Graham’s Corvette Blog and Studebaker bits ‘n’ bobs

I’m exchanging the original crack prone heads from the L48 for a set from a GM crate motor #83417369. The Internet AI info about these heads is as follows-

“The GM 83417369 is a cast-iron cylinder head with a 76cc combustion chamber and 1.94-inch intake/1.50-inch exhaust valves. These were basic, non-performance heads from the “smog era” often found on Goodwrench crate motors. For a performance upgrade, they are often paired with an RV cam, a dual-plane intake manifold, and a 600-650 CFM carburetor to improve low-end torque. “

And that is about what I’m going to do with a Stage 1 cam, flat top pistons, high rise intake and the standard Qudrajet 4 bbl.

The valves and heads are in good shape so I can use them as is with a bit of work. First I’ll clean them up and then cc the combustion chambers to see how even they are. I’m not trying to do an expert blue printing job. I have done this in the past and feel that it is good to get the heads even and also same with the piston and rod weight. The closer I get the smoother the engine will run. The last engine I did this on was a Studebaker 259 R1 (stage one cam from factory) and the engine is very smooth with just a light lope at idle.

Here I’m cleaning up the combustion chambers with a brass wire wheel so as to not damage the valve contact surfaces. There wasn’t much carbon residue.

After cleaning the combustion chambers, including the valve openings, I cleaned up each of the valves on a wire wheel – being careful not to hit the valve/head contact surface. the exhaust valves were fairly clean, but the intakes had significant carbon deposits. May have been the result of poor valve seals on the intakes.

With the valves in place I went on to blocking the spark plug hole with a blob of dum-dum – carefully flattened to the head casting surface.

I used this plastic plate for earlier cc jobs – ignore the hole at the side. The two smaller holes at the top are the important ones. The head is tilted slightly so the to holes are a little up. The plate is sealed to the head with a smear of vaseline around the combustion chamber edge.

I picked up a pipette from Amazon some years back. It is marked off in ccs. I fill it to the top (0 cc) and then fill the combustion chamber. I fill it until the two holes are filled to the top and all the air is out of the chamber. I’m looking for an even combustion chamber volume. t The little extra water in the two fill holes will give me a slightly higher reading, but it will be the same for all cylinders. The final number may be a bit off, but they will all be the same and it’s the evenness that counts.

This particular cylinder is showing about 73.7cc The range of volumes is between 72.0 cc and 75.0cc. So I will need to open up all combustion chambers to about 75.0 ccs. From what I have read it’s best to get them within 1cc of the largest chamber. The heads are rated at 76cc.

There will be very little extra volume in the plug area so I’ll just go with 75 cc heads in my compression ration calculations. In truth it will be a fraction less because of the two holes in the plastic cover plate.

#2 cylinder was the smallest at 72.0cc. I used a small ball grinding bit on my dremel tool to scrape a small amount from the chamber surface and remove some of the shrouding around the valves. The amount removed from each cylinder varied. Final result was all cylinders within 1 cc of 75 cc.

Took a moment to clean out the plug holes after removing the dum-dum used to seal them off while I did the cc work.

Next : More heads than one

New Melling stage 1 cam and lifters have arrived. They should mimic the L82 in that department – ‘Excellent Low End Torque and Horsepower; Good Idle and Daily Usage’ is their claim.

Cam in place with a generous coat of Melling assembly lube. I like the stuff if is thick and very sticky.

With the cam in place I’ll go ahead and put the crank in. I’m using Lubriplate No. 105 as my assembly lube for other than the cam and lifters.

Following instructions that came with the rear seal, I’m adding a dab of red sealant to the ends.

Crank in place with a dab of red sealant on the ends of the rear seal. I may have overdone it a bit. Likely should have only put it on one side. Hopefully it won’t come back to bite me and I end up having to replace the seal with the engine in the car. I’ve done it before. Not too hard, just a bit messy and a bother.

Crank firmly in place with mains torqued to 80 ‘#

With the main caps in place it was time to check the crank end play. I moved the crank back and forth with a rubber dead blow hammer and then did the check. The clearance wasn’t even all the way around. I got measurements between 0.002 and 0.003 where I could get the feeler gauges in. So within spec of 0.002 and 0.006.

