1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Thanks Duke, I chuckled at your last sentence.....

I just got back from a 1 1/2 hr round trip(3rd time this week) to borrow a 18" machinists straight edge from the machine shop. Jay's coming over Sunday to teach me how to use it. I know how to, but but I want to watch his methods and test patterns. I'm looking forward to his shop visit.

Okay, so here's the story. This car isn't mine, it's a friends. I got it in pieces after the frame was restored, body painted and dropped back on the frame. I got it from there. The engine was previously done as a short block with heads cleaned up(as mentioned thought decked, but actually sanded) and I came in late to get it assembled, installed, run-up, cam break-in, final test, etc.

Yes the block was decked. I then discovered the deck surfaces were then "cleaned-up", on a special electric powered device that simulates something.

When I first got the short block, a buddy and I checked deck clearances, etc. We assumed the 962 heads were a specific volume, and knowing we're using the Felpro composition gaskets(about 0.045" squeezed, and I have proof now unfortunately), we came up with about a 8.75:1 CR. Not true 270HP spec, but it is what it is, as delivered, so on I went. The rest is history.

If we take another cut, say 0.010", then that'll get the decks flat again, based on my data above(max 0.008" delta), excluding the "ears", and give us a 0.020' DC and bump the CR up a bit more. The owner will probably not want to replace anything if it's not broken. This unseen task will be costly in both lost time and new materials.

The cam is the 097 spec ordered for the owner by the initial shop from Comp Cams. Next time it'll be the Sealed Power CS133R. Lifters came from another supplier, maker unknown, in a box that looked "un-American".

Thanks,
Rich

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Jay Howell was here this morning. We used the straight edge to check areas of the block. He brought his set of feeler gauges. We were able to verify a few of my readings, easiest was the ears.

Then he asked me to get the surface gauge setup I used. We set it on the mill table to zero it, and took some measurements of the decks on the same areas as before. They matched very closely.

Jay said he actually liked my test setup better than the straightedge/feeler gauge method. He liked it because it gives pinpoint moving samples of the surface.

More to come this week.

Rich

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Update.....Extricated the remaining engine hardware from the car yesterday. The cylinder block head surfaces will be decked to become "flat" again. I had the two heads totally rebuilt, properly decked and required over 0.005" to clean up and remove the wells around all cooling port holes from the improper belt sanding process. All holes are now nicely sharp edged from this process. All new stainless steel valves, slightly oversized after milling of the port sealing surfaces. This was done because there were several slightly recessed valves when inspected. Guides reworked and milled for positive seals, hot tanked, ports cleaned, overall proper rebuild. They look great.

After rebuild....
PA170026.jpg

Now for the block....After seeing some substantial dirty debris in the oil pan after removal, along with what appears to be gold/brass fine particles floating in the oil, I decided to remove a crank journal cap and inspect. This engine ran for approximately one hour total. Before the installation, the oil was primed on the engine stand via a distributor drive tool until all oil passages were filled and seen out of each pushrod and visible oil galley.

This is what I've found...

Bearing....The bearings appear new, marked 10-11 STD on the backside. Now rubbish.
PA220059.jpg PA220061.jpg

Crank journal...Scratches felt with a fingernail.
PA220062.jpg

There is much more work to be done. Updates to follow.

Rich

[Dick W.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Update.....Extricated the remaining engine hardware from the car yesterday. The cylinder block head surfaces will be decked to become "flat" again. I had the two heads totally rebuilt, properly decked and required over 0.005" to clean up and remove the wells around all cooling port holes from the improper belt sanding process. All holes are now nicely sharp edged from this process. All new stainless steel valves, slightly oversized after milling of the port sealing surfaces. This was done because there were several slightly recessed valves when inspected. Guides reworked and milled for positive seals, hot tanked, ports cleaned, overall proper rebuild. They look great.

After rebuild....
[ATTACH=CONFIG]48687[/ATTACH]

Now for the block....After seeing some substantial dirty debris in the oil pan after removal, along with what appears to be gold/brass fine particles floating in the oil, I decided to remove a crank journal cap and inspect. This engine ran for approximately one hour total. Before the installation, the oil was primed on the engine stand via a distributor drive tool until all oil passages were filled and seen out of each pushrod and visible oil galley.

This is what I've found...

Bearing....The bearings appear new, marked 10-11 STD on the backside. Now rubbish.
[ATTACH=CONFIG]48688[/ATTACH] [ATTACH=CONFIG]48689[/ATTACH]

Crank journal...Scratches felt with a fingernail.
[ATTACH=CONFIG]48690[/ATTACH]

There is much more work to be done. Updates to follow.

Rich

Some of the crank damage MAY have occurred when it was run the hour if the engine was full of trash, but my guess is that most was done prior to the rebuild.

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Dick,

I also now think there was debris in it when I got it. What I had to do to clean the heads was telling me something, but had no direct control to force a rework. I advised, but it didn't happen.
.
.
.
.
I just dropped it off at the shop to be redone. I'm glad I was convincing enough to pull for re-decking the block as opposed to using thicker head gaskets, now to find this latest issue substantiates my recommendation.

I may have to use thicker gaskets due to all of the decking. Heads came down 0.005", block will need apx 0.010". i have a set of FelPro 501SD which are spec'd at 0.039"-0.042" compressed.

I understand that previously calculated the CR of apx 8:75:1 may be compromised further but it all may be a wash after reassembly. I will end up with a DC of apx 0.020".

Rich
p.s. a few pics of the oil contaminants. It's very gritty, like rust or fine shavings. I suspect the brass particles are from the bearings.
PA230067.jpg PA230069.jpg PA230071.jpg

and a shot of the pieces........second time around.
PA230074.jpg

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Update. The block was re-decked (it's now flat!), properly hot tanked, properly cleaned oil galleys, rebuilt with the properly decked and rebuilt heads.

