Stiff head bolts....

rockdemon

rockdemon

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Staff member
Hi all,

another newbie question from me ;o)

I'm currently in process of swapping the heads from the spares sd1 engine onto the p6 engine ( which has a snapped manifold bolt and extractor stuck in one of it's current heads).

I managed to remove the heads from the sd1 engine reasonably easily. took about an hour but the head bolts came out with a little effort.

However, on the P6 engine that's in the car some of the bolts are extremely tight and wont budge with my wrench.

Question is, is it a good idea to get a longer wrench ( without a ratchet) and apply more leverage, apply heat to the bolts etc or am i missing something?

The engine that's in there annoyingly looks to be in excellent condition apart from the snapped bolt and extractor... and the rocker gear is much less cruddy than the ones in the sd1 engine. Is it a good idea to transplant the p6 rocker gear onto the sd1 head?

Other question is about whether i should get new head bolts - and if so from where - they seem overpriced on ebay at about £40 a side...

Any thoughts gratefully received!

Rich.
 
Hello Rich,

How long is the arm that you are currently using? The arm that I have used in the past would be 2 ft long or so. The bolts will tend to make a loud "crack" when the seal breaks and the bolt starts to move.

The head bolts used in the P6B and SD1 engines are all high tensile and can be re used. Only stretch bolts as used in Rover V8 engines from 1994 onwards for cylinder head retention are to be used once and once only. Stretch bolts are also used by other European car makers such as BMW and Mercedes Benz.

If you would like to fit new high tensile head bolts, then Real Steel is a good choice. Either way be sure to use an anti seize lubricant on the threads.

Ron.
 
Hi Ron,

It's 9 inches to a foot long - the ones that have come off have 'cracked' as you describe. Thinking that a deeper socket and a longer arm will make it more direct ( no extender bar ) and the lack of ratchet coupled with extra leverage might help. I've seen bars 45 - 60 cm long. was going to go for the 60 cm one...

Rich.
 
Excellent - i shall make it so :eek:

What do you think about the rockers - if i swap them will i have to mess about with preload? (I'm not exactly sure what preload actually is hence my wariness of it!) :O)

Thanks,

Rich.
 
Hi Rockdemon. Use an impact socket that grips all six flanks of the cyclinder bolt heads, don't use a 12 pointed thin wall socket that only grips the corners of the bolt heads. Never use a torque wrench to undo bolts that have been tightly torqued up. Use a long breaker bar and, as you say, don't use an extender bar. Sorry if I'm teaching you to suck eggs.
Regarding re-using rocker gear, inspect very carefully, bits of steel swarf imbed themselves in old alloy rocker arms and can quickly wear out new rocker shafts, better to refit the rocker assembly complete than to only use new shafts on old rockers. Try and find proper Rover parts, perhaps try Rimmer Bros., I have heard from various Rover V8 engine builders on another forum that there are currently lots of cheap and nasty rocker shafts and rockers on the market that don't last very long at all before disintegrating!
If you're using a standard camshaft and not building a high revving racing engine, but restoring a road going Rover V8 for further road use, don't worry about preload! They didn't at the factory!
I'll probably get shot down in flames by somebody more knowledgeable in a minute... :LOL:
 
The only problem with using Impact Sockets is that the walls are too thick to get down to some of the bolts, (the ones under the rocker cover), even a normal socket can be too big. I've got a very thin walled Britool socket that I've used for years, but TBH now I wait for it to crack every time I use it, it's been OK so far, but it will happen eventually.
 
hi mrtask:)

it's only teaching to suck eggs if i knew this sort of thing which i patently dont - so thanks the answers from yourself and harvey are a great help! I think i'll refit the p6 rocker gear wholesale as that engine does look very good inside - like the good picture with a very light brown coating which they show as good on the rpi website. I wont put new shafts etc on unless i have a problem.

I shant worry about the preload either on the basis of what you say - maybe in a year or 2 when undoubtedly i'll feel the need to improve it no doubt...

Hi harvey - the sd1 engine is looking much smaller and easier to move around without it's heads so i can move it now so i'll take a look at the timing cover again soon :)
 
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