Next: on to the heads.

I wiped the mains before setting the crank in the block on new bearings.

I put a short strip of plastigage that can measure between 0.0015 and .003 on each main.

I then put all the main caps in place with the new bearings and torqued them all down to 80 ‘#. I measured each and I came up with between 0.0015 and 0.002 for numbers 1 – 4 and 0.003 for the rear main. So all withing GM spec 🙂

Main bearing caps in place. Best way to avoid damage to the new bearings. I’ll leave the crank out until the new cam arrives. It will help to have access to it from inside the block so the chances of bearing damage is minimal. So waiting on Rock Auto now.

Next: Cam and crank

The mains and journals are showing minimal wear. The journals are at 2.1″ which is the original dimension and the mains are at 2.447 which is close enough to the original 2.448 for me to go with standard mains and journals.

Just a bit of sanding and polishing to clean the mains and journals. I’ve used 1000 wet paper followed by wet 1500 and then dry crocus cloth to clean them up a bit. This should do the job nicely for my DIY engine job.

The rear seal mating surface is not nice at all. 20 years of sitting and some condensation rested on the crank in that spot and I can’t get the pitting out with hand polishing. I may have to live with a little leakage at that point. Although the engine when it was running, didn’t leak excessively from that point. More came from the trans front seal – red oil.

Last task in the crank cleanup is running a brass wire brush and WD40 through all the cross oiling holes. With that done the next job will be to set the crank in place with the new main bearings and check the play with plastigage.

I’ll want to hone the cylinders before I start setting the crank in place.

I tried using my bar hone to do the cylinders but for some reason the cross hatching looked course even with lots of oil. The oil may have been too heavy.

I borrowed a ball hone from my buddy Don and went at it spraying varsol on the ball and in the cylinders.

I came up with a nice fine cross hatch. There are still some minor imperfections, but the engine ran fine before – baring the burnt valve – so I don’t see why it shouldn’t with new rings..

The out of round measurements are all 0.0015 or less and the taper is .002 or less. That is a bit outside of the limits in the GM manual, but what I am reading online about GM 350 engines says that I’m OK with it’s present shape – not perfect, but likely serviceable for a good may miles.

Next: getting the crank in place.

I couldn’t put newly upholstered seats back into the rusty chipped seat frames. So I’ll take a bit of time and clean them up a bit. and put some black rust paint on the metal parts.

Next warm day I’ll get a couple of coats of light beige paint on the frames and hinge covers.

The stainless on the seat tracks is rusting a bit, but I won’t worry about that too much. The mounting plates have some more serious rust so time to clean off the rust and coat with black rust paint. Good time to lubricate the little ball bearings with WD40 and they now run smoothly.

Next: Back to the block

Back from R&D all cleaned and with new cam bearings installed.

I”m using some Permatex thread sealant on the frost and oil plugs just to sure of a good seal. I’ve used this on head gaskets as well.

I needed to get the frost plugs, cam hole cover and oil passage plugs in place before putting the engine on the stand for re-assembly.

Ready for re-assembly. Before I fit the crank I’ll hone the cylinders with engine oil and a bar hone to remove any glazing. I have a new cam and lifters, pistons and full gasket kit coming from Rock Auto.

Next: back to interior

The ‘proper’ antenna for the Chevy to replace the generic 3 part mast on the car.

First problem is that the tabs need to be bent inward for the antenna base to fit properly.

Here it is finally in place. The original setup didn’t allow enough treads to show above the fender to allow the big top nut to fit. In the end I had to use a dremel tool to cut the mounting plate grooves lower to allow the antenna base to rise farther up the hole in the fender. It should have been an easy fit, but as is often the case with aftermarket stuff the fit is bad. Also the parts book and some venders show a large ground plate of thin aluminum that should be mounted between the ground plate and the fender. No way I could have made that fit. As it is I was just able to get the big nut on the top to fix the antenna in place!

Getting the soundproofing in place. A real bear of a job getting in all the tight corner spots at the back. Lots of sharp edges so lots of scrapes and cuts.

