Anyone know bellhousing bolt sizes?

[Mycarispurty]

I got an engine stand last night that I'm going to put my bare block on, but I need to know the size of the bellhouse bolts so I can go to Ace and buy some. Also should I look for a certain type of bolt to hold all that weight? Such as Grade 8, stainless steel, etc?

[Pop N Wood]

3/8" by 16 pitch, inch and a half long, grade 8

 

Stainless bolts typically are not as strong as regular steel

[Mycarispurty]

I took a bolt out of the bellhousing on my 280Z and it appeared to be m10x1.5. I got 110mm long bolts at Ace for $2 each. Now I just need to find someone to help me pick the engine up and put it on the stand

[Warren]

Old head bolts work well for holding the engine to the stand, just get a couple of fender washers for the hex head side and you'll have no problems threading them into the block, same thread pitch.

[mom'sZ]

3/8" by 16 pitch, inch and a half long

Pop... are ya kidding?

[2003z]

Like said above, M10x1.5, I bought grade 8 bolts at home depot for mine

[Pop N Wood]

Pop... are ya kidding?

 

Guess I should say for my GM LS2 V8.

 

Never occured to me that you might have a different engine.

[Mycarispurty]

Ahh, in order to correct in case someone searches this for an answer in the future, for the upper bolts I used bolts that were a weeeee over 2.5-2.75" long, and for the bottom, ones a hair over 3.5". I bought enough washers to space just in case they were still too long. The 4.5" ones were WAY too long

[2003z]

I guess the length might vary with any particular engine stand. I think I used 3 45mm and 1 40 mm bolts.

[BRAAP]

I got an engine stand last night that I'm going to put my bare block on, but I need to know the size of the bellhouse bolts so I can go to Ace and buy some. Also should I look for a certain type of bolt to hold all that weight? Such as Grade 8, stainless steel, etc?

 

Datsun L-series Main cap bolts is what I use for holding L-series blocks on the engine stand, 10mm x1.5. I even attached short pieces of angle to the sides of all of my engine stands that hold four Datsun main cap bolts for L-series and GM LS-x engines and four 3/8” x16 bolts for SBC engines.

 

 

 

Guess I should say for my GM LS2 V8.

 

Never occured to me that you might have a different engine.

 

 

 

Please oh please tell us you did NOT use SAE bolts in the bell housing of your GM LS-2 V-8? Whatever you do, do not use SAE bolts to hold up your GM LS-x engine on your engine stand. Those bell housing bolt holes on the GM LS-x V-8’s are also metric, in fact they are the exact same threads as the Datsun L-series, 10mm x1.5

 

Here is a GM LS-1 out of a 2000 C-5 Vette currently in our shop attached to one my engine stands using Datsun L-series main cap bolts…

 

 

[Pop N Wood]

OK now you are scaring me. So far the bellhousing has only been set finger tight while I am fabbing mounts. I am using the bolts that Keisler engineering sent with the LS housing I bought from them. To tell you the truth I didn't realize they were SAE bolts until I checked them with a pitch guage for this thread. They seem to fit perfectly. The engine is a crate motor and has only sat in the wooden crate and not on a stand.

 

Let me take a closer look at them.

[BRAAP]

OK now you are scaring me. So far the bellhousing has only been set finger tight while I am fabbing mounts. I am using the bolts that Keisler engineering sent with the LS housing I bought from them. To tell you the truth I didn't realize they were SAE bolts until I checked them with a pitch guage for this thread. They seem to fit perfectly. The engine is a crate motor and has only sat in the wooden crate and not on a stand.

 

Let me take a closer look at them.

 

SAE 3/8” x16 bolts will go in approx ½-1 ½ revolutions by hand before they get too tight for finger insertion. The 10mm x1.5 will go in all the way by hand. If you have an old Datsun engine laying around, use one of the main bolts or head bolts and thread it into a bell housing hole that you have not put a bolt into yet.

 

My guess would be that if a reputable shop sent you bolts for the bell housing, they should indeed be the correct bolts and those bolts should be 10mmx1.5, which is really close to 3/8” x16.

 

Our fingers are crossed that all is well….

[Pop N Wood]

I think the LS bellhousing bolts are in fact SAE. I have a bunch of M10x1.5 bolts I am used to attach lift plates to the heads and motor mounts to the block. I also have the 3/8x16 SAE bolts that came with my LS specific bellhousing. The metric bolts will not fit into the bellhousing holes and vice versa.

 

Summit racing lists only SAE bellhousing bolts for "Chevrolet" applications. Same with the ARP web site.

 

Are you sure LS blocks use metric bellhousing bolts? The metric and SAE pitch are noticably different, even with a pitch guage. It would take quite a bit of effort to force the wrong one into the block.

[BRAAP]

Your sources are totally credible, now I’m scared…

 

I’ll get back to you on this one…

[BRAAP]

Ok. Here is what I’ve got thus far… (Maybe we should query the V-8 forum about this as well?)

