removing pistons from rods without damage

Seight-V8 · Post by **Seight-V8** » Fri Dec 05, 2008 1:38 pm

hiya all,

After various problems my next one is this.

I stupidly had my new pistons fitted to the rods before trying to get the internals balanced.

Now the engine balancer says he cannot do them without them been split.

And everyone i've talked to says....the pistons will be damaged/useless
after they are split.

So a brand new set of cast pistons for the bin.....hmmmm

Can anyone help to get them apart without damage.....

the more i try to get this engine done, the further it gets behind.

cheers

scott

kiwicar · Post by **kiwicar** » Fri Dec 05, 2008 1:49 pm

This is perfectly doable, you need a press, a drift to fit the press and that is a good fit on the pin, with a pilot that goes down the centre of the pin, and a V block with a hole in it to hold the piston (or better still a 1/4 cylinder to hold the piston in with a hole in it. Then push them out, if you can stick them in a hot oven first then all the better (use good oven gloves). Did it on my first RV8 build with a set of 10 to1s (suposadly the weakest piston) provided you take your time and have the right tools (hammer, bolt and socket no good) you should be fine, after all how did you put them on there?
Mike

Boosted LS1 · Post by **Boosted LS1** » Fri Dec 05, 2008 5:23 pm

The problem is that the skirts and side bosses aren't designed to take the load of a press. I've had pistons pressed off before now and got away with it though. The rv8 workshop manual mentions a tool which inserts between the inside of the boss and the gudgeon pin. It's probably steel and free standing on the bench or in a vice. This is to prevent loads being applied to the skirts?

stu8 · Post by **stu8** » Fri Dec 05, 2008 8:17 pm

What happened about the pin fitting tool?

http://www.v8forum.co.uk/forum/viewtopi ... highlight=

/

ChrisJC · Post by **ChrisJC** » Fri Dec 05, 2008 8:23 pm

I've done mine with some suitably sized thickwall tube and an 18mm socket. And a hydraulic press. I cut one piece of the tube to sit on the side of the piston and just press on the thick part of the piston and not the skirt.

I've switched around various pistons & rods, but the engine is still in pieces so we'll see if it's OK......

Chris.

Boosted LS1 · Post by **Boosted LS1** » Fri Dec 05, 2008 8:30 pm

^ Good link Stu. That was probably the tool I saw in the workshop manual. They used a hand screw mechanism to remove the pin from rod and piston.

Seight-V8 · Post by **Seight-V8** » Sat Dec 06, 2008 10:48 am

hiya,

I've looked in the rover manual, and yes they use a hand tool.

But done a google search and came up blank with the numbers listed in the manual.

And if i could find something that might work, it aint cheap...

Cheaper to get a new set of pistons, and cut my losses.

I just haven't got the gear needed to be able to do it myself.

Anyone point me in the right direction of somewhere that might help...before i waste more of me money.

cheers

scott

CastleMGBV8 · Post by **CastleMGBV8** » Sat Dec 06, 2008 10:52 am

I would have thought any decent engine builder or auto engineeering firm could do it for an economic price.

It is the interference fit between the rod and the gudgeon pin so with some modest heat to the rods the pins should press out without excessive pressure.

Kevin

Post by **katanaman** » Sat Dec 06, 2008 1:38 pm

always just used 2 bits of angle iron welded together and a press. Must have done easy a dozen sets and never had a problem. Cant say you would never have a problem but I never have.

ChrisJC · Post by **ChrisJC** » Sat Dec 06, 2008 1:39 pm

Looking at the land rover tool, it does just compress between the pin and the side if the piston.

I think the trick is that it uses a torque wrench to check that the fit is OK.

Chris.

Seight-V8 · Post by **Seight-V8** » Sun Dec 07, 2008 11:27 am

gonna do some more ringing around locally.

Failing that gonna send them down to V8D and see what they can do...

Just with the cost might be better to just buy a new set of pistons, and bin the old set.

As they might crack and fail inside the engine later....if i do manage to get them split....gonna have em crack tested at work first...to make sure.

scott

ChrisJC · Post by **ChrisJC** » Mon Dec 08, 2008 9:55 pm

Here's my setup:

Chris.

topcatcustom · Post by **topcatcustom** » Mon Dec 08, 2008 10:20 pm

Fairly common practice to split the pistons/pins/rods I thought, never heard of issues with busted pistons afterwards- unless someones tried to do it with a club hammer or something stupid! Anyway the tight fit is between the con rod and gudgeon pin isnt it?- the pin floats in the piston...

minorv8 · Post by **minorv8** » Tue Dec 09, 2008 8:10 am

I once removed a set of pistons (which were scrap anyway) with a drift and big hammer. I sat down, put the piston/rod combo on my legs (a suitably soft surface) and hit the pin with dift and hammer. Apart from several bruises on my legs it worked OK.

I have since refined the disassembly procedure, especially with pistons that are to be re-used. In case someone wonders, I kid you not ! I think this qualified in topcat´s stupid-category...

topcatcustom · Post by **topcatcustom** » Tue Dec 09, 2008 8:53 am

I was more referring to the people (I know some) who would lay it in a vice and belt the life out of it to get it out. Then use a club hammer to push the squashed pistons back in the cylinders after