Passcar 455 block?

Matt Colie

Matt Colie

Well-known member
Aug 15, 2008
11,101
807
113
South East Michigan near DTW
It turns out the block of our engine is already 30 over and the crank 20 under.
I have a passcar block that I believe to still be 4.125. I also came with a good N crank.
Does anyone know of a difference other than the oil fill?
That is anything that I can't correct?

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Matt, here is a link to Jim Bounds' daily muse where he states an F5 block is the higher nickle block. There is also a photo of the marking on the
block. You will have to scroll down a ways to read the info.
http://www.gmccoop.com/gmc-motorhome-i-hate-glass-fuses/
--
Patti & Jerry Burt
73 Gmc 26' Canyon Lands -
77 Palm Beach
Members: FMCA - GMCMI - GMCWS - Pacific Cruisers - 49ers
 
Boring to .060 if fine. It has to have a lot of miles on it. So it's well seasoned. I'd go with the block that you have the most past history of. Build it now. With a well maintained engine' Your good for 200,000 miles. Bob Dunahugh
 
> Boring to .060 if fine. It has to have a lot of miles on it. So it's well seasoned. I'd go with the block that you have the most past history of.
> Build it now. With a well maintained engine' Your good for 200,000 miles. Bob Dunahugh

I got a message relayed from Dick Paterson that 60 over is ok, but I am still going to do the inspection on better of the passcar blocks that I have
here before I make any decision. The damage is small enough that 40 over should clean it, It almost cleaned with my ball hone. Unfortunately, a lot
of shops don't like to cut just 10 over because it means that their setup have to be real good and they don't like having to take the time to set the
boring bar up that well.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Jeeze if your machinist can't cut .010 I'd look for a new shop!
More importantly whats the availability of 040 over pistons?

Are you going to do the roller cam or stick with flat tappet?
Seems like a roller is the thing to do these days, I _almost_ wish I had done a roller when I rebuilt my engine, but it sure was a cost adder!
________________________________
From: Gmclist on behalf of Matt Colie
Sent: Friday, March 2, 2018 12:42 PM
To: gmclist
Subject: Re: [GMCnet] Passcar 455 block?

> Boring to .060 if fine. It has to have a lot of miles on it. So it's well seasoned. I'd go with the block that you have the most past history of.
> Build it now. With a well maintained engine' Your good for 200,000 miles. Bob Dunahugh

I got a message relayed from Dick Paterson that 60 over is ok, but I am still going to do the inspection on better of the passcar blocks that I have
here before I make any decision. The damage is small enough that 40 over should clean it, It almost cleaned with my ball hone. Unfortunately, a lot
of shops don't like to cut just 10 over because it means that their setup have to be real good and they don't like having to take the time to set the
boring bar up that well.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

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> Jeeze if your machinist can't cut .010 I'd look for a new shop!
> More importantly whats the availability of 040 over pistons?
>
> Are you going to do the roller cam or stick with flat tappet?
> Seems like a roller is the thing to do these days, I _almost_ wish I had done a roller when I rebuilt my engine, but it sure was a cost adder!

Kieth,

40 and 60 over pistons are real available.

The problem with only cutting 10 is that it is 005 on a side and cutting tools like to have more to cut than that and old worn out boring bars deflect
that much.

I am going to investigate the roller option. My followers don't rock on my surface plate.

Did we ever decide if oil that was by-passing the filter still went through the cooler??
I should put up a picture of the piston.

I have to go check in the order of stuff from Rock and start measuring what I do have.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
I am going to jump in here. Most production machine shops today have a
schedule of machining operations that they automatically do to engines that
do not have special handling intended. That would include, but is not
limited to, cylinder boring (usually with an automatic honing machine like
a Van Norman CK-10 or equal machine. Those machines use a more or less
rigid hone set to enlarge bore sizes. Kind of a set it up, and let it run
until it stops machine. Old school machinists, like me, use a rotary boring
bar with an adjustable cutter. A different set up for each cylinder bore.
Both machines can do a very precision job of enlarging cylinder bores, or
they can screw up an otherwise usable block. The CK-10 uses the crankshaft
centerline to align the center of the cylinder bores. Extremely accurate.
complex, exacting. The old school boring bar aligns to the old worn
cylinder bore and the deck surface. If you use the warped deck surface, or
the worn portion of the old bore, accuracy will be affected. That is the
reason for cutting .030" instead of .010" It allows for some slop in the
setup. Just so you know. Ask your machinist how this is performed in his
shop. Your money, spend it how you see fit.
Jim Hupy
Salem, Or
78 GMC Royale 403

> Jeeze if your machinist can't cut .010 I'd look for a new shop!
> More importantly whats the availability of 040 over pistons?
>
> Are you going to do the roller cam or stick with flat tappet?
> Seems like a roller is the thing to do these days, I _almost_ wish I had
> done a roller when I rebuilt my engine, but it sure was a cost adder!
> ________________________________
> From: Gmclist on behalf of Matt Colie <
> matt7323tze>
> Sent: Friday, March 2, 2018 12:42 PM
> To: gmclist
> Subject: Re: [GMCnet] Passcar 455 block?
>