 

 

Our engine is an LS-1 out of a 2000 C-5 Corvette purchased brand new by a friend of ours. This engine received a cam, ported heads, LS-6 intake and exhaust mods, (produced 379 RWHP when all said and done). After quite some time, he broke a valve spring then bought a “new” stock LS-1 from GM to meet “Super Stock” class rules for SCCA Solo-II. Ron Tyler then acquired the original C-5 engine in trade for helping tune the chassis for maximum effort SCCA Solo-II Super Stock competition. Ron then stipulated to me that whoever starts a project worthy of this engine first, gets to use it. (Since I’m neck deep into a Super Charged traditional SBC V-8 Z project now, don’t you all think that Ron should take on a Mid Engine LS-1 Z project? He already has a 240 Z shell modified for an L-6 mid engine set up…) Any how, this engine was pulled directly from said 2000 C-5 Vette, set on a wooden crate that sat in my barn for a couple years and as of last week installed on this engine stand pictured above. The car was purchased brand new by a friend of ours and he was the sole owner so we are very sure of the engines history, (for whatever merit that has in regards the bell housing bolt specs

 

Using 2 different bell housing bolt holes on this LS-1 short block not touched or used by “any” bolts since the engine was removed from the car, I inserted a 3/8”x16 bolt as tight as I possibly could get it with my fingers only, (picture on the left). Thread engagement was 5-7 threads. In the first 3-4 threads, the bolt felt sloppy loose, not quite right, but then at around 6-7 revolution’s it locked right up. Next up was the 10mmx1.5 Main cap bolt from an L-28 block in a completely different hole. That bolt threaded in perfectly till it bottomed out. The bolt felt great from the first revolution all the way till it bottomed out, (picture on the right). I then swapped the bolts in their respective holes with the exact same results, the metric bolt bottomed out and felt perfect, the SAE bolt reacted just as it did in the other hole, the SAE bolt was sloppy and didn’t feel right and then tightened up as I continued to install it by hand. Ron Tyler than came out and duplicated my results.

 

The bottom pic is of the 3/8” 16 bolt, (Silver), and the 10mmx1.5 Datsun Main cap bolts, (Black) and my thread pitch gauges. The threads are fairly close, but not the same size or thread pitch as can be seen.

 

 

 

 

 

 

 

Conclusion at this point…

 

Well, there is no doubt that this particular 2000 Corvette LS-1 definitely has metric bell housing bolt threads and it is possible that GM switched “back” to SAE bolt threads for the later model LS-2. That would be a “Ford” maneuver changing things on a similar engine in mid production, which is not like GM, but?..... After going out to test this and having Ron duplicate my results, I am still fairly confident that the GM LS-x has metric bell housing threads. Well, at least the 2000 Corvette LS-1 has metric bell housing threads.

[Pop N Wood]

Looks like my brand new crate motor block now has SAE thread holes.

 

For the life of me I can't remember cross threading these holes but I must have. I am usually not this stupid.

 

The Keisler bellhousing I bought is an adaptation of of a standard SBC unit that allows Muncies and TKO's to be bolted to an LS series motor. All they did was recast one bolt hole to make it fit the LS blocks. When they first sent it to me I called them up asking if it was the correct piece since none of the inspection plate hardware they sent will work with an LS motor. The guy assured me it was, and the extra bolt hole at 12 oclock proved that. You would think if you are going to rework a mold, you would go all out and make it fit the oil pan too.

 

Guess the keyword in your previous post was the word "reputable".

 

Think the wrong type bolts had anything to do with the runout being 14 thousands? I would hate to replace the dowel pins before I get the correct bolts in place.

 

Moday I give a call to Keisler then one to McMaster Carr to get helicoil inserts. Found this on LS1 tech

 

http://www.ls1tech.com/forums/showthread.php?t=519920&highlight=bellhousing+bolts

 

Funny thing is the SAE's seem to thread and hold perfectly right now. Suppose I would be a double dildo if I tried to use them. Especially since the engine is out of the car making the repair relatively straight forward.

[BRAAP]

Pop-n-wood,

You haven’t ruined your block and installing threadserts, helicoils, etc is relatively easy and will fix any thread damage may have been done and it should be relatively inexpensive as well.

 

That Heli-coil link is great, thanks.

[280zwitha383]

You lost me on the whole LS1 bit. However, I have used the bolts supplied with the engine stand (I guess ment for a traditional chevy) to hold up an L28. They're damn near identical like (and with) a 14mm and 9/16 head. But I've been known to do some stuff that other people don't deem as safe.

[Pop N Wood]

You don't think it is important to use metric bolts in a metric bolt hole and SAE in and SAE hole? They are pretty damn close, but then again not really.

 

Do you really think a cross threaded bolt will hold as well as a properly threaded bolt?

[dimsum]

Hello

 

Just wanted to add some information on bolting the engine to an engine stand. I just did this and had some trouble finding the right bolts.

 

1. Many people recommended using the transmission bellhousing bolts. I wish I used this because they only cost $2 each at Nissan and should be plenty strong enough.
   
2. SAE and metric bolts have different classifications for hardness. SAE bolts are have "normal," grade 5, and grade 8, with grade 8 being the strongest. If you really want more information on how the strength of these grades compare, go here: http://www.rockcrawler.com/techreports/fasteners/index.asp
   
3. Most metric bolts fall into one of three classes: 8.8, 10.9, or 12.9, with 12.9 being the strongest. I think that class 10.9 is considered automotive grade. The class should be stamped on the bolt head.

With all that said, I went looking for M10 x 1.5 bolts yesterday to mount my L24 engine to a stand. Ace Hardware, Orchard Supply, and Home Depot all did not have those bolts in class 10.9. I finally found the right bolts at Kragens, but they came in packs of two bolts, one 80 mm and one 100 mm. The package said that the bolts are intended for an alternator of some sort.

 

The 80-mm bolts were just the right length for my stand on all four locations (where the transmission bellhouse bolts to the engine).

 

I hope this information is helpful.