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RE: Compression Test

To: "'MG List'" <mgs@Autox.Team.Net>
Subject: RE: Compression Test
From: DANIEL RAY <danray@bluegrass.net>
Date: Sun, 18 Jan 1998 17:57:58 -0600
Ted,
Well, maybe "slight" shows my frame of reference, my main experiences =
are on a stock VW bug, and with that engine, a miss created in the =
combustion chamber, i.e. not ignition or fuel, is quite obvious in the =
lurch and bang and slowness. Maybe it's a ratio thing, if you start with =
less hp, then every horse lost makes it obvious.=20
I'll be saving the money based on the need for a new head piece, so I =
won't be disappointed when the magnaflux shows the need, and so I won't =
be frustrated waiting for one after I've bought all the little pieces. =
As with many of us, this is ONLY a hobby for me, and the amount of work =
done is directly proportional to the amount of disposable income =
available.
That's why I asked about running it...at least the rack and suspension =
work fine (knock wood).
The mechanic at the shop told me I was "thinking wrong" being only =
worried about the head. This is true, because I should just wait and =
pull the engine and do the whole damn thing.=20
The problem I have is its "verboten" to do car work in the driveway when =
you live on a military post. And I have no garage, so when I pull it, I =
have to pay a daily rate for the engine stand and for storage of the =
car... althought its pretty cheap, every day costs. If I can pull the =
head, fix it, and bolt it back on in the driveway, then I save some =
bucks. If I have to pull the motor, different story.
I'll keep you in mind, Ted, and probably need some parts! Thanks!
If I do need a new head, I'm going to see how much that cryogenic =
treatment costs...$100 or so might be worth it for an indestructible MGB =
head!
Dan
----------
From:   Ted Schumacher
Sent:   Sunday, January 18, 1998 3:27 PM
To:     DANIEL RAY
Subject:        Re: Compression Test

DANIEL RAY wrote:
>=20
> Well, the wet test came out the same, so I guess the rings are ok, =
which is confirmed by the lack of smoke. And I did it correctly this =
time, unscrewing the dampers and opening the throttle.
> So....the head is toast, and the slight miss is probably the one =
cylinder which reads at 55! In conjunction with the leaky exhaust, of =
course.
> Do I risk further damage by driving the car small amounts with this =
low compression, suffering head? I don't want to turn a small problem =
into a bigger one, like busting the head when all I need to replace now =
are the valves, seats, springs and guides. I would think a couple of =
miles a week overall will not affect the head's status.
> The guys that work at the craft shop said, "Well, then, drive it!" =
Their disdain for this non-American, furrin, tiny little car was quite =
amusing, but they were nice about it.
> Dan
> '73 B
> Ft. Knox, KY
>=20
>=20
dan, thjer is no such thing as "slightly" pregnat".  55 psi compression
is more than a slight miss.  there is a very good chance the head is
cracked, not because of the low compression check, but we find that over
1/2 of the heads we remove and check are cracked.  a little driving
won't hurt it but you should really figure you may need a cylinder head,
not just a valve grind.  word of caution, don't buy a used cylinder
head.  it's got a good chance of being crakced.  we sell rebuilt heads
and the first thing that happens after the head is cleaned in a "hot"
tank is a pressure magnaflux to check for cracks.ggod luck and let us
know if we can help. ted
--=20
Ted Schumacher=09
TS Imported Automotive
404 Basinger Rd.
Pandora, Ohio, USA 45877
Ph. 800/543-6648 (sorry, USA only)
Ph. 419/384-3022 - tech./general information
FAX 419/384-3272 - 24 hrs
New-Used-Rebuilt-NOS-Performance British car parts.
We also have used sports cars for sale.
Always 200 - 300 cars for parts in our British-only
salvage yard.




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