1973 Sedan Devile 472 CID motor rebuild

[wheikkila]

Hi Steve
You did you plan on using for the machine shop in Austin. 3 week turn around is very good. Hope to see you around Austin.
Thanks Wayne

[Steve S Heracleous]

Got a call from the machine shop today. It looks like the block will have to be honed 0.030" over which means new pistons. Any recommendations on piston manufacturer and vendors that cater to Cadillac internal engine parts?

[TJ Hopland]

Wow 30 is a lot for one of these. Not a lot as far as how thin the block will be but you usually don't see that from wear its usually because it sat at some point and had some rust pitting issues from moisture. 

If it was me I think I would be looking at cadco.  cad500parts.com.   Proabbly the Silvolite or RC cast pistons.  I have not bought from them before but they seem to have that small operation vibe and have been around a long time.  Used to buy from MTS but they just don't seem to be what they used to since the main guy passed several years ago.  Just now looked to see what their current name and site was because its been changing every time I look and I'm not even sure anymore what it is.   Cadco has been around for at least 25 years and as far as I know is run by the same people.

["Cadillac Kid" Greg Surfas 15364]

Steve,
You have a choice here.  You can either replace the pistons with "soap dish" low compression pistons or go to the "1970" version with a 10:1 compression ratio.  In either case I would work through your machine shop since they are the ones that will be responsible if you purchase the pistons through them.  Egge Machine in Terrel Texas makes both pistons so you might point the machine shop in their direction.
Regarding 0.030 over being excessive, It seems that if properly maintained and oil/filters changed the cylinder wear is an absolute minimum. I had over 500,000 miles on one motor and not enough wear to catch your fingernail on the ridge.  But, if neglected the motors can wear excessively. Hence the first oversize commonly listed is 0.020 over, and with  any minute scratches in the bore, .030 is a safe choice.
Greg Surfas

[Steve S Heracleous]

Got the block, crank and heads from the machine shop a few days ago. I decided to stay stock and got original pistons (8.5:1, .030 over) from cad500parts.com. Got the rings, main bearings and rod bearings (.010).

First order of business will be to mike everything just to make sure everything is ok (main, rod clearances). In the mean time, I will have to put an order in for a gasket set, oil pump etc. Camshaft, lifters, pushrods seem to be ok and planning to re-use them. Once I get to them, I will check the cam/lifters using a degree wheel to make sure parts are not worn.

I want to replace the cylinder head bolts since they are the original ones - the ones that go through the exhaust ports are cruddy anywhere. I am not able to find a bolt kit - instead, I can get a stud kit. I'm kinda liking the bolts since it makes head install / removal a little easier. Any sources out there for a cylinder bolt kit?

[wheikkila]

Hi Steve
What machine shop did you use here in Austin?
Thanks Wayne

[Steve S Heracleous]

Wayne,

I actually used Duffin Engine Service in San Antonio. A drive from where I live but what the heck. They gave me a turnaround time of 3 weeks. Including the snowcalypse we had in Texas it ended up being 5 weeks.

S.

[TJ Hopland]

Cadco should have the bolts and oil pump.    I would buy all I could from a source like them because a company that just sells parts for one family of oddball engine has more incentive to try and get the best quality stuff than someone that just sells auto parts. 

I too would re use things if they looked good.   Ya never know what the quality would be like with replacement stuff but you know what you have lasted so far.   Its a one thing leads to another and you end up replacing a lot of stuff and any of the new parts could be the weak link. 

[wheikkila]

Hi Steve
That is a great turnaround time. I will have to keep them in mind for my next machine work.
Thanks Wayne

["Cadillac Kid" Greg Surfas 15364]

Duffins is a great shop.  I would never think of having anyone else doing my work here in San Antonio.
Greg Surfas

[Highwayman68]

Since you are ordering from CadCO they have a high flow oil pump that helps maintain better flow when letting off of the gas or when sitting at idle.

[Steve S Heracleous]

After about a year of hiatus, I am back on board in putting the 1973, 472 CID Cadillac engine back together. Measurements on the cylinder bores checked out fine and then proceeded to check the crankshaft main bearing clearances. I am doing the measurements the "accurate" way by utilizing a micrometer and a bore gauge to measure each main journal clearance.
The factory manual calls for a clearance on the main bearings of 0.0005" to 0.0028". All measurements that I took on all 5 main journals range from 0.0045" to 0.0055" (bore gauge accuracy to 0.0005"). Doing some research on the net the recommendation from engine builders is to use 0.001" of clearance per inch of the journal diameter with a max clearance of x 1.5 the measurement obtained. So, on this crankshaft, the main journal diameter is 3.25" so a proper clearance would be 3.25 x 0.001 = 0.0033 (rounding up). Max clearance would be 0.00325 x 1.5 = 0.0049". Wide range of clearances.
Not sure there is much to do here other than use 20W-50 grade oil on this engine and ensure that I have a high output/flow oil pump and call it a day for this topic.
Any thoughts? I will next measure the crankshaft rod journals for clearances and will report back.

I had some pictures to share but the web site does accept them - I get a 500 HTTP error code.

[Scot Minesinger]

I'm late to this post, but on the exhaust manifold bolts, with engine out of car you can grind the stuck bolt heads off and then remove the exhaust manifold.  Now a stud extractor should work OK because you can get the heat, chemicals and etc close to the where the threads penetrate the head.  If that does not work you can buy the tool and go to town, and you are no worse off than before.  But the upside is saving yourself the $500 tool cost.

BTW I'm with you; supervise and do as much of it yourself as you can to avoid a potential mess up. 

[Scot Minesinger]

The intake manifold requires real good seals at the corners.  If you just RTV around the 8 intakes it will leak and idle rough, with timing all over the place.

[Steve S Heracleous]

Measured the rod bearing clearances using a micrometer and bore gauge. They all measured between 0.0015" and 0.0025". The manual calls for 0.0005" - 0.0028". So, I am happy with these measurements.

["Cadillac Kid" Greg Surfas 15364]

Steve,
Regarding the head bolts, for a stock engine bolts are adequate and used bolts can be cleaned up and "thread chased" then re-used. Again, if you haven't yet gotten one, a stock oil pump will provide all the oiling you motor needs. If the oil pump housing is not scored, you can get replacement gear sets to bring it back to "new" conditions. If you gave Russel or Donald at Duffins the pistons before they bored the block, they built in the proper clearances for you, and again, for a stock motor the best intake gasketing solution is the "turkey roasting pan" and the rubber end seals, being sure to apply something like "the right stuff" at the corners. I personally get real liberal with the sealer and ensure the ends of the intake are completely sealed to the block's "china rails".
Did you have ARP bolts installed and the rods resized?
Greg Surfas

[Steve S Heracleous]

If you gave Russel or Donald at Duffins the pistons before they bored the block, they built in the proper clearances for you

Yes I did. I am assuming the clearances are good for this motor.

Did you have ARP bolts installed and the rods resized?

Greg,
Yes, the rods were resized and the ARP bolts installed. I am in the process of checking ring gap now before installing them on the pistons. After ring gaping, I will check the block threads for the cylinder head bolts (chase and clean), followed by installing the camshaft and then the crank. That's the plan for the next couple of days.

["Cadillac Kid" Greg Surfas 15364]

Sounds like you have a handle on it.
Greg Surfas