Engine Rebuild Gasket Alternative?

Modern engine assembly (general done by robots) entails the use of RTC sealant in place of gaskets in much of the secondary component assembly areas. Has anyone re-assembled their engines using this method as opposed to the paper gaskets found in most kits and to what success? Water pumps, pans, valve covers, etc? Brian Mytype

Yes: used on the front cover ( as Dick Maury does) will result in a seep-free cover, plus a number of other areas.

If I had it to do over again, I would have given my pan, front cover, and cam covers to a friend of mine, who could have CNCed a small groove on all the sealing surfaces, like many modern cars have,

Use sparingly, and donā€™t get ā€œsqueezy wormsā€ inside, and itā€™s great stuff.

Iā€™m lucky that the Rover uses ā€œcorksā€ in place of a front cover, and the gasketless oil pan NEVER leaks!

ā€œseepā€-free cover?..

Thanksā€¦ fixed.

Damn rented flingererlers.

:wink:

For the XJ-S V12, I have been recommending for years that the cam cover gaskets be omitted in favor of Loctite 518 or equivalent. This is for a very specific reason: This joint includes rubber half moon seals. The half moon seal creates a soft spot where the cam cover gasket is not properly compressed between two hard surfaces, and hence that joint will soon leak ā€“ usually between the gasket and the cam cover, not between half moon seal and gasket. I believe you 6-banger owners contend with the same half moon seals.

The alternative fix is to replace the rubber half moon seals with solid aluminum plugs, forming a properly rigid surface to tighten the cam cover gaskets against. This idea is so good that Jaguar adopted it, its later cars come with solid aluminum half moon seals. They donā€™t fit earlier cars, though, so friendly machinists on the XJ-S forum occasionally churn out a few sets for members.

The simple fact is that Jaguar clearly was not an authority on leak-free assembly. If you donā€™t want your car to be incontinent, you need to toss the official repair manual and think for yourself about the best ways to seal joints up during assembly. This can often involve modern sealants, as they are truly excellent and often superior to paper gaskets.

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Yes, often with the same outcome.

Canā€™t say Iā€™ve had much success with silicone type sealers without the gasket on anything on an XK engine. The aluminum expands at a different rate to the iron and over time starts to leak IME. But then the paper gaskets leak too. What to do what to do! (Got some Hylomar on order - weā€™ll see)

Note that Hylomar, the blue stuff, is a gasket dressing, not a sealant. It never hardens, it just stays gooey. It was often used as a sealant by racing teams whose cars came apart every other week because it would stay in place that long and was easy to clean off. But used without a gasket in a street car, it will eventually ooze out of the joint and cause a leak. And yes, Iā€™m aware that the official Jaguar ROM recommends its use in gasketless applications. Thatā€™s a mistake on their part; I got that straight from a Loctite rep. If you want a joint to be sealed without a gasket, donā€™t use Hylomar; use Loctite 518 or Ultra Black or something else appropriate.

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Iā€™ll bet there are a few here familiar with the sealing process used on aircraft engine crankcases: A thin bead of sealant with a silk thread laid on it. Thereā€™s a spec for the silk thread, and thereā€™s a spec for how the ends of the silk thread are to overlap. The silk thread serves two purposes: 1) it prevents the parts from coming completely together and squeezing all the sealant out; and 2) This process is used for crankcase halves, and the precise separation of the two halves of the crankcase ā€“ one silk thread thickness ā€“ establishes the desired clearance in the main bearings.

I have had good luck with the use of Cometic gaskets. Upon assembly this time will also use Hylomar with the Cometic. I am also experimenting with the use of aluminum crush washers instead of copper, they are softer and hope seal better. I also use a small amount of RTV at critical spots as the half moon seals. Engine has been leak free in the past except for oil pan and there have solved my leaking problems?
Glenn

Cometics generally donā€™t need RTV: I used them on my cam boxes, with only a wee bit of RTV by the rear plugs. Great product, those gaskets.

When I got my old S1, the engine would peg the oil pressure gauge, except at hot idle. I had two reputable Jag mechanics tell me ā€œjust a sign of a healthy engineā€.

When I pulled the oil filter housing, I was shocked to find that someone had installed it to the block with nothing but clear silicone. I replaced it with a standard gasket, and immediately had normal oil pressure again.

Iā€™m a bit fan of using ā€˜Right Stuffā€™ to seal up corners, and perhaps any low-pressure interfaces where the surface contact is questionable, but overall, I prefer conventional gaskets.

Oil leaks are one of my pet peeves, and Iā€™ve almost always been able to achieve leak free engines with my approach. Iā€™m really putting that to the test these days by restoring a Land Rover, which are well known for leaking like a sieve. Up to this point, it appears that a dab of sealant here and there has the potential to make them virtually leak free.

Yeah, thatā€™s probably destined for disappointment. Better plan: Take your brand new copper washers out of the package and anneal them before installation by heating them red hot, possibly just on the stove. Doesnā€™t matter how you cool them. It makes them buttery soft once ā€“ as soon as you tighten the fitting down, they are hard again. But you can anneal them over and over.

And, IMHO, a better plan yet: Forget both the copper and the aluminum washers. Instead, find a washer made of any type of metal with an ID thatā€™s 1/8" larger than the fitting in question. Assemble the fitting with a 1/16" cross section O-ring that fits snugly around the fitting and this washer around the O-ring. When you tighten it down, the washer will prevent over-crushing the O-ring. The washer also prevents the O-ring from blowing out. Iā€™ve used this scheme on everything from drain plugs to A/C fittings and Iā€™ve never had a leak. Sometimes Iā€™ll even reuse the O-ring ā€“ but O-rings are so cheap thereā€™s scarcely any reason to. The metal washer lasts forever.

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