Camshaft Disaster

[happypatrol 5]

As some of you may know I've been trying to rebuild my 1.9 8v for some time in between a load of other things. Ive now completed the bottom end. And tonight went to putting the head together again having had the camshaft removed/inspected and it was my intention to check the valve clearances, i should have done this before i removed the camshaft. I know.

 

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on putting the camshaft back in tonight I've cracked the no 2 bearing cap. I was being careful and doing it slowly bit by bit. But no2 did get a bit tight and i obviously went too far and broke the bloody thing. My question is can i get another bearing cap. And will it be ok. I know often these are matched to the head. Ive spent way too much money on this car now and to be honest I'm about to crack with it all. Does anyone have any quick/cheap answers as to what i could do.

I would really appreciate the help.

[welshpug 1,661]

they are matched and line bored in situ yes, so you either need it repaired or another head, its not as simple as taking a cap from another head

[happypatrol 5]

they are matched and line bored in situ yes, so you either need it repaired or another head, its not as simple as taking a cap from another head

Can it be repaired though? It has a hairline crack right across the bearing cap contact area. It hasn't broken in two but is definitely cracked. What would you do with it. A new head isn't an option if i can avoid it?

Im so annoyed with myself.

[petert 589]

The only way is to strip the head and find a replacement cap. You may get lucky and find one very close, that only needs scraping. Otherwise, you'll have to get the head line bored. Unlike an Mi16 head which has very small journals, it's a very straight forward operation.

[happypatrol 5]

The only way is to strip the head and find a replacement cap. You may get lucky and find one very close, that only needs scraping. Otherwise, you'll have to get the head line bored. Unlike an Mi16 head which has very small journals, it's a very straight forward operation.

The head is off the car at the moment. Would a decent machine shop be able to check that i guess??

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​Thanks guys.

[happypatrol 5]

If i can find another cap somewhere. Checked the usual sites and not one for sale anywhere. I just had the head skimmed/valves recut/

rebuilt too.

[TAG 25 1 Cars]

I guess it depends how much deviation there would be in production.

If you could find a spec for running clearance on the bearing caps, and manage to source another bearing cap, you could confirm.

It would be a shame to give up on that head straight away in light of you having spent out on some machining already.

[hoodygoodwood 71 3 Cars]

Nightmare ,but I wouldn't give up on the head yet seeing you have spent money on it . Remove valves and springs then refit the cam well oiled with the 4 good caps torqued down , the cam should now turn by hand pressure on the pulley . Once you have bought a spare head or caps you can try the replacement cap in place and use plastigauge to measure the clearance . They made thousands of heads a day on pretty accurate machinery and there is probably not a great difference between them , remove the caps either side of the damaged one and use a depth micrometer ( not a vernier - not accurate enough ) to measure the depth of the semi circle ( it will be almost exactly half the journal diameter ) then find a replacement cap with the same dimension . I think the caps have a little bit of float side to side built in as they do not fit tight on the bolts so it should self centre .

If its No2 cap you cracked another head would have 2 spares to try iirc - 2 and 4 . I may have an old head lying around and could measure the depth of those caps and compare to yours .

Got to be worth a try .

[happypatrol 5]

Thanks guys

One of the other guys on the forum Dobboy knows someone that might have a decent head so i will await getting that and see how I get on. Ill get this thing running if it kills me. I did see a fast road head on eBay right enough. If it hadn't been £250 i would have went for that option.

[happypatrol 5]

Just a quick update if anyone is interested. I got another head. One of the bearing caps was too small and one too big. I took the whole lot to an engineering shop in Glasgow called West of Scotland Engineering. They were 100% confident they could do something for me. So i dropped it off.

Now it is back they measured it up to the cracked cap and machined the spare cap to a suitable match. Rebuilt the head adjusting the valve clearances too and even torquing down the camshaft. So all it needs is refitted. Cost £58. So I'm pretty chuffed and confident that i won't have any bother once its rebuilt. So I've now kept my original head/camshaft etc which had been all prepped and ready to go prior to me breaking the cap. Happy days.

[TAG 25 1 Cars]

Glad to hear this is resolved!

[Leslie green 111]

Got a similar issue myself the end cam bearing nearest the gearbox on my 1.9 gti , the thread on top that holds the rocker cover down is stripped and cracked ,tried some chemical metal in it and a helicoil but it hasn't been a success ,The actual bearing is ok but the oil is leaking out the rocker cover . guessing Id have to find a end one as it is machined to mate up the the thermostat housing.

Don't really want to change the head for such a minor fault .