K head bolts/head finish

[KenEvans]

I'm in the process of putting a used vvc head onto my 1.6K

 

I've been examining the head bolts as specified in the manual by screwing them into the block/rail and taking measurement "A" which is supposed to be less than 97mm. All the bolts are considerably less than 97mm for example 65 to 70 mm. Is this right? Do torque to yield bolts really stretch that much? I haven't even bothered to see if the bolts bottom out before taking the measurement since they are well under 97mm. I assume they're ok to use again.

 

Secondly, I took my used vvc head to a local engine reconditioner who will happily skim it for me. They certainly seemed to know what they were talking about, but I neglected to ask about surface finish and on the way out saw a cast iron head sitting on a shelf waiting for collection. It had obviously been machined with a fly-cutter and the surface finish was noticeably grooved, I could play a tune on it with my fnger nails, obviously not desirable on our sort of high output engine. Does anybody have any experience of how to express the sort of surface finish we should be looking for on the head? I'd like to talk a bit knowledgeably and mention grinding vs milling etc - they know it's likely to produce 170bhp-ish from a 1600 engine so if they know their stuff it shouldn't be an issue of course. Anyway, I've used to many words but your comments would be appreciated.

 

Ken

[oilyhands]

You must be measuring the bolts wrongly, the order of stretch is minimal..

 

The iron head has been cut with a knife edged tool in the fly-cutter or the tools traverse across the workpiece is too high, the operater should know better, a radiused tool with give a better, finer surface finish. Just make sure you let him know what's expected.

 

Oily

 

Oily

[KenEvans]

Errrrmmmm - no Oily, I've measured from the top of the block to beneath the bolt head. On further investigation though I notice the bolts go a nadgers tighter at around 97mm having screwed in for around 40mm already, but they happily continue screwing in for a further 25-30mm or so with bit of socket on them.

 

I'll make that "bite point" the point at which I measure the 97mm though it seems a bit imprecise to me.

 

Ken

[CHRIS CLARK]

Ken.

I assume you are screwing each head bolt back into the hole from whence it came?

 

If you have the oil rail off, then the best way (IMHO) is to screw each bolt into the o/rail until finger tight (not with a socket). The distance is then checked from the upper (contact) face of the oil rail to the underside of the bolt head.

I quote:- "If full length of thread is engaged, bolt may be re-used. If full length of threads is not engaged, measure distance from top face of oil rail to under bolt head. 378mm or less, bolt may be re-used. Over 378mm, new bolt must be used."

 

I wonder if you have 'opened up' the oil rail threaded hole at all by winding the bolt down with a socket hence eliminating the slight tight feel? It should be done just with fingers for checking purposes.