Small Block restoration finishing tips

[Eric S]

I am working on a non Ford small block engine and since I need advice that may benefit anybody working on any engine, I thought I may ask here.
Ray suggested to post in this section.
So the engine is a GM small block but again my questions are quite generic.
I pulled it, removed heads, pans, covers and will have it painted.
I will change freeze plugs and pull off plugs and sensors.
Questions hence is what do I need to make those parts tight.
I guess freeze plugs are simply pushed in place. Plugs and sensors I removed had some kind of white (teflon like) material around.
What are the products used here to make everything tight and leakless?

[simplyconnected]

For coolant devices with threads, use a Teflon PASTE, not Teflon tape. This stuff is sold at Home Depot, Lowe's, etc., for about US$4. The brush is in the cap.

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Just about any brand that show 'PTFE' works well.

For core plugs (with no threads), simply clean the machined hole to get all grease and dirt out, spread a thin layer of Permatex Ultra RTV in the hole then pound the plugs in. I use brass plugs and I buy them in a kit at Amazon.

(((Please consider donating to our site, especially for non-Ford help.))) <--My mistake and I apologize, Eric. At the time I wrote this, all of our tags below our names were missing and I didn't realize you ARE a paid member. You are certainly entitled and welcome to post about anything you like. - Dave

[Eric S]

Dave,
no problem, I ask so much here, I can't imagine not being a paying member...

I finally had a chance to check my supplies in my garage and have well a PTFE paste and regular engine gasket. So I should be all set.
Just have to find time to work on my (too many) ongoing projects.

[Eric S]

I was looking at a video from Fel-Pro about surface finish on engine block and heads surfaces.
I thought it was just a matter of cleaning the surface, make sure it's smooth and straight and that's it.
Watching this video makes it looks like we need to get different surface depending on material and gasket used.
So how should I prepare the surfaces for head gasket and how smooth should it be?

https://www.felpro.com/technical/field-test-garage/checking-cylinder-head-surface-finish-flatness.html

[simplyconnected]

In my opinion, 'out of flatness' by four thousandths is too much. I measure heads (end-to-end) by the combustion chamber volumes. I always go over my exhaust manifold, block deck and cylinder heads with a long flat mill file.
When I was a teenager, I overhauled Pontiac 389 engines. Our car had one from the factory, with deep, circular tool marks on the block's deck. I could catch my fingernail on the grooves. It didn't matter, the original head gasket never leaked and neither did the replacement (also a multi-layer steel) gasket. I haven't seen another block quite that bad but it taught me NOT to sweat the small stuff. The file works well.

Ford uses a huge Cincinnati Milicron (flat) broach on their blocks and heads, not circular cutters. - Dave

[Eric S]

Thank you Dave.
I read and watched a lot on FelPro's web site and I should have rather provided this link : https://www.felpro.com/technical/tec...ce-finish.html
It's where they talk about the different required finish depending on the gasket used.
I never heard of that and all the engine builder I talked too were not too concerned about the actual grain used on the surface.

[simplyconnected]

In my opinion, 'out of flatness' by four thousandths is too much...

Eric, I looked at the FelPro site you mentioned. I find conflicting information like this:
"For example, no block or cylinder head should exceed .003" out-of-flat if there are 3 cylinders, as there would be in an inline-3 or V6 engine. Inline-4 and V8 applications should never exceed .004" out-of-flat and so on. No block or head should not be more than .002" out-of-flat across the width of the surface."

So, which is it. two or four thousandths?

The flatness of MY block better be UNDER one thousandth or it's going to the machine shop. Same holds true for my heads. More importantly, what is the difference between combustion chambers? How can any engine be smooth if compressions of all cylinders are 10% or more between the highest and lowest measurements?

