Thread: My thanks to Scouse...

Originally Posted by daf11e

Scott,Ron, does there appear to be any reason for the gasket fail that you can summize?

Not to my eyes but both head gaskets were leaking around several fire rings meaning that if the failure didn't happen where it did, it was about to happen in several other places.


One odd thing that Ron picked up on was that the engine was assembled with the old type head bolts, rather than stretch bolts. As the engine was assembled by a very well known Land Rover expert, I can only assume it was done for a good reason.


There was no sign of coolant leakage into the block bolt holes which might have indicated a weakness there & resulted in a loss of bolt tension.

I've measured the heads and they are pretty much on the limit for machining.

According to RAVE, the cylinder head height at each end of the head when new should be as shown below.



On my heads, they are:

LH:
A = 22.7mm
B = 62mm

RH:
A=22.45mm
B = 61.95mm

I've emailed the engine builder and given him a link to a lot of the pics. I need to go and see him so I've asked when he'll be there.

This is what happens when you use bolts. The TTY bolts just plain suck ass. The early bolts are thinner and let the heads move.

PEOPLE EVERY THREAD THAT THIS COMES UP IN I STATE:

FOR THE LOVE OF GOD USE ARP STUDS!

Theres a reason nothing else gets used in race/rally/top fuel-alcohol etc etc etc. They just plain work. Follow the intruction FOR THE STUDS FINAL TENSION. The torque steps for a 4.0/4.6 are:

Fit studs, lubed with ARP lube, finger tight. Using a short allen key with ONE finger push a little tension onthe stud into the block. Fit heads, note D2 will, P38 may need the rear most studs fitted post head placement as the head won't go over the studs in car. On a stand no issue. Lube both sides of washers and place on. Lube underside of nut, fit WITH LETTERING UP (theres small engraving on the nuts) it's not a noted requirement but at tension it may grab the washer, cause an issue. It's a small thing and besides, all those nuts all looking the same looks good.

Tensioning, by memory ARP say 85lb with their lube, 90lb with oil.

1st. 20lb, in sequence.
2nd. 40lb, in seq. Wait 15min. Check @ 40lb.
3rd. 60lb, in seq. Wait 15min. Check @ 60. Wait 15min and recheck again.
4th. 75lb, in seq. Wait 15min. Check @ 75. Wait 15min and recheck again.
5th. 85lb, in seq. Wait 15min. Check @ 85. Wait 15min and recheck again.

I usually cover the engine at this point and leave overnight and recheck everything again next morning. If anything is down, recheck again after 30min. If still loose, remove all studs and test lengths against ARP lengths, pre & post tension. They do occasionally get a stray thread that doesn't play ball.

And Ron the block is non saleable, but I have a good use for it.

Hoges: Tighten up those studs. Studs requirement overrides gasket.

Does make me wonder if it's worth considering using ARP studs.

Honestly Ron, I'd just get rid of it. In fact I'll start heading down with a trailer now.

Or, you and Scott could have it together shortly and be having fine with such a fine P38 in no time.

Originally Posted by clubagreenie

This is what happens when you use bolts. The TTY bolts just plain suck ass. The early bolts are thinner and let the heads move.

PEOPLE EVERY THREAD THAT THIS COMES UP IN I STATE:

FOR THE LOVE OF GOD USE ARP STUDS!

Theres a reason nothing else gets used in race/rally/top fuel-alcohol etc etc etc. They just plain work. Follow the intruction FOR THE STUDS FINAL TENSION. The torque steps for a 4.0/4.6 are:

Fit studs, lubed with ARP lube, finger tight. Using a short allen key with ONE finger push a little tension onthe stud into the block. Fit heads, note D2 will, P38 may need the rear most studs fitted post head placement as the head won't go over the studs in car. On a stand no issue. Lube both sides of washers and place on. Lube underside of nut, fit WITH LETTERING UP (theres small engraving on the nuts) it's not a noted requirement but at tension it may grab the washer, cause an issue. It's a small thing and besides, all those nuts all looking the same looks good.

Tensioning, by memory ARP say 85lb with their lube, 90lb with oil.

1st. 20lb, in sequence.
2nd. 40lb, in seq. Wait 15min. Check @ 40lb.
3rd. 60lb, in seq. Wait 15min. Check @ 60. Wait 15min and recheck again.
4th. 75lb, in seq. Wait 15min. Check @ 75. Wait 15min and recheck again.
5th. 85lb, in seq. Wait 15min. Check @ 85. Wait 15min and recheck again.

I usually cover the engine at this point and leave overnight and recheck everything again next morning. If anything is down, recheck again after 30min. If still loose, remove all studs and test lengths against ARP lengths, pre & post tension. They do occasionally get a stray thread that doesn't play ball.

And Ron the block is non saleable, but I have a good use for it.

Hoges: Tighten up those studs. Studs requirement overrides gasket.

This is very good info...thank you! I'm thinking however that given the noise is like a small trumpet blast, that I need to replace the gasket. I will definitely stage the head tightening as per the above next time.

Just for info...how does one properly re-tension a head without removing it...
Do you begin in the middle and simply tension it in correct sequence with the max recommended setting on the tension wrench... or does one start from the outside, "de-tension" completely and then re-tensiuon as per the above sequence?

You don't with TTY bolts.

With the studs you shouldn't need to either (or std bolts for that matter) gasket material usually dictates re-tensioning requirements. The payen monotorque gaskets were a revolution (composite) in gaskets. as they didn't require re-tensioning. Some MLS (multi layer steel) need it, as do older type steel. The gasket dictates re-tensioning requirements, fastener type dictates tension.

Rover TTY bolts had a range of approx 28% in final tension, stretch at different points on the bolt as well. Some were twisting the head without shaft rotation etc etc.

With approx $3000- spent on testing just the rover and it pretty much followed the results of testing the Toyota UZ series TTY bolts I haven't built an engine, infact any critical fastener (head, main cap, rod, flywheel/flex plate, diff etc etc) have been nothing but ARP fasteners.

I used the ARP studs and the Elrin composite gasket but limited the torque to 70ft lbs... probably not enough So I'm guessing I need to replace the gasket and tension it as per prev. post?