Getting my hands dirty on a Chevy 235 [infos welcome]

"Rustholes-Are-Weight-Reduction" (rustholes-are-weight-reduction) 10/25/2016 at 10:08 • Filed to: BEL AIR, WRENCHING

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After having a 2 hours commute (4 hours a day) for 18 months leaving no time at all to have an actual life, I quit my job 10 days ago (I actually quit a while ago, but had a 3 months notice).
So I’ve been jobless since last week, but have not been (entirely) lazy.

The 6 cylinder 1960 Bel Air I bought sight unseen some weeks ago didn’t run well, so I decided to check its compression:

First I cried, then I considered calling Steve Lehto, and finally resigned to opening the engine.

Head out:

Pistons out:

The piston rings were all broken, my first hope was that throwing in a new set would fix the problem. Then I saw this:

The first piston ring on cylinder 6 broke in small pieces and destroyed the piston. Two small pieces even overlapped and stuck in the groove. And the walls of cylinders 3 and 4 looked like this:

After measuring the cylinder diameter, I figured it must have been rebuilt in the past, since the original 90,50 mm diameter had become 90,90 mm. and the pistons were Mahle pistons, which are not original either. 0,40 mm is about 0,016" oversize, so there should still be enough material left to go to 0,030" or 0,060" oversize (the grooves are deep).

I took the rest of the engine out to get it rebored:

The alternative would be to get new cylinder sleeves and take it back to original specs. I haven’t found a source for cylinder sleeves yet, but that would be the first choice (I’m open to any suggestion).

crowmolly > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:14

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So it’s already .040 over and you want to go another .030 or .060?

You *MIGHT* be able to go up to ~.090 over but you won’t get .130.

Getting pistons might be tough as well, they are probably going to be a custom order.

I hate saying this, but how hard is it to get another Chevy engine? It may be cheaper than going to the trouble of rebuilding a 235 in this condition.

Snuze: Needs another Swede > crowmolly 10/25/2016 at 10:16

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I think he’s .040mm over, which is only 0.016", so he should be able to go up to 0.030" or 0.060" with no problem. It’s all going to depend how deep those grooves in the cylinder walls are, though.

cletus44 aka Clayton Seams > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:17

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Have you considered buying another straight 6 engine/block and building that?

Snuze: Needs another Swede > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:17

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I would lug it to a machine shop and ask them to look at it first. Over-boring will be much cheaper than re-sleeving the block, so long as there’s enough meat in the cylinder walls to do it AND you can get pistons for it. It would probably be worth the few extra bucks up front to investigate before diving right in.

Rustholes-Are-Weight-Reduction > crowmolly 10/25/2016 at 10:24

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As snooze said, it’s 0,40 mm over, so I have a little room left. But it depends on the depth of the grooves.

I would swap the engine, but getting one in Europe will be tough. I’d rather go to a V8 then, but that would be illegal in France.

Rustholes-Are-Weight-Reduction > Snuze: Needs another Swede 10/25/2016 at 10:24

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Exactly, I hope I can save it.

Snuze: Needs another Swede > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:25

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What about doing a V8 swap is illegal in France? Do they not like V8's, or does the engine have to be the same configuration as what’s in the car or something like that?

crowmolly > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:26

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Thanks, I wasn’t sure if I was following right as going .016" in the USA is odd. :)

.030" or .060" is no big deal then!

OPPOsaurus WRX > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:29

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whats the legal limits on engine swaps? Could you go electric motors?

Rustholes-Are-Weight-Reduction > Snuze: Needs another Swede 10/25/2016 at 10:30

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It depends on the price of the sleeves, I can get it rebored for 60€ per cylinder. If the grooves are shallow enough, of course. I can install the sleeves myself, with the help of my father.

Rustholes-Are-Weight-Reduction > cletus44 aka Clayton Seams 10/25/2016 at 10:31

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Not really an option here in Europe. I have a 5 cylinder Volvo engine I could put in, but that wouldn’t be legal here.

