garage on the way to church, and am thinking about tapping threads for a larger bolt in the aluminum arc, and thus making it possible to remove the plate without molesting the sump by attaching it from the outside of the block. I screwed a longer bolt thru the arc and the plate, and then test fit the timing cover, it it does not interfere with the cover. I don't think there would be interference with the sprocket, either.

But surely Dodge had a reason for making this more complicated than it needs to be. I am reluctant to use a heli-coil inside the block, because I would fear some small steel part would get somehow into my oil gallery.

Anyone have experience with this possibility?

NV
ashyers
MSGT
MSGT
Posts: 820
Joined: Mon Jan 05, 2015 8:20 pm
Location: Oakland CA

Re: Tap aluminum front seal plate?

Post by ashyers »

NV,
I suspect it was done the way it was so you can swap main bearings w/o disturbing the timing cover. There may be an interference issue with the cover too depending on hardware selection. I'll take some photos today.

Andy
just me
1SG
1SG
Posts: 1195
Joined: Fri Nov 28, 2014 4:25 pm

Re: Tap aluminum front seal plate?

Post by just me »

It isn't an interference issue in the chain case. It may ( bolt head ) interfere with the timing cover itself. The other two bolts are part of the timing cover bolts.
"It may be ugly, but at least it is slow!"
ashyers
MSGT
MSGT
Posts: 820
Joined: Mon Jan 05, 2015 8:20 pm
Location: Oakland CA

Re: Tap aluminum front seal plate?

Post by ashyers »

Here's some photos that may help:
Front Cover Bolt End View.JPG
Front Cover Bolt End View.JPG (97.92 KiB) Viewed 688 times
Front Cover Bolt Top View.JPG
Front Cover Bolt Top View.JPG (105.67 KiB) Viewed 688 times
I will say if you have to swap bearings in the chassis it is nice that you don't have to pull the timing cover off. If you were to install a button head or flathead cap screw it looks like it would clear the chain and gasket area. In the photo you can just see where the gasket was.
Post Reply