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Torqing head for 1725cc engie

mamoose124

Gold Level Sponsor
I just installed my 1725cc engine and am on the first 300-mile leg of the break-in period. My question is the torque speck for the final 700-mile leg of the break-in period. The Workshop Manual spec calls for torquing the head to 48 ft/lbs. However, the Roots Bulletin 68/3 on 28 Feb 19689 reduced this figure to 45 ft/lbs. My problem is I don't recall which spec I used when I initially torqued my head. In retrospect, I probably used the 48 ft/lbs spec as my manual was close at hand at the time. Assuming I use the original spec, is there a problem if I torque the head to the 45 ft/lbs spec when I torque the head for the final 700 miles? Or should I torque the head to the older 48 ft/lbs spec?
 

Gordon Holsinger

Diamond Level Sponsor
I just installed my 1725cc engine and am on the first 300-mile leg of the break-in period. My question is the torque speck for the final 700-mile leg of the break-in period. The Workshop Manual spec calls for torquing the head to 48 ft/lbs. However, the Roots Bulletin 68/3 on 28 Feb 19689 reduced this figure to 45 ft/lbs. My problem is I don't recall which spec I used when I initially torqued my head. In retrospect, I probably used the 48 ft/lbs spec as my manual was close at hand at the time. Assuming I use the original spec, is there a problem if I torque the head to the 45 ft/lbs spec when I torque the head for the final 700 miles? Or should I torque the head to the older 48 ft/lbs spec?
Use 48 if you reduce to 45 you mite be replacing a head gasket!
 

Tim R

Silver Level Sponsor
Rootes reduced the torque figure to prevent premature head gasket failure. Ideally all Alpine heads should be torqued to 45ft/lbs ONLY.

Rootes did this because people were over squashing the gasket leading to premature failure. It is absolutely vital to use an accurate torque wrench as some will barely notice a difference of 3 ft/lbs! It is also vital to torque the head when it is stone cold and to to back each Head bolt off one flat before you re-torque it to overcome inertial stiction.

If I was in your position and unsure of the torque figure used I would back bolt number one off one flat. Then torque it to 45ft/lbs. If it tightens up MORE than one flat I would leave it there (usually they tighten 3-4 flats). If it tightens one flat or less I think that you will have originally torqued it to 48ft/lbs and should go with that figure for all of the other bolts (tighten them in sequence). If you have torqued to 48 ft/lbs then you have just done what all other Alpines had done to them before the workshop bulletin, it is not a huge deal, it is just that 45 would have been better.

 
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65beam

Donation Time
Rootes reduced the torque figure to prevent premature head gasket failure. Ideally all Alpine heads should be torqued to 45ft/lbs ONLY.

Rootes did this because people were over squashing the gasket leading to premature failure.

Are you saying that there has been no advancement to the quality of the gaskets in the last 50 plus years???



















 
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Tim R

Silver Level Sponsor
Hi 65beam,
Truth is I don't know if gasket quality has advanced. Eyeleted gaskets were meant to be the big modern improvement and look how prone to failure they turned out to be! We only ever use original copper style gaskets on our own cars so it kind of makes sense to follow the advice that Rootes gave.
As always people will do what they think is best for them and their own car.
Tim R
 

alpine_64

Donation Time
Tim...I'd say many modern replacement parts for our cars are worse as they suspect they are less used and less abused...

So they build lower than oem spec.. Look at all the repro ball joints and rubber parts that wear quickly from India, China etc....

Given you do higher millage in your cars than most id stick with your advice....
 

65beam

Donation Time
I guess if current parts don't meet specs then we're all in trouble. SS tells me his parts are made using originals as patterns. I've known Rick for 40 years and I have no reason to doubt what he says. I may not have the parts problem because for decades I've been collecting NOS and older parts that date back to when the cars were being built. I also have many current production new parts in stock. I've added many parts since this photo was taken. When Doug has rebuilt suspensions for me he's happy with the original QH pieces I have. 107_1047.JPG If something breaks I can either rebuild or replace. If owners intend to keep the cars for years I would suggest buying and stocking parts.
 

Gordon Holsinger

Diamond Level Sponsor
I guess if current parts don't meet specs then we're all in trouble. SS tells me his parts are made using originals as patterns. I've known Rick for 40 years and I have no reason to doubt what he says. I may not have the parts problem because for decades I've been collecting NOS and older parts that date back to when the cars were being built. I also have many current production new parts in stock. I've added many parts since this photo was taken. When Doug has rebuilt suspensions for me he's happy with the original QH pieces I have. View attachment 18565 If something breaks I can either rebuild or replace. If owners intend to keep the cars for years I would suggest buying and stocking parts.
Bob, I have been stockpiling parts for years, but not like you. Just bought a set of nos valve springs for my SV, found a place in the UK that has the OD escutcheon. Alpine innovations has an OD relay that is a modified SRB 111 that has all of the stuff inside the case. Gordon
 

65beam

Donation Time
If you're talking about the rubber piece that goes in the steering column surround I bought several in the UK a few years back. They're nice.
 

65beam

Donation Time
I saw on one of the facebook pages that someone said they were outbid for one of these. Must have been you.
 

mamoose124

Gold Level Sponsor
Any more suggestions about the proper torquing of the head? While I'm satisfied with the suggestions already received regarding torquing the head, I think this thread has gone somewhere else.
 

bernd_st

Bronze Level Sponsor
I'm torqueing all my Rootes cylinder heads since years with 66Nm which equals 48.6 ft/lbs. Never encountered any troubles with it...
 
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Gordon Holsinger

Diamond Level Sponsor
I'm torqueing all my Rootes cylinder heads since years with 66Nm which equals 48.6 ft/lbs. Never encountered any troubles with it...
I have allways used an accurate torque wrench I have a good micro adjusting wrench. I also have a number of friends who are professional mechanics who have loaned me tools that I would rarely use. I just had my torque wrench checked against my friends very expensive one difference +_1%
 
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