[Healeys] Backfire in rebuilt engine with less than 500 miles

[WILLIAM B LAWRENCE]

Sounds like too much spark advance.
________________________________
From: Healeys <healeys-bounces at autox.team.net> on behalf of Michael Oritt <michael.oritt at gmail.com>
Sent: Monday, January 25, 2021 4:56 PM
To: john harper <ah100tech at gmail.com>
Cc: Healeys <healeys at autox.team.net>
Subject: Re: [Healeys] Backfire in rebuilt engine with less than 500 miles

...or an exhaust leak, or too rich or too lean, or too much advance, etc.

You might have to put the car on a chassis dyno in order to replicate and cure the issue.  Or stop going so fast, but who wants to do that?

Best--Michael Oritt

On Mon, Jan 25, 2021 at 11:51 AM john harper <ah100tech at gmail.com<mailto:ah100tech at gmail.com>> wrote:
David

It is possible that your fuel pump cannot quite keep up with the fuel needed at this top limit. I don't know what pump you have fitted but the square base version or the double version give a higher flow rate.

Before making major changes it might be worth checking that the pump has the correct diaphragm travel.

On Mon, 25 Jan 2021 at 16:41, David P <frogeye at porterscustom.com<mailto:frogeye at porterscustom.com>> wrote:

..or a momentary loss of power to the fuel pump or delivery pressure.. or a sticking valve.. many possibilities..

On 1/25/2021 9:20 AM, Kees Oudesluijs wrote:

Some parts like i.e. the distributor or carbs are taken of the engine when it is rebuild and then after having lain on the shelf for months or even years are put back on the engine the way they came off, without resetting or cleaning.

In the distributor are the bob weights inside the body that regulate the mechanical advance. These need regular maintenance (mostly forgotten) to prevent them from corrosion and sticking. It is not seldom that these get stuck or do not move freely which might be a cause for backfiring. Also check the plugs and wires.

If the car is still on points check the dwell angle and points condition. Also check the timing.


Kees Oudesluijs




Op 25-1-2021 om 15:57 schreef rfbegani at gmail.com<mailto:rfbegani at gmail.com>:

Listeners:



I have been driving my 67 BJ8 since rebuilding and working on the rest of the car the past year.  After installing the new shock absorbers and the new speedo, I took the car for a ride.  With the new shocks and the new Shaved tires, she drives like brand new car down the Tamiami Trail at 50-70 mph, so I decided to push it a little more.  However at 4000 plus rpms and about 90 mph, I was not looking so closely at the speedo or tack, the engine back fired, so I let off the gas and returned to normal highway speeds.  Engine ran fine all the way home. Suggestions what could cause the backfire at high speeds?



Bob Begani



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--
Porter Custom Bicycles 2909 Arno St. NE Albuquerque, NM. 505-352-1378 My World go here: WWW.PORTERBIKES.COM/<http://WWW.PORTERBIKES.COM/>

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