retightening 505 xn1 cylinder head bolts after initial running
- Thread starter 2pac
- Start date
2pac,
Take a good hold of your computer chair because you are about to have a torrent of answers to your query.
Most of the replies you will find in previous posts from those with experience but all varying in content.
I will start my well worn reply from the initial stage fitting as found in the Factory 504 xn1 instruction.
Stage 1. Tighten to 36 foot lbs.
Stage 2. Loosen each bolt then tighten to 15 foot lbs. { Each stage tightening to be done following the correct order* }
Stage 3. Tighten 90 degrees. [quarter turn].
Re tightening after warm up and absolute cool down.
Stage 1. Loosen No 1 bolt.
Stage 2, re tighten to 15 foot lbs.
Stage 3. Tighten 90 degrees.
* The bolt tightening sequence ie. 10 6 2 3 7
Front [4] [3] [2] [1]
9 5 1 4 8
2pac,
My posted tightening sequence has been incorrectly posted.
Follow the tightening order as per your manual.
My posted tightening sequence has been incorrectly posted.
Follow the tightening order as per your manual.
The idea is to make sure it isn't binding so slackening off is just to "break" the thread first
Sent from my F1f using aussiefrogs mobile app
Sent from my F1f using aussiefrogs mobile app
2pac,
At the re tightening stage just loosen one bolt at a time in the right order. [Remember at this stage there will be coolant in the engine]
Sherman's point above explains the reasoning behind this method.
I can't say what should be done, but here is what I was taught by a couple of Pug mechanics and has never let me down :
Use plenty of Hylomar on the head gasket.
Tighten in stages to 70 ft/lb.
Don't worry about re-tightening.
......................................................
If you want to re-tighten, loosen off less than 90 degrees, keeping in mind that oil and water can get past the gasket if you slacken it too much. You just want to crack the thread.
Then do up to 70 ft/lbs.
Use plenty of Hylomar on the head gasket.
Tighten in stages to 70 ft/lb.
Don't worry about re-tightening.
......................................................
If you want to re-tighten, loosen off less than 90 degrees, keeping in mind that oil and water can get past the gasket if you slacken it too much. You just want to crack the thread.
Then do up to 70 ft/lbs.
my head job failed. all the coolant in the expansion tank disappeared after 15 minutes and the car wouldn't idle.
before removing the head again i tested the torque, and 90 degrees which i tightened equals about 50ft/lbs.
there's a bit mayo in the oil.
i ordered the compressor tool for the liners, to do it right.
before removing the head again i tested the torque, and 90 degrees which i tightened equals about 50ft/lbs.
there's a bit mayo in the oil.
i ordered the compressor tool for the liners, to do it right.
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Well, I guess the reality of that puts to rest the old debate about angle tightening vs torquing.
All the same, I would have thought that it would not leak at 50 lbs. Except that things did not get initially compressed and seat properly....
All the same, I would have thought that it would not leak at 50 lbs. Except that things did not get initially compressed and seat properly....
On my 505 XN engine I used the original bolts which are not TTY bolts and have been on the engine since day one (500,000 miles to date) when I replaced the head gasket some 10 years ago.
Tightening was along the lines of 25 Foot lbs,
then 50 foot lbs,
and finally 65 Foot lbs.
And I re-tightened after a warm up and cool down cycle and then rechecked and re-tightened again after 500 miles.
Cheers
Roland
Tightening was along the lines of 25 Foot lbs,
then 50 foot lbs,
and finally 65 Foot lbs.
And I re-tightened after a warm up and cool down cycle and then rechecked and re-tightened again after 500 miles.
Cheers
Roland
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Peter,
That is correct but the 2.7 litre PRV6 used the angle tightening method as well but with re-usable bolts. Not TTY.
Hi 2pac,
I remember measuring the protrusion because I borrowed a dial gauge from the local mechanic.
So I must have had the liners clamped down to do this.
I do remember the protrusion being quite different from one end of the engine compared to the other so I had to make adjustments using different liner seal thicknesses until I was within limits.
