[Kenth]

Don´t forget the washers:

Bolt Oil Filter Adapter 3/8"-16 x 1 1/4" #9418994
Lockwasher Oil Filter Adapter 3/8" #120382
Flat washer Oil Filter Adapter 13/32" ID x 13/16" OD x 1/16" #120394

HTH

[tempest1964]

Originally Posted by Dragncar

Rule of thumb is you need as much thread as the bolt is wide. A little more is OK.
There is such a thing as too much thread.

As a machinist I was always taught that maximum bolt engagement strength is achieved at 1.5 times Ø of thread.

[johnta1]

Kenth, using facts?





I am cheap. I save all the intake bolts and bellhousing bolts from engines I tear down. (3/8" course thread) They fit the majority of the bolt holes on the Pontiac engine.
Some may need extra washers for the too long bolt.
(the motor mount bolts are ones to save, oddball size)

[punkin]

Originally Posted by steve25

wow!
I would be very insulted if it was me who answered your question and now your posting back questioning my answer, HS!

Sorry...I suppose I should have clarified. I was hoping to add some reference material to my little collection. It would be great to have a look up for the garage without bugging folks for something this seemingly simple.

I thank you.

[punkin]

Originally Posted by i82much

maybe he just wants to know where to look stuff up next time?

Exactly correct.

I really should have clarified. No insults or mis-trust intended. I was impressed that someone had a look-up reference for this. Would be great to have something like this available in the garage for a quick reference if it's available.

I thank you.

[punkin]

Originally Posted by PAUL K

If I wanted to try and figure this out I would assume the OP was trying to put his oil filter housing on his aftermarket Pontiac block and wanted to use the correct length bolts. I would also assume the first gentleman gave his answer based off past experience. I would assume after the OP tried to use the first responders (no pun intended) advised bolt length and found out they were the same length bolts he already tried and didn't work (note time of posts). The OP came back and wanted to confirm with the "first responder" (again no pun intended) why he came up with the same length bolt that he already had come up with and for some reason the bolts were way too long. Now with that being said and already knowing that a bunch of aftermarket blocks aren't threaded as deep as a lot of factory blocks and there is a slim chance a 1.5" long bolt is going to work, I figured I'd politely try to help the OP. Also since I am a weight conscious racer (even though I eat too much) I know a 1" long bolt will work with the factory oil filter housing. Also since I have performed many high end stock type rebuilds where the guys want all the correct bolts where they belong and I have a fairly good memory for unimportant stuff, I recall the factory length bolts are either 1" or 1 1/4" long, but pretty sure an inch and a quarter. However if this seemed like a concourse restoration, which it might be (I assumed a lot here) and it'd give the OP a warm fuzzy to know for sure he was wanting the exact correct OEM length bolt I never would've replied in this thread until I was at the shop tomorrow and could post accurate information by checking a correct length factory bolt..... Fwiw

I went through something like this a few weeks ago where I thought I knew what size bolt/nut I needed and went to the hardware store. Came back and found that I was mistaken. Just wanted to save my back-and-forth hunting for hardware at the store.

I really didn't expect this thread to get this long. I surely didn't mean to insult anyone. I was imagining there might be a table or a reference/easy look up that I might get my hands on. If something like that was available I imagined laminating it and hanging it up on the wall over my bench.

Thank you everyone.

[track73]

My machine shop teacher told me "you don't get much more strength after 3 threads".

[Sirrotica]

FWIW, the old Pontiac parts manuals many times listed the bolt dimensions in the drawings. Pontiac parts departments usually carried bolts in bulk, rather than specific GM parts (same way a hardware store offers them). The parts man could just refer to the bolt size in the drawing, and pull it from the bulk bolt stock for the customer, or mechanic.

I was friends with the parts man at the Pontiac dealer where I used to work and when he got new parts manuals, he offered the old set to me (late 70s). I had them for many years at my garage/gas station, but when I moved I didn't have room for everything and I tossed the parts manuals, in hindsight not a well thought out move. Many times I regretted tossing them, but they took up a lot of room. Some members here have these manuals and I assume that's how the part numbers with all the specs came from.

I guess my memory is still adequate...........

[1968GTO421]

Originally Posted by punkin

I went through something like this a few weeks ago where I thought I knew what size bolt/nut I needed and went to the hardware store. Came back and found that I was mistaken. Just wanted to save my back-and-forth hunting for hardware at the store.

I really didn't expect this thread to get this long. I surely didn't mean to insult anyone. I was imagining there might be a table or a reference/easy look up that I might get my hands on. If something like that was available I imagined laminating it and hanging it up on the wall over my bench.

Thank you everyone.

I had hoped to find a chart of bolt sizes for Pontiac engines in Rocky's book on Rebuilding Pontiac V-8's but I went through the whole thing----nada. I also tried Google, got lost in irrelevant BS but found my way home again----still nothing. There may be such a chart out there but I don't know where other
than some times in the factory shop manual (mine is somewhere )
Best of luck with this.

Treed by Sirrotica!

[HWYSTR455]

Just to say, one time I had an oil leak at the filter housing, and it was only under higher psi. The filter housing bolts being too long was the culprit. Took a while to figure that out by the way.

.

[Sirrotica]

Originally Posted by 1968GTO421

I had hoped to find a chart of bolt sizes for Pontiac engines in Rocky's book on Rebuilding Pontiac V-8's but I went through the whole thing----nada. I also tried Google, got lost in irrelevant BS but found my way home again----still nothing. There may be such a chart out there but I don't know where other
than some times in the factory shop manual (mine is somewhere )
Best of luck with this.

Treed by Sirrotica!

So my reactions, as well as my memory is still pretty good...LOL That's good to know.........

[Dragncar]

Originally Posted by tempest1964

As a machinist I was always taught that maximum bolt engagement strength is achieved at 1.5 times Ø of thread.

Sure, but its a oil filter adapter. Nowhere near maximum strength of a 3/8 bolt. Even grade 5.
I would also think it depends on if the threads are in steel, iron or aluminum.

Pontiac decks have bolt holes that have a bottom, we all know that. So bolt length is critical. One a hair too long and you have a big problem.
1/2" bolt, hole is 1/14" deep, threads go to 7/8" max so you had better have 3/4" thread engagement max to give yourself a little room.
No way you could get a full 1" of thread in the block if you wanted too.

I lost a few head bolts for my HO heads. So I have one grade 8 bolt and 2 CAT bolts in my engine. They have a hair over 5/8 thread in the block. Never lost a head gasket in my life.

[tempest1964]

I think 3/8 X 1.5 is 9/16 or .562. You are absolutely correct about the steel vs aluminum. I believe the 1.5 X diameter was a rule of thumb. And like you said, it goes w/o saying: make sure your bolts don’t bottom out in the blind holes.

[punkin]

Some really great info and advice. I thank you all.

[4zpeed]

Originally Posted by punkin

Some really great info and advice. I thank you all.

This is the place for it, and FWIW don't pay too much attention to the post by steve25, it was just a misunderstanding, if you hang around you'll see he helps Allot of folks.

Things and topics can get controversial, and obviously since this is a forum, lead to some acidic comments, steve25 since he helps Allot, is at the brunt of many of those.

Not an excuse, just an explanation, good luck with your build.



Frank

[punkin]

No offense taken. In hind site I really should have better qualified my second question. I do appreciate the feedback and the folks here have always been very helpful. Hopefully one day I'll be the person with the answers. This posting turned into quite an interesting series of exchanges and I learned even more than what I was hoping for.

You're all great in my book!