[Mk2] [Turbo] Turbo engine rebuild time, advice needed...

[doeboy]

Posted: Mon Oct 17, 2011 8:59 pm    Post subject: Turbo rebuild time, advice needed....
Hi all
Recently had the inevitable news that my 116000 mile rev3 tubby has cracked a ring land on cyl4, so going for a forged rebuild and doing it myself with some help from some good mates in the know in my little garage.
I got some 86.25mm cp forties I got off a guy on here, and have dropped and stripped the engine down the the bare block ready for acid dipping and boring, got a couple of questions for the experienced people on here.
I'd like to see around the 450/500hp mark although I don't want to chase figures and want a more torque focussed engine than out and out power.
Looking at this sort of power would I need to do rods aswell?
And I'm looking to do oversize valves and bigger cams is there any other head work recommended to squeeze some more ponies out as I've been heard that there pretty good head on them as stock?
Any other recommendations or links to good info would be greatly appreciated.
Thanks in advance
Steve

[Chris]

All you need is,

A set of pistons, A set of ARP Headbolts, New water and oil pump, New Rev3 Toyota (genuine) HG. Set of big end and main shells.

The head will do all you want it to do, no need for cams or oversize valves. My old car did over 600bhp on a totally stock head. Be better if you could stick to 86mm pistons though if possible. Are the bores damaged?

[doeboy]

no damage to the bores, cracked ringland on 4.



got it early all is well.

[Chris]

Maybe have the bores checked for ovality and stick to 86mm if possible. Bit of a pain if you have already bought the pistons, but best to be on the safe side if you are planning on high power.

[doeboy]

why no cams or valves?

[Chris]

Why do you need them? If my old car made 635bhp on a totally stock head, and would of made more but the 1000cc injectors were maxxed out, what is the point for 400-500?

I am currently building another, the head will stay stock. Spend your money elsewhere.

[craig_mr2_mk1]

I 100% agree with Chris, the Stock Rev 3 head, valves cams, inlet manifold ect will flow really good fiqures.

[gazrev1tubby]

I tend to agree with Chris here Steve, i've heard of a stock (ish) rev1 head flowing 580 bhp So rev3 should be much better.

You could have it port matched to help against flow turbulence, although it's not essential. If you're planning on big boost, it might be worth considering having the bores lined for extra strength

[Steve Horrocks]

Another vote for stock rev3 head. 476bhp I had on mine.

Stock cams help early spool & good torques!

[Shmed]

So does that mean that you wouldn't expect to see any gains from using cams, or just that they aren't necessary for 400bhp?

I'm only asking because I was aiming for the mid 400's, but have rods & 264 cams..... does that mean I'd breeze 450 (ignoring my fuelling shortfalls), or that I'd get the same power from a stock head as I will from my head with cams & valve springs?

[craig_mr2_mk1]

I peronally would use the stock cams, after market cams will raise your power band up the rev range. I made a conservative 465hp and my rev limit is set at 7.5k. Speak to ryan and he will give you the best advice as he's mapped so many of them

[Shmed]

He'll be mapping mine too, as long as I have it back by 1st Nov.....

[RyanRs]

Stock rev3 head here & 500 bhp. fuel pump give up so had to stop but defo had way more in it!

[george_m]

460 bhp on stock rev 3 head and cams

[doeboy]

Stock rev3 head here & 500 bhp. fuel pump give up so had to stop but defo had way more in it!

What fuel pump were you using?

[craig_mr2_mk1]

You'll either need to get a Bosch 044 in tank or a Walbro in tank pumping into a swirl pot and then a 044 to pump it too the rail.

[Chris]

A 255 in tank is plenty, swirl pots and all the extra pipes is just more to go wrong and leak!

[doeboy]

Already got a walbro 255 ready to go in tank, Chris you got pm on imoc.

[Century Motorsport]

Headwork and cams will yield more power ... just to clear that one up.

However, the stock head design is a good one and if you only have a goal of 500hp then agree'd it's not a necessity!

[doeboy]

I love that "only have a goal of 500 bhp" lol
What else is recommended to achieve these sort of figures?