I definitely used a thin smear of sealer on the liner seals when I assembled the block.
Cheers
Roland
Beano,
I don't think a debate is necessary I feel it's more that there are two methods that have been in use over time.
The simple torquing down of the head bolts was early technology ie 203. 403. 404. 504. Although still adhered to in Haynes ?
Torquing with a final angle tightening possibly came about because of improved gasket material and the observance of bolt behaviour. See Sherman's Post *5.
The latter method is to be followed according to the factory manual.
Because we aren't observers it is difficult to wonder what has gone amiss.
Rolands method in his post *11 has served him well. As I mentioned in my reply *2 there will be many and varied replies to this question.
Personally, if the overflow bottle emptied so fast, I'd suspect a leak between inside a liner and the water jacket.
Which usually amounts to cylinder head surface condition/corrosion in where the "ringed" area of the head gasket mates with the head.
But we really need to wait for forensics from 2pac before double guessing.
And in spite of my varied methods of tensioning XN cylinder head, on one occasion without a torque wrench, on the side of the road, tensioning by guesstimate with a ratchet handle with plug spanner over it for more leverage.
I've never had a leak on start up nor when I come to think of, ever.
So I 'd suggest torquing is less important than the condition of the mating surfaces.
A nice spread of hylomar helps I'd think.
Which usually amounts to cylinder head surface condition/corrosion in where the "ringed" area of the head gasket mates with the head.
But we really need to wait for forensics from 2pac before double guessing.
And in spite of my varied methods of tensioning XN cylinder head, on one occasion without a torque wrench, on the side of the road, tensioning by guesstimate with a ratchet handle with plug spanner over it for more leverage.
I've never had a leak on start up nor when I come to think of, ever.
So I 'd suggest torquing is less important than the condition of the mating surfaces.
A nice spread of hylomar helps I'd think.
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I haven't seen any great improvement in gasket material over the years in ALL brands. There is one brand which has the (crappy) hard, mono-torque material. And in other gaskets they still put a minimal amount of heat-activated sealant on critical areas. Hence the recommendation for Hylomar.
And bolt behaviour in 505s is the same as in 504s....they are basically huge springs. But they are very robust bolts.
Yes, we are not there to see what happened. Some odd thing may have occurred. That was a substantial water leak...
Hey 2pac.....what did the rear exhaust-side cylinder bolt thread (in the block) look like ? Good thread ?
Not that this would cause a water leak like you had. But it's a weak point.
And bolt behaviour in 505s is the same as in 504s....they are basically huge springs. But they are very robust bolts.
Yes, we are not there to see what happened. Some odd thing may have occurred. That was a substantial water leak...
Hey 2pac.....what did the rear exhaust-side cylinder bolt thread (in the block) look like ? Good thread ?
Not that this would cause a water leak like you had. But it's a weak point.
Idont recall if 2pac removed the liners and replaced the seals . in the last 50myears I have built many engines ad use Aero grade hylomar on the base seals and NOTHING on the head gasket but torque to 70 pounds and retoque to 70 on all xn engines no bolt slackening bullshit and never had a customer engine complaint.
i put new liners and seals and cleaned as best as possible the mating faces down the bores.
i bought the head reconditioned, but i'll take it to check the mating face condition.
could it have failed because i waited 2 months from installing the head until i started it?
roland- what kind of sealer did you use on the seals?
ianrobbo- what kind of hylomar did you use on the liner seals? the Hylomar M aerosol?
how do one use the peugeot compressor tool?
i bought the head reconditioned, but i'll take it to check the mating face condition.
could it have failed because i waited 2 months from installing the head until i started it?
roland- what kind of sealer did you use on the seals?
ianrobbo- what kind of hylomar did you use on the liner seals? the Hylomar M aerosol?
how do one use the peugeot compressor tool?
I doubt it.
I would have used a silicone type sealer - much the same as you would use nowadays to seal rocker covers or sumps which have no gasket.
Cheers
Roland
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