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no start after rebuild (x2)

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westirmax

Contributing Member
All,

Had both engines rebuild last winter. re-builder found heads no longer serviceable. Replaced all four.
We managed to install and plumb both engines last spring but could not test and do final setup, engines started briefly to winterize.
Mechanic swears they ran, not well but fired up.
Fast forward to now, one engine cranks but no fire, ignition tested, plenty of spark, fuel in carb, 150psi of compression. tried a shot of ether, no joy.

other engine- 60 psi compression on most cylinder, one at 120psi, suspect stuck rings or bad valve job.

Things to check- tdc on both engines, make sure distributor is not 180 degrees out.
verify firing order is correct?

What could we have missed?

Greg
 
On the engine w/ 150PSI of compression, if it has plenty of spark and fuel in the carb, I'd start by making sure the fuel is good...no joy w/ ether suggests the timing is way out...I'd be inclined to check the initial timing before doing anything else.

on the engine with 60PSI of compression, I'd be inclined to figure out why before proceeding...could be something simple or could be something more ugly - better to eliminate that now...

any signs of water when those spark plugs were pulled for the compression test?
 
Mark,

No water on the plugs, though they did look a bit oil fouled. on the 60 psi ( starboard) was 30 PSI- after a tablespoon of oil the PSI went to 60. still too low.

I am thinking the new heads, valves not sealing properly or with the improvement adding the oil does that indicate a ring issue?

agreed the port engine with good compression, first thing is to check the distributor.

Need to find TDC on #1 cylinder and set the distributor. We've moved it so many times it may be way into the woods by now.
 
Probably be a good idea to identify what engines you have...assumptions can lead to disastrous results...

The improvement after adding the oil really isn't definitive as you have a zero hour rebuild...ie the rings likely have not seated.

Very likely the bulk of the 'leak is due to the valves - a leakdown test will tell you for sure. Assuming this is a chrysler, with the fixed valve train, the likely candidates to me are valve seats cut too deep, wrong components used in the valve train, improper assembly of the valve train....I'm sure there are a few other possibilities as well..

I don't think any distributor adjustment on your starboard engine is gonna matter - compression that low won't make significant torque and you will not be happy...
 
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