Compression Readings 79 Cherokee

[GRAT]

Any help would be appreciated and thanks in advance.

I did a compression check today,

The dry readings were:
1. 135 2. 130
3. 30 4. 95
5. 120 6. 120
7. 135 8. 130

The wet readings on 3 and 4 did not change. I pulled the rockers on 3 and I noticed that the bracket (bridged pivot) which retains the rockers has a concave part in the center of the rocker through which their is a screw that attaches the rocker to the rocker pedestal.

My questions are:

My 78 has these same concave pieces, but the are not attached to the bridged pivot, whereas on the 79 they appear to be attached. One of the concave pieces, however was not attached on one valve but attached to bridged pivot on the other. My feeling is that it should be attached, bacause part of the bridged pivot is bent.

Bottom line, should they be attached or not ?

My second question is, when I attached shop air to #3, so much air escaped though the other spark plugs hole that I could not keep the valve seated to the cylinder head.

Does anyone know why this would occur, it sounds as if air is escaping mainly through #7 spark plug hole ?


I know this is a lot, but thanks in advance for the help and advice.


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79 Chero WT/ TH400 /QT /360 /3" Flowmaster / K&N

78 Chero WT 360 TH400

[TPIGUY]

Grat,

Sounds like you've got a serious blowby problem on #3 which is letting air into the crankcase. The air in the crankcase would then go out through the PCV valve and into the intake manifold. Since the firing order is 18436572, #7 is in the middle of its intake stroke so the intake valve is wide open. So you have a direct path outside the engine through #7 spark plug hole.

[GRAT]

TPIGUY,

Thanks,

I am an Acountant by trade, and I can follow instructions to turn a wrench. What does all of this mean and how can it be fixed ?


Thanks

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79 Chero WT/ TH400 /QT /360 /3" Flowmaster / K&N

78 Chero WT 360 TH400

[archiele]

Yank and rebuild

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Currently a 1965 Wagoneer
bone stock.
also have an '88 Zuki

[jeepbob]

was there air escaping out the exaust pipe or carb also? if so there could be a burnt valve in #3. ON AMC motors there are 2 different style rocker pivots, a 3 piece unit (2 pivots and a bridge) and a 1 piece and I have seen both on 78 motors so that seems to be the change year. IF it is an aluminium bridge it is a 1 piece unit, if it is steel then it is 3 piece. Air could escape through another hole because of an open valve in that cylinder as the compression in #3 indicates a problem. At the least you are looking at a valve job.

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65 wag. 360/edelbrock rb4/t400/20 t-case/4:10 d27/d44 tracloc/onboard air/onboard 110v power(no inverter)/1999 Lincoln t.c.leather buckets/taurus ctr console/winch/33x12.50/tunes/water proof door pads
soon to have new motor/d44frt/d60r(4:10)welded diff/custom bumpers
see ya in da mud

[GRAT]

Thanks JeepBob,

I don't recall if air was escaping through the tailpipe, and I did not check the carb. I wil check come daylight.

On the pivot and bridge, I should have either the one piece or the three piece, not a two piece and it is aluminum.

Thanks

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79 Chero WT/ TH400 /QT /360 /3" Flowmaster / K&N

78 Chero WT 360 TH400

[jeepbob]

If its 2 piece, its broke!

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65 wag. 360/edelbrock rb4/t400/20 t-case/4:10 d27/d44 tracloc/onboard air/onboard 110v power(no inverter)/1999 Lincoln t.c.leather buckets/taurus ctr console/winch/33x12.50/tunes/water proof door pads
soon to have new motor/d44frt/d60r(4:10)welded diff/custom bumpers
see ya in da mud