Engine and Transmission Tech

I am getting ready to re-install the heads on my 1969 Rover 3.5.
The gaskets are being replace because last fall I experienced some overheating problems. Upon investigating with a leak down tester I found that #1 was blowing by the head gasket into the water jacket. Also while removing the head I noticed that the inner bolts seems to be torqued tighter than the out bolts.
This engine was re-built several years and I can’t remember if I re-torqued the head or not. But I do remember torquing the heads to (as per manual) 65-70 and the outer head bolts to @25. However upon removing the head we could find nothing wrong with the heads (all is straight) and concluded that for or some reason one head backed off it’s torque. We could see evidence of a little blow by on #7 and of course the water leak on #1

When I was younger I would have just thrown the head back on with a new gasket and torqued her down. I must be getting older because now I want to know exactly what I am doing.

My plan is to re-install the heads with new gaskets and bring her up to operating temperature and re-torque. This of course involves removing the rockers, but I would not re-torque the outer head bolts which would involve removing the block hugger heads. Not a very easy job when the engine is installed
After @ 500 miles re-torque again?

Should I use ‘never seize’ on the head bolts?

Head re-installation tips gratefully accepted


Bruce



Edited 1 time(s). Last edit at 02/23/2009 09:25PM by Bruce Mills.

Eeeek! I just came across this thread in a search for info... and I feel real bad that Bruce didn't get any answers already.

I'm bolting some Rover 4.0 (10 bolt) heads to my Buick 215 (14 bolt) block today, and the new head gaskets I bought for it are different than what I've used before so they raised some confusion. I'll pass along some notes:

The new gaskets are Fel-Pro "Permatorque Blue Stripe" head gaskets... part number "7984 PT". These are apparently an oddball product even within the Permatorque line because they have both one composite (rubbery) side and also one plain steel/metallic side. There's no marking on either the gasket or the instruction sheet to indicate which side goes up! The instruction sheet says "Use No Sealer" on its front side, but on it's back side it says "Fiber faced gaskets are to be installed dry. Metal faced gaskets require a thin even coat of sealer applied to the metal sides of the gasket." I tracked down two opinions on this and they agreed (yea!) - my friend Chuck at Abacus Racing said his intuition would be to put metallic side down after first applying gasket sealant (the copper kind that comes in a spray can) to the metallic side only. I trust Chuck's intuition, but still wanted a second opinion to be sure. I finally tracked down Fel-Pro's technical service phone number... it's 800-325-8886. The helpful service guy confirmed - yes! put the metallic side toward the engine block. He said the copper coat sealer is fine, but Fel-Pro's official opinion is that Permatex "High Tack" sealer is a superior alternative.

Both Chuck and the Fel-Pro guy agreed that no type of monkey snot (e.g. "Right Stuff Gasket Maker") should be applied around the water jacket holes.

The Fel-Pro guy prefers that a little bit of thin oil be used on the threads. He doesn't recommend anti-seize for this purpose - that surprised me actually - I know D&D uses anti-seize paste liberally applied to threads and both sides of the hardened washer with an artist's paint brush.

Standard practice is to run a tap through the bolt holes first, and clean them with a wire brush. Re-used bolts should also be wire-brushed spotlessly clean.

The Fel-Pro guy says it's really true - there's absolutely no need to re-torque a "Permatorque" head gasket ever. He said that it won't hurt anything if you insist on doing it anyway, but it really really isn't necessary. (Remember, old metal gaskets were customarily re-torqued after one heat cycle and then again after 500 miles. FWIW, I'm 99 percent certain I never re-torqued the composite gaskets I used last time.)

Now... about those old gaskets on my engine. They were Victor composite gaskets - rubbery on both sides - and I used the copper spray-on sealant on both sides when I installed them years ago. Of course the sealant stuck pretty good... it takes a fair bit of gentle scrubbing with brake cleaner solvent on a shop rag to get it off. The good news is that the inside of the engine looks very clean.

