Going in

[travis martin]

>Next we have valves. What is the proper grind for a motorhome? 3 angle
>5 angle or what? I dont want to read anymore on the subject. Then we
>get to SS valves or not. What is the good word? Any thoughts on valve
>springs? Some of you must know something! ZAK what am I missing here?

I will weigh in on this one issue. There are two reasons to go with a
3-angle valve job: first is a slight increase in flow as the valve begins to
open---not terribly important in MH service---and the other being better
sealing and longivity, which is important in MH service.

This is because the narrower seat--the 45 degree part--increases the seating
pressure per square area. Thus carbon etc are much less likely to keep the
valve from closing and sealing well. Poor seating/sealing is what causes 'em
to burn.

5-angle is a 3-angle job with 2 more transitions for yet better (though
slightly) flow.

My advice and what I do on all my stuff is 3-angle.

Travis

 

[john wright]

Arch,
Just refreshed my memory on compression checking. When I check the
factory Olds manual on engines they state, "the lowest reading cylinder
should not be less than 70% of the highest and no cylinder reading
should be less than 100 pounds". 70% of 155# is 108.5 As for the
timing chain, when I was at the spring rally in South Carolina Dick
Patterson said the only chain to us is the Cloyes true double roller.
Mondello also uses the Cloyes chain. As for cams Patterson gave 4 that
were good. Wolverine WG1112, Mondello JM14100, Crowler 56260 and a
speed pro for which I don't have the number.

J.R. Wright
GMC GreatLaker
77 Eleganza II
Michigan

>
> GMCers
>
> Sure would like some help here. I have enough myths here for us to sort
> out for the next year. It looks like we are going in on my engine. I have
> 155 lb on all but one cylinder----120 on that one. So the heads are coming
> off. I have a lot of questions and want a lot of answers-----I will sort it
> all out.
> First, the timing chain, Caspro says their chain is better than racing
> timing chains because it will last. My friend the drag racing fiend says
> he would never run a Coyes (sp?) chain for more than one year because
> they get to much slack. Yeah but he tries to hurt them----0 to who knows
> in 8 seconds. Does anybody have any experiences here?
>
> Next we have cams. Mondello cams seem to be the same ones he
> sells to racers. I want one that gives me low end torque and mileage.
> Caspro's new cam is said to be ground just for our motorhome. Its now
> new and there is no core charge. Any help here?
>
> Next we have valves. What is the proper grind for a motorhome? 3 angle
> 5 angle or what? I dont want to read anymore on the subject. Then we
> get to SS valves or not. What is the good word? Any thoughts on valve
> springs? Some of you must know something! ZAK what am I missing here?
> What about seals-----Teflon or not?
>
> Sorry but I am getting close and want to be on the road not in the shop.
> Any thoughts or ideas are welcome. I will sort them all out.
>
> Take Care
> Arch

 

[zak zehnacker]

Arch,

>First, the timing chain, Caspro says their chain is better than racing
>timing chains because it will last. My friend the drag racing fiend says
>he would never run a Coyes (sp?) chain for more than one year because
>they get to much slack. Yeah but he tries to hurt them----0 to who knows
>in 8 seconds. Does anybody have any experiences here?

We use a gear drive in our race cars (no chance of slack there!). Many of
the high power cars now use belt drive systems which allow the timing to be
changed much more easily. I don't see them changing the belts all the time,
so I'm inclined to believe that a Cloyes chain would last a long time before
slack became a problem. We went with a Cloyes during our rebuild.

>Next we have cams. Mondello cams seem to be the same ones he
>sells to racers. I want one that gives me low end torque and mileage.
>Caspro's new cam is said to be ground just for our motorhome. Its now
>new and there is no core charge. Any help here?

We had good results with our Edelbrock Performer cam. It really isn't a low
RPM cam, but it (along with their intake and a Holley carb) really picked up
our power over stock at all RPMs. I can't say which piece made the difference
since they were all done at the same time. I believe that Mondello has a cam
recommended for a small block Olds (403) that is supposed to work well as a
low RPM cam for the 455. This doesn't sound like the ideal situation, but it
(or something similar from somewhere else) might be the best option since the
cam companies aren't going to rush to develop an idle-3000 RPM cam for the 455
any time soon.

>Next we have valves. What is the proper grind for a motorhome? 3 angle
>5 angle or what? I dont want to read anymore on the subject. Then we
>get to SS valves or not. What is the good word? Any thoughts on valve
>springs? Some of you must know something! ZAK what am I missing here?
>What about seals-----Teflon or not?

I wouldn't look for much power here. Anything you are going to gain in the
heads is going to be at upper RPMs. You might gain some by going to an
earlier style head since the J's are VERY restrictive on the exhaust side.
You still aren't going to gain much if any low end though. I would suggest SS
valves as they should be a little more durable (less chance of burned valves)
and not much more expensive.

