head resurfacing and timing, techs wanted

[BAlbertiX]

....I bought a set Here for ~$10/ea, and I'm very happy with them.

Great stuff Northern. Thanks for the heads up, for $5ea I'll be shipping them out to Cali this weekend.

[BAlbertiX]

timing

Some updates >








Head and gasket in, timing TDC and clearances .010, got fuel and spark.

Before first start, I figured I'd hand crank the engine a few times to verify timing.

I know there's resistance on the compression strokes, but it feels more than usual. I can rotate through these points, but they feel much tougher than usual. The head was resurfaced twice in its lifetime and is down anywhere from .006" to .010" total. I took .003" off the head this last rebuild. I'm worried about interference. How much room do I have to play with?

Can I advance or retard timing on the cam to correct for potential interference?

[BAlbertiX]

in the garage

should I feel resistance through TDC cranking by hand?

[SpecM]

Yes, you should feel resistance. It may be more than before because of you new head gasket. Take the plugs out and turn it over if it makes you feel better.

You will feel the engine STOP if you crunch a valve

[BAlbertiX]

Yes, you should feel resistance. It may be more than before because of you new head gasket. Take the plugs out and turn it over if it makes you feel better.

You will feel the engine STOP if you crunch a valve

that will certainly take compression out of the equation, might as well... Thanks Spec.

[uturn]

Thicker head gasket if needed maybe?

[BAlbertiX]

Thicker head gasket if needed maybe?

I might have to, but would rather not have to tear it down again. Searching through posts it looks like every cam gear advances or retards the engine 7.5deg, and from what I've read valves will find interference quicker retarding timing than advancing. I'm curious if advancing timing 7.5 degrees is too much on a stock setup.

I set the cam one tooth ahead last night, and for what it's worth, turning the crank by hand with plugs out, I don't hear or feel interference.

[BAlbertiX]

I might have to, but would rather not have to tear it down again. Searching through posts it looks like every cam gear advances or retards the engine 7.5deg, and from what I've read valves will find interference quicker retarding timing than advancing. I'm curious if advancing timing 7.5 degrees is too much on a stock setup.

I set the cam one tooth ahead last night, and for what it's worth, turning the crank by hand with plugs out, I don't hear or feel interference.

Started the car last night with 7.5deg advance (1 tooth) on the cam, and can at least report there was no interference, but idle was fairly erratic; idling high and surging.

I'm going to tear down the timing side of the engine this weekend, set both cam and crank to tdc, and set head clearances to .010, again. If all else fails, +.30 gasket will be on order.

[4x4_e30]

You need to check the overall height of the head. 4.929" is stock, 4.909" is the limit. I'm at 4.909" and kept everything the same cam timing wise, the clay test showed I had plenty of clearance. So I'm down -.020" and have no timing issues what so ever, you should be fine as well.

[BAlbertiX]

You need to check the overall height of the head. 4.929" is stock, 4.909" is the limit. I'm at 4.909" and kept everything the same cam timing wise, the clay test showed I had plenty of clearance. So I'm down -.020" and have no timing issues what so ever, you should be fine as well.

Did you get any numbers off the clay?

Thanks 4x4, this sounds like good news. I will measure this weekend.

[BAlbertiX]

Re:

Forgot calipers at work so could not get a height number... still went ahead, set TDC again, and fired it up. As expected, there was tapping coming from the engine. Going through the head, it turns out two eccentric screw nuts, on the exhaust side of cylinder's 5 and 6, were stripped. Given 4x4's words of wisdom, and how smooth the idle was, I'm definitely not worried about interference anymore. The eccentrics must not of floated much, just enough to make plenty of noise. New screws and nuts on order. Lesson of the day, torque specs are set for a reason.

[goldenbb]

Torque specs on the eccentrics? Those little guys? It must be in inch pounds!

[BAlbertiX]

Torque specs on the eccentrics? Those little guys? It must be in inch pounds!

Believe it or not, 7.38lbft [10Nm] to be exact

[BAlbertiX]

Turns out the stripped eccentric screws were not the issue. The head is still ticking. Again here are the knowns:

Crank and cam set to tdc
Brand new eccentric screws and nuts tightened to spec
Brand new valve guides, and guide tubes polished
Eccentrics free of excessive wear
Rockers and cam lobes free of excessive wear or pitting
Valve clearances set to a loose .010"
Rockers centered on valve heads
Head sprayer working
Head bolts torqued to 45lbs, waiting on final 90deg torque down

http://youtu.be/kwE6vPHLHHk

The ticking is coming from the front of the head, does not change with engine temp, and certainly gets louder with rpms. Given how smooth the idle is... a sticky exhaust valve coming back up late?

Thoughts?

Compression test to follow.

[BAlbertiX]

re:

Compression test results:
1 150
2 125
3 120
4 140
5 60
6 130

Leakdown showed cylinder 5 to be head related. Soooo I pulled the head again tonight assuming I'd find a bent valve on 5. Nope, intake valve on 6 was sticking... Not sure from what, but a SS pipe brush took care of it.

AND, both valves on cylinder 5 looked fine, not bent, seats were good... I'm done asking questions.

Reassembling this weekend. Hopefully more good news to follow.