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Discussion Starter #1
The head gaskets are on the way out on my RRC and after reading the advice on this forum I'm going to install Composite Gaskets instead of the current metal ones , as it sounds like people have had good experiences with them.

I'm trying to find out whether swapping to composite has any impact on the torque i need to apply to the cylinder head bolts. Should I just follow the workshop manual or should the bolts be tighter/slacker with composite gaskets? The heads are 14 bolt and its a 4.2 non serpentine engine (40D suffix A). I'm fitting brand new (non stretch) bolts

Final question, what's everyone's opinion on the lower row of 4 bolts, pinch tight, follow the manual, or leave them out altogether?? I read somewhere they can pull the heads fractionally out of alignment and cause problems

Thanks , Simon
 

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hi, well i have an LSE and had to do this job. There is no problems with fitting the gaskets, just follow the book! however they are abit thicker so reduce the compression ratio abit, not that that is a problem in real terms. Better still if you have the heads skimmed then this will return it to where it should be.
Bolts need the same settings and as far as the outer four go i would fit them but just pinch them up to stop them falling out.
Later blocks have these blanked out.
John
 

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SimonB said:
The head gaskets are on the way out on my RRC and after reading the advice on this forum I'm going to install Composite Gaskets instead of the current metal ones , as it sounds like people have had good experiences with them.

I'm trying to find out whether swapping to composite has any impact on the torque i need to apply to the cylinder head bolts. Should I just follow the workshop manual or should the bolts be tighter/slacker with composite gaskets? The heads are 14 bolt and its a 4.2 non serpentine engine (40D suffix A). I'm fitting brand new (non stretch) bolts

Final question, what's everyone's opinion on the lower row of 4 bolts, pinch tight, follow the manual, or leave them out altogether?? I read somewhere they can pull the heads fractionally out of alignment and cause problems

Thanks , Simon
What makes you think that you have metal head gaskets. Landrover only used metal gaskets in the 3.5 motors.
Use ARP studs instead of bolts.
 

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Discussion Starter #4
Thanks for the advice John, I was hoping to avoid skimming the heads but until I open it up I can't be sure. A slight loss in compression doesn't bother me too much, I don't do too many drag races away from the lights in the Rangie....

Ian, i'm just assuming it has metal gaskets, i've got a copy of the Land Rover V8 service manual (1996) for the 3.5/3.9 & 4.2 and it states 'engines without suffix B have a steel gasket whilst engines with suffix B have a composite gasket'. mine is a suffix A so should in theory have a steel gasket though who knows what the previous owners might have done.

I considered the ARP studs but they're fairly pricey, do they offer any great benefit??
 

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SimonB said:
Ian, i'm just assuming it has metal gaskets, i've got a copy of the Land Rover V8 service manual (1996) for the 3.5/3.9 & 4.2 and it states 'engines without suffix B have a steel gasket whilst engines with suffix B have a composite gasket'. mine is a suffix A so should in theory have a steel gasket though who knows what the previous owners might have done.

I considered the ARP studs but they're fairly pricey, do they offer any great benefit??
The 3.9 heads where shaven to cater for the composite gaskets.

The major reason for head gasket failure is incorrect tensioning of the heads. This can still happen with the torque yield bolts that you are planning to use for a number of reasons. Studs do away with the tension issues associated to bolts. If you are ever unfortunate enough to have to take off the heads again, you can reuse the studs where you cannot reuse the bolts.
 

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p76rangie said:
SimonB said:
Ian, i'm just assuming it has metal gaskets, i've got a copy of the Land Rover V8 service manual (1996) for the 3.5/3.9 & 4.2 and it states 'engines without suffix B have a steel gasket whilst engines with suffix B have a composite gasket'. mine is a suffix A so should in theory have a steel gasket though who knows what the previous owners might have done.

I considered the ARP studs but they're fairly pricey, do they offer any great benefit??
The 3.9 heads where shaven to cater for the composite gaskets.

The major reason for head gasket failure is incorrect tensioning of the heads. This can still happen with the torque yield bolts that you are planning to use for a number of reasons. Studs do away with the tension issues associated to bolts. If you are ever unfortunate enough to have to take off the heads again, you can reuse the studs where you cannot reuse the bolts.
I have just had the work done on the same engine including a skim. The old bolts are not stretch bolts and according to LR themselves can be re-used just like any other non-stretch. This is what I had done. Torque was the same but check again and adjust after 100 miles. Oh and my original gaskets were tin.

700 miles under the belt so far and loving it

:pray:
 

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p76rangie said:
SimonB said:
The head gaskets are on the way out on my RRC and after reading the advice on this forum I'm going to install Composite Gaskets instead of the current metal ones , as it sounds like people have had good experiences with them.

I'm trying to find out whether swapping to composite has any impact on the torque i need to apply to the cylinder head bolts. Should I just follow the workshop manual or should the bolts be tighter/slacker with composite gaskets? The heads are 14 bolt and its a 4.2 non serpentine engine (40D suffix A). I'm fitting brand new (non stretch) bolts

Final question, what's everyone's opinion on the lower row of 4 bolts, pinch tight, follow the manual, or leave them out altogether?? I read somewhere they can pull the heads fractionally out of alignment and cause problems

Thanks , Simon
What makes you think that you have metal head gaskets. Landrover only used metal gaskets in the 3.5 motors.
Use ARP studs instead of bolts.
Studs are a good way to go, LR used tin up to the sepentine engine. As far as skimming goes do check the heads carefully, you may find they don't need a touch. The 4.2 has a lower compression ratio than the 3.9 anyway. The blocks are the same only the 4.2 has a longer stroke.
I used the original bolts, using the method i posted before, covered 40k now.
J
 

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john-sussex said:
Studs are a good way to go, LR used tin up to the sepentine engine. As far as skimming goes do check the heads carefully, you may find they don't need a touch. The 4.2 has a lower compression ratio than the 3.9 anyway. The blocks are the same only the 4.2 has a longer stroke.
I used the original bolts, using the method i posted before, covered 40k now.
J
I stand corrected. My understanding was that the heads changed with the 3.9 motor, but you are correct and they changed with the interim motor in 1994. Heads with 14 bolt holes will have metal head gaskets and ones with 10 will have composite.

