Head to water pump bolt

[The Veg]

How important is this bolt? I can't for the life of me make the holes line-up; the head is all the way back against the studs (had been converted from bolts) but its hole is still too far forward relative to the hole in the pump. I'm guessing that from how stout that part of the head looks, there's not much structural importance to this bolt but figured I'd better ask.

[rgh0]

Its to ensure the front part of the head bolts down properly and evenly on the gasket and it also helps retain the gasket in location and not squeeze out. Never seen it not line up in all the builds I have done but I guess its possible especially if using a new front cover.

Potentially the front cover assembly is not seated properly or the gaskets / sealant used is too thick or the cover and back plate dimensions just wrong. I would try to understand the root cause of the misalignment as it may be affecting other things such as chain clearance

If the amount of misalignment is small and its just due to the hole location in the front cover being a little wrong I would look at reaming out the hole in the head to allow the bolt to align or getting another front cover

cheers
Rohan

[2cams70]

Are you using ARP head studs instead of the original bolts? Looks like you might be from what little I can see in the picture. The studs will be thicker and therefore allow less tolerance for head adjustment. I much prefer the ARP bolts to the ARP studs. The bolts are the same diameter as original.

[redcarandco]

Dear Veg from my experience... problem are in the studs... It is a very good way to work mechanicaly speaking better than bolts BUT BUT studs are a little bit too thick in diameter and you have zero gap in head hole so I suppose you also have difficulty to raise head from block and impossible to fit that damned bolt on water pump casing The only solution for us was to come back to bolts (it is probably not a coincidence if ARP bolts are also available ) or you try to enlarge every head bolt hole a little bit but I must tell you my engine builder has always refused to do that .....So we have forgotten ARP studs and we use ARP bolts with zero head gasket failure ( AJUSA gasket) in much more than 25 years of races....
Roger

[2cams70]

Yes the studs aren't needed for a road engine. Too thick and therefore not enough "springiness" to accommodate head to block movement at reasonable bolt torques. The nuts are a finer thread to standard too which means the clamp load versus bolt torque relationship is no longer what it was originally

[alan.barker]

How was it possible to slide the Head down
Without shortening the Timing Chain Rubbing Block.
Alan

[alanr]

Something is indeed odd and I would suggest not quite right for this bolt not to be in line?
It would be interesting to know if you can you get the 2 x 5/16ths bolts in at either side of the head? Are they out of line as well?.....The one above the Tensioner adjuster that goes from the head down into the water pump casting and the one on the alternator side that goes up from the water pump casting and into the head?

Alan

[The Veg]

Something is indeed odd and I would suggest not quite right for this bolt not to be in line?
It would be interesting to know if you can you get the 2 x 5/16ths bolts in at either side of the head? Are they out of line as well?.....The one above the Tensioner adjuster that goes from the head down into the water pump casting and the one on the alternator side that goes up from the water pump casting and into the head?

Alan

The one above the alternator goes in just fine, the hole for the other one looks a little mis-aligned but I seem to have mislaid the bolt so haven't tried it.

[The Veg]

Are you using ARP head studs instead of the original bolts? Looks like you might be from what little I can see in the picture. The studs will be thicker and therefore allow less tolerance for head adjustment. I much prefer the ARP bolts to the ARP studs. The bolts are the same diameter as original.

I think they are ARP; I tried ordering bolts from DBE but they were out of stock so I was offered the studs for the same price.

They were enough of a bugger to install, so I am *NOT* looking forward to removing them if that's what must be done.

[The Veg]

Its to ensure the front part of the head bolts down properly and evenly on the gasket and it also helps retain the gasket in location and not squeeze out. Never seen it not line up in all the builds I have done but I guess its possible especially if using a new front cover.

No, same front cover as before.

Potentially the front cover assembly is not seated properly or the gaskets / sealant used is too thick or the cover and back plate dimensions just wrong. I would try to understand the root cause of the misalignment as it may be affecting other things such as chain clearance.

Same old back plate too. The new gasket for it is paper-thin, pretty sure the old one was too.

If the amount of misalignment is small and its just due to the hole location in the front cover being a little wrong I would look at reaming out the hole in the head to allow the bolt to align or getting another front cover

The reaming idea is tempting, but since the hole over the tensioner doesn't appear to be quite in line either (but the one over the alternator had no problem), I'm not sure if that's really the right way to go. Hard to tell looking down such a deep hole but I suspect the distance off is about 1mm past what would allow a thread to catch.

[alan.barker]

Strange situation.
So how did you lower the Head over the Timing Chain Pad.
Alan

[The Veg]

So how did you lower the Head over the Timing Chain Pad.

I don't recall having a problem with that, maybe just a slight jiggle to the left to clear the end of it that hangs over before coming down, but no fore/aft interference with it. It's not a huge misalignment, maybe a mm or so. Just enough to mess-up getting the bolts in beyond any ability to knock or pry things together. No idea if the pad is the original item or design either- it's black plastic FWIW.

[alanr]

Something is indeed odd and I would suggest not quite right for this bolt not to be in line?
It would be interesting to know if you can you get the 2 x 5/16ths bolts in at either side of the head? Are they out of line as well?.....The one above the Tensioner adjuster that goes from the head down into the water pump casting and the one on the alternator side that goes up from the water pump casting and into the head?

Alan

The one above the alternator goes in just fine, the hole for the other one looks a little mis-aligned but I seem to have mislaid the bolt so haven't tried it.

If these two bolt holes are indeed in alignment and the middle long one that goes through the cylinder head isn't then something is mishapen..either the water pump casting or the timing chain end of the cylinder head.

Having head studs or bolts I can't see would make any difference at all to this position.

Just thinking what you can do...Have you tried getting this bolt in before tightening /torquing the head down?. If you have torqued the head down, that I suggest is causing the issue. I would slacken all the head nuts all off again and then try getting the long bolt in and also the two end up/down small bolts and then retorque the whole lot up all again and all at the same time.

Alan.

[The Veg]

Something is indeed odd and I would suggest not quite right for this bolt not to be in line?
It would be interesting to know if you can you get the 2 x 5/16ths bolts in at either side of the head? Are they out of line as well?.....The one above the Tensioner adjuster that goes from the head down into the water pump casting and the one on the alternator side that goes up from the water pump casting and into the head?

Alan

The one above the alternator goes in just fine, the hole for the other one looks a little mis-aligned but I seem to have mislaid the bolt so haven't tried it.

If these two bolt holes are indeed in alignment and the middle long one that goes through the cylinder head isn't then something is mishapen..either the water pump casting or the timing chain end of the cylinder head.

Having head studs or bolts I can't see would make any difference at all to this position.

Just thinking what you can do...Have you tried getting this bolt in before tightening /torquing the head down?. If you have torqued the head down, that I suggest is causing the issue. I would slacken all the head nuts all off again and then try getting the long bolt in and also the two end up/down small bolts and then retorque the whole lot up all again and all at the same time.

It all fit together before, and none of the parts have been subject to any abuse in between.

I'm a step ahead of you about loosening things. I fully removed the nuts from the studs and also the washers too as the washers have a little 'collar' that goes down into the hole. Gave the head enough of a shove for the studs to be against the front sides of their holes instead of centered and even after that I still can't get the long bolt to engage, so going back to bolts still looks like the solution at this point. I've discarded the old bolts already so can't directly compare, but as said earlier in the discussion I don't recall them being as thick as these studs.

[alan.barker]

Hi the Veg,
has the Head just been worked on by someone else.
If so did they drop it and when it hit the floor did it get bent
Have you tried the Cam Cover on to see if the Head is bent in at the front.
I hope not
Alan