3.2 engine failed agian!!!

[P Clingman]

Hi all. heres my problem I just overhauled my 3.2 after a spun bearing from over reving. I replaced all needed parts except P/C
I used ARP rod bolts and used a rod bolt stretch gage and did
what I thought was a very good job cleaning all parts and oil
passages used a new front cooler and had my engine cooler professionally cleaned. Engine started and ran great I changed oil
after about 20 minutes and cut the filter to check for metal all
oil plug magnets were clean there was a small amount of metal and 574 bits in the filter but not alot. I took the car to the track
and during my first 20 min run group it blew up again!!. I disassembled it and found I spun #2 rod bearing. What did I do
wrong? I kept it below 7k rpms I did notice my oil was foamy before my run group but thought that was just oil left in the case and it was clear after I got it to the pits the oil pressure and temp were good during run could I have over filled it and foamed the oil? any help here would be great I don't want this to happen again! Thanks Palmer

[Shuie]

I didnt know you could 'spin a bearing' from an overrev. I thought that was from not having any oil in the case. How long did you drive the car after the overrev?

did a machine shop check your crank, rods, & case before you reassembled?

[P Clingman]

I streched a stock rod bolt by over reving thats what spun a bearing during the first blow up. And yes the rods were re sized and re bushed the crank was repaired and I meshered all parts before assembly.
Palmer

[cgarr]

I hope they pulled all the crank plugs and cleaned it very well, the last shop I used didnt really want to pull the crank plugs, thats why it was the last shop I used!!

Craig

[P Clingman]

I had EBS do the crank the plugs looked new after the repair but i didnot ask if they were pulled I did clean it before assembly (brake clean
thru every oil hole) I think it has to be ether dirt in the oil or lack of oil
or I screwed up rod bolt streching I will say the bearings all showed
wear and last time it happened only the spun one was bad. Palmer

[Vapors]

Just a few Ideas. How accruate do you think your tach is. I have seen some tachs that read low and slow, so when you think you are shifting at 7000 rpm it could be 7400 by the time the tach catches up to the engine. But it still should not blow up the engine. I have seen cranks that are nitrated and the aluminum plugs will no longer be tight in the crank thus leaking pressure. I have also seen some crank rebuilders just re-pound in the exsisting plugs after treating, not cleaning out the oil passages. The salt base nitriding leaves chunk's of salt residue in side the oil passages if the crank was nitrated. Also, you may want to install cam tower oil line restricter passage fittining on each side of the engine, this should maintain better oil pressure at low rpm to the crank. What type of oil are you using? Just curious. Good luck.

[P Clingman]

I was running 20/50 castrol, oil pressure seemed good but I was paying
attention to the track at the same time.Palmer

[asphaltgambler]

Some thoughts........Did you plastic gauge the rod journals to double check the clearance? How did the rods feel (rotational drag)after torquing? Did you follow Waynes book where he specifically addresses this to final check rod bearing crush / fitment?

If so; the only other possible reasons are oil contamination or starvation.

If it were my engine, even a full race deal, I would have allowed more break-in time. 20 mins then off to the track is too soon. The parts haven't gotten friendly yet.

[P Clingman]

I didnot plasti gauge my rod bearings but I did mike the rods an the crank all were in spec. The rods felt good after torqing not tight
My own experance is that breakin is more for rings than bearings.
I agree that it has to be one of those three things, I will be putting engine back together next week or two and will triple check every thing
thanks Palmer

[asphaltgambler]

Best wishes.......it's bad enough to have the engine go south the first time, but right after the build is.........well it really just sucks.

Hang in there and don't throw in the towel. There may be something lurking from the first time that's causing this.

[P Clingman]

Thanks for that its just another step in the learning process
Palmer

[350HP930]

Nothing scares me worse than the idea of getting my engine back together and then having something catastrophic happen to it.

[dtw]

That was my worst fear as well - at least you have the benefit of experience. Mine was the first engine I'd ever done a bottom end or cam timing on....

Good luck Palmer.

[ChrisBennet]

When we hear of a first time motor builder's motor failing right after a rebuild there is a tendency to shrug it off and think "That couldn't happen to me. I'm more careful than that."

What most of you aren't aware of is that Palmer is a very careful guy who has built a lot of very expensive motors (just not Porsche motors). I know when someone like Palmer gets bit in the ass it makes me worry. I'm thinking "If it could happen to someone as savvy and careful as Palmer, I'm not safe either."

-Chris

[350HP930]

So true. Bad stuff happens to even the best parts and people. Just last month I did a bunch of top notch machine work on a sweet SR20 nissan motor that was being set up to produce around 500 HP.

After it was put together by a very talented builder and tuner here in the central florida area one of its new valve springs broke and it ate the valve in the worse possible way.

Having a motor turn out just right is involves some converging probabilities but for the same reasons there are thousands of ways that a motor can die.

[Tinker]

When you take it apart, I would be extra vigilant in examining the parts that failed. It should give you a good idea what cause the failure.

I would guess oil starvation due to a piece of debris from the prior failure.

Let us know if it was the same journal and make sure you blow out all the oil passages and squirters with carb cleaner and compressed air.

I have seen motors rebuilt after similar damage with a high degree of attention placed on cleaning the coolers, cases, lines, oil passages, and thermostats. Even these motor produced some shavings after being run for the first hours.

Let us know what you find.

Tinker

[P Clingman]

It was not the same journal. Last time it was #6 this time it was#2 the first time it was me being stupid (stock rod bolts and no revlimiter)
I think you are right about oil starvation #2 and #5 are prime journals
for oil starvation the new crank I have is cross drilled that should help
oiling at high rpms. Whats better for cleaning brake clean or carb cleaner I have allways used brake clean? THANKS Palmer

[davidppp]

Hello Palmer.

IF the oil pressure was good then you have a blockage somewhere..and the wear on all bearings is not normal, suggesting its close to the pump but beyond the prssure sensor...

BUT if you have any doubt at all, then look for a leak..could be mainbearing fit, cracked block, pressure relief valve, loose gallery plug.

A good test Ive done before is to test fit all the mains crank and rods and pressurise the system with red diesel to see where the oil comes out..very instructive..

Ive also seen an engine which blew three times before the owner realised he had connected the dry sump system wrongly..creating a low-flow situation..

I'm afraid you'll need to determine with certainty what the problem was before this can be bolted together..it will be quicker by far to buy a core engine to get back together ..



Good luck
David

[350HP930]

Originally posted by P Clingman
Whats better for cleaning brake clean or carb cleaner I have allways used brake clean? THANKS Palmer

I would suggest something a little more serious than spraying in a few squirts of cleaner with a can.

With multiple failures its time to pull some case plugs and use bore brushes and compressed air to spray through large amounts of parts cleaner.

[john walker's workshop]

it's almost like it has a scavenging problem, where the case fills with oil, leaving none in the tank. spun bearings are from running out of oil.