OLDS 455 heads, and cam duration and lift

thomas g. warner

New member
Mar 24, 1998
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I am going to make an exception and only do this once since I do not have
time to send lots of messages to individuals. The proper way to set up olds
455 heads. I have received so much email about it. Said I was not going to
get into one of these silly discussions again. You guys seem to like to
interject your past experiences with other engines into the olds 455
discussions and quite simply you can not for the most part do it. In my
opinion much of the information I have seen posted during the last several
days about the 455 heads is incorrect. We talked about this extensively
several months ago, but for some reason like the E rated tires discusion
some think the discussion should be resurrected every so often, for what
reason I cannot fathom. You prepare the heads like you are suggesting and
the only thing you will get is a short lived head, if you get it to work at
all. Arch you can call this authoritarian or what ever you want but quite
frankly there are experts of over 40 years experience that have been there
and done that, and I rely on them for the details i have. Here are the
facts. The smart ones can use these details(in fact you will pay the $24
for mondellos technical reference manual for the olds 455 engine) to rebuild
your olds 455 blocks and heads, all others do what ever you want. Free
world.I have not included everything because quite frankly there are a lot
of details to consider. These came from the various Mondello technical
books or seminars.

You guys talk about going to Caspro, Cinnabar etc and in my opinion they are
not experts in this area. They farm their engine work out to local machine
shops. If you really want the facts get mondellos technical manual on the
455, it is the best there is, Period. And for you guys paranoid about
authoritarian opinions, what can i say.

1. The olds 455 uses A NON ADJUSTABLE VALVE TRAIN. Because of this valve
stem heights are very critical as this effects the lifter preload on your
camshaft. Unless you are lucky enough to have a machine shop that regularly
does olds head, you are almost sure to get a bad head job, because the valve
stem heights will not be set up right.This leads to premature wear on the
cam and even binding valve springs and broken valves

2. mondello makes a special valve stem height tool (HG-455)that allows your
machine shop to set up the valve stem heights correctly and thus get the
proper hydraulic lifter preload, adn rocker geometry.

3.The toronado heads require special clearances in the valve guides and you
cannot use the standard factory settings for a 455. Why? Because the
toronado utilizes dual heat cross over passages. Cylinders 3,5,45,and 6 are
the problem children. Correct intake valve guide clearance if .0015" to
.002". Exhaust valve guide clearance .002" to .0025. Set them closer and
they will stick and either break the valve stems or burn the valves.

4. preferred valve guide is the K-line bronze bullet liner.

5. If you want long lasting 455 heads than use 45 degree seats, not 30 degrees.

6. There are no teflon valve seals that will fit stock type un-machined
olds valve guides. Yep another authoritarian remark.

7. With unmachined valve guides you cannot use a camshaft of over 1/2" of
lift. If you do the valve springs will bind.

8. Want to really screw up your engine fast just buy a timing chain without
knowing how to order them. How many know that the Cloyes True roller timing
chain comes in 4 lengths. Which one is the right one for you? And we wonder
how come we put in the best timing chain money can buy (Cloyes true roller)
and the engine does not run right. The technical manual tells you how to
measure and tell which one you need. And no you cant call anyone for the
correct one for your engine. you have to measure it. And yes we talked
about his several months ago to.

9. If you are going to replace your cam and you do not install a cam button
you have made a decision to do it half assed(sorry i used this word but cant
think of any other word to describe how I feel).Want accurate and long
lasting valve timing install a button.

10.. For you guys discussing lift and duration what are you going to use it
for? But here goes if you need to know:

Duration is always specified at a specific lobe lift. The valve lift and
cam lift are not the same.multiply the cam lobe lift by the rocker ratio to
get valve lift. For instance if you have .340" of lobe lift and a 1.6 rocker
ratio you have .544" valve lift. Like wise you can measure lobe lift and
valve lift and calulate the rocker ratio.

To calculate duration add the valve closing event to the valve opening event
and add 180 degrees. If we measurre a 20 degree BTDC intake opening and a
48 degree intake closing ABTC, than the duration would be 20 degrees + 48
degrees +180 degrees = 248 degrees at the valve lift specified for the cam.

