Can a rod bearing spin on startup?

[Ironhead]

Sorry for your loss. Could the engine oil have been a contributing factor? I thought the speculation was that an S14 using modern engine oils with insufficient Zinc (ZDDP) would occasionally kick a shim out.

What I don't understand is the simple physics of it....how two objects cannot occupy the same space at the same time.

If the valve clearance is even in the ballpark of being correct....I mean even in the correct zip code....how can a shim pop out? There is nowhere for it to go.

Now if there was a bent valve....that kept the valve from closing completely....then I could see a shim kicking out. I wonder how many of these cases might involve a bent/sticking valve?

[jimmy p.]

What I don't understand is the simple physics of it....how two objects cannot occupy the same space at the same time.

If the valve clearance is even in the ballpark of being correct....I mean even in the correct zip code....how can a shim pop out? There is nowhere for it to go.

Now if there was a bent valve....that kept the valve from closing completely....then I could see a shim kicking out. I wonder how many of these cases might involve a bent/sticking valve?

I agree with everything you posted. I can't figure out how the hell it can even happen.
However, I did see with my own eyes when George Diaz engine kicked a shim out at Watkins Glen. I coudn;t believe it was possible but I did see that one myself. That incident did happen on a built motor at high RPMS though so the circumstances were way different and I don't know if was precipitated by anything like a bent or dropped valve. I never heard the post mortem.
I did see the shim out though.

[pete914]

Ironhead, I agree, from photos of the top end of an S14 it seems physically impossible!?
The engine was running 100% synthetic 10w30 (thought it was 10w40) and was about a quart low the first time I checked it. I added 100% synthetic "high mileage" 10w40 to top it off. I know mixing oil weights isn't ideal but couldn't get in touch with the PO to confirm oil weight and was on the road home. I just knew he was running 100% synthetic. Could this be a factor? Seems unlikely...

I thought the Zinc in oil just helps to preserve metal parts but is not absolutely crucial.

Last question, I want to order the new timing chain tensioner, has anyone ordered the entire spring/housing/gasket setup as one piece or does it need to be ordered part by part? If so, where did you order it from?
This is what my order looks like so far, anything I missing for the previously mentioned issues?

[Ironhead]

Ironhead, I agree, from photos of the top end of an S14 it seems physically impossible!?
The engine was running 100% synthetic 10w30 (thought it was 10w40) and was about a quart low the first time I checked it. I added 100% synthetic "high mileage" 10w40 to top it off. I know mixing oil weights isn't ideal but couldn't get in touch with the PO to confirm oil weight and was on the road home. I just knew he was running 100% synthetic. Could this be a factor? Seems unlikely...

In my opinion, the mixed oil or being a quart down could not possibly be a factor.

I thought the Zinc in oil just helps to preserve metal parts but is not absolutely crucial.

My perception also....but with lubrication questions everyone has their own opinion...most of them largely uninformed....mine included. This is a sophisticated topic. If you were running good oil and it did not have 50K miles on it or something like that, the oil was not a factor IMO.

Last question, I want to order the new timing chain tensioner, has anyone ordered the entire spring/housing/gasket setup as one piece or does it need to be ordered part by part? If so, where did you order it from?

I have been using the E36 tensioner for....something like 14 years now. It is a self contained unit that is not meant to disassemble.

[HANDBLT]

I agree with everything you posted. I can't figure out how the hell it can even happen.
However, I did see with my own eyes when George Diaz engine kicked a shim out at Watkins Glen. I coudn;t believe it was possible but I did see that one myself. That incident did happen on a built motor at high RPMS though so the circumstances were way different and I don't know if was precipitated by anything like a bent or dropped valve. I never heard the post mortem.
I did see the shim out though.

somehow the valve/bucket/shim has to have trailed the cam lobe enough so that it got 'kicked' out by the piston coming up. Valve float at high RPM's, or stuck valve/bucket/spring on low RPM's

think of is how you have the change the shims. lobe is up and you push the bucket down, shim comes out.

T

[Brandon]

couple of things. has the engine ever been rebuilt? Did they use forged pistons? I have an engine that is loud rod knockish on startup but it goes away after warmed up. The forged pistons are looser in the bores than cast and have piston slap on cold starts. also check exhaust header gaskets. if one is loose the exhaust gas will make the header knock against the head and sound internal.