A quick comparison of the Victor and Fel-Pro gaskets reveals that the cylinder diameter is smaller on the Fel-Pro's... about 3 5/8" vs. almost 3.75". I think they're probably about the same thickness - but I'll check that. The Fel-Pro's are supposed to compress to about 0.040" thick.



This Fel-Pro training program may interest some of you: [extranet.federal-mogul.com]

Head gasket and head bolts installations come with a myriad of conflicting installation guidelines and confusion becomes the general result.
When installing my Ford Motorsport heads and gaskets and ARP head bolts, there was enough conflicting installation information, that I called the Ford Racing Hotline for correct torque and instal info.
When in doubt, do as Curtis did, and consult the supplier experts.

WOW I'm sorry I missed this one too. I was in Las Vegas when it was posted so I guess that's probably why. Anyway I hope you are still looking for it, Bruce. Really convenient timing for me too, BTW. I was just wondering if I needed to spray the copper stuff on the composite gasket. Now I know.

Thanks guys.!

Then there's the question of what torque spec to use for the head bolts. Different sources give different numbers.

1) 45-55 lbf is the number in my good old Olds 215 shop manual, but frankly that doesn't seem like enough to me. (Note: Olds heads used six bolts per cylinder.)

2) 66lbf... according to this Rover shop manual [www.roversclub.org], the torque spec should be 90NM (Newton meters) for the ten main head bolts. (That converts to 66 lbf.) That same source gives a lower torque spec (60NM) for the four bolts across the bottom row, which I'm not using at all on account of I'm installing a later-model Rover head and those bosses aren't even drilled. When Rover switched to ten bolt heads, they also switched to torque-to-yield head bolts, and with those bolts you actually torque to a given spec and then rotate the bolt through an additional specified angle... I'm not using that kind of bolt though.

3) 68lbf is the number in the original MGB GT V8 service literature, as shown here: [www.britishv8.org]

4) 65-70lbf for the ten medium/long head bolts (and 40-50lbf for the other four), according to this wonderfully illustrated web resource: [www.rover-v8.nl]

None of these sources explicitly say that composite head gaskets need a different torque than the old steel shim gaskets.

I've had thread stretch issues with practically every BOP 215 I've assembled. In my opinion (fwiw) This is a design area that was compromised in the original design and is made worse with age. It is not unusual to feel the threads begin to give when approaching the upper end of the recommended torque range, and it is absolutely essential to have good thick high quality heat treated washers under the bolt heads. That is the other problem area. If the washer gives even the slightest bit the boss will deform, and with some of them I'm not sure if you can even machine a large enough flat area to entirely prevent that. Once the boss begins to deform you cannot achieve torque on that fastener. The first step is to get extra thick, extra large diameter heat treated alloy washers. I'd shoot for the .150-.187" range and the largest diameter that will fit the area and then spotface the heads to accept the washers. Next would be to use studs, as you can get more thread engagement and the final torque is done with the fine threaded external end. Finally, the last step is to helicoil the block. At this point, I would consider that a mandatory step when building one of these engines, and I would use a long helicoil, at least 2x the bolt diameter. This applies to the mains also. Building the engine this way will overcome the existing compromises and should allow it to hold torque on all of the head fasteners throughout it's useful life.

Now granted, I've been building to the 300 hp power level, but you fellas aren't far off that mark so it's just as applicable. There are few things I dislike as much as tearing down the engine and finding the head bolts have loosened up. As for anti-seize, ARP universally recommends molybdium disulfide assembly lube on the threads of their fasteners. Coating the washers also gives more uniform torque. That's the way I do it also. It's a slippery/sticky goo that will stay put and is a much better high pressure lube than either motor oil or anti-seize. Just what is needed in the threads of torqued fasteners.

Jim

Thanks for the advise guys.

I have re-installed the heads using the standard metal gasket, never seize on the bolts and torquing to 65 for the longer head bolts and 40 for the other 4.

This coming weekend I should be able to fire her up bring her up to operating temperature. Then let her cool off a re-torque.

Bruce

Let us know how it goes. Thanks Bruce.