I really do not have time for any more and yes there is a lot to properly
setting up the olds 455 block and heads.Hope this helped just a little.

>In a message dated 10/6/99 9:49:09 PM Central Daylight Time,

>
>> Also, using stock instead of high-perf.
>> springs should keep the wear on lifters and cam lobes to a minimum. OTOH,
>> if
>> installing an aftermarket "tweaked" camshaft, check with the manufacturer,
>> as
>> some quick-opening/closing grinds may require heavier springs too.
>>
>Rick
>
>As always I thank you for the reply. I plan on talking to Caspro again
>in the morning to see if I can find someone who knows what they are
>talking about. Cant seem to get somebody who knows about lift and
>duration. Oh well will keep trying.
>
>Take Care
>Arch
>
>
 
Tom, great summary.
I spoke with Joe Mondello at the Olds Nationals for
quite a while. He has a lot of experience on these
engines and even worked for the Olds development group
for a while. He had even put a plastic window into
the oil pan to see at what RPM the oil will all be
sucked out. Almost got an autographed "tech manual"
but UPS messed up the shipment.

In the seminar he kept mentioning some motorhome guy
that had 200k plus on a 455 engine (Dave).

Bill

=====

__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com
 
I have talked a lot wiht Joe Mondello and in my opinion he has the most
practical knowledge on the olds engines that I have ever seen. He sent me
autographed copies of all of his manuals.

The guy he is talking about is Dave Greenberg who has over 370,000 miles on
a mondello engine. Thats what oyu can expect from these engines when you do
the things Joe recommends.

>Tom, great summary.
>I spoke with Joe Mondello at the Olds Nationals for
>quite a while. He has a lot of experience on these
>engines and even worked for the Olds development group
>for a while. He had even put a plastic window into
>the oil pan to see at what RPM the oil will all be
>sucked out. Almost got an autographed "tech manual"
>but UPS messed up the shipment.
>
>In the seminar he kept mentioning some motorhome guy
>that had 200k plus on a 455 engine (Dave).
>
>Bill
>
>
>=====
>
>__________________________________________________
>Do You Yahoo!?
>Bid and sell for free at http://auctions.yahoo.com
>
>
 
Chuck I absolutely feel that we can build olds engines and get 300K miles on
them just like Mondello does. And I do not think that Daves engine is an
exception to the rule. I do take issue with your comment "It was built in an
era where we didn't expect a geat deal of quality from Detroit,ISO 9000 etc
was not being practice like it is today and so on" The toronado engine was a
very precision engine with all of the speed goodies standard in it. A
windage tray is but one example.

In my experience the olds Toronado 455 engine is one of the most rugged and
best engines that GM has ever built. I have had 10 toronados and everyone
of them was tough and powerful. They all went way beyond 100K miles. If you
want to build a 300K mile engine in my opinion you need:

1. To have the knowledge and the technical guidelines to build the engine.
Mondellos technical manuals and parts book will give you that. He knows how
to put them together to stay. He also has all of the parts you need for the
455 and keeps them in stock.

2. Have the proper tools and know how to use them

3. Use quality recommeded parts such as Cloyes true roller chains, speed pro
rings and childs and albert stainless steel valves.
4. Properly and religiously service the engine with good quality oils ands
filters.

5. DONT ABUSE IT.

>Tom:
>
>You can do everything that Modello recommends and you will not necessaily get
>that kind of results. My suspicion based on information on this web site,
>reading Mondellos books etc is that Greenbergs is a statistical anomoly.
>
>There are many GMC owners who have without question performed routine
>maintianence with a great deal of discipline and have not come close to those
>results. That engine was not designed with that life cycle in mind. It was
>built in an era where we didn't expect a geat deal of quality from Detroit,
>ISO 9000 etc was not being practice like it is today and so on.
>
>I absolutely believe in the maintainance pracitices you have so eloquently
>stated, but I think it is mis leading to say by practicing 300 plus thousand
>miles is to be expected.
>
>Hopefully I am wrong.
>
>Chuck D
>78 Royale
>Stillwater MN
>
>