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1965 El Camino 327 engine project

John Conroy

John Conroy

member
Premium Member
My buddy Al had been chipping away at this 65 El Camino for as long as I've known him, more than 30 years. He's a licensed, highly skilled autobody technician, now retired. Like me he now has time to take on and finish projects we didn't have time for while we were still had those pesky jobs. Some 20 years ago I rebuilt the heads for this engine and now that the body work is getting close to finished Al wants to get the rest of the engine ready. He dropped off the block, crankshaft, pistons and connecting rods at my shop last week. The parts are all quite a mess as they have been stored in an unheated, leaky shed for more than 40 years. I got to work cleaning away the years of bodyshop dust and rust on the block and crank to prep for machine work. The rods and pistons were all very corroded so I wanted to press,out the wrist pins and glass bead the rods before sending them to be re-sized. After a full day of cleaning, measuring, disassmbly and bead blasting I dropped the block, crank and rods, off at Trac Engine, my go to engine machine shop in Edmonton. I'll post more pics here later and update as the project develops.
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That's awesome John! Glad to see there's more people out there than just me. I bought my '68 Shelby in 1978, and it's been apart since 1982! I've been rebuilding it since I retired five years ago. As luck would have it I picked up a motor block from the guy that I bought the car from bought the car from, just last summer. He is pushing ninety and still into sixties cars along with his son. It's been a long time coming, but keeping the car keeps the dream alive and reading posts like yours is inspiring!
 
Those rods and pistons didn't just come out of the block didn't just come out of the block did they?:eek:
 
The bead blasting on rods came out nice. Can you do a similar treatment on pistons or that's off limits because it alters critical dimensions?
Those are cool vehicles. Cant be too many of them driving around.
 
The pistons and rods were out of the block and had been stored in a shed. The block and crank were in his shop and covered with 30 plus years of bondo dust.

This is an original L79 small journal 350HP 327 but not the original one. The engine number identifies it as a 1966 model year. Made to sing, peak power at 5800 rpm. It came with 11 to 1 compression forged pistons, most of these did not survive as they usually got abused heavily. We have a set of period correct .030" over size pistons and the crank will be re-ground to .010" undersize on the mains and throws. We have a OEM L79 camshaft and the small chamber big valve heads that were used on these. Trac Engine Service will bore the cylinders and fit the pistons, re-grind the crank, install the new pistons onto the rods after the rod big ends are re-sized and replace the cam bearings. I'll do the rest and document it here.
 
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I wanted to bead blast the rods before sending them to Trac so I made the tools for the job. I'll post pics of that later but for those of you who have never seen this done I posted a short vid on YouTube. The wrist pins are a very tight interference fit into the rods. The small end of the rod must be heated before pressing a wrist pin out or into a rod or the small end bore will be galled and the rod ruined. When I put the rod/piston in the press I preload the press with about 1000 lbs of force on the wrist pin. If you listen during the vid you will hear two pops as the pin releases from the small end bore of the rod after I start heating it. It takes about 1500-2000 lbs force to finish removing the pin. Normally I would have the machine shop separate the rods and pistons but I wanted to clean up the rods.

 
It's important to use the correct fixture when pressing a wrist pin in or out. If you screw up here the piston, rod or both can be ruined. With pressed in wrist pins there is no way to do it without heating the rod. Engine machine shops have a "rod oven" where the small ends are all brought up to temp and the pins pretty much drop in on assembly. Removal is done with less heat and more force as show in the video. If the pin does not press out smoothly not enough heat has been used and the rod could be damaged. This is the tool set I made for these pistons. The narrow shoulder on the piston around the pin boss sits on the similar sized shoulder on the tool and keeps the piston pin bore vertical during the pressing. The 2 flats on the sides are to clear the ring area. The pusher part is made from an old differential pinion shaft with one end turned to match the ID of the wrist pin.









During clean up of parts I found the cause of this engine's demise. The number 5 piston shows evidence of heavy detonation. The telltale signs are the broken ring lands and the "4 corner seizure" you can see by the vertical galled strips on the edges of the skirt on both sides of the piston.





 
The L79 327 came from the factory with a Holley 600 CFM carb and an aluminum intake manifold. Somewhere in it's life this engine got an Offenhauser intake manifold and the 780 CFM Holley that started life on a 1965 Chevelle Z16 396 big block.
I picked up a rebuild kit for this 4150 series dual fuel inlet carb. It's a liitle odd as it only has 1 accelerator pump and has vacuum secondary venturi control. The sales guy at Mopac said this kit has enough parts to do a 4150 or the later style single fuel inlet 4160 carbs. I hope he's right.









 
Awesome @John Conroy - well done!! For our small end bearings we dry ice or liquid nitrogen them into place - same with cam bearings. For removal the small ends are 20 ton press with custom tooling and the can bearings are 16 ton. Not an operation for the faint of heart - especially the cracking into place
 
Where does someone come across dry ice these days? Cylinder set liners for my tractor are due to arrive any day and this was a method recommended to fit them


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@kevin.decelles, we typically order in a cylinder of liquid nitrogen. The dry ice is too slow for the most part costs more and - takes longer to cool the bearings. We have also used liquid oxygen - just once - major clean required and never will do again. You can do “something” with CO2 like spraying an extinguisher but ya gotta be fast
 
@YYCHobbyMachinist - any grease/oils are highly reactive with oxygen - rapid oxidation and possible explosion. Probably more so where pressure is involved- but, to remove all danger, we had to scrub everything with degreasers. Final parts were cleaned with acetone.
Parts in question were the connecting rods and the small end bearings. The bearings are about 150 mm diameter. New bearings(bushings) are clean but the con rods are oily. Given the con rod weighs about 130 to 150 pounds and the bushing is about 3 pounds it takes a few feats of strength and precision- a good work out.
 
Brent H said:
@YYCHobbyMachinist - any grease/oils are highly reactive with oxygen - rapid oxidation and possible explosion. Probably more so where pressure is involved- but, to remove all danger, we had to scrub everything with degreasers. Final parts were cleaned with acetone.
Parts in question were the connecting rods and the small end bearings. The bearings are about 150 mm diameter. New bearings(bushings) are clean but the con rods are oily. Given the con rod weighs about 130 to 150 pounds and the bushing is about 3 pounds it takes a few feats of strength and precision- a good work out.
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Yup which is why petroleum products are never used on anything having to do with oxygen. Pressure regulators on oxygen tanks for example must never have any oil on the threads or in the mechanism.
 
kevin.decelles said:
Where does someone come across dry ice these days? Cylinder set liners for my tractor are due to arrive any day and this was a method recommended to fit them


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Click to expand...
Air Liquide in Edmonton carries dry ice Kevin, maybe the Calgary branch does too.


Brent I think I'll stick with connecting rods I can lift with one hand! LoL
 
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Way back in my mechanic career working in an engine machine shop, we never heated rods to remove wrist pins. Just pressed them apart. The issue with heating is that you would be heating both rod and pin so little use as the both will expand equally. Seldom were the pistons and pins reused anyway, but they really did not gall or mar coming out.

For assembly, heating the rod small end was done using the task specific heater you described which made the pin slip through the rod freely. You had to be quick though to get it in before the rod cooled. Part of the heater we used had a special fixture for holding the piston and had a stop guide to ensure the pin ended up centered properly once it was pushed through. Over the five years I worked in that shop I probably did a thousand or more of those.

This is the same unit we used.
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I had a 327 with the offenhawser spreadbore intake and a 650 holly spreadbore with vacuum secondaries we found the 750 was too much for it.
 
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