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0 compression on freshly rebuilt engine


mark105

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The wrong oil viscosity will cause the lifters to pump up when thrashed on a race track. After 10 mins at idle that isn't possible. And given that the other 5(?) pots have compression you can rule oil out.

10-5: If your leakdown test is pointing to #1 inlet then keep looking there. A sticky bucket would do it on an OHC motor but if you have hydraulic lifters then I assume you don't have buckets and shims.

If the valve stem to "rocker/cam" clearance is correct cold then check it again hot. Use the old HG. It will be fine.

I do not know RB engines nor their valve train arrangement so I can not be of much help except to say: You should have put pushrods in it (all of the same length).

The only other thing I can think of is that #1 piston is the wrong size but even then you should see some compression. Check the cam for a missing lobe.

Is there fuel in the oil?

One more thing: Compression will be zero if no air is getting INTO the cylinder. Got throttle bodies?

Yuh. I am smoking kingfish with manuka logs. It is fun to be me.

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yeah but does the cam actuate a rocker arm which on end operates the valve and the other end is attached to the hydraulic lifter seated in the head, or does the cam actuate a bucket with a hydraulic lifter seated between the valve and the bucket? SRs are the former.

*edit* just saw your build thread, it's the latter

11122009006.jpg

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Smack something with a hammer. That always helps.

If your lash is good then take a look at that #1 inlet lifter/bucket and the exhaust side too. This is a phyisics problem. Either no air is getting in or all the air is getting out. A rag down the inlet tract on #1 would do it too

Much lubs.

Pushrods!

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Have you tried bleeding the hydraulic lifters?

Would be interesting to see if the problem has changed cylinders as I bet the engine builder probably didn't put the same lifters in the same place, if it still on number one cylinder maybe try swapping the lifters to another cylinder and see if the problem follows it.

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i was just informed on skylinesdownunder than 10W is supposed to be the thickest you should go for nissan hydro lifters.

i am also going to re clean and re flush my lifters to see if this helps and change my oil.

When I was servicing vehicles I used 20W 50 on Skylines when the customer asked for a budget lube.. Never had any issues or comebacks - maybe 10W is recommneded but I don't see it causing a lifter to pump up to the extent of causing zero compression (the valve needs to be open a reasonable amount to bleed that much compression out..)

I am not even sure it is a lifter but where does the oil drain from the lifter, the oil will need somewhere to go - check the drain is clear for all the number 1 valves..

I have a few more suggestions to try but rather than confuse things more - just try some of the suggestions already put forward and then come back if no joy..

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