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Joined: Mar 2009
Posts: 293
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2009
Posts: 293 |
Putting my motor back together and was looking up torque spec's for the: main bearing caps, head bolt's, and con rod's and could not find any info on these spec's.
Does anybody know the torque specs for these parts? any help would be great.
Keeping vintage Chevy alive.
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Joined: Jun 2005
Posts: 408
Backyard Mechanic
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Backyard Mechanic
Joined: Jun 2005
Posts: 408 |
Well these things were before the concept of "Torque Specs". They used words like "tight".I do however remember asking an engineer about torqueing down a cylinder head and mentioned 75 lbs which was what was listed for a 1950 Holden. His reply was that 50 lbs was enough.I am sure other people will come up with figures that have evolved but basically "tight" but don't keep going.
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Joined: Jan 2002
Posts: 809
ChatMaster - 750
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ChatMaster - 750
Joined: Jan 2002
Posts: 809 |
Torque specs relate to bolt type and size, nothing to do with the brand or car. The main thing to consider is "are the bolts stretched" head bolts usually are. My suggestion is to replace the bolts with studs and tighten down with nuts, lessens the problem of stretching. Remember how old these bolts are and the quality of original ones way back then.
Basics I use are
Head max. 50lbs
Conrod bolts 30 add
Mains as tight as you can get them, around 80-100, helps reduce failure of bearings
Any bolt supply firm should be able to give you specs as would possibly a Google search
Chris
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Joined: Mar 2009
Posts: 293
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2009
Posts: 293 |
Thank's for all your help guy's, now I can finish up my motor and awaken this old motor from a 40+ year slumber.
Can't wait to hear the motor fire up.
Keeping vintage Chevy alive.
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Joined: Mar 2009
Posts: 293
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2009
Posts: 293 |
I forgot to ask what should the connecting rod clamp bolt to piston pin be for torque 30lb's ?
Doing a final check on everything and hope to have it running this weekend.
Keeping vintage Chevy alive.
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Joined: Dec 2001
Posts: 10,379 Likes: 1
Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
Joined: Dec 2001
Posts: 10,379 Likes: 1 |
30 to 35 is sufficient for the piston pins.  
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Apr 2010
Posts: 1,284
ChatMaster - 1,000
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ChatMaster - 1,000
Joined: Apr 2010
Posts: 1,284 |
Hi Jay28,
Good luck with the first start up, there is nothing like it.
Last weekend I helped a mate on the first start of his thumping big 38 Lasalle V8. Fired within 2 seconds, timing out to buggary,turned the dizzy, set the timing with the earchrometer, purred like a kitten. Almost as good as, well you know what.
Let us know how you get on.
Cheers
Ray
Some say "Street is neat". I prefer "1928 is great" I have documented my 45 years with a 1928 Chev Tourer, from 1973 to 2018, and regulary add other items that I hope are of interest to others. Your comments are most welcome.The story of the Red Chev can be viewed at http://my28chev.blogspot.com/
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Joined: Mar 2009
Posts: 293
Backyard Mechanic
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OP
Backyard Mechanic
Joined: Mar 2009
Posts: 293 |
Thank's Guy's for all your help with the torque spec's.
I checked all my bolts for torque and had a couple out so re torque them.
I primed the oil pump and primed the fuel pump and a little shot of gas down the spark plug holes for a guick fire to get things going, then tried to start the motor, it took a few crank's and then she fired up and burped a couple of times then started, followed with the bad smell of 40 + years of not running,but soon went away, had to tweek the carb a bit and now is running better.
I'm going to run it until it heats up good and then I'm going to recheck the torque on all bolt's to make sure they are with in spec, it is sure nice to see that all my hard work trying to get this motor built and finaly get to see it running, what a thrill and I would like to thank all VCCA members that helped make this happen.
You guy's are great and thank you very much.
Keeping vintage Chevy alive.
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