Re: packard 1936 standard 8 1402 engine problems
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Forum Ambassador
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I'm reasonably familiar with that engine, it's essentially the same as the 320 engine in my 34 with the exception of having insert rod bearings. Sounds like you've got the rods and pistons assembled correctly; the squirt holes in the rod big end should face the "thrust" face of the bores (camshaft side of the engine). Ditto for the slot in the piston though Packard earlier on had them the other way, changed to the cam side and said it wasn't all that critical. This is mentioned in the early Service Letters.
Which valves are giving trouble, intake or exhaust? The exhaust valves essentially run with no lubrication and the intakes only get lubrication when manifold vacuum can draw mist up the guide/stem during the intake stroke. If you remove the valve covers, is the area dry or oily? Your problem sounds to me like the valve stem-to-guide clearances were not set to specification. Did you check the guide clearance and ream if required? A bit of a long shot might be too much clearance on the lifter bores which can give a lateral or side thrust to the valve stem, making stem wear more rapid. BTW, that model is an Eight, not a Standard Eight - the Standard designation for that engine was dropped after 1932. PS - here's some excerpts from Packard Service Letters about the big end bleed holes and the piston expansion slot.
Posted on: 2014/4/3 0:19
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Re: packard 1936 standard 8 1402 engine problems
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Just can't stay away
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today i have remove the head manifolds and the valve, the problem valve is and exhaust valve which has eaten the valve guide made it oval,before i removed the valve i had the car running and had a look at the hole to see if there was oil comming out which there was a constant dribbile equal from each one,i had emagined that there should be a small spray from these and not a dribble,i have also checked the conrods oil hole and the oil hole is facing the valves also the piston cut out lined up with the cylinder bore holes.
question the cylinder holes should they spray or dribble, my assumption which is the valves were dry,valve guides which were new may be too tight when warm not reemed out maybe causing the valve to seize. tommorrow im taking all the valves and checking and fitting a new valves guides where ever needed,luckly i have spare valves and guides, has anyone had this problem before!! cheers dave p.s thanks for your help and advise greatly appricated!!
Posted on: 2014/4/3 11:27
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Re: packard 1936 standard 8 1402 engine problems
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Forum Ambassador
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In case you didn't have this information, minimum stem to guide clearance specifications (inches) are:
Intake: 0.0025 Exhaust: 0.004 PS - There are several ways to measure the clearance, most obviously a dial indicator. You could also use a good micrometer to measure the valve stem and then a "bore gauge" like the Starrett shown below (but in a smaller size range) to measure the inside diameter of the guide. The end of the gauge is an expandable split ball which is inserted into the bore and then the ball is expanded via the thumb screw until it contacts the bore accurately, and then withdrawn and measured with a micrometer. Though I have a dial indicator the bore gauge is my preferred method as you can make measurements at various positions along the length of the guide. BTW, a fine looking car!
Posted on: 2014/4/3 16:19
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Re: packard 1936 standard 8 1402 engine problems
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Just can't stay away
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update on valve problem , I removed head manifolds etc removed all valves number 6 valve was wearing the new guide away .I fitted a new guide and valve and rebuild .I took the car out last Sunday and did 90 miles no problems fingers crossed seems to be running quieter and smoother now.
what I believe the engineer shop had just fitted the valve guides and did not ream them to size. many thanks again for the info. on to the next problems
Posted on: 2014/4/22 15:22
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Re: packard 1936 standard 8 1402 engine problems
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Home away from home
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Hi Dave:
Standard, small, big, whatever 8. You do get lubrication of the exhaust valve from the crankcase, but on a much smaller scale than the intake. After each exhaust pulse there is a small negative pressure that pulls a little mist into the guide. That is why motors run with valve overlap. So it's important to check the stem clearance. Make sure as well that the tappet face is parallel to the stem. If a tappet is pushing cock eyed on the valve that will cause problems. Another issue might be the spring. If one of the coils is weak that might cause a problem. Make sure as well that none of the crankcase vent holes is covered with gasket. I've run into that problem with store bought gaskets. This kind of problem is not common in Packards so you are correct to be concerned. Also, if the car has a gypsy rod it may have a small squirt hole in number 6. Packard played around with small squirt holes, but went back to a number 30 drill or something like that (oh that's up above - don't I have a great memory?). If you think you have that problem somewhere around here I have the squirt hole bulletin. I suppose the rod bearing could be upside down as well which would cover the hole with bearing. Most modern inserts do not have a top and bottom shell.
Posted on: 2014/4/22 17:19
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