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white block 850T5 head on a wb P2 V70T5 block??

Janspeed

Active member
Joined
Sep 5, 2005
i probably have a burnt exhaust valve in the engine of my V70T5 2001

I was wondering, are the castings of the 850 T5 head identical to those of the P2 T5?
Would it be possible to install an 850 T5 head on a P2 block ?
I would want to use the P2 the cams and the ignition equipement and manifolds,etc
(i suppose the cams won't work since the valve actuation is different)

Why? because the 850 valves have thicker stems and valveguides and the head has hydraulic lifters which is ideal when running on LPG.

any advice welcome!
 
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I'm pretty sure CJ was able to make this work. I don't think he just slapped it on though. There was a bit of modification needed to make it all work together.

2.5_0.jpg
 
It will fit fit some minor mods but as said you will lose VVT, don't think the P2 ECU is going to like that.
If you search.. Very early RN engine's, MY99, came with hydro lifters and the big valve stems plus exhaust VVT.
 
OK thanks guys, that is good to know
@Johann this would mean i have to look for a head from a V70R '99 classic or a late C70T5 mk1, correct?

Maybe if i can't find a RN '99 head i could use an 850 T5 head and just leave the VVT actuator connected. Would that be sufficient to fool the ECU?
 
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MY99 head with exhaust VVT was on any Turbo model - so, GLT, XC, AWD, etc, all had exhaust VVT, hydro lifters & fatter stems.

The 850 head will present issues with torque mount, inlet ports won't align with intake manifold (smaller in head).

Leaving the VVT solenoid plugged in won't resolve the problem (with using a 850 head), you will get codes when the system determines it cannot adjust the timing as intended.
 
how about swapping in a complete RN '99 T5 engine? including the manifold. Does that engine also use the Magneti-Marelli ETM?
That torque mount could be made to fit i suppose.
 
MY99 head with exhaust VVT was on any Turbo model - so, GLT, XC, AWD, etc, all had exhaust VVT, hydro lifters & fatter stems.

The 850 head will present issues with torque mount, inlet ports won't align with intake manifold (smaller in head).

Leaving the VVT solenoid plugged in won't resolve the problem (with using a 850 head), you will get codes when the system determines it cannot adjust the timing as intended.

Yours has both the vvt block off plate and a new cam gear correct? I've got a 2000 motor for my 245 but I'm going to run it on 4.3 with Karl's COP conversion. As long as the vvt is locked, should be ok I assume. (I want the later head and vented crankcase).

Edit: read this backwards, not an RN head on an early motor, op wants vice versa.
 
how about swapping in a complete RN '99 T5 engine? including the manifold. Does that engine also use the Magneti-Marelli ETM?
That torque mount could be made to fit i suppose.

Complete '99 T5 motor should be a direct swap with yours, no reason to use the manifold.
 
Yours has both the vvt block off plate and a new cam gear correct? I've got a 2000 motor for my 245 but I'm going to run it on 4.3 with Karl's COP conversion. As long as the vvt is locked, should be ok I assume. (I want the later head and vented crankcase).

Edit: read this backwards, not an RN head on an early motor, op wants vice versa.

Best thing to do is get a solid hub to make sure there are no issues with the VVT hub.

Is there a thread on Karl's COP kit? I wouldn't mind having a spare M4.4 ECU with COP for backup purposes
 
there are new embarassing developments.
It turns out that i had switched the connectors on coil 4 and coil 3... The popping exhaust can also be explained because if in one of those 2 cil's the ignition comes way to late it will be when the exh. valves on that cil are already opening...

So for now, no new head needed...phew. I got away with that one...

That said, the idea of a head with hydraulic lifters and VVT in my P2 has stuck in my mind!
 
From what I remember of engine shens is that you're after an 01+ (top or bottom end). Solid lifters/thin stems (for better high RPM grocery getting), as well as a stouter bottom end than the earlier one (longer rods, shorter pistons, nice crank and mains...that kinda stuff). Do be aware though, that motor mounts are not always in the same places and each variant seems to have different ribs and fins ground off for fitting into their respective cars.

From what I recall, the VVT on 850's exhaust is pretty much exclusively for fast warm-ups (CAFE 90 seconds to cat operating temp), and isn't used during actual driving, whereas the later gen with dual VVT did a bit more under operation...again, different engine and ECU.

It's all fun and games till someone loses a rod!
 
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