14 replies to this topic

[edge04]

Number 4 went on my 1993 1.6 SM. No idea how many miles, laps, etc. I don't race it but it is my secondary track car. After replacing all the bearings there was an immediate knock again. So I'm guessing it went due to some kind of oiling issues. I know very little about these engines other than they are easy to work on. Can you help by pointing out where or what I should be looking at? Thanks for your help. 

[Tom Sager]

Did you inspect and measure the crank journals when disassembled?  Did you plastigauge or otherwise measure bearing clearances with new bearings before finishing assembly? 

[edge04]

Did you inspect and measure the crank journals when disassembled?  Did you plastigauge or otherwise measure bearing clearances with new bearings before finishing assembly? 

Yes. 2 and 4 were slightly oversized and the others were close to stock clearances. Thanks 

[Steve Scheifler]

Did you take pictures of the old bearing shells? How did the others look?

Any idea of the history of the engine; stock, old pro shop like Sunbelt or RE, ...?

[edge04]

So its number 4 again which tells me there's an oil blockage somewhere

[Steve Scheifler]

That seems reasonable but it’s not very common, and short of an obstruction in the passage in the crank to that journal, it wouldn’t hit just one. Others should show at least some signs of unusual wear. I assume you confirmed that the rod was not damaged.

[Jim Drago]

did you change the rod? is it round?

[edge04]

have not checked the rod yet as I was hoping replacing the bearings would do the trick. Now I need to decide if I want to do a complete rebuild or buy a used engine.

[Jim Drago]

have not checked the rod yet as I was hoping replacing the bearings would do the trick. Now I need to decide if I want to do a complete rebuild or buy a used engine.

if it is the same rod, it was likely distorted the first time and failed quickly the second time around

[Steve Scheifler]

That seems reasonable but it’s not very common, and short of an obstruction in the passage in the crank to that journal, it wouldn’t hit just one. Others should show at least some signs of unusual wear. I assume you confirmed that the rod was not damaged.

See, there I go assuming, You did plastigauge but didn’t check for round?

[steveracer]

have not checked the rod yet as I was hoping replacing the bearings would do the trick. Now I need to decide if I want to do a complete rebuild or buy a used engine.

 

I have NEVER seen nor heard of just putting a new bearing back in work.

Damage to the crank journal and rod end would indicate that machining or replacement is necessary.

[edge04]

I have NEVER seen nor heard of just putting a new bearing back in work.

Damage to the crank journal and rod end would indicate that machining or replacement is necessary.

I went the cheapest, easiest route and that didn't work. So now its a question of rebuilding or swapping in a used engine. 

[Dave D.]

Not really cheap or easiest, how did you change the rod bearings? Either dropped the subframe to get at the pan or pulled the engine. Either one is enough effort and expense to drive home the point of doing it right the first time WILL be the cheapest and easiest way.

[edge04]

Not really cheap or easiest, how did you change the rod bearings? Either dropped the subframe to get at the pan or pulled the engine. Either one is enough effort and expense to drive home the point of doing it right the first time WILL be the cheapest and easiest way.

Pulled the engine, it comes out, on the stand and pan off in less than a hour. Anyway, question now is rebuild or swap. Do SM uses stock bottom ends? Would it be best to just try and find a short block? I see complete drive trains out there between $800 and $1200 but those are stock and who knows what kind of miles. Thank you

[Jim Drago]

Pulled the engine, it comes out, on the stand and pan off in less than a hour. Anyway, question now is rebuild or swap. Do SM uses stock bottom ends? Would it be best to just try and find a short block? I see complete drive trains out there between $800 and $1200 but those are stock and who knows what kind of miles. Thank you

 

If you have run the bearings to metal twice already?  You need to take the head apart as well and clean it or you will be doing this a third time.