Sorry for the poor image. This is the 120 mil product I’m using. One package covers about 30 sq. ft. that was enough to get the back done and the front sections of the foot wells. I plan to use it on the hood as well so I’ll need to order another package. The total will be about $200 by the time I’m done. Oh yes, not made in Russia, but in a country that used to be part of Russia – Kazakhstan.

Next: the engine block is back 🙂

Seam sealer applied to all the seams where the original material came loose. Not as neat as the factory work, but functional. It was the end of my can of seam sealer and it was not as soft so it didn’t want to go on with a brush. In the end I used a putty knife to apply it.

While waiting for the paint to dry I sandblasted the seat hinge covers and will paint them in fawn vinyl paint. This was the winter to do the interior work. I wasn’t planning on doing the engine as well. I still hope to have it all together for the spring. My work on the “66 Studebaker will have to be delayed. It’s working fine, but I did plan on replacing the rear end with a rebuilt twin-traction unit. That’ll be next winter’s project.

Lots of bits to paint. The pan bolts tend to rust so I decided to paint them and the whole pan as well. It’s stainless, but it was actually starting to rust on the front side.

The package shelf trim needed a repaint and I did it in Tremclad satin black.

Hard to get a good shot of black paint. The paint came out OK. I put it on thick so it took a day or so to dry. As soon as my sound deadening mat arrives I can get the interior finished.

Next: antenna install and on to putting in the sound deadening mat.

The security blind is mounted with three 1/4″ bolts across the front and one on each side – above is the left side. they are all mounted in brass rubber insulated nuts. If the screws had also been brass they would have come out nicely, but they are steel and they rusted of course. The three back bolts came out through the 1/2″ holes in the fibreglass. The end nuts were also seized and just spun in place.

My answer to the end bolts was to use a metal cutter to free the frame from the bolt head. Worked well as there was a raised area around the bolt head and so I didn’t cut into the fibreglass.

A much bigger hole, but I can handle that with large body washers that have small holes to handle the 1\4″ bolts

With the head free from the frame I was able to push it back and then get a hold on the rubberized nut on the back with vice grips.

Bolt out and no damage to the 1/2″ hole.

I had to expand the three blind holes holding the main body of the security blind so I could get these plaster board 1/4″ screw fittings in place. The grommets will seal the holes in the fibreglass. The two other bolts will hold the ends in place. I’ll push the bolts in from the wheel well(with sealant around the hole) and use nuts to tighten it all up. The grommet will fit in the fibreglass 1/2″ hole to help keep the bolt steady.

The body mount bolts on both sides are a bit rusty, but still quite solid. I’ll give them a good coat of heavy rust check once the sound deadening material is in place.

A layer of 50 mil sound deadening mat covering the area behind the security blind roll and frame. The mounting holes have been expanded from 1/2″ to 5/8″.

I’m using the left over Kilmat product here. I won’t be buying anymore as it’s produced in Russia. I’ve ordered another product (120 mil) that is likely made in China, but could be from the US. It’s a Siless product.

A bit of work and the security screen and bracket are in place 🙂

Next: more floor work.

Seats out once again and cushions removed and ready to go the upholstery shop.

Besides the engine work, which I had not planned on, I was planning to add sound deadener to the interior panels. All the carpeting needs to be removed for that.

A previous owner had fitted 1/2″ foam to help keep the noise down. I’m told that foam is good for absorbing sound inside the car to keep it from reverberating, but you need heavier buytl like stuff to keep the sound from coming into the car.

Lots of crud build up on the floors and most of the paint was loose . This year of Chevy used the metal floors. I’m surprised they lasted so well. Some surface rusting, but still quite solid. Just need a cleanup, resealing the joints and then a good coat of paint.

Lots of scraping needed.

A lot of the seam sealer came away with the crud on the floors. Looks like a factory drain hole in the floor – likely helped to save the metal. I’ll keep that open just in case…

Not sure what happened here. The hole may have been there or maybe I did the damage moving engines in and out.

First layer of fibreglass in place. I’ll add another layer to the inside and then two to the outside.

Ditto as to crud on the passenger side. Although a lot less paint peeled away.

Not showing was a layer of felt like material that was on the flat area and the back up to the security blind. The nice factory insulation over the wheel wells is still in place and in good shape.

Next: problems getting the security blind out.