When the block and heads are milled, how can OEM pushrod lengths be correct now that they are longer? What if one head or one block deck height is mismatched from the other side? Does the machine shop care? Most don't, but I do for my builds, so I measure and then balance the crankshaft. All this takes time but no more material costs. That's why I measure everything for myself. My engines are smooth and well balanced, using modern materials (NOT OEM materials from back in the day) and modern methods. When an engine is 'custom built' I expect a 'better than production' result. That is why finding a GOOD engine machine shop is so important. - Dave

[Eric S]

Dave
Don't talk about finding a good engine machine shop. My Cobra's FE 427 Shelby engine failed at 14.000 miles with seized rockers on Private Messages First shop failed, 2nd closed his shop before completing the work (he had a bench and when he ran the engine the work from 1st one was so bad we damaged the engine further) and now at the 3rd one. In works since 2017. That's why I try to do as much I can myself even if have to learn a lot...

Anyway back to my original question, how do you condition the deck surfaces? FelPro says it depends on material and gasket used and that the surface's smoothness has to be "right" depending those conditions.

[Bob C13]

Thank you Eirc & Dave for all this info. I am amazed at your knowledgeable input. It helps me better understand.

[simplyconnected]

Yes, I will talk about a good engine machine shop. Engines are precision machines and as such, they need precision equipment and methods to overhaul them. A good engine machine shop will include a warranty in his price, just like OEMs do. They build their reputation on their work and the employees are very proud of the work they produce. If this is not your machine shop, do not do business with them. In my Detroit area, I can cite at least two shops that fit this description (I'm sure there are more). Good machine work is not cheap. They also offer sound advice for the fuel and oil used, cam selections, rings and piston choices, etc., to match the service your engine is intended for.

I don't understand this post:

...Don't talk about finding a good engine machine shop. My Cobra's FE 427 Shelby engine failed at 14.000 miles with seized rockers on Private Messages...

Rocker arm assemblies are not very technical. Aside from decent rocker arm alignment and using detergent oil to keep them clean and lubricated, hydraulic lifter rocker arms don't require maintenance. OEM rockers usually last until the next overhaul (100,000 miles) and beyond. Of course, solid lifter valve trains require scheduled tuning.

Change your oil every 3,000 miles and make sure the oil has at least 1,700 parts per million of ZDDP (phosphorous and zinc) for flat tappet engines. Use an additive if your oil needs more. ZDDP is sacrificial meaning, it gets consumed as the oil ages.

Surface quality is a function of the machine shop. I have never had an issue with this from a good machine shop because his cutters and grinders are sharp, aligned properly and not worn out. One shop I use overhauls Duesenberg straight-eight engines. Most shops only go up to straight six engines.

Cast iron is naturally porous, which is why you never see it polished. By definition, cast iron is at least 2% carbon which is a natural lubricant (graphite). Being porous to hold oil AND being a natural lubricant makes cast iron a perfect metal for cylinder bores. Engine Engineers got it right from the beginning, evidenced by modern engines that still use cast iron blocks. - Dave

[Eric S]

Dave
we don't understand either over here why the rocker seized.
I had a really tiny noise that I can hear over the engine noise (side pipes makes some noise) when I was driving along a wall where this really tiny noise was bouncing off the wall.
I ended thinking I was a bit paranoid and gave up. Until while on a 10 days trip to Czech Republic in 2017 I had a loud steel noise like a plate was loose under the car and ready to fall. Noise disappeared at stop and running the engine makes no abnormal noise. Until my friend jumped out of his car while arriving at an hotel one evening on our way back to France. My friend could then hear the noise from his Cobra which was not the case until then. So we took off the LH rocker cover to see that rockers on Private Messages were not moving !
Being 3 days from home he advised to drive back home "easy". I still think it was the thing to do.
Once home I removed the rocker ramp to realize the rockers were seized on their tube, push rods bent, hydraulic lifters being held firmly has been machined down by camshaft, and subsequent disassembling revealed that the cam shaft lobe was also machined down.
To this day I never been able to find the WHY of this. The only thing I noticed was that the rocker ramp bolts that are located where the oil channel run up along were not machined down per the picture below. I read that their smooth portion should be slim down to allow for more oil to go through.
Another explanation might be debris blocking an oil channel...
Then, as I explained earlier, more damaged was made to the engine later when we bench tested the freshly rebuilt engine...

