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1968 250 Horse Non-Turbo Mack


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According to Mack the part is discontinued/not available even from aftermarket suppliers. Looking for old equipment/antique junk yards......anywhere.

The whole problem is the pitch of the thread, it is 7" long - 3/4" diameter - main bearing cap bolt, that according to our bolt supplier has a 6 - 12 pitch.

That means mudd to me, it is not metric, not standard, not SAE. Machine shops are scepticle at cutting threads on to a grade 8 bolt, because they are

not sure of the alloy composition of the main bearing cap bolt and also, they say the original threads for that bolt are cold rolled into the original bolt.

Again, this is all mudd to me. We have called all over trying to locate this part with no luck so far.

So, that being said, anyone with any ideas throw them at us please.

@ Glenn......we will try to get some pictures, it is still in frame, only naturally aspirated, not turbo. In an old rust bucket Mack Haul Truck.

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There is no part number matching what you have posted (409GC157) in the parts system. There is a 409GC167, is that what you meant? There are still none in stock, but the parts system says it is 13/16" diameter with 12 threads per inch. Is this from an 865?

"Mebbe I'm too ugly and stupid to give up!"

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I am familiar with the number you posted via the Mack dealer here who said the (409GC157) is the one we need and that the (409GC167) is for the turbo version. The Mack dealer also states that at least to the best of his ability and knowledge that the bolt we need specifically is no longer available through Mack or aftermarket sources available to him so far. Really know very little about the motor any more than it is supposed to be a 250hp, V8 Mack naturally aspirated.....finding parts has been very difficult, one machine shop locally found main bearings in Mexico because we couldn't find those any place else. If you have any other sources or places to obtain parts for these motors, we would be glad to hear from you. They are a great running motor when they are running, but they are problematic. This motor is in an off road haul truck, thus it is getting severe duty application. Thanks for the input thus far!

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I am familiar with the number you posted via the Mack dealer here who said the (409GC157) is the one we need and that the (409GC167) is for the turbo version. The Mack dealer also states that at least to the best of his ability and knowledge that the bolt we need specifically is no longer available through Mack or aftermarket sources available to him so far. Really know very little about the motor any more than it is supposed to be a 250hp, V8 Mack naturally aspirated.....finding parts has been very difficult, one machine shop locally found main bearings in Mexico because we couldn't find those any place else. If you have any other sources or places to obtain parts for these motors, we would be glad to hear from you. They are a great running motor when they are running, but they are problematic. This motor is in an off road haul truck, thus it is getting severe duty application. Thanks for the input thus far!

What truck is this, an M15, M20, M25? If its used for a daily worker have you considered an engine swap? Moving to a newer more modern mechanical engine may be the way to go. A 237 Maxidyne should fit nicely and have all the torque you will need. Parts are easier to find as of now.

Engines will break down and when they are that old and rare, its gets increasingly harder to find parts as time goes by. If that engine blew up and was beyond repair, then what? I say look into the cost of a swap. You might be able to get an old truck with a 237 for around 3000 USD. Better to upgrade now than chase a crank shaft or pistons/connecting rods down later on.

-Thad

What America needs is less bull and more Bulldog!

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After looking at a parts book I see that you are right, there is/was a 409GC157 bolt, it just doesn't come up in the parts system currently.The parts book does not give dimensional data about the bolt however, so if you can post that information (nominal bolt diameter, thread size and threads per inch) it may be helpful.

You might try a scrap yard, but it's doubtful that you would fiind what you need. Assuming you need to get the truck working again ASAP, you might try giving these guys a call and see if they may be able to come up with something: http://arpdiesel.com/

Their contact information as follows:

Automotive Racing Products (ARP)

1863 Eastman Ave. Ventura, CA 93003 USA • Toll Free 800-826-3045 Local: 805-339-2200 • Fax: 805-650-0742

What happened to the original bolt?

"Mebbe I'm too ugly and stupid to give up!"

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I'm not certain you should reuse any main cap bolts from that engine. The block should be check for trueness through the main saddles and the bearing cap would be very suspect. If you engine is an 864 series there will be parts show up someplace so patience will be necessary.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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Thanks guys!! I should have known to post it here first. Didn't even get one atta boy on the ATHS post!!. I am restoring a 1966 R 719 that was sold new in CA and ended up in the Mary Hitchings fleet.

As it turns out Don at the museum helped me with info on the engine and only 34 of the twin turbo 864's were built. I will get a new post going with pics soon.

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Thanks guys!! I should have known to post it here first. Didn't even get one atta boy on the ATHS post!!. I am restoring a 1966 R 719 that was sold new in CA and ended up in the Mary Hitchings fleet.

As it turns out Don at the museum helped me with info on the engine and only 34 of the twin turbo 864's were built. I will get a new post going with pics soon.

This site is THE authority for Mack. Why post anyplace else?

Too much like a communist republic over there, (ATHS) for me. In the words of another member referring to the ATHS board; "What a bunch of pricks"!

Good looking engine as it is apparent you have taken great care to get it that way.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

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This site is THE authority for Mack. Why post anyplace else?

Too much like a communist republic over there, (ATHS) for me. In the words of another member referring to the ATHS board; "What a bunch of pricks"!

Good looking engine as it is apparent you have taken great care to get it that way.

Rob

hehe,,you know thats very interesting,,,im also a member,aths,,and thats just about what i think of them,,,as well as a buncha worthless.sobs...i was so furious last year,when they had thier national show in pleasantan,,,i thought cool ill take the ole lady on the harley,and truck on over,,its not far from me,,,and those dicks held it like friday,saturday,,ended on saturday,and it was a friggen 3 day weekend,and i couldnt make it,,cause i had to work friday night,,,but they pull crap like that all the time,,,they just dont seem to give a dam about members that have to work...they did the same thing here in reno,,last week 3 day weekend,,and they held the show on saturday,,,what the hell is this,,,so i made the show,,,but had to work all night,,,and show up exhausted,,,and yes(THEY ARE A BUNCHA PRICKS)bob

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