Rebuild not starting, retorque head bolts?

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BaliLover
Posts: 1070
Joined: Sat Apr 26, 2003 1:50 pm

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Recently got around to dropping my rebuilt motor(rebuilt head installed onto rebuilt block) in but on first try it just stumbled and sputter, caught once then died rapidly. While it was running I heard a repeatative snapping noise from the head. Upon removal of the valvecover I see I have 2 collapsed HLA's and a rocker arm with the guide on the wrong side. I replace the HLA's, and move the rocker arm guide to the correct side (the guide was stuck to the opposite side and not allowing the arm to move smoothly, causing the snapping noise.) I crank everything over by hand and theres no noise to be heard, but under its own power it still won't start, just seems to almost catch then flood out. I checked the timing 3 times, both cams are where they should be, pointer is at TDC on the crank pulley, and the timing marks on the chain are set perfect. Double checked the CAS, reset it for good measure, and still no luck.

At this point I decided to do a compression test to make sure I didn't bend a valve, and quickly discovered that all 4 cylinders are sitting around 85psi, well under the manufacturer minium specs of 110. The pistons are 8.8:1 weisco, and the HG is an Apexi 1.1mm that got copper sprayed but I don't think that would cause such a low compression reading unless I'm wrong. What I'm assuming, since its low evenly across the board, is that I didn't get the headbolts tight enough when it was on the stand. The headbolts were brand new Nissan bolts so I'm assuming they should be fine, but what is the proper retorque technique? If I loosen all of the bolts to start over I'm sure I'm gonna pour coolant into the cylinders and ruin $50 in syn. oil, but I don't really have any other way to know how much more to turn the bolts since the manual never gives a final torque figure, they just tell you to torque it to a certain point, then turn it 90 degrees.

Anyone got any tips/pointers/or opinions?


BaliLover
Posts: 1070
Joined: Sat Apr 26, 2003 1:50 pm

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Update:

Reread the manual and noticed it says to turn the bolts 90 degrees twice; I only remembered turning them once. Go through the BS to pull the cams so I can access the head bolts, turn them another 90, reassemble everything and now I'm MUCH MUCH worse off. A compression test now shows almost no compression on 1 and 2, 95psi on 3, and almost nothing on 4. FML

compactfean
Posts: 2602
Joined: Thu Dec 03, 2009 10:28 am
Car: 89 240sx s13 sr gt3071r 23psi
B14 sentra ser sr20de-t 7psi
daily
Location: reno nv

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I would tear it down and start over. Who knows what else is off.

ivantk6
Posts: 76
Joined: Tue Dec 05, 2006 5:54 pm
Car: 1993 240sx X2

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should never run a rebuild motor on syn oil . intill after break in ....

StockAsFuhS14
Posts: 59
Joined: Thu Nov 15, 2012 6:05 pm
Car: Bone stock S14

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ivantk6 wrote:should never run a rebuild motor on syn oil . intill after break in ....
:dblthumb:


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