Team Camaro Tech banner

1 - 9 of 9 Posts

·
Registered
Joined
·
126 Posts
Discussion Starter #1
Rear Main Seal2.jpg

I'm attempting to fix some oil leaks by replacing the rear main seal and oil pan gasket on my DZ302 engine.
I was able to remove the oil pan by supporting the rear of the engine and jacking the front of the engine up as
outlined in the chassis service manual. I only had to lift the engine about 1" to gain clearance for the pan.
At first I thought I had to rotate the crank to gain clearance but quickly found the crank position does not
matter in the DZ302 due to the oil baffle hanging from the block cap journals.
I've got the pan cleaned up and painted and I think I have all of the parts. I've been doing some research
on camaros.net and in person and have found there are a variety of methods used for installing the seal and oil
pan gasket. It takes some work to get the pan off and I want to ensure I get things back together correctly. I
am also putting in a new clutch - a Centerforce II. I'm outlining my process for installing seals below and
welcome comments from fellow camaros.net participants.
I'm using a Fel-Pro BS40013 seal. The new seal will be lubricated with engine oil for installation using
the provided "shoe horn". The large sealing lip is towards the front of the engine. I will ensure the
mating ends of the two halves are cleaned of oil and no RTV is used on these seal halves. A small amount of black
RTV will be used on the bearing cap, applied to both mating surfaces. Outer bolts on 4 bolt cap are 65 ft-lb and
inner are 75 ft-lb. Note there may be a long period of time between installation of the seal and when the engine
is started - several weeks.
I have a one piece Fel-Pro OS34509T Perma-Dry oil pan gasket. This is the thin seal for use on the older pans
with the 5.5" by 2.25" front of pan depression. I will use a small amount of blue RTV at each of the four corners
on the block side where the pan transitions from the flat to the semi-circle depressions. It appears I will have
to buy some more 1/4" bolts since the ones I got from Classic are only 3/8" long and the pan gasket installation
tip recommends at least 5/8". The one piece gasket is 5/32" thick. Specified torque from the manual is 80 in-lb
for 1/4-20 and only 65 in-lb for 5/16-18, however I see higher specs on the larger bolts listed in other sources.
The pan gasket installation tip listed over 200 in-lbs for these corner bolts due to the metal grommets.

Another thing I am torn on is the pilot bearing. Based on what I have read in camaros.net the solid bearing
will work fine. However, I talked to someone the other day who tried hard to convince me to use a roller bearing.
Thanks,
ColoradoZ28
 

·
Premium Member
Joined
·
11,167 Posts
I would use the solid bronze bushing. I have used the roller and they came apart . They were also dry when I pulled them the next period usally within 2 years. I am an advocate for the GM bronze bushing as some aftermarket bushings don't seem to have the true mixture of alloy, they have more iron in them . I don't know it the manufacture is trying to strengthen them or just make them cheaper. But the GM bearing appears softer and most of all I want to protect the input shaft of my transmission from wear so that's another reason I would go with GM # 10125896 bushing .
 

·
Registered
Joined
·
3,222 Posts
I surmise you are rehearsing your procedure so as to have your act together. I like that. I've got a couple new guys I'm trying to teach that trick to. It's how you foresee problems and save time.

Loosen all main caps a round or so. Saves hassles.

If you haven't pulled the distributor yet, pull it now because it won't re-spline to the oil pump drive when you reinstall the oil pump.

Clock the seal about a 1/4 to 3/8" off from the parting line so it does not coincide with the parting line. Use a measure on the half sticking out of the block and then the same measure on the cap half to minimize the amount the cap has to correct the clocking as it goes home. I always put a teeny bit of silicone on the parting line of the seal, as well as the back area of the cap. Lube the lip of the seal.

Remember to bump and hold thrust as you snug the rear main.

Both my rotator cuffs are ripped up and I have to dream up ways to not use my shoulders more than absolutely necessary. I'd have a bucket and a scissors jack or a floor jack holding that pan up for me .

Good luck.
 

