[parptarf]

So this winter I might park the car a couple of months to fix up a few bigger things.



One of them is to rebuild the engine head completely. This is a pretty straight-forward normal job right? Take the head off the engine and sent it to someone to restore it, then put everything back together? (Obviously changing the timing belt and everything that goes wit hit in the process)



Then you have the rod bearings. I don't think they're going bad as I can't say I'm noticing anything. But my car has almost 300k kilometers so it won't hurt to take a look. How do I change these? Take off the oil pan and it's an obvious remove and install job from under the car?



Lastly the piston rings. For this I have to take out the pistons obviously. And I don't wanna do that unless I really have to. If I rebuild my head can i just do a compression test and see if they're alright?







Luckily my car has a VERY detailed and well followed service history. But still it's 300k kilometers.

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[parptarf]

Nobody?

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[AJG]

How is the oil pressure lately? Because I believe that the pressure drops as the clearance in the bearing shells increases as it is easier to pump oil past them.



Andy

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[parptarf]

Can't say I trust the gauge 100% but it sits around 4 when I'm driving. And when the engine is properly hot it sits around 3 at idle.

So from what it seems like the oil pressure is good. It doesn't burn any noticeable amount of oil either.



The last 25k kilometers the car has gotten a new filter and 10W40 oil every 7k kilometer.

Seems like the oil has been changed at about 10-15k previously in it's life.

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[flash]

to get to the rod bearings, yes, the pan comes off. to get to that, you have to drop the cross member.

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[JTP]

With all the work you're describing, wouldn't it be easier to pull the engine out?

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[parptarf]

Well, I don't have anywhere I could put it outside of the car.

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[paulzebo]

300,000KM=186,000 miles. How do you drive the car? Do you track it or baby it? If it's a car for cruising and sees no rough duty I'd say go with the head rebuild and stop. Keep in mind Porsche recommends that you replace the connecting rods when you replace the rod bearings. Which means you will be tearing down most of the engine. Given the oil pressure as you state it is good and it burns no oil, I would rebuild the head and keep cruising.



   

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[parptarf]

I daily it and use it for "spirited" driving on country roads. That's what it has been mainly used for the the last 140k-ish kilometers. Before that it was used in Germany as a highway cruiser it seems. It has been used for auto slalom for around 2-3 years though, and it will see a few trackdays next year.





I read somewhere that changing the rod bearings is usually done when you are changing the oil pan gasket. Since you're already under there. And it seems like a straight enough forward job, but I have never been under there so I don't know for sure.

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[flash]

yeah - if you get as far as removing the pan, which means you dropped the crossmember and all that, changing out the rod bearings is a no brainer, especially at that mileage. changing the rods themselves is an entirely different matter. while the later rods are stronger, as stated, it is a bugger to change them. that being said, the early rods are known to stretch and fail on the track. apparently they don't do well with extend and repeated high revs.

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[parptarf]

I might have to look at that if I'm gonna do any serious track driving.



But while I'm changing the rods, any point in upgrading them?

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[flash]

you mean to something like carrillo? sure. i did. lighter and stronger, which means snappier revving. of course the stiffer rods also mean more stress transferred and potentially more pounding on the bearings and crank. no telling if they can handle it long term or not yet. so far so good, and i haven't heard of any failures yet, but you never know.

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[parptarf]

Might be worth considering.

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[flash]

that's why i did it. i knew what i was going to be doing with the car, and the $1500 for the rods was not that big of a deal. in your situation, it would probably be less expensive than changing to the later rods.

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[parptarf]

Have you had any experience with R&R Pro BIllet Steel Connecting Rods?



They're about 12.000NOK which is not that bad for connecting rods.

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[flash]

no, but realize that if you remove the rods, you are then into a full rebuild situation. based on conversations with some builders, it is my understanding that the rods cannot really be removed without removing the pistons, which means new rings, honing, etc, and that to do so without addressing the pistons is not recommended. this could get really pricey at that point, and is exactly how i went from a $5k job to a $20k job.

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[parptarf]

If I change anything but the bearings I'll have the entire engine out of the car and do a full rebuild.

Just checking my options here.





And while were in on this topic: As longs as my pistons look OK, all I need to do is clean them, right? Obviously new bearings and rings, but is the piston itself up for another 300k kilometers? What else would be smart to do while I'm already having the pistons out of the engine and having the block hones and refurbished?

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[flash]

as long as you don't need to bore out the block, or for some reason otherwise have to change pistons (like a buggered wrist pin hole, etc), yes, they should be fine.



in my case, i had buggered some rods, and the bores ended up getting buggered as well. this meant larger pistons had to be installed.

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[parptarf]

Doesn't honing change the bore too? Or is that difference so insignificant that it will work with a different type of rings?

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[flash]

done right, and assuming the block is not damaged or worn, the honing will not require any other changes, and a new set of rings will do it. not sure if they make over-sized rings for us or not. never looked.

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