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Need more bolt sizes

SnowDrift

SnowDrift

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I went to use the bolts from my original engine in my new one and realized the Optimizer has metric threads in it. In particular, can someone tell me bolt sizes for the following (or part numbers if available):

1) starter support bracket
2) motor mounts
3) starter bolts
 
I don't know if the optimizer is the same as mine but for the starter I used these from Summit. they are a M10x1.5x115mm iirc.

www.summitracing.com

ARP 430-3511 ARP Starter Bolt Kits | Summit Racing

Free Shipping - ARP Starter Bolt Kits with qualifying orders of $109. Shop Starter Bolts at Summit Racing.
www.summitracing.com www.summitracing.com

the bracket to block is ether the same thread or an m8x1.25 others will have to chime in on this to be exact. I see other places online are showing M8x1.25x20mm
 
Most everything on the engine is a M10x 1.5. The motor mounts from my '95 fit my P400 just fine but I can check the thread sizes on the block for ya tomorrow after work

x2 on the starter support bracket being M8x 1.5 but I can check that tomorrow too

I'd also recommend new starter bolts, don't use regular hardware store stuff even grade 8.
 
just to be clear, I myself did not know this until getting into the parts side of things and I'm sure others already know this, but here is how bolts are measured. from under the head to the end of the thread. just sharing for others.

1696814266507.jpeg
 
dbrannon79 said:
I don't know if the optimizer is the same as mine but for the starter I used these from Summit. they are a M10x1.5x115mm iirc.

www.summitracing.com

ARP 430-3511 ARP Starter Bolt Kits | Summit Racing

Free Shipping - ARP Starter Bolt Kits with qualifying orders of $109. Shop Starter Bolts at Summit Racing.
www.summitracing.com www.summitracing.com

the bracket to block is ether the same thread or an m8x1.25 others will have to chime in on this to be exact. I see other places online are showing M8x1.25x20mm
Click to expand...
I use tge Summit starter bolts and have an extra new set in the box with my spare starter.
 
I never thought of using a stud in the block for the starter brace. As much trouble as I have getting my hand in there to start the bolt, I will be trying that when I finally get to installing the starter on the 94.

I was amazed to be told the 1/4-20 stud in the starter was missing.
I usually use blue locktite.

Hopefully I'll get to that this week.
 
Yeah the stud on the back of the starter being 1/4" I think should have been at least a 5/16", they shear too easy. since installing a Powermaster starter on my rig, I haven't had any issues. I think for the design and lighter weight there should be less stress on the rear stud and bracket. Though I ended up making a bracket that's more stout anyway.
 
I’ve never tried the power master starter but I hear they are really good.I’ve bought the aftermarket gear reduction starters on eBay for my 6.2/6.5 engines which have always proven to be good.Both my trucks also use new acdelco battery cables which I’m pretty happy with.

Your right about the 1/4” size stud being too small.It should have been 5/16 indeed.
 
I know on mine, it's got so much torque and speed that there is no "bumping" the engine over LOL trying to bump it and you've got at least half or a full revolution on the engine! it's a starter with some balls for sure!
 
DieselAmateur said:
Most everything on the engine is a M10x 1.5. The motor mounts from my '95 fit my P400 just fine but I can check the thread sizes on the block for ya tomorrow after work

x2 on the starter support bracket being M8x 1.5 but I can check that tomorrow too

I'd also recommend new starter bolts, don't use regular hardware store stuff even grade 8.
Click to expand...
If you don't mind, that would be great @DieselAmateur . The one I found for the newer engine is visibly larger than the ones that came out of the '95 engine.
 
Sorry I didn't get to it tonight, 12 hour day putting up a deck and just got home. Eat bed turn around do it all over again. I'll try to report back tomorrow

What is visibly larger, the motor mount to block bolts?
 
@SnowDrift the motor mount to block threads are M10x1.5 as I thought. The starter brace to block was a bit more tricky. M8 x 1.25 seemed the closest but I didn't want to chase it too much on the block. My tap kit doesn't go any more coarse than 1.25. In searching around it seems the correct size is M8x 1.25
 
I found a bolt that will work for the starter support. I found six bolts that are the correct thread for the motor mounts, but they're 25mm in length which is too long. I'm guessing they're supposed to be 20mm but if someone can confirm, that would be great.

I picked up two exhaust manifold bolts today from the dealership which were the 14028923 part number. They screw in by hand about 2-1/2 threads before they get snug. I didn't force them any further. Is it typical for new exhaust manifold bolts to be very snug? I've not tried to thread them in with a ratchet yet, but planned to find a nut to try to thread on to see how it acts. Thank you @Twisted Steel Performance for the suggestion. The pitch and size seems correct, but they just seem unusually snug.
 
the manifold bolts only going 2-1/2 thread before snug sounds like there not the right thread pitch. the engine might possibly have mix matched heads. block a bit on the newer side, but the head might be of the older variety and have SAE threading. grab up on a 5/16" and a 3/8" bolt and see if one of the two thread in. also check the intake bolts too. if this is the case, your accessory bracket bolts will need to be checked too.

of course this is by no means any issue for operation and performance. iirc the older heads have larger valves for more flow = mo power 💥
 
BTW now that I think about it, GM actually did things like this on the assembly line. and it was right around the time metric was starting to be a thing. I had an old el camino that was mixed with both metric and standard bolts all over it's engine! I had to have two socket sets to work on anything under the hood!
 
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