> > Boring to .060 if fine. It has to have a lot of miles on it. So it's
> well seasoned. I'd go with the block that you have the most past history of.
> > Build it now. With a well maintained engine' Your good for 200,000
> miles. Bob Dunahugh
>
> I got a message relayed from Dick Paterson that 60 over is ok, but I am
> still going to do the inspection on better of the passcar blocks that I have
> here before I make any decision. The damage is small enough that 40 over
> should clean it, It almost cleaned with my ball hone. Unfortunately, a lot
> of shops don't like to cut just 10 over because it means that their setup
> have to be real good and they don't like having to take the time to set the
> boring bar up that well.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
The shop here has do 4 GMC engines lately. They tend to go short of .010 or .020. Then custom size each bore to the size of each piston. Each engine must be balanced. They don't recommend high volume oil pumps. Because of the details that they put into their machining of parts. They install the intake, distributor, oil pan, fuel pump,water pump, and oil in the pan with filter. Then it's delivered with a custom steel engine stand, and lifting device mounted by the carb bolts. Then leaves with a case of oil, and detailed install/break-in instructions. I dare you to find anything dirty, or messy there. The place is spotlessly clean. And that cleanliness shows up in the quality of their workmanship. Bob Dunahugh

________________________________
From: Bob Dunahugh
Sent: Friday, March 2, 2018 12:13 PM
To: gmclist
Subject: RE: Passcar 455 block?

Boring to .060 if fine. It has to have a lot of miles on it. So it's well seasoned. I'd go with the block that you have the most past history of. Build it now. With a well maintained engine' Your good for 200,000 miles. Bob Dunahugh
 
Normal for competent machine shops to stop a bit shy of piston size. On
matched sets of high quality pistons, they will vary a bit in final size.
Sometimes as much as a thousandth in a set of 8. I normalize the pistons to
the block, and carefully measure them. Then, I fit them, starting with the
smallest piston and going to the largest. That way, if I stroke a bit too
much with the finishing hone, I can fit a slightly bigger piston to that
bore and all is good. All in knowing your equipment and how it cuts. Like
Bob D says, you cannot have it too clean. Surgical theater clean is about
right.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> The shop here has do 4 GMC engines lately. They tend to go short of .010
> or .020. Then custom size each bore to the size of each piston. Each engine
> must be balanced. They don't recommend high volume oil pumps. Because of
> the details that they put into their machining of parts. They install the
> intake, distributor, oil pan, fuel pump,water pump, and oil in the pan with
> filter. Then it's delivered with a custom steel engine stand, and lifting
> device mounted by the carb bolts. Then leaves with a case of oil, and
> detailed install/break-in instructions. I dare you to find anything dirty,
> or messy there. The place is spotlessly clean. And that cleanliness shows
> up in the quality of their workmanship. Bob Dunahugh
>
>
> ________________________________
> From: Bob Dunahugh
> Sent: Friday, March 2, 2018 12:13 PM
> To: gmclist
> Subject: RE: Passcar 455 block?
>
>
> Boring to .060 if fine. It has to have a lot of miles on it. So it's well
> seasoned. I'd go with the block that you have the most past history of.
> Build it now. With a well maintained engine' Your good for 200,000 miles.
> Bob Dunahugh
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Pistons, rods, pins, rings. All reciprocating mass. Yes. V-8's right side
vs left side static balance. All rotating mass is dynamically balanced.
Inline engines are different, as are V-6's. Singles and twins, different
still.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> Do you weigh each piston?
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> > Jeeze if your machinist can't cut .010 I'd look for a new shop!
> > More importantly whats the availability of 040 over pistons?
> >
> > Are you going to do the roller cam or stick with flat tappet?
> > Seems like a roller is the thing to do these days, I _almost_ wish I had done a roller when I rebuilt my engine, but it sure was a cost adder!
>
> Kieth,
>
> 40 and 60 over pistons are real available.
>
> The problem with only cutting 10 is that it is 005 on a side and cutting tools like to have more to cut than that and old worn out boring bars
> deflect that much.
>
> I am going to investigate the roller option. My followers don't rock on my surface plate.
>
> Did we ever decide if oil that was by-passing the filter still went through the cooler??
> I should put up a picture of the piston.
>
> I have to go check in the order of stuff from Rock and start measuring what I do have.
>
> Matt


Matt,

The engine oil cooler in my aluminum radiator was full of metal from the spun bearing as were several other rod bearings and some of the main
bearings. It took four + hours of repeated flushing with an AC flush can and air pressure to get it clean. So, the answer to the above question is
yes. Clean that cooler thoroughly or don't use it again.

