Losing Coolant

[collins_dan]

Getting ready to retorque head. Have read the archives, will ease off 10 degrees then tighten. Workshop manual says 60-65 lbs. What do people actually use? 63? Thanks, Dan

[collins_dan]

No joy with retorquing. Extremely tight. Was finally able to loosen back left ever so slightly and when I went to retighten, it was already 65. What about a slight smear of high temperature gasket sealant along the back edge where the block and head meet? I don't want a blown head gasket and would like to put off head removal until winter. Thoughts? Dan

[rgh0]

Hi Dan

Head bolts can by very "sticky" especially if they have been in place for a while and the torque readings misleading as it takes some effort to break them free and start them moving. I would retighten the bolts to the position they were orignally plus a little more and watch the torque as i did it.

i.e.
If you loosened the bolt 10 degrees then retighten the same 10 degrees and then go another few ( may be 2 to 4) degrees. Watch the torque required to do that and dont go over 75 to 80 ft lbs. The bolt may be sticking on the head or the thread or both. If its the thread end thats sticking then going above 80 ft-lbs may break the bolt if its a standard reduced shank bolt, even 80 ft lbs is pushing it for these bolts, with ARP bolts or the full diameter shank bolts 80 ft-lbs should be no proboem. If you cant retighten the bolt to its orginal position with 80 ft-lbs then you either take your chances and use more or remove the head and change the gasket as leaving it 10 degree loosened will almost cetainly result in head gasket failure sooner rather than later.

In addition you could try one of the epoxy putty products generally sold for fuel tank repair to seal the area where it leaks temporarily.

cheers
Rohan

[collins_dan]

As always, thanks. The bolt heads read GKN on the head. Dan

[collins_dan]

Is it odd to get a leak like this between the head and block and no steam?
Dan

[rgh0]

I have seen the water leak out the rear of the block a few time and especially in race engines before. I have personally not suffered it but a friend who builds the same engines as me has suffered it repeatably and he only fixed it by using ARP head studs and doing them up to 80 ft lbs after trying a range of different head gasket styles. He had it happen 3 times before he cured it but only had the head gasket to cylinder fail once and had the water leak symptom only the other times. He observed it once on the dyno with a new engine with the water squirting out under pressure under high engines loads as the cylinder head lift slightly under the pressure loads in the cylinder - the rear appears to be a weak spot for this.

The GKN bolts will be the orginal ones and may be the reduced shank style so be careful when going about the 65 ftlbs level with them.

cheers
Rohan

[JJDraper]

I would worry about the face of the head-to-stud pads when over torquing the studs. This is not a race engine after all. Age and over torquing could 'squish' the alloy leading to more problems. Is it worth taking this chance rather than giving in and changing the head gasket? This would give the opportunity to see if there is an underlying problem.

Just my thoughts, I don't run a workshop..!

Jeremy

[rgh0]

Hi Jeremy
yes the "right" fix is to replace the head gasket.

However if you want to use the car and try to fix the leak in the interim this summer I believe there is no risk of "squishing" the bolts into the head and damaging the head if you return the bolt to its orginal position plus a few degrees. The excess torque that this may require may break a bolt and require the head removed and the bolt and gasket to be replaced but it is not generating higher clamping loads as the bolts are sticking in the threads and requiring a higher torque load for the same clamping load.

cheers
Rohan

[collins_dan]

Thanks for your replies. I'm going to have a friend come over this weekend and work on retorquing the head and hope that solves it, but am not optimistic. Can I get your opinion on what looks like damage around the tappet caused by the cam lobe. The picture is not great. The tappet is fine, there is just a notch cut into the rim pressed into the head (don't know what it is called) about 1/3 of the way through. Does this need to be replaced? Thanks again, Dan

[rgh0]

looks like the cut out in the cam follower sleeve has not been perfectly aligned with the cut out in the head itself so the cam lobe has hit the sleeve.

This could have been original installation or the sleeve may be rotating in the head (which i have experienced before). The sleeve should be replaced as soon as you have a chance. Have a close look at the other sleeves to see if any of those are also rotating and not aligned with the head cut out.

In the short term it is probably ok provided the follower is moving smoothly in the sleeve and not binding and the sleeve has no through cracks down it length and its just the chip off the top corner that is missing.

If you choose to keep using without replacement in the short term check the clearance with the cam lobe to the broken section of sleeve at the full limits of the cam float forward and back to ensure it will not hit again and check after running again a couple of times to verfiy that the sleeve is not moving in the head.

Sometimes with non standard cams you need to slightly enlarge the cut outs in the sleeve and head to account for larger lobes or slight axial movement of the cam lobes versus the cut outs.

regards
Rohan

[collins_dan]

Thanks Rohan. I'm beginning to resolve myself with the reality that the head needs to be removed, and the head gasket, bolts and cam follower sleeve need to be replaced. The frustrating thing is that I had someone 'reputable' rebuild the engine for me just a couple of years ago, but have found numerous problems (water pump installed upside down, this cam sleeve issue and if you saw the gasket under the timing case, you would think he was caulking a tub!). The combination of which is undermining my confidence on the rebuild. Cheers, Dan

[collins_dan]

I'd like to try to retorque the head, but am reluctant with the old and original head bolts. Could I replace them with ARP bolts, then retorque? If so, what would the procedure be? Go through the correct sequence and remove and replace one at a time? What torque setting would I shoot for? I can determine what the current setting is. Thanks, Dan

[rgh0]

Relacing the head bolts one at a time you could try. I have never done it so i dont know the odds of success. If I did this I would replace the bolts to the original torque first then tighten to maybe 70 ft lbs to try to get the gasket to reseal ok.

good luck it may work
cheers
Rohan

[collins_dan]

What's interesting is that I noticed my radiator cap was rated at 10 lbs, so I replaced it for a 7lb cap. More, not less, came out. I'll try the new head bolts. Sounds like it couldn't hurt. Dan

[collins_dan]

Unfortunately, I have to bring this post back up. I replaced the original bolts with ARP and retorqued to 70. No joy. Had the head gasket replaced along with switch to QED 360 cams in early 2013. The shop checked the head and said it didn't need to be skimmed. Seemed fine when I got it back. Didn't put many miles on the car, so didn't retorque. Had the car painted last year, getting it back late this fall, so no significant mileage. I generally start it and let it warm up every other week over the winter. Started it up today and it came up to temp. Turned it off and noticed coolant at the back of the block. Oil and coolant look fine. No milk. Same symptoms as before. I will retorque head bolts up to 70 in sequence tomorrow. Any thoughts and suggestions. Dan