My coolant oil mix was not the headgasket

[carguyinok]

So yesterday I pulled apart the L28 that I thought had a bad head or head gasket. I was very shocked when I found what had been the cause of my milk in the oilpan.

Of all the things that could happen....... It was the timing chain tensioner!!!!! I pulled chain cover and found that the tensioner had some how come out of the hole it should be in. It was outside the hole on the top and kicked over like a wedge with the lower part still in the hole. With that it took out the front lobe of the cam, stretched the chain, pulled the cam gear loose, ate up most of the cam gear, and opened up a coolant leak near the waterpump

All of that without one odd noise from the motor.....

I still cant understand why or how this could happen :tapemouth Like I have said it was a very strong running fresh motor that was running like a top when I pulled it a few years ago. Anyway thats what I have found.

I also took the time and pulled apart the locked up motor that came in my 72. I found that the lower end was locked up solid with two pistons rusted in place. But the head on that motor is fine.

Now I have my SBC motor and trans mocked into my 240. But after my findings I am going to take the head from the locked motor and swap it onto the good lower end and see what happens.

Yes, today I am cleaning up the lower end that had the milk and checking all the bearing. The chain gear on the crank dose look fine and some how didnt get the damage the cam gear did.

I am not sure how this will work out. I say this because it was a fresh motor that had alot of work on bolth the block and head. The block had the crank, rods, and pistons changed for a higher compression. But I didnt build it and dont have a clue for what was used or what the real numbers for stroke or compression.

I know it was a custom cam grind with larger valves and port work. So going back with a stock head and cam has me wondering whats going to happen. But I am gona give it a try and find out.

I will keep you all updated on how things work out. With alittle luck and everything going togather headache free I should have it togather tonight and back in the car by tomorrow. That if all my gaskets and chain came in today.......

[ChrisZ]

Your -72 motor will most likely have a E88 head, that's if it is stock, can't you just pull the cam from that head and swap it over to the other ?, what head is on your L28, are you sure you don't have a stock or bent valve on cyl one, causing the cam to be eaten.

Try to soak the frozen pistons with ATF they might get loose, a Carl Beck advise.

Glad to here you stay R6

Chris

[carguyinok]

Yes, I could just swap the cam over and try it that way. But for now I would rather keep that head off. Then save up alittle money untill I can get the new cam for that head then get it set-up correct.

Plus I am not sure what other damage could have been done with that much pressure on the front of that head. So I am just gona pull everything from the head and get it checked for any hidden damage as in cracking or warping that could have happened.

Then I can just swap back with my good head and cam at a later date. Then I can sleep easy knowing 100% that its a head that I can trust.

I am betting that I can get the other block free. Then get it apart and work it over from there. But, for now I am just gona put it on a stand and toss a cover over it. Yes with atf on the pistons. But it's gona take alot of work before that lower end is a runner. The best I can say for it its that its an extra block at this point.

P.S. Did you get the flywheel bolts yet?

[ChrisZ]

Nope, the bolts havent shown up yet, luckely i was able to borrow a set.

Don't you want me to pay for shipping ?, no need for you to carry that expence.

Chris

[carguyinok]

I will get you a PM soon. I had a hacker messing with my paypal last week. So I was waiting unill that was taken care of before having anything sent into that account.

Odd but you should have seen them by now. I will drop by the PO today and see if they can tell me anything.

[ChrisZ]

I think it's our usual custom clerance delay, nothing to worry about, i hope.

Chris

[240ZGL]

Check your exhaust ports. My #6 port was eaten thru on the stock E88 right into the coolant passage. The rest of the motor was great.

[carguyinok]

I dont think it was anything more the the tensioner piston stuck outside the cup and stuck @ about a 45. I am talking MAJOR pressure on the timing chain, cam, and front motor cover. Thank goodness everything else looks fine.

Edited March 19, 2009 by carguyinok

[john mcgarvie]

Well you did it you scared me im ordering a new chain,tensioner and runners.Wen i just put them together thay looket iffy.

[MikeW]

I dont think it was anything more the the tensioner piston stuck outside the cup and stuck @ about a 45. I am talking MAJOR pressure on the timing chain, cam, and front motor cover. Thank goodness everything else looks fine.

My first concern was valve interference when the chain slipped but since your pistons have valve reliefs you should be fine.

[carguyinok]

Well good, atleast I know some kind of good came from this mess then. But I feel that you should know this was a new part that failed. But I was not the one that installed it!!! The PO of my 73 built the motor back in 01 and I have had it in storage since then.

My guess is he installed the part wrong and it just now gave up. Keep in mind even tho its years later the motor only had a few hours of run time on it.

But if yours is worn I vote replace it and sleep well knowing it's good.

[Nigel1943]

Well good, atleast I know some kind of good came from this mess then. But I feel that you should know this was a new part that failed. But I was not the one that installed it!!! The PO of my 73 built the motor back in 01 and I have had it in storage since then.

My guess is he installed the part wrong and it just now gave up. Keep in mind even tho its years later the motor only had a few hours of run time on it.

But if yours is worn I vote replace it and sleep well knowing it's good.

I take it you wedged the timing chain before you stripped the motor?

FORGET THE ABOVE, DIDN'T READ THE THREAD PROPERLY.

Edited March 19, 2009 by Nigel1943