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2jz engine rebuild failure

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Hey guys

So let me start by saying this is the first engine I ever built and learned a lot from it but what happened really made me scratch my head.

First the engine specs it is a 2jz-gte with 3.4l stroker crank and tri-beam manely rods and cp pistons.

Head is resurfaced and ported with over sized valves and dual springs and GSC S2 cams.

Yesterday I started the engine for the first time and it was running perfectly for about 15 min and suddenly it seized. I tried to start it again and it won't turn. I checked the timing and it was correct. I tried turning the crank by hand still will not turn. Removed the spark plugs all looked fine no problem there.

So I started to remove the timing belt and tried to turn the camshaft by hand, ONLY the exhaust cam turn while the intake cam was stuck and will not move an inch.

I removed the intake cam and this is what I found.

As you can see from the pictures, the cam started rubbing on to the first cam cap and seized and also the cam is damaged.

I will pull the head later today and see what else is damage to determine if the engine is repairable or not.

Also after removing both cams I started to turn the crankshaft by hand, and it was turning without any problems.

I'm trying to source a new head for the engine in the meantime.

I'm scratching my head here as to what could cause this kind of failure just on one cam?!??!?

Is the damage to the head fixable or not??

Attached Files

You would have to think that was either oil supply to that bearing or contamination on assembly or in the oil galleries. Probably worth putting solvent through the oil galleries and blowing it all out with compressed air before reassembly. Check for any obstructions in the oil paths.

My first thoughts were the cap was mixed up with another or was fitted the wrong way round - neither would seem possible in this case, unless the exhaust is identical, as it's unique to that position.

However, I can say with confidence the position is actually what led to the failure. It appears the sealant was incorrectly applied, was extruded into the bearing area and so would have compromised lubrication, to the point where it ran dry and started to transfer material and finally seize.

It may be possible to repair the cylinder head back to OEM dimensions, but it would be rather expensive and something to discuss with a professional head repair specialist.

If the head is otherwise in good condition, especially as you have invested in additional work on it already, and you are also looking at a new camshaft, an option may be to have the head line bored oversized for the damaged side and have the replacement camshaft custom ground with oversized journals to match - it's still going to be expensive but you're going to have to make the call on repair or replacement, with the latter possibly being even more expensive once the reworking has also been done.

Hey guys

So an update on what happen

First I took the head to a shop that has worked on a lot of supras and he told me that the damage is repairable and the cam was in good shape, just need a little polish and it's back to normal, he will check if there is any bend on the cam later. As for the valves he will do a complete leak down test, and hope that is nothing wrong with the valves.

As for what happen, according to the shop he said I used too much ARP assembly lube on the head studs, and that could damage any bearing on the engine.

What do you guys think could it be from the ARP assembly lube????

As for now I was check the oil line and oil gallery for the block. I drained the oil from the block and seems to be ok no bits of metal. I pulled the oil filter out and there was A LOT on oil in there like stuck in there. I have an oil relocation kit with line going from the oil filter location to the adapter. I will check the lines of the oil relocation kit later and see if there was a problem or something is stuck in them.

Thanks for your feed back guys hope everything gets back and resolve this problem.

Hello don't take this the wrong way but has the oil even got up to the cam it looks very clean except for assembling lube?

have you checked the plumbing of the relocation kit to check the direction of flow through the oil filter? the pressure would still read great in most cases depending on where in the line the sensor is.

I would suggest it to be MOST unlikely - I am aware of claims made that some moly' based anti-scuff pastes/lubricants could block oil filters and/or pickups if massive amounts used, but excess lubricant on head studs would need to be washed from the bolt area, through the return galleries, mix with the oil in the sump, before passing through the pump and filter before, supposedly, blocking an oil feed to the cam' journal - it would be mixing and being diluted all the way!

I'm sticking with the incorrectly applied sealant being the problem, as that is clearly visible and would cause the exact problem you have.

Not sure about the oil filter - they have check valves incorporated into them to prevent drainback and help initial oil feed on start-up, so they are expected to hold a lot of oil.

most filters won't flow in the incorrect direction tho Gord, I see it done often with cars coming to my shop for first startups they will have 120 plus oil pressure but barely any going past the filter, well worth checking amongst other things mentioned above.

Thought I'd replied - must be old age kicking in...

Sorry, Ross, for the confusion - I was responding to the other chap, and mis-read your comment. You raise a good point, as while most filter heads have direction arrows it'd be easy to mis-route the hoses at the adaptor end, or cross them over, and that nice check valve wouldn't be so nice. Same with the oil pressure sender position as many are tapped into the block at the pump, or even the actual pump casting - when possible I figure the best place is to the rear of the main bearing oil gallery drilling.

I've known instances of folks doing this, mixing the hoses, with dry sump tanks and wondering why they weren't getting oil pressure - fortunately running the pump from a drill to prime, rather than cranking... One of the reasons I like to run larger diameter hoses and fittings on the suction side.

Hey guys, sorry for the long wait I was trying to get some used cam caps, and I managed to find a full set for both intake and exhaust.

Anyway upon inspecting the cam caps, all of them seem to be in good condition. But there was a slight difference between the number 1 intake cam cap for the one that I have. I attached the photos and highlighted the difference.

The last photo has both caps. The one on the right is the original one from my engine cylinder head.

And as you can see the original cam cap oil grove is all the to the back, while the used one I got to is not.

Is it still possible to use it on the head or not?

Of course I will take the head to a machine shop and line hone the cam caps.

Also the original cam cap for the right, I polished it and cleaned is and it seem to be in good condition with minor scratches.

Is it possible to use it or not?

Attached Files

I'm 99% sure that isn't an "oil groove", but a channel that's intended to divert excess sealant away from the bearing, to greatly reduce the chance of the sealant compromising the oiling.

Have a look at the actual sealant requirement - where the oil might weep out from under the cap, and where the seal and cap bearing surface is, to see what I mean.

If it's getting line bored, anyway, I'd use the longer groove version. If it was one of the other caps, it would be an easier call, as they're all loaded primarily in the cap, from the valve spring' forces, and the head surface is much less important - but the front also has the cam drive applying a force pulling that journal into the head. With an eyeball inspection (well, with a magnifying lense, I'm old), I may even decide to run it as is, with the ORIGINAL caps(!), mixing them will guarantee a failure! While a perfect surface over the full width/length is normally best practice, unless it's a full on engine, or at least highly stressed, 90%+ coverage may be acceptable - not my call, though, and not my engine.

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