Reinstalled the assembly Thursday afternoon and put all the bits back together. Ran it up yesterday and all appears to be fine. A bittersweet success.

When I get the hood on and it's 100% done I'll post a few completed pics. I thank you all for the help and guidance along the way.

Rich

PB020001.jpg PB020002.jpg PB020003.jpg PB020007.jpg

[John D.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Rich, Probably a typo but the sealed power number of the Duntov 097 is CS 113R. Not 133R. Lifters from Sealed Powere aka Federal Mogul are AT 992. Good luck, John

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Rich, Probably a typo but the sealed power number of the Duntov 097 is CS 113R. Not 133R. Lifters from Sealed Powere aka Federal Mogul are AT 992. Good luck, John

Hi John, good catch, a typo. too late to edit so I'm glad you caught it. AT992 lifters? Maybe? The box was unmarked but you're probably correct. All of the pieces came from NAPA.........

.......Yes, just checked and it's SEP AT992.....here.

Thanks
Rich

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

A delayed update.....

Last week.....after the 2nd rebuild, re-decked block(0.008"), fresh heads, Felpro .040" CT gaskets, etc, the problem of combustion gasses in the coolant still exists, not as severe as originally, but unfortunately still there.

I have diagnosed again to help find root cause, and cylinders 5 and 8 are now the suspects. Cyl 8 showed signs of a problem on the first iteration of troubleshooting, but never a high leakdown reading. Plug 8 now shows signs of water cleaning.

Compression Leakdown Test
Cyl %Leakage
1 11
8 17
4 12
3 11
6 12
5 17
7 12
2 14


6 and 7 are now fine according to my leakdown tests and spark plug observations. I am going to run leakdown tests on the 2 suspect cylinders(5,8) with pistons at the bottom of the bore(with rockers loosened of course) to either exacerbate the problem if it's a cracked block low in the walls, or if the readings are the same, then suspect head gaskets/flatness issues again.

I have a few (so-so quality but effective) video clips of the run up showing the effects of combustion gasses in the coolant, and using a block dye test to test for gasses. If the dye turns green or yellow it's the issue. As you'll see that's what's happening. Last month the dye turned yellow after a few seconds. This time it takes about 30 second to see traces as it turns green. Remember that blue + yellow = green.

Engine Startup and Preparation for Diagnosis. Notice no white smoke ever observed from the exhaust.

http://youtu.be/h7yNt89dsBc

Combustion Gas Dye test and overflow #1.

https://www.youtube.com/watch?v=UQ_6vhfu0Ts

Combustion Gas Dye test and overflow #2. It overflows at the last few seconds of the clip.

http://youtu.be/Td-DYIgnurY

Rich

[Timothy B.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Richard,

I was once told by a old mechanic that if you put a drop light light bulb inside a cylinder for a day it will show a crack. I can't verify this but the expansion from heat shows the crack.

After all your hard work I can't offer suggestions, the owner has to be sick.

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Hi Tim, Never heard that one before, interesting.

At this point I'm just trying to get a little closer to root cause with whatever troubleshooting ideas I can come up with, before we even consider pulling for a 3rd go-around. I won't give up the ship until I find out the details but taking a sabbatical from it for a while to get refreshed. Yes we're all pretty distraught about this one. We've put an enormous amount of time, $'s and effort to this point. I thought I was done a month ago.

As Loren said earlier in this thread the horse is still kicking but we may have to put her out of her misery. The owner will be back here in a few weeks so the ole' girl is resting in the stable for now. When he gets here we're going to get back to diagnosis. I'm taking a little breather from the task until then just to keep the head clear. I actually worked on some Jaguar stuff today and I felt good. I'm tired of Corvette engines at the moment. I'll figure it out.... eventually.

Rich

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Today we spent the day diagnosing the continued problem of combustion gasses pressurizing the cooling system of this engine. Recall it was rebuilt a second time, after the block was decked again to remove inaccuracies in the deck surfaces shown in my previous posts. Both block decks had 0.008" removed.

We have concluded that cylinders #5 and #8 are at fault via cylinder leakdown tests and telltale identifying features on their spark plugs. This is what happens when the coolant temperature reaches approximately 180*, and after about 15 minutes of idling time.....

http://www.youtube.com/watch?v=UQ_6vhfu0Ts&list=UUX13k501TPEFWCCwezJaoXQ

We have concluded that this engine either has internal problems such as cylinder wall crack(s), or has been damaged beyond repair due to improper machining. The block had been decked, then belt sanded, then decked again to re-flatten the uneven deck surfaces. The heads were belt sanded, then corrected by decking 0.005", pressure tested, magnafluxed, properly cleaned, then rebuilt with new stainless steel valves, etc.

Unfortunately this horse will never rise again. I think Loren called it from day one. It has been decided to shoot the horse and put it out of it's misery. Another correct 519 block will be searched for in the somewhat distant future, but for now the carcass will have to lay down in the stable until a future race comes her way.

I appreciated the support, ideas, and diagnosis aids to help with this.

I have now graduated from the following 2 night courses at my local Community College:

Catastrophic Engine Failure & Initial Diagnosis 101

and some extra credits in....

Combustion Gas/Cooling System Intrusion Principles and Analysis in Aged Chevrolet Small Block Engines

Thanks,
Rich

[Rob M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

I feel sorry for all the misery for you and the car (engine) owner but reading this thread was a learning experience for me (and probably many others)...

[Richard M.]

Re: 1960 283 Cylinder Block Deck Surface Flatness Tolerance ?

Thanks Rob, It sure has been for me, and many of my engine expert friends.

And if you want more info, check out this follow up thread I just posted.

https://www.forums.ncrs.org/showthre...olant-Violence

Rich