If you are switching to composite on a 14 bolt head you should have at least 0.030 inches shaved from it or 0.040 inches to bring it in line with the later heads.

The old non-stretch bolts are actually the worse to use. Again they changed with the move to 10 bolt heads. The problem relates to metal bolts going into alloy heads, the inconsistent resistance this causes, the course threads required, etc. This means that it is more luck than anything else in getting the heads correctly tensioned. That is why Land Rover went to Torque to Yield bolts. These are an improvement on the old bolts, but still have similar issues with the old bolts. ARP studs are the best way to go.
 

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p76rangie said:
john-sussex said:
Studs are a good way to go, LR used tin up to the sepentine engine. As far as skimming goes do check the heads carefully, you may find they don't need a touch. The 4.2 has a lower compression ratio than the 3.9 anyway. The blocks are the same only the 4.2 has a longer stroke.
I used the original bolts, using the method i posted before, covered 40k now.
J
I stand corrected. My understanding was that the heads changed with the 3.9 motor, but you are correct and they changed with the interim motor in 1994. Heads with 14 bolt holes will have metal head gaskets and ones with 10 will have composite.

If you are switching to composite on a 14 bolt head you should have at least 0.030 inches shaved from it or 0.040 inches to bring it in line with the later heads.

The old non-stretch bolts are actually the worse to use. Again they changed with the move to 10 bolt heads. The problem relates to metal bolts going into alloy heads, the inconsistent resistance this causes, the course threads required, etc. This means that it is more luck than anything else in getting the heads correctly tensioned. That is why Land Rover went to Torque to Yield bolts. These are an improvement on the old bolts, but still have similar issues with the old bolts. ARP studs are the best way to go.
You can can make your own mind up about bolts, true that studs are better, however in my case i reused the old ones without problem.
I have a high compression 4.6 that has been played with fitted with the front cover and dizzy, sump, oil-pump (re-built) and skimmed heads from my 40D 4.2 non serpentine engine.
This with LPG and one or two other bits makes a very good driver. my block does not have the four outer holes drilled so it just has the ten plus compo gaskets. 40k+ so far!!
 

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Discussion Starter #11
Thanks for all the great advice. I'm going to have a go with the composite gasket and standard bolts, just because I was a bit wary of the stretch bolts and the studs were a bit pricey, no doubt a false economy but never mind, when i'm doing the gaskets again in a couple of months i'll have learnt my lesson!!

I'll see what condition the heads are in but if I do skim them then from what everyone's said it makes sense to skim a bit extra to maintain the current compression ratio. Thanks again all, D-day is next saturday so we'll see how it goes....... :pray:
 

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in the case of head bolts on the 14 bolt suffix a engine remove and throw in the bin have replaced three sets of arp studs over the years and returned to the standard head bolts gasket failure and coolant leaks have caused the studs to fail or corrode to the head and are a pain to remove i always use new bolts and in the old engine do the torque procedure and the latter engine torque and degree never had a gasket failure did my dads old lse with a 4.6 bottom end and original heads with comp gaskets and new standard bolts 90,000 miles without a problem still going somewhere i belive.
30 thou is required to make the heads the same a sufix b engine
suffix a engine 36cc combustion
suffix b engine 28cc combustion
with the thicker gasket it is then the same combustion chamber size.

only problem i have found with comp gaskets over the tin is they leak oil over time worse on a gas converted engine
 

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p76rangie said:
SimonB said:
The head gaskets are on the way out on my RRC and after reading the advice on this forum I'm going to install Composite Gaskets instead of the current metal ones , as it sounds like people have had good experiences with them.

I'm trying to find out whether swapping to composite has any impact on the torque i need to apply to the cylinder head bolts. Should I just follow the workshop manual or should the bolts be tighter/slacker with composite gaskets? The heads are 14 bolt and its a 4.2 non serpentine engine (40D suffix A). I'm fitting brand new (non stretch) bolts

Final question, what's everyone's opinion on the lower row of 4 bolts, pinch tight, follow the manual, or leave them out altogether?? I read somewhere they can pull the heads fractionally out of alignment and cause problems

Thanks , Simon
What makes you think that you have metal head gaskets. Landrover only used metal gaskets in the 3.5 motors.
Use ARP studs instead of bolts.

You are wrong. Good call on the ARP's.
 

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Speaking of better late than never...

Hopefully John-Sussex got this, but if you're removing engine heads with a tin gasket and reinstalling them with the composite gasket you must use the (LR) torque sequence and instructions for the "suffix B" composite gasket heads when retightening. The difference is the last two tightening sequences are turning the bolts 90 degs, instead of to a set torque. Most suppliers of the composite replacement gaskets send an instruction to this effect with the gaskets.

Also watch out that you don't over lubricate the bolts prior to installing them. The pooled oil at the bottom of the threaded hole can create a hydraulic lock up that could damage threads. Another good arguement for studs.
 
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