T

I've been told by one of the big three names when it comes to S14s that piston skirt teflon coatings are very highly recommended on new builds for this very reason. Also recommended having the tops ceramic coated while you're at it.

[Brandon]

Hey Pete, not sure where in VA you're located, but if you're in the greater DC/NoVA area, I'm happy to help you wrench and get that thing back on the road.

I feel your pain as I recently found a crack in my #3 cylinder, so I'm building my 2.5. Luckily, I've been planning for this for years and have all of the parts necessary, save for pistons at this point. Hope to have the old engine out and the new one built soon.






Best of luck to ya!

[Ironhead]

I've been told by one of the big three names when it comes to S14s that piston skirt teflon coatings are very highly recommended on new builds for this very reason. Also recommended having the tops ceramic coated while you're at it.

I was going to do the ceramic/teflon coating thing on my recent build....but it has actually become kind of controversial. Particularly the ceramic. I got advice against it from a couple of knowledgeable sources (both of whom would have made more money by selling me coatings). The basic issue is that the ceramic coating only provides a very brief delay to higher temperatures reaching the underlying aluminum, with the bigger problem being that it provides a source of diamond hard material that can possibly dislodge from the piston crown and circulate in the engine. Supposedly even "cost no object" racing engines have abandoned these coatings and use plain aluminum pistons now.

The consensus I got about the teflon was that it cannot really hurt anything...do it if it makes you feel better.

Regarding piston slap....I am on my second 2.5 with forged pistons....never had the least amount of slap with either one. Not sure what that means...but that is my experience.

[jimmy p.]

I know this is veering off topic for this thread but we coated pretty much everything in my engines (club racer and Gruppe a car). Last time the club racer engine was apart for refresh the pistons still looked new.

Im a huge fan of coatings (I used Swain) tops,sides, combustion chamber, valve faces and exhaust ports.

So so far I have not seen anything to make me believe they are snake oil in the least.

[pete914]

Couple photo's of the damage after taking a look today.
Going to get a compression test in case there is a bent valve or something...

[AlpineRunner]

Crazy story. I agree that the bucket must have gotten compressed with the shim somehow. I would think the cam tray could be repaired though... simply by removing or compressing the bucket and filing that spot down. The cam tray doesn't do anything that special besides hold the cams and contain the oil.

[Dave @nz]

Hi
The area of the cam tray which you have arrows pointing to I think that is what gets machined off when using BMW high lift motorsport cam shafts, correct me if I am wrong here so that section of the casting may not be important.
To be 100% sure of a good repair removing the cam tray and careful file to remove any minor burrs and polish with fine wet and dry inside of the cam bucket holes and then carefully test the friction of moving the bucket through the hole possibly bearing Blue would work well in identifying any distortions in the hole.

The noise from the engine in the video is quite loud it possibly had something going wrong then or what is being heard is excessively large valve clearance which allowed the shim to displace I don’t think it happened as you started it up.

[pete914]

More bad news.
Compression was roughly 225, 35, 105, 225 first test, then roughly 225 ,120, 105, 225 second test. So, we likely have bent valve/valve spring issue or worse....
This is supposed to be God's chariot. What sin have I committed to deserve this in my first week of ownership? LOL
Having my mechanic pull the rest of the head to evaluate. Id love to do this myself but it's above my skill set. I'm thinking VAC motorsports for a full stage 1 head rebuild. Any other suggestions for rebuilders that do good work for reasonable cost?
FML

[jimmy p.]

More bad news.
Compression was roughly 225, 35, 105, 225 first test, then roughly 225 ,120, 105, 225 second test. So, we likely have bent valve/valve spring issue or worse....
This is supposed to be God's chariot. What sin have I committed to deserve this in my first week of ownership? LOL
Having my mechanic pull the rest of the head to evaluate. Id love to do this myself but it's above my skill set. I'm thinking VAC motorsports for a full stage 1 head rebuild. Any other suggestions for rebuilders that do good work for reasonable cost?
FML

If you are on the East Coast, also highly recommend talking to Ron Checca, Don Fields or Mario Langsten.

If you are on the west coast go straight to Mario Rigoli / E Ticket Motorsports (Phoenix AZ) or Marc Norris at Bavarian Workshop (LA area)

Pick whichever one is closest to you (and can take the head in).

[L James]

Ditto on what Jimmy has recommended.

[pete914]

OK thanks I'm going to try to find contact info on them