Rebuild or service?

[Blakeo]

Timing belt replacement is coming up on my 33. I can't decide if I should get the motor rebuilt or not. I'm ordering $1400 of parts to do the timing belt replacement (needs new harmonic balancer, crank belt drive, thermostat, clutch fan etc etc). The only reason I am thinking of rebuilding is because the engine has a slight oil weep between the head and block. Ideally I will replace it with an oem headgasket and reuse the arp head bolts. Car only makes 450rwhp and shouldn't need the mls one. Is it worth spending the extra and pulling the motor out now to refresh it with new rings, bearings and do a few oil control mods?

[GTSBoy]

How would we know? How many miles has it done at this power level? How hard has it been run? What are the compressions? etc?

[Blakeo]

2 hours ago, GTSBoy said:

How would we know? How many miles has it done at this power level? How hard has it been run? What are the compressions? etc?

I'm thinking out loud, don't have many mechanically inclined people around me to discuss with.

It has done about 20,000km @ 450rwhp on a PowerFC. Car has a total of 97,000km and has no previous history of being rebuilt. 

Compression is between 154-160 psi across all 6. Hasn't got any rod knock, or any other reason for concern just thought it would be good preventative maintenance. 

The only issue with the metal headgasket in it now is it has a slight weep from the turbo side rear. Its fairly minor. Would it be best to put a factory headgasket back in and reuse the arp headstuds? 

The old factory headgasket failed at 400rwhp, but could that be due to the factory head bolts stretching and with the arps I may not have the same issue?

[Duncan]

You don't want to rebuild it because you are spending $1,400 on timing belt etc. Cheap and dirty will cost $5k, basic rebuild $10k and of course the sky is the limit depending on what you want to change.

Rebuild means labour for engine in and out, then disassembly, cleaning, measuring, new gaskets, head and rod bolts. Machining, Measuring, rings and bearings. Yes you can save on that, particularly if you can do most of the labour, and you can decide how much you want to reuse, but it will still be 3-10x what you are already spending.

BTW are you sure the oil leak is from the head/block and not the cam seals? It is much more common there. If you really wanted to deal with that, head off while the timing belt is off is an option, but it sounds like that may have been done before, and obviously not 100% successfully if it is leaking there (suggests head or block may not be flat...)

BTW, if you are doing timing belt, always change the idler and tensioner stud/bolt, and consider doing the water pump, cam and oil pump seals while you are there.

[KiwiRS4T]

RBs should do 300,000 if looked after (and with a bit of luck). Get some engine cleaner and get the area of the leak completely clean and dry so that you can see where the oil is coming from. Ideally you would find out why the head gasket failed rather than hope that its fixed. Did you get the head planed and crack tested and check the block with a straight edge?

[Blakeo]

9 minutes ago, KiwiRS4T said:

RBs should do 300,000 if looked after (and with a bit of luck). Get some engine cleaner and get the area of the leak completely clean and dry so that you can see where the oil is coming from. Ideally you would find out why the head gasket failed rather than hope that its fixed. Did you get the head planed and crack tested and check the block with a straight edge?

The head was skimmed and crack tested. The block I used a knife sharpening stone to get a good surface finish, and then tested with feeler gauges and a straight edge. Couldn't get 0.02mm gauge under any point. 

Permaseal MLSR was used with Holomar, I thought the block was machined but going over receipts I can see I didn't do it 100% properly and that annoys me. To do it properly I'll have to pull the motor out and completely disassemble the block to have it decked won't I?

[GTSBoy]

I'm with them. ^^^.

Unlikely to be weeping oil from the head/block interface. Much more likely to be coming from somewhere above that. Clean and inspect after some more driving.

[BK]

At that compression you would be retarded to want to rebuild that. Stock rb26 is 171psi factory which nobody ever gets from stock, 160 odd is awesome. Pull head off, keep engine in car. Sort head, gasket, timing belt, done.

Check valve clearance while your down there, be silly not to.

[KiwiRS4T]

2 hours ago, Blakeo said:

The head was skimmed and crack tested. The block I used a knife sharpening stone to get a good surface finish, and then tested with feeler gauges and a straight edge. Couldn't get 0.02mm gauge under any point. 

Permaseal MLSR was used with Holomar, I thought the block was machined but going over receipts I can see I didn't do it 100% properly and that annoys me. To do it properly I'll have to pull the motor out and completely disassemble the block to have it decked won't I?

No that sounds like you did it properly. Its rare that the block needs machining and as you have checked it there should be no need. Look elsewhere for the oil leak. Check your receipts to see if the cam cover gaskets were renewed. Some people re-use the old one and don't have a problem but of course they may leak. The bits for the half moon need renewing and usually sealing with something.