OT - 327 Chevy wrist pin gouges cyl. wall

Billy NY · Jul 1, 2020

Never came across this before, any idea the cause?

Then back story is the motor was rebuilt, say as was needed, cylinders just honed, new pistons, forget what was done in the heads, this was late 90s. So that cylinder lost compression. Friends 62 SS impala.

In my new shop, we just got the motor out and on the stand.

We've got a motor done by a reputable machine shop/engine buider going back in. Done right. My thoughts are that something was off with the previous work or parts, knowing the fine details of proper machine work.

The car has been brought back from the ground up,years in the making, long long story there

Steve@Advance · Jul 1, 2020

The wrist pin just presses in the eye of the rod, no clips, just a press fit.

Something allowed it to move. It probably got pressed crooked and stretched the hole in the rod or split it.

That's a shame...

rustred · Jul 1, 2020

i had the same thing happen in the 1970's on my 390 ford engine. snap ring came out and was in the oil pan and wore the same groove in a cyl. this one must not have had the correct press fit.

Billy NY · Jul 1, 2020

Like you and Steve said, seems to be the cause, amazing the gouge, that block was bored 2x anyways, new one is or was a numbers matching 327 corvette motor, bored 1x now, he used 202 heads on it, should run really nice, the previous was not right for quite some time. We both can't wait to get it done, been down there helping him for 2 weeks now.

Pycoed · Jul 1, 2020

(quoted from post at 23:49:15 07/01/20) Never came across this before, any idea the cause?

Then back story is the motor was rebuilt, say as was needed, cylinders just honed, new pistons, forget what was done in the heads, this was late 90s. So that cylinder lost compression. Friends 62 SS impala.

In my new shop, we just got the motor out and on the stand.

We've got a motor done by a reputable machine shop/engine buider going back in. Done right. My thoughts are that something was off with the previous work or parts, knowing the fine details of proper machine work.

The car has been brought back from the ground up,years in the making, long long story there
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto49168.jpg">

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto49169.jpg">

<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto49172.jpg">

Mini Cooper "s" back in the day had the same issue. Gudgeon pins were a press fit in the con rod & floated in the pistons. I had one go on a special rally mini I built - but only after 60,00 miles . Exactly the same as the pictures shown. The recognised prevention was to machine Teflon or ally buttons in the ends of the gudgeon pins which prevented them moving & shaping the bore.

neverfear · Jul 1, 2020

Ouch! No matter the cause,that's just nasty!
Keep us posted on what you find with that rod when you get it pulled down.

CenTex Farmall · Jul 1, 2020

If forged pistons then it might have full floating pins then it could be a snap ring got loose or probably wasn't secured in the first place.

Press fit pins don't move but it is *possible* that is was pressed in the wrong distance but had just enough to allow assembly. The rod side clearance allowed it to rub. I say "pressed in" but in reality you heat the rod end and then quickly set the rod in place and slip the pin through. Once it cools it shrinks on there. A fixture is typically used so the pin ends up where it is supposed to.

It possibly could be sleeved if the block is important. Some of those early 60's blocks were pretty generous with iron and have thick walls. Some of the early 283's would take a .125 overbore and you could build yourself a 301.

gab · Jul 1, 2020

I've seen that on the floating pins when a snap ring comes off but never on a Chevy engine.

Philip d · Jul 1, 2020

That’s a beautiful car! Wonderful job on the resto! My Dad would have loved that car,he had a 62 Impala SS but with only a 6 cyl but then had a 63 4dr hardtop Pontiac with a hot 327. Again congratulations on a great job restoring a beautiful car.

D Slater · Jul 1, 2020

Worked in a repair shop in the early seventies and sleeved one hole in a few blocks that happened to.

Hobo,NC · Jul 1, 2020

Someone's best guess was wrong...

I have done 100's but no more one bit me, now I have it done by someone that has the equipment and the jig/set up to do it... I stopped guessing : )...

Hobo,NC · Jul 1, 2020

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

timcasbolt · Jul 1, 2020

I did that one time. Was trying to install the rods on the pistons without the correct press fixture. You heat up the rod and put the wrist pin on ice. Then, as quick as you can, you shove the pin in while simultaneously holding everything perfectly straight. Yea. Once. I didn't realize you could permanently enlarge the hole in the rod if you get it hot enough. On the upside, we sleeved that hole and put it back together. Ran good.

teddy52food · Jul 1, 2020

That pin is too loose in the piston. When the pin gets hot from the rod heat , it will
be tight in the piston until the piston warms up too. Also the pin & piston should be
oiled before assembling.

Goose · Jul 1, 2020

I'd say the wrist pin wasn't centered properly, assuming it was a press fit.

Back in the day when I rebuilt lots of SBCs, I fabricated a press specifically for doing SBC wrist pins.

buickanddeere · Jul 1, 2020

As previously stated, sleeve the block .
I wonder if anyone makes a 3.75 stroker crank and 6.0 rods in the small journal size . Another 56 cubic inches will add lots of extra snort .

dr sportster · Jul 2, 2020

A wrist pin clip must ne installed with the opening on the top or bottom not facing the side where inertia can pop it out.

Billy NY · Jul 2, 2020

Will do, we are both curious to see what it looks like.

Billy NY · Jul 2, 2020

I'll forward your kind words, his dad had 2 of these, think both were 409's. The removal and replacement of rusted out steel was a very tedious process, amongst other things, he could write a book about this restoration, I think he should.

Billy NY · Jul 2, 2020

Really appreciate hearing everyone's feed back on that wrist pin and cylinder wall!

OT - 327 Chevy wrist pin gouges cyl. wall

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