--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
Carl
If it were my engine I would not trust that the radiator cooler was 100% clean! All it takes is a tiny piece of that wiped out bearing to lunch your
new motor in less then 5000 miles. I would go to the trouble of installing an air cooled coil with cooling fan in front of the radiator and cap the
existing cooler even though it is relatively new. It just isn't isn't worth the risk been there trust me.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
> Carl
> If it were my engine I would not trust that the radiator cooler was 100% clean! All it takes is a tiny piece of that wiped out bearing to lunch
> your new motor in less then 5000 miles.

I agree with this 100%, but another option is to have the cooler professionally cleaned. I'm into Mazda rotaries, which are 1/3 oil cooled, so oil
coolers are very important on those engines. They are also large and expensive to replace. These guys have a good reputation in the rotary world, but
I would think any aircraft oil cooler service company would achieve a level of cleanliness that could be trusted:

http://www.oilcoolers.com
--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
 
There's this machine also:

http://www.hotflusher.com/automotive/Jay-Leno-Hot-Flush.cfm

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Mark Sawyer
Sent: Saturday, March 3, 2018 8:52 PM
To: gmclist
Subject: Re: [GMCnet] Passcar 455 block?

I agree with this 100%, but another option is to have the cooler professionally cleaned. I'm into Mazda rotaries, which are 1/3 oil
cooled, so oil coolers are very important on those engines. They are also large and expensive to replace. These guys have a good
reputation in the rotary world, but I would think any aircraft oil cooler service company would achieve a level of cleanliness that
could be trusted:

http://www.oilcoolers.com
--
Mark S.
 
> I am going to jump in here. Most production machine shops today have a schedule of machining operations that they automatically do to engines that
> do not have special handling intended. That would include, but is not limited to, cylinder boring (usually with an automatic honing machine like a
> Van Norman CK-10 or equal machine. Those machines use a more or less rigid hone set to enlarge bore sizes. Kind of a set it up, and let it run until
> it stops machine. Old school machinists, like me, use a rotary boring
> bar with an adjustable cutter. A different set up for each cylinder bore.
>
> Both machines can do a very precision job of enlarging cylinder bores, or they can screw up an otherwise usable block. The CK-10 uses the
> crankshaft centerline to align the center of the cylinder bores. Extremely accurate. complex, exacting. The old school boring bar aligns to the old
> worn cylinder bore and the deck surface. If you use the warped deck surface, or the worn portion of the old bore, accuracy will be affected.
>
> That is the reason for cutting .030" instead of .010" It allows for some slop in the setup. Just so you know. Ask your machinist how this is
> performed in his shop. Your money, spend it how you see fit.
> Jim Hupy
> Salem, Or
> 78 GMC Royale 403

Jim,

A voice of experience is always welcome.

As the aftermarket guy for McCord Gasket, I called on more than a few of the production rebuilders. I have seen the quality that they all turn out
and that is exactly what I do not want.

Right now, I am inspecting and measuring what I have and when I get a real good idea what I have, then I will go and look at and talk to the three
local shop that don't know that they are in line for this job. There were just two that I used for test and prototype engines, but they are both
gone. One got closed when the GM bankruptcy went bad (along with about 40 other small businesses in this area) the other was that story we have all
heard where the original owner retired and the younger generation did not carry the flag, so they became another fast "speed shop" and lost the good
clientele and the money making part of the business.

I am planning to build an engine that I can trust to take us to Alaska or the PCH without any reservation. I know that means money, but it also means
getting it right the first time.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
If it were my engine I'd bore the minimum possible, say .020 or .030". I've had very good luck with Ross pistons. They will make a set to whatever
bore size you specify as well as CR, based on stock valve size and chamber volume but can modify that as well. I've built two engines with Ross
pistons and found them to be within .001 diameter and a couple grams in weight within the set. If it were my engine I'd specify a CR of about 9.3:1.
That provides a "free" torque bump of about 6-10 lb ft over 8:1. Only downside is the wait. They take about 6 weeks to make pistons. Just what I
would do...
--
Chris Geils - Twin Cities
1978 26' Kingsley w/ very few mods; Headers, Progressive Dynamics 9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, 50k mi
 
I'll go with Roy on the oil cooler. I'll flush, and reuse the stock cooler if the engine just finally got tired, and didn't chew parts up. If there was a case of chewed up parts. Spend the small amount of money to replace the cooler. Cheep piece of mind. Or just run without an oil cooler. In the big pitcher. Our oil coolers aren't much of a cooling factor. If you don't use it. You'll never see a raise in temp on the temp gauge. We have really big radiators. Just check the temps on the lines to, and from that stock cooler.

Bob Dunahugh
 
Carl lives in southern Arizona and tows a fair load of off road equipment in hot desert temperatures. Under those conditions I would feel better
having a large oil cooler rather then not . I would also be using synthetic oil and during the rebuild I would install a high temperature front and
rear engine seals. The reason I suggest this is my engine running in the desert heat would go above 250 degrees on a hard climb and the stock nitrel
seals are only rated for 250 degrees. I had to replace my seals with hi temperature seals when they started leaking . After that no more leaks.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
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