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New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 07:07AM

Finishing up my 180 turbo rebuild. Entire rotating assembly balanced, .40 over Clark's forged pistons, Clark's .10 bearings, Otto cam with fail safe gear. Plastigaged rods and crank bearings. Right on spec.

Everything went together without issues. Crank/cam install went easy and spun smoothly. After Heads were installed I noticed turning over the engine by hand, no plugs installed, with a wrench it seems to require more effort at one point then gets easier again. Could this be due to freshly bored cylinders and resistance to new moly rings?

Being a bit paranoid here but I don't want to fire the engine if this is not a typical condition for a fresh engine.

Thanks

Reston, Virginia

1965 Corsa Turbo Coupe

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 07:14AM

What was your piston skirt to cylinder clearance???
At .040 overbore, the cylinders will distort, sometimes up to .002 out of round if not bored in a fixture simulating the block and head.
Also once every revolution, or every other one ?
The latter could indicate a cam related issue.
Back off the valves and try again ??

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: alphasud ()
Date: November 16, 2020 07:20AM

I don’t think you are being paranoid. I would call it being cautious. After you torqued the engine case did you turn the engine over before you installed the piston/rods? And like Bod said could be something on the top end binding.

David North Idaho
1965 Corsa Turbo converted to 140
1971 Super Beetle with 2.5L Subaru engine
1965 Corsa mid engine project
1973 Mercedes 280 project

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Re: New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 08:07AM

It is once every revolution. Cylinders were bored using a fixture.
I did rotate the crank after torquing the case. Rotated without any noticeable change in effort. Did not need to bang on the case at all during the torque process. Skirt clearance was .002.

I checked the rotation using a beam torque wrench. starts around 16 ft lbs changes to about 22-25 ft lbs half way through the rotation.

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 08:16AM

I set skirt clearance on Turbo engines with the forged pistons to a min of .0035", measured on the diameter, 90 degrees to the pin, about .750" up from the bottom of the skirt.
Using less has resulted in scuffed skirts.
I suggest opening the clearance up.
Before you disassemble however, check to be sure nothing is between the piston and the heads at TDC.

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: MattNall ()
Date: November 16, 2020 08:40AM

Isn't "cold Breakaway" torque on a fresh build around 15 ft. lb.? [ from memory]

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 08:44AM

It is once every revolution. Cylinders were bored using a fixture.
I did rotate the crank after torquing the case. Rotated without any noticeable change in effort. Did not need to bang on the case at all during the torque process. Skirt clearance was .002.

I checked the rotation using a beam torque wrench. starts around 16 ft lbs changes to about 22-25 ft lbs half way through the rotation.

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 08:56AM

Hi Matt,
Depends on clearances and the lube used ...
Pure STP, probably...
With 20-50 oil and race clearances I sometimes find the crank by itself spins by hand.
With installed pistons and cylinders / ring type , it can vary a lot depending hone finish, ring tension and cylinder lube.
And the more you spin during assembly, the torque required diminishes.
It can be a feel sort of thing.
Like torquing lug nuts.

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 08:57AM

B Marsh
Were the cylinders bored in a fixture that simulated a block and heads, torqued in place ?
A single cylinder boring fixture is not the same thing.

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: MattNall ()
Date: November 16, 2020 09:11AM

dryenko Wrote:
-------------------------------------------------------

> It can be a feel sort of thing. Like torquing lug nuts.

===================================

exactly. OP is talking about an engine ready to start. "Rough spot" normally is not good.

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: New Engine question
Posted by: Wagon Master ()
Date: November 16, 2020 09:46AM

bmarsh52 Wrote:
-------------------------------------------------------
> I checked the rotation using a beam torque wrench. starts around 16 ft lbs changes to about 22-25 ft lbs half way through the rotation.


But NO issue was FELT till the heads were installed. This rules out,
Crank
Cam
Rods
Pistons
Rings
Bore Clearance
Cylinders
Go back to the last step before it got tight. As suggested start with removing the pushrods and retest rotation before removing the heads.
Report back.

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Re: New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 09:54AM

I will back off the rockers and retest the rotation and advise the results.

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Re: New Engine question
Posted by: jjohnsonjo ()
Date: November 16, 2020 10:03AM

Might have a push rod that missed the lifter dimple

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 06:43PM

I backed off all the rockers and no change. While slowly turning the crank I could hear a clicking noise from inside the crankcase while slowly rotating the HB. The clicking noise is at the same spot in the rotation just before the engine gets harder to turn. I decided to pull the top cover to see if anything was obvious and it wasn't. The noise is located near cyl number 6 and the bell housing. Checked rod bolts and they are at 30 ft lbs which is the specification from ARP for their rod bolts.

Reston, Virginia

1965 Corsa Turbo Coupe

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Re: New Engine question
Posted by: Wagon Master ()
Date: November 16, 2020 06:59PM

Head stud screwed into the crankcase too far for the ARP for bolts? This is very tight even with the stock hardware.
Were the big ends of the rods resized after the ARP bolts were installed?


'29 Ford Model A Tudor
'61 700 Lakewood 110 4 speed
'69 Monza Convert. 140 Auto.
'70 Dodge Challenger R/T 440 4 speed

Been aircooled since 1973
Northwest Ohio

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 07:32PM

At what point in the #6 or #5 rod rotation does the noise occur ?
Perhaps when the rod goes over center at BDC or TDC ?

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: bmarsh52 ()
Date: November 16, 2020 07:46PM

Big ends were resized. I will check the clearances tomorrow.
#5 and 6 are at mid stroke when the noise occurs.

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Re: New Engine question
Posted by: RexJohnson ()
Date: November 16, 2020 07:52PM

Is the noise coming from the timing gears. I have had old cam gears make popping noises. Is the cam and gear new? If new it could have a defect?

RJ tools
Salem,Oregon

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Re: New Engine question
Posted by: dryenko ()
Date: November 16, 2020 08:01PM

What was the cam to block journal clearance?
Especially at the flywheel end.
Cam may be shifting sideways.
You may have to pull bell housing to investigate any movement.

Bob C aka Dryenko
Dobson, NC 27017

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Re: New Engine question
Posted by: alphasud ()
Date: November 16, 2020 09:26PM

It’s a good thing he is taking the time to investigate that could be a potential heart ache if he wasn’t being observant.

David North Idaho
1965 Corsa Turbo converted to 140
1971 Super Beetle with 2.5L Subaru engine
1965 Corsa mid engine project
1973 Mercedes 280 project

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