My Diy Attempted Rb25\30 Build - Is Running But There Are Some Issues

[DVS JEZ]

good idea, better to be safe than sorry this time, its already been on and off once,

[fatz]

mate you have it appart

deck the block

my first rb26/30 was a slapper and i didnt have the block decked ,head gasket leaked out the front cylinder once warm

50 bux to deck it and some new gaskets and a days work... worth every penny

[Adriano]

Problem is you need to disassemble the bottom end to deck the block

[The Mafia]

yeah, the bottom end is still in the car, and looking great, The bores look like they did when I got the block back from the machinist. I am going to check its flatness with a straight edge, and if its really f**ked, I'll pull it, if its good, then I'll slap a gasket on and whack the head back on.

I admit, I should have had it decked when it was getting an acid bath and hone. Stupid of me, but I think the machinist did say it was fine, as they checked it.

Will update you. I'm learning valuable lessons here when building a slapper - Don't cut corners too much. An extra $200 and you can have a perfect slapper build. (All for under $1,000).

[sky30]

i was always told to re-tension the head bolts after the engine was ran for the first time. i have always taken the car for a decent drive to get some heat into the head/gasket ( No boost), then left to cool overnight and re-tension the next day. This process used with stock graphite gasket and NO hylamar has never leaked on a few engines ive seen. Hylamar wont hurt if you gona use it.

[cactus]

One thing I would also check ..

When you do the ARP bolts up, make sure they are not bottoming out. When I first put ARP studs into my built 25 (and my now RB30DET), I had to use two washers on each stud because they were too long. Yes - quite strange, but it was two different sets of studs and did the same thing each time.

The only way I spotted this was when I had finished building the motor, and put in all coolant/oil, it was up on the hoist and I noticed water dripping from between head and block was devestated!

[The Mafia]

One thing I would also check ..

When you do the ARP bolts up, make sure they are not bottoming out. When I first put ARP studs into my built 25 (and my now RB30DET), I had to use two washers on each stud because they were too long. Yes - quite strange, but it was two different sets of studs and did the same thing each time.

The only way I spotted this was when I had finished building the motor, and put in all coolant/oil, it was up on the hoist and I noticed water dripping from between head and block was devestated!

Hey mate - I'm already using 2 x washers.

The head is finished finally! I am going to pick it up today and start getting it assembled again. Just need to put the manifolds on, and drop it back onto the block. I am going to check the block surface with a straight edge today and measure the clearances.

Apparently 2 thou and under is ok.

Really hope the block doesn't have to come out again.

[The Mafia]

Hi Everyone

I managed to get it all together on the weekend and running.

Plenty of Hylomar on the Head gasket (Whole can - 3 coats) and ARP studs done up nice and tight. I also re-torqued them this morning - Its surprising that you can feeling the tiniest difference in some. But all done up back to 81 foot pounds.

After the exhaust port job, the car seems to gowl a lot more now. I'm loving it.

So. There is my slapper.

If you have a good head - Mine cost $700 to recondition, and this is what I had them do:

- Cold Dip

- re-cut valve seats

- deck

- 1 hour of porting on exhaust

- valve heights checked

- Valve Stem seals

- welded VCT feed

- welded water galley for more head gasket clamping area (it about 3mm un touched, now 8mm welded)

- Drilled oil drains to 9.5mm

As for the block:

- New main and rod Bearings

- New Rings

- Acid Dip

- hone

- GET IT DECKED.... (Don't forget to like I did)

Assemble and rock and roll.

Here is a tip - Buy a crank collar for $80 and have it installed when they do the block.

This all cost me around $1k. If you already have a good head, then half of that I think.

Thanks to all that helped too - I was really lucky, I checked the deck flatness, and it wasn't out at all. I couldn't even get a 1 thou feeler guage under the straight edge. Whew.

Hopefully not having a crank collar won't limit me.

I've learnt a lot.

[Beer Baron]

well done mate. sounds like a good effort. hope it lives for a good while.

[boostn0199]

Good work on finding out the probelm and sticking through it and eventually getting it all right. This is probably going to be my next thing to do if my bottom end lets go in my 25 as I have just recently rebuilt my head so the price should be quite good just building a 30 bottom.

