Head bolts

[jerry_hoback]

Thankfully the register is back! Its lucky that I'm ready with a question for the group- I wonder what the consensus is on re-using head bolts. I have the head off of my 66 to repair low compression in #6. The head bolts seem shiny enough "at a glance" and at $30 each I would rather not have to change them All if I dont need to. I ask because in the process if replacing a blown head gasket on my 94, I learned that Those bolts can be re-used up to twice. The 3.8 motor in my 66 does not appear to have been taken apart before and looks to be overall in relatively good condition. I checked the shop manual and did not See any reference but I may have missed it. Thanks all!

[cass3958]

Hi Jerry. The S Type engine does not have head bolts so I am assuming you are referring to the head studs over which the head slides and then there are chrome domed head nuts on top.
The studs on my 3.4 I reused without any problems when I rebuilt my engine but like you I think it was the first time it had ever been taken apart. The problem you will find with the studs is corrosion. They are made of iron and screw into a cast iron head and if you have an old engine that has blown a head gasket which might not be bad enough to effect the compression but allows water to seep across between the head studs they can become rusted in. Removing them becomes a nightmare and studs can shear off in the block. Then we come to iron head bolts going through an aluminium head and there is a chemical reaction that can occur causing the alloy to fur up and lock the bolts into the head. This then makes the head a real pain to remove and when I removed mine I had to use an engine crane to take the weight of the head on chains and gradually ease the head up off the studs over a couple of hours. One stud came out with the bolt the rest stayed in the block.
If you have removed the head I would then remove the studs from the block to check for corrosion in the threaded area, change the ones that show corrosion or possibly change them all. If they are like you have said clean, shiny and look in good order I would clean out the thread with a suitable tap, ream out the hole in the alloy head and reuse the studs using a decent carbon grease to coat them when refitting the head and in the thread.
The studs are part number C2270 and SNG Barrett sell them but they are not cheap at £21.55 each when you need a set of 14. https://www.sngbarratt.com/English/#/UK ... 20studs%60

All my studs were in good order so once cleaned up I reused them all.

Removing the head with the help of an engine crane

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All studs except one stayed in the block.

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[jerry_hoback]

Thanks Rob,
Studs. Of course. Chalk it up to sloppy thinking. I had 2 studs come out with the nuts. I used an engine hoist as well along with a load balancer which I bought for this project. The head came off pretty easily I think, considering all that I was thinking could go wrong. I will mention that I did not, but should have removed the heater box beforehand. It encroaches by about 1/2 inch- well beyond what can reasonably be "jostled past." I read a few posts on that subject and some said to remove, some said dont need to. I suspect that it may have something to do with the condition of the engine mounts, or with the way the body itself was assembled. Im not sure, but I had to. Back to the studs, I will probably remove them as you suggest. I was considering it if only to clean them up and to make cleaning the top surface of the block easier.

[jerry_hoback]

I got all but 3 of the head studs out. Those remaining are stuck hard enough that I was concerned they may snap off. They are 3 of the ones that the lifting hooks are on when assembled. I presume that these loops being under the top nuts allowed moisture to get in. I don't see any evidence of failure in the head gasket. I tried the old double nut method to try to twist but no joy. I have elected to leave that can of worms for some later time due to limited finances and completing tasks involving other smaller cans containing fewer worms during this whole endeavour. My parts should be here soon and reassembly will commence shortly....

[cass3958]

Heat is your best friend here Jerry. The heat expands the metal breaking the bond of rust between the stud and head. An old trick I was taught years ago was when the stud is hot get a candle and allow the heat of the stud to melt the wax so it runs down into the thread. Allow it to cool a little and then turn the stud out. I use a stud removal tool but it can damage the shaft of the stud as it has a serrated cam cog that bites into the metal. Ok if you are replacing the stud or the damage can be cleaned up so the double nut method is just as good.

[jerry_hoback]

I did finally get the last 3 studs out using heat, Kroil, and a big visegrips low down just above the lower threads. I was initially very leery of using uneven heat right next to the cylinders like that, but no apparent harm was done.
At this point head is back on, cams are mounted, tappet guides checked for gap and reshimmed as needed (3 pairs appeared to have simply been swapped). I believe that the problem valve where the low compression existed was because of a too- thick shim. The valve does not appear bent or damaged but there is evidence of some activity in that area, including the cam timing not agreeing with the crank timing and the shims mixed up. (It seems like every time I fix a problem in the engine bay, I end up wondering why this car ran when I got it.)
I am at the point of setting the cams timing to agree with the cranks' TDC mark. There appears to be about 5 degree disagreement. I have read the shop manual, and maybe my Queens English is lacking (I wouldnt be surprised) but I dont understand how to remove the adjustment plates from the cam sprocket gears. I have the clips out. I found a pair of nuts to put on the guide pins to hold the assemblies off the cams, and tapped- as the manual stated- on the sprocket to try to knock it off the plate but no luck. I was contemplating sliding some sort of shim between the front of the cam and the plate, but am worried that whatever it might be would fall into the abyss below. As it is I tried Kroil there too, along with a bit of heat, but I am essentially ending up hammering against that front guide plate via the nuts I have on the guide pins. I also read another thread here which stated that to install them, the plate and sprocket must be square with each other or they will bind. I suspect this may be my problem but it seems like a special puller would be needed to overcome it. Thoughts?
Thanks guys!

[cass3958]

Sorry Jerry never had to do this on my engine as I had the machine shop set the cams and shims for me.
You might be better taking this question to this Jaguar forum as there are more members who have Mk2s and the same engine than just the few of us here on the S Type forum.
https://www.jaguarforums.com/forum/mki- ... aimler-61/

[jerry_hoback]

Thats fine, Ill try asking there. i think I know the answer I'll get though..... Heat. I dont want to scorch the chain after Ive got this far but done evenly enough I suppose it will be fine.

[jerry_hoback]

For everyones further info, I let the problem simmer in my head for a couple of days and concluded that I needed to re- remove the camshafts yet again. My initial plan was to put a puller on the back sides of the sprockets but there still was not enough room for one- I tried several. I ended up risking all (dropping things into the oil pan below) and removed the guide pins holding the sprocket and plate in place, fiddled the assemblies out of the chain and then knocked the plates out on my workbench. The plates were both stuck quite solidly in the sprockets and I dont think I could have done it without collateral damage while they were on the motor. I left the parts to soak in a can of parts cleaner. Im sure some other little problem will crop up soon and I will be back with another numbskull question. (Why doesnt he just read the manual?!?!?)

[jerry_hoback]

my painted air filter box

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A small thing I wanted to get done during this escapade was to get or make an air filter box bracket. Here is my filter box mocked up. I ended up simply making 2 "C" shapes out of some flat steel stock that I have. It was quite easy and took much longer for the paint to dry than to make them. I also found the silicone sleeve at the head of it on a site called Siliconeintakes.com of all places. Its an excellent fit.