justaguy

Brian I would put the cap back on and mike the rod end to confirm size & roundness should be easy if the engine is out of the car and the crank is out ok the motor. If the rod eye needs to be honed you may be able to pull it and reinstall from the bottom( if you are not pulling the heads) but I would get professional advise before trying that. Hopefully it will measure OK and you wont have to worry about it.

Mark A is to be comended for his support and genersioty, What a stand up guy!

entropy_engineering

If it spun the bearing it will have circular lines with the circumference of the rod and the rod bearings will have their "ears" knocked off. If it didn't spin it should be fine.

I posted this on the old crank discussion, but I don't think many have seen it because it's old now. I've tried to narrow down what only affects the 2/6 rod versus the others, and it seems to be the oil distribution in the pan. Other fixes are very very good band-aids. Good oil helps a lot. Drilled crank helps a ton. Dry sump as well. People have still had failures with dry sump without drilled crank and vice-versa, hence my comment on them being very good bandaids. Not detonation related since it affected early motors too. Not aeration as dry sump motors still had failures on 2/6 without drilled crank.
What I'm getting at is...Has anyone drilled the back of the #2 main bearing web and made a tight fitting tube that screws in from the block plug in the valley and piped oil directly to the cap from a pressure source near the oil filter (or dry sump for you guys). Should be dirt cheap to make compared to even a crank (not to say a crank and other mods wouldn't still be necessary). It's one hole you could damn near carefully drill by hand (I wouldn't). With an aftermarket intake all three center mains could be done if deemed necessary. I know that would interfere with the knock sensors on the later cars. I would relocate them or something I think. Worth it to not toss motors all the time.

Darklands

Hi,

a friend of me has here in germany a 86.5 racer.Last month his engine has a headjob with grinded camshafts (the engine has now a totally different characteritic and likes reving much more ).

The shop reshaped the oilpassage to 2/6 also and bernd the owner tells,the oilpressuredrops in sharp turns are gone.
the owner of the shop,Jochen Ehrhardt (www.landsharks.de ) has 3 928 Racer from his clients to work on and all oiling modifications done are the passage to 2/6.
No engine has broken 2/6 yet.

AO

Mark Anderson is the man!!!!!!!!!!!!!

GlenL

The 928 world wants pictures of this, desperately. I know I do.

entropy_engineering

I wondered about reworking the oil passage in the "antfarm" as well. Not exactly sure what my plan of attack would be though. If anyone is confused I have pics of a torn down block I can put up. Mark Anderson is the man that's pretty nice.

FBIII

This post is deteriorating into a lot of band aid cheap remedies. This car is being driven only on a race track! The engine needs to be completely disassembled and every component checked for roundness and clearances. You do the cheap fix and you'll be back again. My favorite suggestion to date.... Push the pistons out the bottom. If it were possible to get them out that way which I clearly doubt, what are you going to use as a stable platform for the ring compressor? Or if you are an old time motorcyle engine builder, how are you going to get your fingers up around the piston to compress the piston rings manually?

GlenL

The pistons can't come out the bottom.

justaguy

Only suggested looking into pulling the piston out the bottom because I did it many years ago(1978) on a 350chevy. I was about 16 or 17 years old at the time so I was probally too young to know it couldn't be done. It can be done on a 350 chevy never did it on a 928 engine. It was just a suggestion to look at only if the rod end was out of tolerence. Only Brian can decide if he wants to completly rebuild the engine. He may only want to repair the 2/6 rod bearing and crank damage and get the car back on the track.Thats what I am hoping to do but I am also hoping not to have to pull the engine.

Darklands

@GlenL

I ask him if he like to share his knowledge.Maybe he write here on rennlist.

Some guy here in germany make in the past flowbenches with oil and a plexiglaswindow on the oilpassagechannels.
At some flowrates the stream interrupted at the crossing to 2/6.

heinrich

We need to set up a flow bench with plexiglass too.

IcemanG17

Guys
In terms of band-aid fixes.....that is not going to happen.... yes I am looking for good fixes that involve less labor time & downtime.. nothing is 100% at this point..... I am trying to get the widow back on track as soon as possible...BUT..only with a reliable engine that will remain functional for at least a couple seasons....

Since everyone knows a broken 928 that sucks lots of $$$$ is not nearly as fun as one that runs

mark kibort

The only quick way to fix this is to get the oversized bearings, but the crank might not be ready for just a bearing replacement as was mentioned. SO, that means the engine comes out ,and the the entire engine needs to be dissasembled. If not, just rebearing it is a chance, and might work and would save a total engine rebuild and pull. I dont think Ive heard of anyone rebuilding the engine, with the heads attached. has anyone?? Im trying to picture how you would do this. I guess flip it over and only split the case and remove the rod bearings and pull the crank out? put the new crank in, hopefully coming from an S4 so it will be balanced, and bolt back in the cradle and then bolt in the rod caps. I guess its possble. I dont think the pistons can come out the bottom and certainly would be tricky to install. Thoughts?

the oversized bearing on that one journal is a good idea. Its a realtively easy fix , not much labor, and if the crank is in good shape and only needs and can be cleaned up a little while in the engine, you could be back in running shape in no time. However, if you are pulling the engine, you might as well re-ring and balance the new crank to the old pistons. do we know the mileage on this car or any of the history??

either way, it is some work!!

mk

FBIII

Mark you must be kidding. That's the kind of technology they used on model A Fords. We're talking about bearings not babbets. As far as taking the girdle apart and leaving the heads in place. You are now placing the block under stress before the bottom end is built. I don't know if thats a great idea.

mark kibort

Hey, that wasnt my idea, it was mentioned here. (to keep the heads in place, lower the pistons out of the block, etc).

Even I would just pull the darn thing and rebuild it! (or if someone said that the bearing area was ok , then just replace the bearings on the #2 and 6 rods) But, I dont think that is the case. sounds like the crank has some damage, so, I would pull it and take the entire thing apart. heck, Bill and I did my engine pull, and I built the engine in a few hours. It wasnt that big of deal. we spent most of the time fussing with the torque angle wrench and cam timing! I have a log book on how long the entire process took , but it was finished and back in the car running in 2 weeks. (thats me and metwrench!)

mk