9 replies to this topic

[z31jaime]

Ok so, I've got a 95 t5 wagon, and among my other volvos I recently picked up a 96 850 NA... with a freshly rebuilt head (less than 3k miles on it). The owner rebuilt it and drove it a few weeks and spun a bearing. Anyways I was planning on taking the NA cams, and TB and intake Manifold to add to my wagon, but then I thought... well WTH, if I'm doing all that why not just take the fresh rebuilt head....

My question is whats the difference? I figure if the cams are a direct swap then they cant be that different... right?

Any input would be great... thanks.

[wizzard_al]

Volvo changed the pistons to change compression, so the heads are essentially the same for all engines of similar years, meaning NA head fits LPT and fits HPT engines without problems, except one. Turbo engines have sodium filled exhaust valves, and NA doesn't. Other big difference came in '99, when they went to mechanical lifters, thinner valves, and VVT on exhaust cam of turbos. You should be able to bolt the head right on, but you risk having a problem that the exhaust valves won't handle the extra heat of the turbo. If you had your exhaust valves from the T5 checked, and they were fine, or merely needed to be lapped in, you could change them to the NA head and be fine. But then it is a half of a rebuild on the head.

[z31jaime]

Thanks for the responce. I'm only thinking of doing this as my current T5 head is starting to show signs of needing valve seals. and Having another head that would be bolt in would save me alot of time and work.

you said I run the risk of burning up the exhaust valves.... how bad of a risk.... I'm going to be running a 16T with 3" DP and ARD tune, so nothing Major.

If its a Slight chance then I might try it, if its a Good chance I'll just stick with what I got....


Also I guess another option I have is to swap the 96 head on to the 93 I have, and get rid of the crappy variable port thing and SAS it has...
No real reason to do that as the 93 runs great, but it would get rid of the SAS.

[wizzard_al]

Volvo went to sodium filled valves on exhaust for a reason, reliability and longetivity. I'd be very reluctant to use NA valves for that reason, but I can't say how long they will last.

[Fishey]

Non-Sodium Filled valves are physically stronger then Sodium filled valves at high tempeture and have a lower failure rate. This is the reason we don't see the use of sodum filled valves in racing. The reason they decided to install sodium filled valves is to increase longevity of the valve guides without using a more exotic valve guide material. There is no reason you wouldn't be able to make non-sodium filled valves last with a simple change in valve guide material.

Edited by Fishey, 31 January 2012 - 04:44 PM.

[ARD - Lucky]

For my build I ran the N/A head, intake manifold, and cam (intake) and swapped the turbo valves into the N/A head.

I ended up switching back to turbo Tbody though as the throttle felt a little too switch at tip in. Otherwise been great for last 18K miles.

[mojojo]

z31jaime, on 30 December 2011 - 08:09 PM, said:

Thanks for the responce. I'm only thinking of doing this as my current T5 head is starting to show signs of needing valve seals. and Having another head that would be bolt in would save me alot of time and work.

you said I run the risk of burning up the exhaust valves.... how bad of a risk.... I'm going to be running a 16T with 3" DP and ARD tune, so nothing Major.

If its a Slight chance then I might try it, if its a Good chance I'll just stick with what I got..ab..


Also I guess another option I have is to swap the 96 head on to the 93 I have, and get rid of the crappy variable port thing and SAS it has...
No real reason to do that as the 93 runs great, but it would get rid of the SAS.

You're pulling cams anyways, at this point, with investing in a $125 tool you don't even require pulling the head.

[erikv11]

Fishey, on 25 January 2012 - 12:27 AM, said:

No, The heads have physically different combustion chamber sizes.

Is this true?

[wizzard_al]

Erik:

Can't say I agree with Fishey. VADIS and VIDA both say for 96 and later cars, the exchange head is exactly the same one, NA or turbo. HOw are we gong to get different combustion chamber sizes with the same head. The difference is in the bor and the piston top.
Part # 8111178

Earlier cars had different number, but this is the update, and is the same for every 850.

[Fishey]

Yea, I think I am wrong. (Edited first post)

I am pretty sure I was thinking about Porsche 944/951 Cylinder heads and not Volvo cylinder heads.

However, The statement of just changing the Valve guide material is still very valid. If you change to a better guide material it will make a standard valve perform much better at transfering heat.

Edited by Fishey, 31 January 2012 - 04:46 PM.