I recently purchased a 1993 850 Glt with a non-turbo 20 valve eengine. I bough the car very cheaply know that it had a broken timing belt with the plan to pull the head and install a different one from a salvage yard. Unfortunately, the salvage car that I had sourced for the new head disappeared before I had a chance to get out there. The only parts cars I can find now are a 1994 850 Turbo and a 1998 S70 non-turbo(i believe).

Will the heads from either of these car work?

I've searched through the archives and have been unable to find anything conclusive.

Thanks for any light you can shed!

 

Um, I don't know, the turbo blocks are "plumbed" for turbos, so I don't know if the head would be different or not. The valves may be different, the cams are different, and I don't know if the motors themselves changed between 93 and 94+ models, since 93 was the off year for 850s. I've also been told that the valve covers are mated to the heads, and if you swap valve covers, leaks may develop, I don't know if it's that way for the rest of the motor or not.

 

Valve covers are mated to the head, they are line bored for the cams. Honestly, probably not a good plan to do since the motors are definately different. I dont know where you live but we have several non turbo heads at the wrecking yards around here. Expand your search. Be sure to get the same engine number too. There should be a sticker on your timing belt cover that has your engine number, look for that engine.

 

I've had both apart in the past 3 months and I have to admit I saw no difference in the heads (this is from a memory point of view only and I did send the NA head out to a machine shop but did the turbo head myself) in fact I just, a few minutes ago, finished installing and assembling the head on my turbo.

I always thought I agreed with Boxpin's position on the line boring for the cam thing but everyone's talking about slapping NA cams in turbo heads without line boring and this is a mystery to me. I always thought new/ different cams required machine work(line boring). Can anyone explain????

The blocks are way different. Another in fact when I measured the turbo's bores I just couldn't accept the readings and kept double checking the bore gauge against a micrometer. They were like 0.001 to 0.002 over, I couldn't measure any taper or out of round. I really can't say this for the NA.

I'd keep looking for the right head but I'd also check the bores, carefully! and don't ignore what you see, like I did.

 

Thanks for the replies. I'll keep looking for a n/a head. According to this thread the intake manifolds have a slightly different shape, so at the very least I would have to also use the turbo intake.


If anybody around Denver knows of or has a n/a head from a B5254 for sale, let me know!



~arnold

 

The valve cover which is also the cam caps is line bored with the head, you cannot swap valve covers with other heads because the bore would no longer be round due to slight differences in each head/valve cover. In some cases you can put the valve cover from another head without the cams and you will feel the misalignment where the cover meets the head. The way they are manufactured, the dowel pins are installed and the bores are roughed in with the cam caps torqued down then the final honing happens. It is a location issue more than a size issue.

modern motorcycles are the same way, usually enough that the cams will bind if another set of cam caps is used.

The reason you can use any cams is that the size of the bore is the same from one engine to another as long as the caps (valve cover) are matched to the head.

and my opinion is that Volvo was very clever in making the cam caps/valve cover one piece.

I hope my explanation is clear. I'm an idiot so sometimes i make no sense.

 

Hey Ross, thanks. Great explaination, very clear, and I understand much better now. and it makes perfect sense. It's always nice to meet new, helpful and forthcoming people on the forum, hope you stick around.