Topic: Delrin wrist pin "buttons" on a daily rider, and other 836 questions

[JLeather]

My daily rider has developed a number of top-end oil leaks which I'm using as an excuse to put together a new motor outta parts I've got lying around.  Got a few Q's.  For starters, I've got a cast 836 kit from ART with a good set of bored jugs and a good set of rings.  I'd like to use it.  Is there a problem using a cast 836 kit a lot?  I'm not planning on turboing or spraying this one, just running it.

Second Q, this set of pistons was removed from an engine I picked up in a trade and they were assembled with these white delrin "buttons" that keep the wrist pin in line.  No circlips.  Can I use these in a daily rider, or are they only good for a strip-use engine?  Do they disappear in a few thousand miles leaving my wrist-pins gouging the cylinders?

Topping this budget winter build is an Andrews "A" Grind cam.  It's listed under SatanicMechanic's website as a mild street-build cam.  Anyone use one of these?  It's the cam that was in the motor when i pulled out the ART 836 kit.

Feeding the build will be a set of 70's "Do It Yourself Eng" twin carb manifolds.  I haven't got carbs yet, but it will probably be a set of Mikuni 34's.  Exhaust is gonna be through an RC Engineering 4-1 pipe.

Dyna ignition with Accell coils and wires for spark.

Anyone got any thoughts, concerns, warnings, tips, etc, etc?  Anything I need to do to the bottom end on this one?  I'd like to leave the bottom end together if I can.

[dusterdude]

cast pistons are fine if you arent going to dog the motor,cant help ya on the buttons.

[Jinxracing]

I rebuilt a VW engine years ago and used Teflon buttons in place of the wristpin circlips. I put about 10,000 hard street miles on it before I sold the car. Last I heard the motor had been moved into a different car but was still going strong. Not sure how that story helps, but thought I'd chime in anyway. 

[bryanj]

One of the most famous names in Industrial/Marine/Truck diesels is Gardiner which will regularly do 500,000 to 1,000,000 miles before rebuild and they use to use brass buttons

[Terry in Australia]

Yeah, it shouldn't be a problem mate, I just bought a stick of 15mm Teflon to machine up some buttons and asked the supplier how long they'll last for, and he said that they'd been selling teflon for this purpose for years, and have heard of a failure yet.

I must check out Axels site, I've got an Andrews "K" grind cam, and need to get it reground to a milder spec for a mild 836cc engine I'm building soon, I had an "A" grind cam in my (otherwise stock) K1 26 years ago, and it pulled really well! Cheers, Terry.  

[Jonesy]

Verify what material they are. If they are Teflon, you'll be fine. If they are Delrin, they will disappear quickly...

[Steve F]

Verify what material they are. If they are Teflon, you'll be fine. If they are Delrin, they will disappear quickly...

My thoughts exactly.  I was told that Delrin isn't good with higher temperatures, whereas teflon is good with it.

[JLeather]

Must be teflon then.  The engine's been run a good bit before I got it and aside from dulling the gloss of the buttons they don't seem to have worn at all.  They're super easy to put pistons on with.  Do it bare-handed 

[Terry in Australia]

That Teflon is amazing stuff, I put a chunk in my lathe and it machines up better than aluminum! Cheers, Terry.

[Jinxracing]

That Teflon is amazing stuff, I put a chunk in my lathe and it machines up better than aluminum! Cheers, Terry.

+1 on that. You ever get a snootful of the fumes when you take a big cut? Supposedly Teflon turns to mustard gas (!) when it reaches a high enough temperature. Scared the bejeezus out of me when I first started working with the stuff. 

[Terry in Australia]

Well I didn't know that Jinxy! Hmmnnn, well that'll explain the recent coughing fits, and maybe my prediliction for Hotdogs? Cheers, Terry.