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Engine Specific Info and Questions => IDI Engine => Topic started by: khanh.le on March 04, 2010, 03:56:53 pm

Title: piston:connecting rod orientation
Post by: khanh.le on March 04, 2010, 03:56:53 pm
This is a stupid question b/c I double-checked and took pics of items during the disassembly...well I lost those pictures.  What is the correct orientation of the connecting rod to the piston i.e. the forge marks (bumps) on the connecting rod in relation to the piston and its crown from the front of the engine.

Bentley says "forged marks must be toward engine's intermediate shaft with conn. rod and piston installed in engine.", but again I wanted to make sure.

Thanks

(http://lh3.ggpht.com/_RJ2lDNDyCZQ/S5BIVoEotUI/AAAAAAAAAdk/-1pVfjZa82s/s512/042_orientation.jpg)
Title: Re: piston:connecting rod orientation
Post by: theman53 on March 04, 2010, 04:51:37 pm
I think you got it right. That is the way I put mine in, so I hope you are right.
Title: Re: piston:connecting rod orientation
Post by: rs899 on March 05, 2010, 06:54:15 am
I agree- mine looked like that when I re-ringed about 500 miles ago and nothing has blown up yet.
Title: Re: piston:connecting rod orientation
Post by: Rabbit on Roids on March 05, 2010, 07:06:33 am
thats how my engine was re assembled 15k miles ago. looks like you got it right.
Title: Re: piston:connecting rod orientation
Post by: rodpaslow on March 05, 2010, 07:58:36 am
You can check when you install them as the little surface deviation you can see (looks like two circles) should be towards the front of the engine, intermediate/oil filter side of the engine.  Bently shows it that way.
Title: Re: piston:connecting rod orientation
Post by: rs899 on March 05, 2010, 08:49:58 am
Can't quite tell from the picture, but I hope you aren't reusing the stretch bolts on the con rods ( if they are the newer stretch bolts)
Title: Re: piston:connecting rod orientation
Post by: khanh.le on March 08, 2010, 12:08:34 am
Thanks for the help guys.  Those are the old rod bolts, was not planning on replacing them but am now considering otherwise.  Is there a difference between rod bolts for mech vs. hydraulic engines?  Where is a good/cheap source for replacements? (i.e. ARP, if it can fit into the budget)
Title: Re: piston:connecting rod orientation
Post by: rs899 on March 08, 2010, 06:11:42 am
According to the Bentley, the factory started using stretch bolts somewhere in the mid-80s.  The earlier 1.6NAs had "normal" reusable (?) bolts.  I re-used the bolts from CR series engines when I re-ringed my later ME engine.  If you are using pistons from the earlier series with their bolts, you should be OK.  Of course, it's always safer to use new bolts, but the prices on these new stretch bolts I think is quite high.

Rick
Title: Re: piston:connecting rod orientation
Post by: theman53 on March 08, 2010, 06:15:08 am
Yeah new rod bolts are high...best I could find was 70.00 at the dealers and it was only 100 for ARP, so I got the ARP and they have already paid for themselves as I have taken the pistons out 3 times now as I keep the never ending project going.
Title: Re: piston:connecting rod orientation
Post by: Rabbit on Roids on March 08, 2010, 07:48:12 am
i re torqued my 1.5 bolts with no problems. they didnt seem to stretch, or have any weird torque spec. and its a way early engine. no way theres stretchers in this engine.
Title: Re: piston:connecting rod orientation
Post by: gnavs on March 08, 2010, 09:52:21 am
does anyone have the ARP part number handy?
Title: Re: piston:connecting rod orientation
Post by: rabbitman on March 08, 2010, 10:31:58 am
http://www.vwdiesel.net/forum/index.php?topic=7919.0 (http://www.vwdiesel.net/forum/index.php?topic=7919.0) found it in the FAQ.........
Title: Re: piston:connecting rod orientation
Post by: gnavs on March 08, 2010, 10:41:14 am
in the FAQ the con rod ARP bolts are listed for 1.6/1.7, are they the same for AAZ? 
Title: Re: piston:connecting rod orientation
Post by: rodpaslow on March 08, 2010, 07:30:25 pm
After reading this post I was concerned about having to replace the rod bolts.  But, my bently service manual 85 thru 92 GTI, Golf & Jetta does not come out and say the rod bolts need replacing.  When checking clearances they say to torque to 22 ft. lbs. and assembly torque is 22 ft. lbs+90 deg.
I imagine the 90 deg is the stretch.  It also says if to be re-used they should never be interchanged, but nothing about bolt replacement....
Title: Re: piston:connecting rod orientation
Post by: burn_your_money on March 08, 2010, 07:54:23 pm
The +90 is a pretty good sign that they are stretch bolts. Guilianot had a rod go through the back of his freshly rebuilt AAZ because the mechanic didn't replace the rod bolts.
Title: Re: piston:connecting rod orientation
Post by: rodpaslow on March 08, 2010, 07:56:16 pm
will do - replace or possible disaster...
Title: Re: piston:connecting rod orientation
Post by: khanh.le on March 18, 2010, 11:15:54 am
Back from the dead...

I have a ME engine and I've noticed that there are casting numbers on later-style engines, unlike my previous MK1 engines.  When I removed the piston and rods, I labeled them accordingly.  The order I have labeled does not correspond to the castings.  Below is a breakdown.

My markings.    Vs.     Casting numbers
     1.                                         3
     2.                                         4
     3.                                         1
     4.                                         2

Essentially 1 and 3, 2 and 4 are switched.  I trust my labeling, but I can see some instances where I could've mixed them (however I doubt in such a systematic way).  I have a MK1 bentley, no MK2 so no mention of this.  Sorry to nitpick.

TIA,

Khanh 
Title: Re: piston:connecting rod orientation
Post by: TurboJ on April 01, 2010, 08:33:56 am
Make sure you replace the rod bolts - if they have the torque + degrees tightening sequence, they are surely stretch bolts. And if the price is high, I suggest looking around, I typically pay around 20$ for a complete set, and they are FeBi Bilstein made. Also, the 1.9 has different bolts, as do the gas engines (which are again different).