need milling tolerances for B5234T
 

2001 v70 T5 2.4L Turbo with B5234T engine, S/N 2107513. My head shop cant find this engine in their book. They only find the X/C edition and they are scared to assume the milling tolerances also apply to my engine. Can anyone help me find the info I need so I can supply it to the shop?

My vehicle had a blown head gasket and the coolant was POURING into the oil. I am milling the heads, reseating the valves, and probably replacing the cylinder rings and rod bearings, rebuilding turbo, and probably replacing all the other sundry components attached to the engine like water pump, timing belt, etc. Looking forward to a like-new volvo.

Something I thought about, after it was too late, is this: When the head is warped, the camshaft bearings are not in a straight line. If you mill it, then the engine block will help hold it with the camshaft bearings curved. So really, you need to send it to somebody who specializes in straightening out aluminum heads using a torque plate sort of a contraption. In my opinion.

thats an interesting thought. make you think the whole endeavor of fixing a warped head could be like chasing ones own tail. but when experienced mechanics tell you to mill the heads, they never also suggest you have work down on the cam bearings. I am just a hobbyist so I cant add much other than your comment makes sense from a common sense point of view. I think they said mine was out 1/12000 of an inch. seems to me like a good gasket and properly torqued bolts should be able to deal with something like this in the first place. All I can say is I hope I dont end up with prematurely worn cam shaft bearings.

anyhow, I was told that the milling tolerances for my engine are the same for those specified for the x/c model. so that is what I went with.

They can't measure within one twelve-thousandth of an inch over the length of a head, and they wouldn't have milled for that. Surely they said .012, twelve thousandths

You are correct. It was out by 0.012 . Also, as soon as I walked in, the guy warned me about the CAMs. He said exactly what you said. However, when it comes to a torq plate, this shop actually has such a thing, but they dont like using it. You are required to heat the head up to a very high temperature and it is possible to alter the aluminum and cause it to become soft.... effectively ruining it. Its a tricky procedure. He said the original head damage usually occurs when someone overheats the head. This shop is the premier shop in San Antonio. They have been doing it for 40-50 years I think. Its run by a bunch of brothers, each of which currently holds various land speed records in a corvette class. They run at the Bonneville salt flats.

I bought a 1998 S70 T5 about 2 years ago. Had blown head gasket. removed the head took it to 'Head Shop'. They told me out of 'flat' tolerance. Because of the overhead camshaft it had to be 'pressed flat' because to mill the head. The camshaft bores would not be straight. They stripped the head, magnifluxed it (checked for cracks), heated and pressed the head, did a valve job, new seals. I reinstalled the head with new head bolts.
I have put about 18k miles on the Volvo. Total cost was about $700. I did the labor myself, but I have a lot of experience.

The shop told me that almost always there are no cam problems with Volvo heads that have been milled as much as mine. But I probably won't know until I install the head, torque it down, and then install the cams.

I find the whole thing interesting because The engine ran fine with a warped head (no cam issues). How can the head warp 1. When it's bolted down so very securely, and 2. Why doesn't the warpage effect the cams right away? Also, it would seem that the cams would not turn easily after the damaged head is removed, but I'll never know because my cams were already off the head. I may bolt the cams in place before I install the head just to see if the rotate smoothly. But either way, I will not judge them until after the head is torqued down.

Just speculative questions posed by an amateur. Hopefully I won't be shopping for a new head.