My machinist said that it should only take 20 ft/lbs to turn my crank and pistons in my new motor, but it's taking 30 to turn mine. Is this a problem??

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Riccioli Performance Motorworks

--RPM Racing--

-Currently building first ever engine. 383 with Super Ram plenum and runners, Edelbrock lower intake, Bosch 24# injectors, AFR 190 heads, MSD ignition.
-Will be installing Baer Brakes
-Will be installing full Spohn suspension in rear
-Art Carr 700R4 trans??


Attention Everyone!!! I will be changing my name on the message boards to HardcoreZ28 sometime in the near future. Just wanted to let everyone know.

 

There is no exact value. 20 seems low to me for a street build, maybe reasonable for a race-only one. 30 would seem reasonable to me for a brand-new motor. It depends alot on what rings are being used, and how the block is honed; and on how much bore clearance the pistons have.

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"So many Mustangs, so little time..."
ICON Motorsports

 

when i turned mine over by hand it was pretty hard.. im sure it was more than 20..

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• 83 Z28--ttops, 200k miles--very ragged out. sold, thank goodness
• 74 Z28--slightly modded 383, TH400 tranny, not too quick but fun to drive

 

I don't think you can globally say a number. Ring tension, piston to wall clearance have a lot to do with it. I don't think GM ever provided a number (or even a range) and I would think their assemblies should have been consistent enough to do such a thing if it were possible on a stock motor.

 

Ok well I think my machinist is going to try to tell me something is wrong, but I don't know. I'm going to try to convince him to come over and take a look at it. Anyone else have an opinion on this??

 

30 Sounds perfectly reasonable, To me.

As long as you used your plastigauge, and were careful, You should Be In Good Shape.




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver 15.26 @ 87.0
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

i just finished a 350 last saturday. i used a regular length 3/8 ratchet to turn the crank socket. took a good bit of effort but i could do it. i'd guess more towards 30ft/lbs.

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

 

Ok well then here's a good question to help me determine if it's too tight. How much space should there be between the rods in the crank journal because I have next to none and I mean none. Also if someone can please read and reply to my post on the cam plate it would be greatly appreciated.

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Riccioli Performance Motorworks

--RPM Racing--

-Currently building first ever engine. 383 with Super Ram plenum and runners, Edelbrock lower intake, Bosch 24# injectors, AFR 190 heads, MSD ignition.
-Will be installing Baer Brakes
-Will be installing full Spohn suspension in rear
-Art Carr 700R4 trans??


Attention Everyone!!! I will be changing my name on the message boards to HardcoreZ28 sometime in the near future. Just wanted to let everyone know.

 

I have had my new 350/360hp crate motor on the stand for a few months. I would say its
at least 30 ft/lbs to turn it.

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Tom K.
84 Z-28 M5 305 L69 HO
pulleys,coil,3:73(stock)
Jet chip, fan switch,
Al dshaft,1.6 rockers,
LCAs and brackets,BFG DRs
14.20 @ 96.74 2.02 60ft

 

On the rod side clearance, I like to see about .015".

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"So many Mustangs, so little time..."
ICON Motorsports

 

I just completed my 383 and I read 300 to 350 In# 0r call it 25-30 ft#. It was hard to get an exact reading because it wanted to jump a bit just as it broke loose. This is w/o cam or heads installed.

After boring I had a regular hone first and then a 'soft' hone which slightly breaks the peaks. This results in a slightly smoother finish.

Looks like we're in the ballpark. This is my first build and I was curious about that as well.

[This message has been edited by Changa2 (edited May 24, 2001).]

 

what rb said. The spec is from .012 to .016 side clearance. If you don't have it you will put a lot of metal in the oil right as you bust it off. It is pretty hard on a new motor.