|
Sponsored Links (Register now to hide all advertisements) |
|
|
Thread Tools | Display Modes |
10-28-2021, 04:05 AM | #21 |
Senior Member
Join Date: Jul 2016
Location: Lake worth Florida
Posts: 1,096
|
Re: Flat spot that just won't go away
Where do you live ? Sorry if I missed it in the post . At what rpm is your flat spot ?
|
10-28-2021, 03:01 PM | #22 |
Senior Member
|
Re: Flat spot that just won't go away
Check the Valve timing ,? remove the manifold to sight the valves at same time check the gasket ,use the Zip tie method or a wire to find TDC ,does it smooth out with the Choke out as 51 Merc suggested,
Last edited by FlatheadTed; 10-28-2021 at 05:49 PM. |
Sponsored Links (Register now to hide all advertisements) |
|
10-28-2021, 04:49 PM | #23 |
Senior Member
Join Date: Nov 2010
Location: NM
Posts: 2,438
|
Re: Flat spot that just won't go away
Maybe I missed it, but did you verify the advance mechanism is working?
__________________
'52 F-1, EAB flathead |
10-30-2021, 11:35 PM | #24 |
Junior Member
Join Date: Sep 2021
Posts: 5
|
Re: Flat spot that just won't go away
Did have distributor apart to clean and check. All seemed good.
Will try what Flathead Ted suggests and report back. Thanks Mike |
12-15-2021, 07:40 PM | #25 |
Junior Member
Join Date: Sep 2021
Posts: 5
|
Re: Flat spot that just won't go away
G'day all
Update... Put on new carb and new e-fire distributor. NO CHANGE! Still have only 11 to 12 vacuum at idle. Does swing a little between 11 and 13 Comments have indicated valve timing could be the problem. Are there any other suggestions before I start tearing the engine apart. Thanks |
12-15-2021, 08:08 PM | #26 |
Senior Member
Join Date: May 2010
Posts: 425
|
Re: Flat spot that just won't go away
Sponsored Links (Register now to hide all advertisements)
|
12-15-2021, 08:10 PM | #27 |
Senior Member
Join Date: Oct 2017
Posts: 563
|
Re: Flat spot that just won't go away
I don't speak Flathead, but with an OHV engine there are simple "non-invasive" methods of checking valve timing. I'd expect there are ways on a Flathead, too. Incorrect (late) valve timing will definitely cause low manifold vacuum.
|
12-16-2021, 02:56 PM | #28 |
Senior Member
Join Date: Nov 2010
Location: NM
Posts: 2,438
|
Re: Flat spot that just won't go away
A real longshot, but there was a gorgeous yellow 48 Merc convertible in a shop here I visited. It had similar issues including the low vacuum. The mechanic pulled the intake and found someone had cracked off the edge of one cylinder's intake port, presumably while taking out valves. The intake had nothing to seat against there, so it leaked. Wondering if the car's owner had it buttoned up and sold it as-is, vs an expensive repair...
__________________
'52 F-1, EAB flathead |
|
|
Sponsored Links (Register now to hide all advertisements) |
|