[DVS JEZ]

Good to hear its back up and running. Now lets see what numbers u can pull with it

[Trav1991]

have you rechecked the head bolt tention when you rebuild a motor u should check the head bolts about 3 times in about 10,000

[Adriano]

Arp head studs wuith a MLS head gasket, dont really think a recheck is necessary.

[NYTSKY]

^^^Agreed. Unless its a drag engine running 45psi of boost.

Well done for getting the motor sorted.

[Stock e-Tune]

After a read through this thread I saw a few area's that could improve your head job's so they last longer.

Don't have a boosted block or head milled. The milling swirl marks are an uneven surface and a head gasket blow out waiting to happen.

Hylomar is great but not required if you do the job correctly, nothing beats a perfectly clean flat surface for making the best seal.

Always get the Block and Head checked and or machined smooth instead of milling.

Always rub down the threaded bolt hole areas on your block with a flat block or glass with some wet'ndry paper attached. (pulling down a head will raise the thread in those area's a few thou).

Run a blind tap through the head stud hole to ensure they are clean and squirt some carby cleaner in them to wash them out.

Never put head bolts in dry, either head stud sealer or suitable friction modifier.

Always smear engine oil on the head stud washers or head bolt washers or you'll never get them torqued correctly.

Follow the specific Torque sequence in stages like 30, 60, 80. I always do the last tension setting twice and but never again.

The larger the head studs diameter, the more torque is required to get the same pull down affect as a smaller bolt/stud.

Blown head gaskets can leak any where;

Water in to oil (easily found by draining the sump and watching water come out first, this can happen after the car has been warmed up and then switched off)

Oil in to water whilst running (usually found at the highest point in the cooling system)

Cylinder pressure in water (blowing up radiators and blowing pipes off)

Blow-by in Oil (making the rocker cover choof pulsations like an old truck)

and blow straight out the side some where.

note: A cracked head or piston can cause some of these symtoms also.

If you suspect cracked head, inspect the cam bearings closely for abnormal wear and/or remove them to inpect for cracks.

I hope this helps

[KiwiRS4T]

What rev limit are you using? My engine seems very similar to yours except for + new rod bolts and N1 oil pump (!?).. Did you put in any restrictors to the oil feeds and / or clean out the drains? I was planning to run 6800 rev/min but will probably start with 6500. On the other hand I will set boost at around 18psi. Robbie from RIPS and others say such "slappers" should make 300kw no trouble but I'll see what happens when it gets on the road ( a few weeks away yet). Be very interested to see your chart when/if you can get it on a dyno.

[The Mafia]

just the 6500 rpm. Worried as I don't have a crank collar.

Head has 1.3mm restrictors, and it seems that they are doing a very good job. Lifters are all fine - no noise.

Will get a dyno one day.

[l67calais]

hi, what oil pump are you using if you dont have a crank collar.

[MBS206]

no, I simply grub screwed it.

Are you supposed to do this?

You have to weld up part of the 25 head or the oil and water mix.

It's in the RB30DET guide.

If you didn't do it, you'll have to pull the head, weld it, and then have it machine.

[MBS206]

Ok, so the head has been removed.

Here is the Verdict:

- The Exhaust cam cover at the back was all sludged up with a caramel looking oil \ water.

- The cams were a little sludged up

- I did actually install the two rear little bolts. The front one wasn't installed.

- The head gasket looked like it wasn't sealed properly where the VCT feed is (and grub screwed).

- The bores are still like new and have very prominent hone marks thank f**k.

- Seems the head gasket was the issue all the way, leaking into an oil drain

Resolutions:

- I will check the flatness of the head

- I am thinking if the head doesn't need to be surfaced, I will Defcon the grub screw in to make sure it doesn't leak.

- If the head needs surfacing, I will get the grub screw removed and weld up the head.

- Might look at adjusting the head gasket to suit the gallery a little more

- Will make sure that little bolt at the front is done up nice and tight.

If anyone has anymore tips, I would appreciate anything you can give me.

Thanks again for all of your help here.

GTRNUR was right on the money, thats for sure.

Just spotted this...

I did a head gasket on my old RB25/30. After I replaced the whole head and headgasket, the motor lasted long enough to be tuned, and into it's 3rd session at Oran Park... After that it smashed itself to pieces.

When a friend stripped the motor, he found the oil pick up was basically blocked with milky sludge. If you can, get the sump off, and check inside.