·
Premium Member
Joined
·
11,167 Posts
I might want to add that I used the one piece pan gasket and had a possible leak at the rear of the pan. One thing that I did not do was apply RTV to BOTH sides of the seal ends. Tim reminded me of this possibility of leak . Second time around I did this.
As for the pilot bushing, I am into this now and did not have a new bushing on hand and today is Super Sunday, GM dealers are closed so I could not use the GM bronze bearing. I just got back from town and at O'Reilley's , I found the Timken PB656HD equivelent bronze. It looks the same as GM, not like the taiwan model. So just in case you are in a weekend repair.
 

·
Registered
Joined
·
1,377 Posts
You replace the rear main seal the same way as ALL SBC with the 2 piece neoprene seals. Slightly off set the parting line with the main cap.
 

·
Premium Member
Joined
·
339 Posts
ColoradoZ28
I just went through a cam change and had leaks after the 302 engine was re-installed I used one of those black-light leak detector kits to find the source. I insatlled a new Centerforce II clutch P/P and a bronze bearing wouldn't use anythinthing else. If your tranny is dead on (have you done any machine work in the past to change crank centerline?) I would use the bronze bushing (a tap makes it come out real easy). Love that centerforce clutch works good.
My recommendation
Buy one of those black-light leak kits there worth there weight in gold!:hurray:

1) Install the starter without the clutch shield and look for leaks after first start-up. If you have a leak the shield is in the way to take a look.
2) I found the outside bolts on the pan (the 1/4"-18 I think) that go through the support tabs need lots of sealer and tightened very tight top of the torque range. This is where my leak source was and took forever to find it this is where the leak detector is worth its weight.
3) Dipstick tube resealed this twice and although it wasn't leaking it is a possible source.
4) If you have the stock valve covers check the rear corners closest to firewall these can leak if a too thin gasket is used as the head casting can ride on the aluminum cast flange for the gasket
5) My personal opinion is use sealant on both sides of seals (except the rear main) I like a dry leak free motor and mine is tight as a drum now:yes:

Also permatex is the best sealant going in all its different flavors forget any silicone based rtv's IMHO
Todd
 

·
Banned
Joined
·
21,341 Posts
I saved this..............

"Napa stores carry a 100% bronze heavy duty pilot bushing. The part number is BK 6151161. Unlike the cheap pilot bushings the 100% bronze bushing is easy to install, won’t gall your transmission input shaft, and will last longer than the clutch. For only $3.29 it is good insurance. Napa also carries the junk iron pilot bushing for $1.69. Don’t buy this one."

pdq67
 

·
Premium Member
Joined
·
8,375 Posts
Last month my son and I installed a new bushing in his 496 that's going into his 69. (I don't know where he bought it.) Then after I left town he ordered a new TKO600, (I thought it was a 500) a dual clutch and new 3.5" drive shaft. I don't know the supplier of the components, BUT, he was told that he would NOT have a warranty unless he used a roller pilot bushing! HUH? :confused: What's with that? I would think that a little moly lube in the bronze bushing will last a lifetime. But I'm a TH400 guy. Why not a touch of grease?
 

·
Premium Member
Joined
·
11,167 Posts
Last month my son and I installed a new bushing in his 496 that's going into his 69. (I don't know where he bought it.) Then after I left town he ordered a new TKO600, (I thought it was a 500) a dual clutch and new 3.5" drive shaft. I don't know the supplier of the components, BUT, he was told that he would NOT have a warranty unless he used a roller pilot bushing! HUH? :confused: What's with that? I would think that a little moly lube in the bronze bushing will last a lifetime. But I'm a TH400 guy. Why not a touch of grease?
Fred, I don't understand the statement about voiding warranty without a roller bearing as this alone is not going to 0 in the mainshaft. Dialing in the bell housing will for sure. But never less, you son could buy the bearing just to satisfy that warranty but install a good known bronze bushing .. I have seen these roller bearing bearing come apart and chew up a mainshaft.
 
1 - 9 of 9 Posts
Top