[simplyconnected]

Eric, you described a catastrophic failure. I don't think any engine can run with only half the valves working.
Certainly, the rocker shaft would be starved of oil if the bolt in the 'oiling stand' had no relief. I have seen, where the correct bolts were not available, they simply ground a flat into the bolt's shank. Rocker arms do not need much oil but they cannot be run dry. It is common to restrict oil flow to the rocker shafts. - Dave

[Eric S]

It was just 1 cylinder that had stuck rockers. As they were not activating the valves that remained closed, we did not had a catastrophic failure.

I read several items about oil restrictions. I came to the conclusion that it was not necessary on this engine. Hope I am right. However I need to get the correct slimmed bolts. Any idea where I can get them? I looked at different places and I am un-successfull so far.
We may turn them in the lathe if can't source a set.

Dave, back to original question, how do you recommend to "clean" the block and heads gasket surfaces? Should I use co****, medium, fine cloth?
I need to get it clean so I can measure with a rule for straightness before we go to the machine shop which should be, considering the overall condition of the engine, not necessary.

[simplyconnected]

It was just 1 cylinder that had stuck rockers. As they were not activating the valves that remained closed, we did not had a catastrophic failure.

I read several items about oil restrictions. I came to the conclusion that it was not necessary on this engine. Hope I am right. However I need to get the correct slimmed bolts. Any idea where I can get them? I looked at different places and I am un-successfull so far.
We may turn them in the lathe if can't source a set.

Dave, back to original question, how do you recommend to "clean" the block and heads gasket surfaces? Should I use co****, medium, fine cloth?
I need to get it clean so I can measure with a rule for straightness before we go to the machine shop which should be, considering the overall condition of the engine, not necessary.

Do you have a steel scraper? Use it to remove any gasket material that remains. Sometimes I use a wire wheel on my drill motor.. A wire wheel will clean down to metal. That's all you need, clean down to bare metal without sandpaper or any grinding, Do not remove metal but simply clean down so that the metal does not have gasket material on it.

If you find the block or heads are not flat OR coolant has made deep corrosion in the castings, bring the castings to a good machine shop and let them mill a few thousandths off. What ever they to to one side, they should also do to the other side so all dimensions are the same on both sides or on both heads.

I 'CC my head's combustion chambers'. Meaning, I use liquid to measure the cubic centimeter volume of each combustion chamber. If one end of the head has larger or smaller volume in the combustion chamber, that means it is machined wrong. They should all be equal from end to end and on both heads. If they are different volumes, you will never have a smooth engine. If your compression readings are >10% from the highest compression to the lowest, again you won't have a smooth engine.

Rocker stand bolts for FE engines are available. Here is an eBay offering:
FORD FE BIG BLOCK ROCKER SHAFT BOLTS 352 360 390 406 427 428 CJ MUSTANG,TRUCK, | eBay

Pay close attention to the bolt shanks. Two are different from the other six. I hope this helps. Make sure you don't install the rocker shafts upside down. The oil holes are on the bottom. This is a common mistake, - Dave

[Eric S]

Thank you for the link on E-bay. I am trying with ARP too*.
The 2 different bolts are what I am looking after. I am also aware of the oil on the bottom of the shaft. I already told this to my engine builder. I also gave him all the printed material I had, my mails to and from Shelby and what I printed from https://www.diyford.com.
American V8s are not really rare here but not the main engines we encounter with engine builders and I wanted to make sure he can understand all the details with those engines. He told me he will read that and he appeared to be willing to learn. I will check that on our next meeting.

Thank you for the tips on cleaning the surfaces. I was ready to "scratch" a bit more than mere cleaning.

*ARP is asking for thread sizes and length. Bolts being with engine builder, do you have this information?