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Have you looked at the WSM section on minimum head thickness in case that head has been milled too far? Volume 1, Section 15, Page 19
If too low, STOP NOW and just find a new head. It will always give you trouble and the car will lope at idle, the compression on one side will be higher than the other side. This is an issue because you are boosted. Makes tuning it a bit of a nightmare.
I see no practical way to alter the WB at the large opening for the engine water jackets.
You will need to follow Carl's suggestion for the best results. I would use all thread on both cylinder heads for uniformity. Both head passages may need to be shimmed.
I took Kevin's advice and put together the good side with an old gasket that cam out and torqued it down.
Here's the gap that exists on the other side.
Putting a feeler gauge into that gap as Stan suggested shows it to be about 1.45-1.5 mm when I sum the blades stuck together. It's tighter at the side and looser in the center because they don't mate well yet.
and with the other side bolted up with a gasket, my flange holes to head holes actually line up pretty well height wise.
So it seems that what I need to do is to get the mating surfaces to mate to each other better and then to fill that extra gap beyond the 1.3 mm gasket thickness, which looks to be only 0.2-0.3mm so doesn't seem like any room for a spacer. Seems like the issue is more related to the uneven surfaces (low spot in the center between the mounting bolts) than to the head being machined too far.
Do you agree?
What about putting 2 oem gaskets together or will that cause me a problem on the other side because the bad side will now be too tall?
How about isolating and repairing the cause, instead of trying to figure out a weird solution?
Try a different water bridge, with the hope that the one you have is warped?
If that's not the problem, pull the heads and figure out why they are not the same. One head must have been surfaced quite a bit more than the other, or one head was surfaced at the incorrect angle.
How about isolating and repairing the cause, instead of trying to figure out a weird solution?
Try a different water bridge, with the hope that the one you have is warped?
If that's not the problem, pull the heads and figure out why they are not the same. One head must have been surfaced quite a bit more than the other, or one head was surfaced at the incorrect angle.
Either senario sucks.
Greg, thanks for the input. I have a message into Mark Anderson about a good used water bridge.
For you guys that do this work all the time, pulling heads and machining and such probably isn't a big deal. For weekend mechanics like myself that have to balance other jobs, family commitments, etc that's easier said than done, so with an issue that looks like I'm not so far away from a workable solution by making two parts fit better together so they don't leak, the "weird solution" is likely all I can put together with the time and money resources I currently have available.
That side of my water bridge is actually high in the center on the axis between the two mounting bolts and I can rock it a little on my metal band saw table, which is probably the flattest surface I have to work on for comparison. Putting a long razor knife blade across the head surface also looks like maybe the center has a gap because where that head was welded and repaired, although it was surfaced there, that portion of the head surface seems to be a little high at the weld position which is the upper rear corner of the square coolant passageway.
I'm going to try and true up both those surfaces relative to each other, put it back together and see if it holds vacuum. If so, I'll hook up the coolant feed line and refill the system, then see if it holds coolant and if so, start driving the car again since I was without it all summer.
Tonight I reworked the waterbridge and head mating surfaces.
The problem was definitely the passenger side head, but with a piece of glass across all 4 mating surfaces, only the driver's side head surface had no wobble in the glass. Both sides of the waterbridge and the passenger side head all let the glass rock anywhere from a little to quite a bit, but not anymore.
Here's where I started working the passenger side head with sandpaper wrapped around the glass block. The darker area at the top is the large low spot on that surface where my coolant leak was coming from.
Now it looks like this
Might still have a very slight lower spot, but I don't want to take the surface down any further as at the right side, it's almost to the head.
The rest of the mating surfaces look like this
This took the light gap from my USB cable light that I ran into the waterbridge from the thermostat opening to the end from this a couple days ago
To this now.
Hopefully this is now small enough and more even across the surface where a gasket will be able to seal up the very small remaining gap.
fingers crossed it may work now….. perhaps i missed it somewhere, but why that "big" repair weld on the head ? i assume your problem now is weld shrinkage of the alu due the weld , no ?
fingers crossed it may work now….. perhaps i missed it somewhere, but why that "big" repair weld on the head ? i assume your problem now is weld shrinkage of the alu due the weld , no ?
I hope so too. This was a used engine I purchased and I knew it had been repaired. The integrity of the weld repair looks good, even if it doesn't look pretty. Don't know why that head cracked where it needed the repair, but hope it's OK. Clearly that repair and the resurfacing afterward is the reason for the uneven surface I just worked to correct.
sure strange place to see a repair weld….. perhaps was frozen cracked or … in a accident ??
I don't know the history or cause of the failure. The engine was put together by member ladybug83, later sold to member BC for a project he didn't complete with his son and then bought by me when I blew the head gasket on my 4.5L. I think it was BC that had the welding repair done.
I don't know the history or cause of the failure. The engine was put together by member ladybug83, later sold to member BC for a project he didn't complete with his son and then bought by me when I blew the head gasket on my 4.5L. I think it was BC that had the welding repair done.
08-26-2019, 12:22 PM
