Which oil pan gasket for my SBC engine???

One word of caution when installing a new oil pan gasket.

The one I installed on my 350 engine came with new bolts for the pan.

I installed the gasket and everything was fine for a about one or two days until it developed a small oil leak so I rechecked all the bolts thinking that maybe I just did not tighten one down enough.

I drove the truck for another few days and once again it had a small oil leak so this time I started looking closer at just what was happening and the problem was the new bolts supplied with the gasket were just a little to long and were bottoming out in the holes.

Once I installed bolts that were just a whisker shorter the problem was solved.

Some new gaskets are thicker then the original gaskets so they supply new bolts just be aware of this happening.

Jimbo

 

Yes, the R/H dipstick is for approx. 80 - 85 with a 2 peice rear seal.

 

I think before doing anything else, I am going to try and re-affirm the casting numbers somehow.

Maybe try and get a mirror back there or even try taking a photo if the camera can get close enough.

Any future SBC engines I acquire I will record the numbers prior to installing them.

 

Almost everybody other than Bruce Lancaster seems to be totally missing the boat on the issue of thick or thin front seal This is an issue regardless of whether you use 1 pc. gasket/seal or the original 4pc. set with 2 side gaskets and 1 ea. frt & rear seals. The year block makes no difference here, except for dipstick location, left or right. .
What does matter is the oil pan itself. Some pans have a larger radius drop from the flat surface on each side that seats against the block to the bottom of the half moon drop at front where the seal fits against the timing chain cover. A straight edge across the flat and a measure down to the lowest point of the half moon on pan will tell the tale. The pans with a longer measurement here will require the thick front seal and those with the short measurement will need the thin seal. Felpro 4 pc. sets have both thick and thin front seals included in the pan set, and also enclose a slip of paper with the measurements for both thick and thin noted thereon. I have this note in a drawer of my desk in a file, but I can't get to the shop for awhile as I'm @ home recuperating from major back surgery.
You might find this info on Fel Pro web site however,

 

Dave , from 1 dave to another .. EXACTLY RIGHT !!!!

dave

 

Dave , exactly correct , the change in oil pans occurred mid-year '74 IIRC , doesn't matter what block or timing cover.

dave

 

Dave , exactly correct , the change in oil pans occurred mid-year '74 IIRC , doesn't matter what block or timing cover.

dave

 

x100!!!

Also consider buying ARP's oil pan stud kit. So much easier to install everything!

 

Wow, that information is a revelation to a non Chevy guy like myself.
I will sure need to check the dimension on that half moon drop.

Before I go looking on websites, if anybody does have the two dimensions discussed above, I'd be happy for them to post it, not just for me but for the history of this thread since it will help others who visit this thread in future searches.

 

This picture should clear up any confusion, just lay a straight edge across the pan and measure the depth of the "half moon".

2 3/8" thick
2 1/4" thin

 

Many thanks for posting the oil pan diagram and dimensions, I am sure that will go a long way to helping me sort this oil leak problem out by having the correct matching gasket to pan senario happening.

Russ.

 

Yeah no problem, I just went through the same thing with a 327 i'm working on. Hope those gaskets don't leak, they aren't cheap!

 

Well, I've just gone into my shop and measured both engines for the pan half moon dimension and both appear to be the 2 1/4" drop.

So I figure from knowing this I will be needing the thin gasket ends.

Any idea what year this end gasket thickness thing changed???

Boy, I hope this one piece gasket setup will do the trick and reduce my oil leaks to zero...

 

Correct me if I am wrong, but this thick/thin seal thing only applies to the front timing cover end of the engine and does not change for the rear seal!!!

 

You are correct, change is only in front. No change in rear until introduction of one piece rear main seal.
Aa for when they changed, I don't think I would bank on year model on this, just measure it. Too many pans out there with the huge numbers produced and swapped around to trust year model. The 4 pc. set like oem comes with both thick and thin anyhow. If you,re going to use the 1 pc. deal, measure before you buy. I,m planning to try the 1 pc on my next oil pan pull on an
sbc.

 

Back onto the old topic of SBC engine oil pan leaks.
Recalling talk about two different front seal thickness choices, I was curious to know if with the new Goodwrench engines which also have dip stick holes on both sides and have a Felpro gasket available for them.
Do the the Goodwrench Felpro gaskets come in two sizes like for the older SBC engine to accommodate front seal sizes or is there only one seal size for a Goodwrench engine???

 

Background is I have a new Goodwrench engine and before installing it I decided to upgrade to a Felpro one piece gasket in the hope that this would reduce my chances of oil leaks.
I installed it dry as per the instructions with the exception of the 4 corners also as per instructions and guess what it leaks at idle.
It leaks front and rear, the front seems worst and it leaks between the oil pan and the gasket!!!
As above, do I have the wrong gasket or should I have used a gasket sealer and not gone dry???

 

i used the one piece thick oil pan gasket and it leaked in the front. it was a milodon oil pan and an oem front timing cover. i dropped the pan and put a strip of gasket paper in the groove of the timing cover and put it back together. no leaks. i don't know why i had to do this.

 

Not a bad idea, sounds easy enough for the front at least.
I sent a "Contact Us" email to Felpro as well, lets see what they have to say!!!

 

Don't use a chrome import pan. They are junk!

 

No, not a chance, I am using the one Goodwrench supplied with the engine.

 

Same here.
I had my latest engine assembled by a pro, I furnished a FelPro one piece gasket and it leaked (bad) on the first dyno run, he replaced it with a standard version, no leaks.

 

Well, I applied some Permatex black sealer to the front and rear oil pan curves and used a strip of gasket paper in the front between the oil pan rim and the Fel-pro one piece gasket.
I can report the rear has sealed totally and the front now has only a slight weep.
I am pretty happy with that outcome as long as it does not leak worse when driven.
I can also report an email to the Fel-pro technical support folks did not even achieve a reply, so much for technical support. Well I guess it is only 1 week that has passed since I emailed them, still time for a miracle reply when I have fixed it myself...

 

Another word to the wise!!!
I changed the oil pan gasket on a 350 to one of the nice new Felt Pro blue gaskets and it came with new bolts and all.

The very next day after changing the gasket I noticed some oil leaking out of the new gasket so I checked all the bolts thinking maybe I missed one when tightening them down but they all were nice and tight.

Then I removed one of the bolts to compare it to the old bolts I had removed and sure enough the New bolts were just slightly longer which made sense since the new gasket was thicker but they were bottoming out in the holes.

A quick trip to the hardware store for some new shorter bolts solved the problem.

The lesson here is always check the lengths of the bolts but my mistake was in thinking well they are longer because the gasket is thicker which at the time seemed to make sense to me.

Jimbo

 

Very good point Jimbo, now you have got me interested, I will check that out, especially the 4 larger ones at each corner, they probably have the most influence over what happens around the curved ends of the oil pan...
I got to say I noted the new longer bolts and made the assumption that Fel-pro had done the maths on the thicker gasket etc.
Knowing how I feel about their tech support, who the hell would know if they even bothered to do the maths or their homework for that matter on bolt lengths.