Uprated Head Bolts/Studs

[ian2000t]

I'm sure I've read about uprated head bolts (or they might even be studs/nuts to replace the bolts).

Where can you get these from, and roughly how much roughly are they?

[v8volvo]

Both ARP and Raceware (US companies) make stud kits for the D24T. By coincidence, as it happens I just priced them today for another motor build project. Raceware is $299 (USD) for a set of 14 studs, nuts, washers, and torquing instructions (D24T takes 14 head bolts or studs). ARP is $212 for a set for a VW 1.6 TD engine, which uses only 10 head bolts, so you need one-and-a-half kits, for $300+. Either one is excellent quality. I am going with the Raceware but others have used ARP with great results as well.

There is no upgraded bolt available, only the stock stretch bolt or the stud upgrade. You would only really need the studs if you were planning to run a major turbo boost increase over stock, though. At stock boost and fueling levels the stock headbolts are plenty adequate. There's no reason to spend the money to put studs in unless you have some major power adders installed elsewhere on the motor.

[ian2000t]

I am planning at some point to up the boost, but this would be to 15psi over the standard 10psi - nothing higher than that.

The reason I ask about the studs:

At the moment my headgasket is leaking oil out to the injection side of the block. It has been like this for at least 3,000 miles (could be much longer - I've only recently bought it this year), and is not mixing any oil/coolant, and not leaking compression into coolant either.

One suggestion I was given was to replace the bolts (as they stretch and may not have been replaced during it's last HG change) - to do this by re-torqueing all bolts first, and then replacing them one by one.

So - I was just thinking if Volvo's standard bolts are £100 then I wouldn't mind spending the bit extra for uprated ones... but that is a little higher $$ than I'd hoped!

Can you suggest anywhere I can get the Bolts cheaper than Volvo (with postage to UK)? I assume mine are the M12 ones (1990 760) - I've read the early ones were M11.

[Jason]

I was running 20lbs of boost on the stock head bolts and fiber gasket for almost two years of very hard use before it blew. Its really more related to fueling than boost, but whatever fuel you throw at it, if it only takes 15lbs of boost to clean it up, you wont be pushing it to the limit. I wouldn't hesitate to do a stock rebuild if thats what your planning for it.

Jason

[ian2000t]

Ok, cheers, will go for the stock bolts! That means I can afford an injector rebuild instead then! :D

Are these the correct headstuds? Mine is a 1990 760 D24Tic:
http://cgi.ebay.co.uk/Cyl-Head-Bolt-VW-1-6l-Diesel-Turbo-Diesel-engines-/310206191166?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4839bad63e

[IceV_760]

For the headbolt question.
On finland few guys are running +30psi with stock headbolts, pulling near 250hv.
And havent read yet anyone blowing gasket, since they heat engine before driving correctly, and "cool" it after before shutting it down.
So my tip would be to update headbolts only if everything else is afforded before, injectors, seals etc,
and an good gasket. Original metallic gasket rocks.

[ian2000t]

Cheers for the advice, went for standard stretch bolts but with an Ajusa Steel head gasket. Try never to use turbo pressure until engine up to temp (gauge in it's half way position) - 5 psi if I have to (auto box on a steep hill for e.g.).

Is that 30 psi with standard turbo? i'm only looking for about 15-18 psi.

[IceV_760]

No way to achieve +30psi with standard turbo :D
They mostly use Holset HX35 here combined with 12mm distributor head.
Standard tune-up and nice results for used money.

Engine isnt correctly warmed up even when gauge shows it. That means only at coolant is on that temperature.
Doesnt mean engine is warmed up everywhere yet to operating temp.

[J_Lanttola]

I set my turbo (hx35) to 30psi, and i use stock head bolts and gasket. The gasket is a metal gasket, elring or something like that. haven't have any problems in the past 10000 miles :)
The most important thing, as said before, is to warm up the engine before going crazy with the boost, and cool it down before turning it off. But that's a "problem" any kind of bolts or gaskets can't fix. Even if the gasket survives the abuse, the head itself don't.