Pulled my Head to Look Inside the Top of the Engine

[Tom Wesenberg]

Last week I had trouble sleeping, so in the middle of the night I pulled the head on my 28 to see what I had. The cylinders are in nice shape and the pistons are stamped +.015, but the rear two pistons don't match the front two, so I'll buy a new set. Notice the rear two pistons have centering pockets, but the front two don't.

After all the overheats this engine has been through, I expected to find a head gasket ready to blow through, but it was still in good shape. I have a better engine to drop in, but want to tear this one down for an overhaul and see what was making the ticking noise. I still think it was piston slap from an overheat, but won't know until the weather warms up.

I was also curious to see how the 30 days of vinegar effected the head gasket, and I was glad to see no ill effects from it. I also wanted to see if the vinegar, and later the Evaporust had eaten away all the rust, and it looks like it did a good job.

In a recent post I mentioned how an engine that uses oil due to worn rings will wash the carbon from the outside edge of the piston tops. This engine used very little oil, but you can see how the carbon has been washed away on the front and rear pistons, which haven't been scraped clean yet.

The valves have a thin edge, so I'll probably buy 8 new valves also. Notice the color on the first valve, just barely showing in the first picture. It might have a slight seating problem.

[hardtimes]

Hey Tom ,
Thanks for sharing ....at 2AM !! Woke me right up !
Notice any cracks at all on top of block ? Those cyls look pretty smooth and can not see any ridge ring. Do you know history, as in how many miles on engine since .015 pistons, etc. LOTS of oil about, eh. A guy once told me...'yup, you want to see lots of oil covering things automotive, because that keeps things in good shape'. Hmm, looks like yours will be in good shape

[Y-Blockhead]

Originally Posted by Tom Wesenberg

This engine used very little oil...

Tom, were the tops of your pistons that 'wet' when you pulled the head? or did you put something on them to clean? or coolant?

[Joe K]

And what did you have for compression numbers prior to the dismount?

If you're like me you may not have a way to read them.

If you're REALLY like me you might not have bothered to get them.

"Impulse wrenching" my wife calls it.

Joe K

[tbirdtbird]

that must be an older 7013 gasket, the webs look wider than what we get now on the R4

[Tom Wesenberg]

Sponsored Links (Register now to hide all advertisements)

Yep, it's an older 7013 gasket and after several overheats and nut retightenings it is squeezed very thin. Wish I could find more like it.

50 lbs. compression on all 4 and good power. I poured oil on top of the pistons and cranked it over a few times, so it won't rust over the winter. No measurable ridge, and I don't know the history of the engine. It's just an "as is" thing I put in to keep the car on the road while I restore the original engine. I'm hoping new pistons, rings, and valves will put it back in good shape.

[mshmodela]

Great post, I look forward to reading how your rebuild goes... I hope you get better sleep...

[MikeK]

Just to throw a little abstract thinking in here, it is possible the front and rear pairs of pistons are different bore sizes. Are all four marked 0.015?

[Tom Wesenberg]

Originally Posted by MikeK

Just to throw a little abstract thinking in here, it is possible the front and rear pairs of pistons are different bore sizes. Are all four marked 0.015?

I was thinking the same thing, but the middle two that I cleaned are both marked +.015. Tomorrow I'll clean the other two and use my inside mic to check the size. I might have to hone them to .020".

[George Miller]

At first when I seen all that oil on top of the pistons. I thought the guy that posted the other day that, we do not need good oil rings had worked on your engine.

[Rex_A_Lott]

I'd be more worried about the rust and the crud around the valves and on top of the block...as in, where did it come from and why is it still there? I've never really seen that on a running engine, although I've only torn down a few.
But, nobody else mentioned it, so maybe I worry about nothing. Good luck with the rebuild.

[Tom Wesenberg]

The rust got there because I used water after each overheat and rinsed the block with water at the begining of August, months before pulling the head. This engine hasn't turned since that time, so it sat around and got some rust. I'll clean it up when I take the engine apart. The main thing is to keep it oiled now so the cylinders don't rust over winter. My garage floor has a lot of road salt soaked into the concrete from my dad driving his cars in every day during the winter, and that salt really makes things rust. I layed down plastic and covered it with old carpet, but things still rust from the damp unheated garage. I wanted to spray ATF on the bottom of my Model A again, but the winter came much too soon.

[BlueSunoco]

Engine looks pretty good overall to me.

Interesting about road salt soaking into your concrete garage floor. Never gave that much thought before. I regularly wash both garage floors, new garage has a sealed floor only one stall there used for a modern car.

[Jim Brierley]

tom, no need to buy new pistons if they all come to the same height and weigh the same. have fun

[Rex_A_Lott]

Originally Posted by Tom Wesenberg

The rust got there because I used water after each overheat and rinsed the block with water at the begining of August, months before pulling the head. This engine hasn't turned since that time, so it sat around and got some rust. I'll clean it up when I take the engine apart. The main thing is to keep it oiled now so the cylinders don't rust over winter. My garage floor has a lot of road salt soaked into the concrete from my dad driving his cars in every day during the winter, and that salt really makes things rust. I layed down plastic and covered it with old carpet, but things still rust from the damp unheated garage. I wanted to spray ATF on the bottom of my Model A again, but the winter came much too soon.

Ah, it makes more sense now.
Years ago somebody gave me a gallon of some stuff called CLP...Cleaner, Lubricant and Protectant. It had a Mil-Spec number on the label, and it was Military Surplus stuff. I really like it for just what you are doing, just put it in a spray bottle and coat it liberally. Not sure if you could find it where you live, and I havent searched for it here lately. Not quite the coating of Cosmoline, it will wash off easily with kerosene or gas.Just a thought.

[C26Pinelake]

Tom. Always read and enjoy your posts. Will keep checking back for Progress reports.
Wayne

[Tom Wesenberg]

Originally Posted by Jim Brierley

tom, no need to buy new pistons if they all come to the same height and weigh the same. have fun

I've never been a fan of mismatched parts, and these are .015, which are hard to come by, so I may have to rigid hone to .020" and buy a new set. With the engine all apart there is no use in trying to get by with worn parts. I could maybe knurl the pistons, but my knurler has vanished (stolen) so I might as well buy new pistons.

When I was in the Army I took my Honda 50 to Texas, and it would only go 30 MPH, while it did 45 when I had it at home. I lapped the valves and installed new rings, but they helped very little. The Honda dealer said I should buy a new piston, even though I told him the rings fit the grooves very nicely with no excess side play. For $10 I put in a new piston and the bike was back to 45 MPH. I wouldn't have believed it if I hadn't seen it first hand.

[Tom Wesenberg]

I used my inside micrometer to measure the cylinder bore at the top 1/8", where the rings don't wear the walls. It's no wonder this engine always sounded so loose. I only measured the middle two, but #2 was .028" over standard and #3 was .022" over standard, while the pistons are marked .015" over standard.

No chance of locking this one up on an overheat.

Sure hope the bottom was done with more accuracy than the top.

[John Duden]

Aww hone it up ad dump some new rings it! she will purr like a kitten!

[Rich in Tucson]

Tom are those 0.015 over on sleeved cylinders and if so what say you on the sleeves-contribute-to-overheating issue?