>Sorry but I am getting close and want to be on the road not in the shop.
>Any thoughts or ideas are welcome. I will sort them all out.

I would also suggest taking a look at the FAQ pages on the
http://www.442.com site if you haven't already. They have some very
informative information on Olds engines. The Olds mailing list and its
archives (I think these are available from the above site as well) would also
be a good place to look for answers. While most of the information at these
sources is for cars, much of it is still applicable to the GMC.

Hope this helps,
Zak

 

[grady1]

|First, the timing chain, Caspro says their chain is better than racing
|timing chains because it will last. My friend the drag racing fiend says
|he would never run a Coyes (sp?) chain for more than one year because
|they get to much slack. Yeah but he tries to hurt them----0 to who knows
|in 8 seconds. Does anybody have any experiences here?

I got my chain from Caspro because I couldn't find that particular chain
anywhere else. With some of the postings we had this winter, I think you
could get it elsewhere if you looked around enough.

With regard to the Cloyes true roller, I put this same model on a '79 Pont
301 years ago and managed to get >330k out of the engine, it still ran
strong when I sold it. (Well -- I guess strong is a figurative term for this
engine.)

In any event, it's better than the OEM chain. It's been told that Cloyes
makes three grades of chains: replacement, true roller and hi-perf.
Conventional wisdom is that the true roller is the best for longevity. In
any event, you get steel gears over plastic.

That's all I know.

Mark

 

[bartz paul]

Arch:

JEG'S and Summit are a couple other sources for your parts.

Paul Bartz

From: mark grady [mailto:grady]
Sent: Wednesday, October 06, 1999 8:02 AM

First, the timing chain, Caspro says their chain is better than
racing timing chains because it will last. My friend the drag racing fiend
says he would never run a Coyes (sp?) chain for more than one year because
they get to much slack. Yeah but he tries to hurt them----0 to who knows in
8 seconds. Does anybody have any experiences here?

I got my chain from Caspro because I couldn't find that particular chain
anywhere else. With some of the postings we had this winter, I think you
could get it elsewhere if you looked around enough.
With regard to the Cloyes true roller, I put this same model on a '79 Pont
301 years ago and managed to get >330k out of the engine, it still ran
strong when I sold it. (Well-I guess strong is a figurative term for this
engine.)
In any event, it's better than the OEM chain. It's been told that Cloyes
makes three grades of chains: replacement, true roller and hi-perf.
Conventional wisdom is that the true roller is the best for longevity. In
any event, you get steel gears over plastic.

 

[nate chase]

Arch,
I'll share what little experience I have with my new Caspro engine. I
drove it back from FC to Omaha (About 250 miles) with Jim Bounds. I have
driven it about another 100 miles locally since then. It pulls very well
from 0-30 mph. Then acts pretty much average till it gets to about 65 mph.
Then it really opens up, hits it power band and flat flies. It has the 3
angle valve seats and Caspro cam. Granted it has about 2K miles on the
engine now and is not totally broken in. Idles a bit erratic (speeds up a
bit then slows down then speeds up, etc).
Since I don't need to cruise at 70 mph wish I'd have had Jimmy add the 350
gears but that's another story. Haven't done a compression check yet but
will shortly. I need to get it winterized since the nights are getting down
right chilly (30 degrees) here.
Not much info but hope it helps...

Nate '75GB (happy in) Omaha

>>>
Next we have cams. Mondello cams seem to be the same ones he
sells to racers. I want one that gives me low end torque and mileage.
Caspro's new cam is said to be ground just for our motorhome. Its now
new and there is no core charge. Any help here?

Next we have valves. What is the proper grind for a motorhome? 3 angle
5 angle or what? I dont want to read anymore on the subject. Then we
get to SS valves or not. What is the good word? Any thoughts on valve
springs? Some of you must know something! ZAK what am I missing here?
What about seals-----Teflon or not?

Sorry but I am getting close and want to be on the road not in the shop.
Any thoughts or ideas are welcome. I will sort them all out.

Take Care
Arch

 

[zak zehnacker]

Arch,

I seem to remember someone blasting the cam button (it supposedly caused
problems) from when I read the 442 faqs a while back. I don't have any
experience with it though.

The Olds mailing list archives might have more current information. The list
itself might also be a good place to ask these same questions. There are many
people on it that have a lot of experience with the 455. The large Olds cars
that used these engines really don't have that much different requirements
than our GMCs. They still want their engines to last a long time. They may
rev them a little higher, but I suspect most of the street driven ones don't
rev them very high at all. The GMC application is going to be considered a
high RPM application pretty soon with all these new gear ratios being tried
.

Zak

Thanks. I have done the 442 thing many times. Here is what it is looking
like. Caspro gear and chain. Caspro cam. SS valves with a 3 angle grind.
Anybody for the Mondello cam button? What about valve springs?