I agree with Greg's and Joe's findings 100%. We found that we had to clearence
them an extra .001 - .002". If not, the valves could stick. The problem seemed
to occur on fresh customer motors which only had a short break-in. One "6"
customer, after being told how to drive while putting the intial miles on the
engine, proceeded to blast out of the shop and could be heard going up the
highway ramp redlining through the gears. Within ten minutes he was back with
the engine having a terrible miss which turned out to be a bent pushrod. After
replacing the "faulty" part and readjusting the valves, he left, and could be
heard really breaking in his motor. Ten minutes later... another bent rod.
His was not the only engine to suffer our ignorance when we first started
using the bronze guides. It was always on fresh head jobs, and always as the
engine was going through warming up. I feel once the engine has reached temp
and everything has equalized the parts "get friendly" as they use to say.
JMTC
-Ed-
--- On Thu, 11/3/11, n197tr4@cs.com <n197tr4@cs.com> wrote:
From: n197tr4@cs.com <n197tr4@cs.com>
Subject: [Fot] Zinc Additive. now use of BRONZE GUIDES
To: fot@autox.team.net
Date: Thursday, November 3, 2011, 9:12 AM
Sent: Thu, Nov 3, 2011 8:25 am
Subject: Re: [Fot] Zinc Additive. now use of BRONZE GUIDES
FROM TED SCHUMACHER:
Why dont you use bronze guides? How did you come to this decision?
Ted,
I discussed with highly regarded performance engine shop.
Whenever they encounter bronze guides they clearance them.
If it doesnt get done, there is a danger of seizing.....which can get very
hard on lifters and cams.
Some engineering folks tell me that cast iron guides provide superior
performance.
And say that bronze cause more heat/friction/wear......................
This and observing various failures over the years caused me change.
Certainly it is the right decision for me.
Others may have a different conclusion and I would invite them to discuss on
this list.
I have long suspected that there have been a lot of failures attributed to
'soft lifters', and faulty cams, when it may have been caused by seizing of
valves or severe drag in bronze guides.
Thanks for asking Ted. It seems like it is an important subject for this
list.
Joe Alexander
-----Original Message-----
From: tedsimx <tedsimx@bright.net>
To: n197tr4 <n197tr4@cs.com>
Sent: Wed, Nov 2, 2011 8:54 pm
Subject: Re: [Fot] Zinc Additive.
Why don't you use bronze guides? How did you come to this decision? Ted
Connected by DROID on Verizon Wireless
-----Original message-----
From: n197tr4@cs.com
To: lang@isis.mit.edu, JAR7U@hscmail.mcc.virginia.edu
Cc: fot@autox.team.net
Sent: Wed, Nov 2, 2011 21:16:11 GMT+00:00
Subject: [Fot] Zinc Additive.
Use of bronze guides is or can be an issue here.
ESPECIALLY those not properly clearanced.
It ALSO seems that cast iron guides are 'slippery' while bronze can create
added friction and wear.
We dont use bronze guides anymore.
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