1951 Pontiac Chieftain

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PhilA
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Re: 1951 Pontiac Chieftain

Post by PhilA »

Thankfully it's not a hugely complicated engine to pull to bits.
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Re: 1951 Pontiac Chieftain

Post by MLOR »

Twice as complicated as my straight 4 side valve engines... ;)







or just as complicated as both the straight 4 side valves engines together I have :lol:
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Re: 1951 Pontiac Chieftain

Post by Junkman »

PhilA wrote: Fri Oct 25, 2019 4:57 pm I managed to capture the tictictic and misfire at idle- seems as though I got me a couple valves that are sticking open.

Gonna pull the head off, pull the valves and check for straightness, cleanliness and all the other good things that cause valves to jam.

--Phil
Even I would do a compression test before ripping off the head. Besides, can't you inspect the valve movement by removing the inspection plates?
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Re: 1951 Pontiac Chieftain

Post by PhilA »

Compression testing gauge is required for that analysis. Mine is in England.

I could pull the plates off and examine but it doesn't do it all the time.


I do need to undo the head bolts to re-torque them in sequence, so lifting it off is quite trivial

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Re: 1951 Pontiac Chieftain

Post by Junkman »

But lifting off the head of a flathead will not necessarily reveal what's wrong.
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Re: 1951 Pontiac Chieftain

Post by PhilA »

No, but it does allow me to pull the valves out.

I really do think one major problem is #8 exhaust which was sticky before and liked to jam open.
I had put stethoscope screwdriver and the racket was coming from that area.
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Re: 1951 Pontiac Chieftain

Post by Hooli »

At least the head is nice & light from memory...
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Re: 1951 Pontiac Chieftain

Post by Junkman »

PhilA wrote: Sat Oct 26, 2019 2:38 am No, but it does allow me to pull the valves out.

I really do think one major problem is #8 exhaust which was sticky before and liked to jam open.
I had put stethoscope screwdriver and the racket was coming from that area.
Must be some carbon deposit that worked itself into the valve guide.
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Re: 1951 Pontiac Chieftain

Post by PhilA »

Junkman wrote: Sat Oct 26, 2019 11:39 am
PhilA wrote: Sat Oct 26, 2019 2:38 am No, but it does allow me to pull the valves out.

I really do think one major problem is #8 exhaust which was sticky before and liked to jam open.
I had put stethoscope screwdriver and the racket was coming from that area.
Must be some carbon deposit that worked itself into the valve guide.
Very possible. It comes and goes so whatever it is surely isn't going to be doing the stem and guide any favors, particularly if it's rust or anything that's harder than the surrounding metal.

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Re: 1951 Pontiac Chieftain

Post by Junkman »

Well, if it's playing up, it needs to be investigated. It's just such a shame, though, since you just put in a new head gasket IIRC. But I think on flatheads you can actually reuse them if they aren't outright defective.
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