Thread: Rebuilding a Rover V8

haydent wrote,...

im fitting a composite gasket , and my head is the 14 bolt type. i read a recommendation elsewhere one could discard the (extra) lower 4 bolts when using a composite gasket as they where with the later 10 bolt model as the extra4 lower ones had a tendency to encourage warping/cracked head.

??

Using 14 bolt heads with composite gaskets will lower the compression ratio by about 0.6 unless the heads have had their combustion chamber volume reduced to 28cc. The standard for 14 bolt heads is 36cc. This is achieved by skimming the head down on the gasket mounting face by 1mm.

You can still fit the lower 4 bolts, but reduce the torque on these to 25 lbs/ft.

You also change the lifter pre load by using 14 bolt heads with composite gaskets, unless the heads have been skimmed as above.

Ron.

ok so my head has just been faced not skimmed as you suggest.

so im i understanding you right that i should only tighten my lower 4 to 25lbs ? (or is that only when using a skimmed head ?)

haydent wrote,...

so im i understanding you right that i should only tighten my lower 4 to 25lbs ? (or is that only when using a skimmed head ?)

The torque on the lower 4 head bolts is not dependent on whether or not the head has been skimmed. In both cases, you can torque them to the lower setting of 25lbs/ft if you wish to.

My original 1974 RV8 ran for 33 years with all 14 bolts torqued to the maximum 70lbs/ft without any problems. One of the original tin gaskets did fail during the 1990s so I replaced them with composite gaskets and then refitted all 14 bolts with them all torqued the same. At the time no suggestion was made to do things differently nor was any comments made regarding lifter pre load. The engine ran for another 12 years or so without a problem seeing over 203,000 miles (327,000km) prior to being retired.

I used an anti seize lubricant on the cylinder head bolts which is made by Loctite. It prevents corrosion in hostile environments. When I removed the heads some 12 years later the bolts undid beautifully. I also use the same lubricant on both inlet and exhaust manifold bolts along with the water pump bolts, and have never had a problem with corrosion or bolt removal.

Ron.

thanks

got the heads and rocker's back on

now ive got another question, is 'stag' sealant suitable for use at the ends of each inlet gasket clamp rubbers seals ??

thankyuyou.

haydent wrote,...

now ive got another question, is 'stag' sealant suitable for use at the ends of each inlet gasket clamp rubbers seals ??

Although I have heard of it, I have never used it nor do I know its specifications, however I have used an oil proof silastic in this area with excellent results.

Ron.

thanks, btw im now also looking into the topic of lifter preload. and am thinking i should be checking it ?

does this method sound ok or is there an easier ?

Fast and Easy Way to Check Hydraulic Lifter Preload when using Non-Adjustable Rocker Arms
With the cam, hydraulic lifters and pushrods in place, install your rocker arm assembly. Use the prescribed method in your repair manual and torque down all the valve train bolts in the proper sequence. Pick a cylinder that you are going to check. Hand rotate the engine in its normal direction of rotation until both valves are closed. You are on the compression cycle for that cylinder. (At this position the valve springs are at their least amount of tension making the job a little easier to do.)
Wait a few minutes, allowing the lifters to bleed down. Now, lay a rigid straightedge across the cylinder head, supporting it on the surface of the head where the valve cover gasket would go. Using a metal scribe and the straightedge, carefully scribe a line on both pushrods. Now carefully remove the torque from all valve train bolts, removing any pressure from the pushrods. Wait a few minutes for the pushrod seat in the hydraulic lifter to move back to the neutral position. Carefully scribe a new line on both pushrods.
Measure the distance between the two scribe marks, it represents the amount of lifter preload. If the lines are .020" to .060" apart you have proper lifter preload. If the lines are the same or less than .020" apart you have no, or insufficient, preload. If the lines are further apart than .060", you have excessive lifter preload. To bring your preload into tolerance, use one of the methods described in the next section if necessary, or call the Crane Tech Line for assistance (904/258-6174).

Here is a link to the method for checking lifter pre load on the RV8.

RPi Engineering - V8 Engines

Scroll down and you will find it about 1/4 of the way down the page. To me this seems a much easier method that the one from Crane.

Ron.