Snuze: Needs another Swede > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:32

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Ahh, gotcha. I’m not terribly familiar with resleeving, I looked into it once on a motorcycle engine, but it was iron sleeves in an aluminum jug and it was going to be absurdly expensive. Iron liners in an iron block may not be too bad then.

crowmolly > Snuze: Needs another Swede 10/25/2016 at 10:33

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Redoing two holes with sleeves in an iron block is not THAT big a deal, especially in a lower power application like this.

Rustholes-Are-Weight-Reduction > Snuze: Needs another Swede 10/25/2016 at 10:33

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You’re not allowed to change the specs of your car in France. You wouldn’t even be allowed to put a weaker engine in.

Rustholes-Are-Weight-Reduction > crowmolly 10/25/2016 at 10:35

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Yes, 0,016" is odd, it must have been rebuilt in Europe. Is has been in Turkey since the 80's. the use of Mahle pistons would suggest that too.

Snuze: Needs another Swede > crowmolly 10/25/2016 at 10:36

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True, as I said in my response to Rustholes, I have limited experience in resleeving - I was looking into it for a niche application and it was going to be extremely pricey. I (wrongly) assumed all resleeving was similarly pricey.

Rustholes-Are-Weight-Reduction > OPPOsaurus WRX 10/25/2016 at 10:37

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Nope, original or bust. Making it legal after a swap is technically possible, but it involves a lot of paperwork and tests and money. Nobody does legal engine swaps in France for this reason.

Snuze: Needs another Swede > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:39

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Hmm, that’s interesting. Also rules out my suggestion.

I was going to suggest looking into an Atlas 4200. It was a 4.2L (254 cubic inch) DOHC, VVT, fuel injected I-6 used in some Chevrolet and GMC SUVs. It makes 270-290HP depending on the application and probably gets way better gas mileage and has way lower emissions than that old 235.

crowmolly > Rustholes-Are-Weight-Reduction 10/25/2016 at 10:39

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A nice thing is that going .030 or .060 over puts you in the realm of off-the-shelf stuff for an American car. I looked up a set of cast pistons for your application and they are ~$120 USD. Will surely be more in France, but you don’t have to get custom ones that are way more expensive.

Rustholes-Are-Weight-Reduction > crowmolly 10/25/2016 at 11:02

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That’s why I thought of those sizes, I can get cheap parts on RockAuto if I go with standard oversizes.

cletus44 aka Clayton Seams > Rustholes-Are-Weight-Reduction 10/25/2016 at 11:09

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Thought that might be an issue. Darn. If it were my car, I’d find some old small block Chevy V8 to swap in just to get it moving around again. it won’t be correct but it would work.

cletus44 aka Clayton Seams > Rustholes-Are-Weight-Reduction 10/25/2016 at 11:10

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Explain to me how that would be illegal in France? I know little of their laws but this sounds odd.

Rustholes-Are-Weight-Reduction > cletus44 aka Clayton Seams 10/25/2016 at 11:17

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A car has to stay in original configuration, so to be street legal, a car has to have its original engine (or the same as the original one). You can’t remove the cat, go from carburated to fuel injected, you can’t add a turbo or supercharger, you are restricted in wheel sizes, and so on.
If I could legally change some things, I would put a modern engine in it and daily it.

BvdV - The Dutch Engineer > cletus44 aka Clayton Seams 10/25/2016 at 11:20

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It not illegal per se, however you need to re-homologate the car. Meaning that all of the used parts need to be up to oem specs. The homologation proces will easily cost €1-2k if the setup is different from what the homologation department knows as how the manufacturer intended it.(this is all based on the Dutch system, however France should be similar due to EU laws)

kanadanmajava1 > Rustholes-Are-Weight-Reduction 10/25/2016 at 11:27

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That’s nasty. I think that pistons rings might have taken the damage when the engine got new pistons and pistons ring grooves moved to different places. Then the new rings had a change to hit the edge caused by the wear. This is fairly common problem if the edge isn’t machined off.

Luckily the pistons were tough enough not to shatter into pieces.

cletus44 aka Clayton Seams > Rustholes-Are-Weight-Reduction 10/25/2016 at 11:29

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Gotta love laws that restrict people from putting cleaner, more efficient engines into cars.