Date: Wed, 29 Jun 2005 05:12:55 -0400
Reply-To: Ken Wilford <kenwilfy@COMCAST.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ken Wilford <kenwilfy@COMCAST.NET>
Subject: Re: Help... Engine troubles, rapid backfiring under load.
In-Reply-To: <42C1F43E.2020809@impulse.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I would check your lifters. There were some bad ones going around a
couple of years ago (Italian) that didn't have a good surface hardening
and the part that pushes against the cam would wear away. If you find
inordinate amounts of wear on your lifters I would replace them all and
start over. You can usually tell the evil lifters. They are about 1/16
to 1/8 of an inch shorter than a new one. Some times they will wear so
much that they wear a hole into the middle of the lifter and then they
will never pump up again. I just went through this with one of my
brother-in-law's campers. Had to use the collapsible push rod tubes and
new lifters all the way around (and one push rod).
Hope this helps,
Ken Wilford
John 3:16
www.vanagain.com
Nate Saylor wrote:
> My '84 Westy has been driving fine (for a car that won't hold tune
> particularly well) lately. Yesterday I went for a short drive and about
> 5 mins into it, it sounded like the engine was banging around when I
> would give it juice. When I would let off a bit it would subside but
> the engine still sounded bad. I limped home and started it today,
> taking it down the street for a test drive. When it got warm it started
> making the noise again when I would try to give any sort of
> accelleration. On further listening I found that it was rapid
> backfiring, not engine noise (my engine is pretty noisey anyway).
>
> Pertinant details:
> Engine backfires rapidly under load when warm
> Engine fairly quiet (not backfiring) when cool.
> Engine has new heads (AMC)
> Engine will not hold tune particularly well
> Valves are clearanced per boston bob
> Engine likes to turn rich a while after being tuned (hence won't
> hold tune)
> Engine has some minor exhaust leaks (but I doubt they could cause
> anything this serious)
> Lifters are pretty noisey (even for a clearanced top end).
>
> I suspect:
> Cat gone bad from running rich
> Temp II gone to hell and doing something wierd to the mix when hot.
> Collapsed lifter(s) as valves won't hold adjustment very well.
>
> Please god don't tell me it's:
> Burned valves, cause I'm just NOT going to go back into that engine
> again (Subaru here I come).
>
> Need help soon as I've got a pretty good commute to work and my westy's
> my only transportation (hello Hertz).
>
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