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assembling a leak free motor?

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Old Jan 20, 2011 | 10:50 PM
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Default assembling a leak free motor?

im getting damn sick of all the leaks on my motor, so im going to be replacing all the gaskets in the next month or so.

i ordered these parts about a month ago...
GMPP composite head gasket
Fel-pro performance 2 piece rear main
Fel-pro performance intake manifold gasket (printoseal)
new head and intake bolts.
i also ordered headers and exhaust manifold gaskets.

on my valve covers and oilpan, i currently have the felpro permadry gaskets.


when i install everything, is there any way that 99.9% effective in sealing all the oil leaks? sealants on the gaskets, or in certain spots, or anything like that?


almost forgot, i replaced the balancer seal and timing chain gaskets last year, those are nice and dry.

Last edited by another-user; Jan 20, 2011 at 10:53 PM.
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Old Jan 20, 2011 | 11:08 PM
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I stopped having leaks years ago when I realized the factory didn't use sealer. Form a gasket always guaranteed a leak for me. Valve cover gaskets are a bit tricky to get on without sealer but will not leak especially if you retighten them after about 100 miles if they are cork. All cork gaskets seal better if they are retightened.
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Old Jan 20, 2011 | 11:28 PM
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i had terrible luck with cork sets. i torqued them to spec, then a few months later torqued them again. the things just oozed oil out of them.

my permadries arent oozing, obviously, but i still some how have a film of oil around the bottom of the valve covers, even when torqued to spec. im wondering if that is some how blow by from the exhaust manifolds though. most of those bolts were barely more then finger tight.

Last edited by another-user; Jan 20, 2011 at 11:30 PM.
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Old Jan 20, 2011 | 11:46 PM
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You probably dont want to hear this but the reason the gaskets are leaking needs to be addressed first. If its a tired engine, the explosion is travelling past the rings and creating pressure in the oil pan and oil valley. This is why new engines dont leak as much as old tired engines.

By changing all the gaskets, you will still leak...not as much, but it will leak. The gaskets can only hold so much excessive pressure. Since you're going to replace the rear main seal........why not just pull the engine, have it rebuilt and do it right?
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Old Jan 21, 2011 | 12:11 AM
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I know several people who don't like cork. I've never used a torque wrench on them either. As for me as long as I clean them to shiny metal with solvent and a scotch brite then retighten in two weeks I have to pry them off once they stick. On the head side I just clean several times with a tooth brush and rag alternately since it is hard to get the oil sheen out of the cast iron pores.

Same with with the thermostat housing. I know a couple of people who only use permatex. I use a flate file or sanding block and cut it to shiny metal then use the gasket only and hit the road.
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Old Jan 21, 2011 | 12:45 AM
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Originally Posted by snoopykissedlucy
You probably dont want to hear this but the reason the gaskets are leaking needs to be addressed first. If its a tired engine, the explosion is travelling past the rings and creating pressure in the oil pan and oil valley. This is why new engines dont leak as much as old tired engines.

By changing all the gaskets, you will still leak...not as much, but it will leak. The gaskets can only hold so much excessive pressure. Since you're going to replace the rear main seal........why not just pull the engine, have it rebuilt and do it right?
i honestly see no reason for a rebuild. theres about 70-80k, maybe 90k miles on it (tach was out for 20 some years, with about 5 of those years being driven. odometers at like 69k right now) the motor runs strong, and compression was 170 on 5 cylinders, with a +/- 5psi on the other 3. i just want the damn leaks to stop.

ill try getting more aggressive with cleaning the mating surfaces. for the heads, i just took a putty knife and some lacquer thinner to them. i think my bigger problem there is the surface finish. its roundish, its rough, and it looks rather pores.

Last edited by another-user; Jan 21, 2011 at 12:47 AM.
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Old Jan 21, 2011 | 09:01 AM
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First off, I do not have alot of experiance with automotive engines, But I do have nearly 30 years of experiance on Marine engines. Especially the Chevy blocks. I suspect alot of your oil leaks are comming from valve covers, intake end seals, and oil pan. I would first verify is main seal is leaking. But if you are going to pull the pan along with the timing cover, now is the time to change both crank seals. Remember to seal properly, and install correctly.
For the pan, I prefer one piece seals, RTV in 4 spots near the corners. Clean all mating surfaces with acetone and a clean rag.
Timing cover, verify cover is flat not warped, repair as needed. On this gasket I use Spray Cooper coat sealant, remember to clean all mating surfaces prior to assy, again use acetone and clean cloth. Torque properly
Valve covers, On these Head designs, I use Felpro composite/rubber impregnated gaskets. I clean all surfaces with acetone, and then I use 3M General Trim adhesive to actually glue the gasket to the cover and block. Torque as needed, no need to retorque.
Intake manifold, Clean head, block and intake with acetone and clean rag, again use Felpro gaskets, I again use Copper coat spray for head to intake sealant, For end seals, I use RTV ultra black, 5/16 bead, in a welding pattern placed on block, Nice seal from gasket to gasket. Both front and rear. I have not had any good luck using the rubber seals. Install intake manifold straight down, do not wiggle front to back.
Intake manifold bolts, use new bolts if needed, I use 3m thread sealant on the threads, torque as needed.
Water pump, clean all mating surfaces with acetone and clean rag, again I use Copper coat on the gaskets, as well as 3M thread sealant on the bolts.

This should completely seal your engine for another 10 years of such. I will tell you the newer production Vortec motors have a much better sealing items available, from timing covers to intakes, especially the valve covers. Good luck Al
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Old Jan 21, 2011 | 12:20 PM
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For what it's worth, one of the things that seems to be a constant cause of leaks especially on the valve covers and oil pan is over tightening the bolts. That causes dimples on the pan and valve covers, and the gaskets never seal correctly. Make sure on those two items and the timing chain cover, that they're flat and not dimpled. If they are, you can correct it with a light touch of a smaller ball peen hammer. I've had very good results with the Fel-Pro one piece oil pan gasket, you don't need the typical sealer in the corners with that piece. I use the heavy rubber valve cover gaskets with no additional sealer and they work great.
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Old Jan 21, 2011 | 12:45 PM
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Here is my list of 'must do's' for sealing an engine:

1) For stamped-steel covers/pans, you MUST flatten the rail surface by using a metal block & hammer when the pan is set on a flat surface. Sheet metal rail surfaces get distorted from bolt torquing [and over-torquing]. If the rail isn't flat, it won't seal. Note: If the rail has a strengthening ridge in its surface, you can only flatten the areas around the bolt hole. If the rail is not able to be straightened properly (very little gap when placed on a known-flat surface), you need to replace that pan/cover.

2) Clean all sealing surfaces well, then wipe down with lacquer thinner or other volatile cleaner. If you want it to seal, you have to get the surfaces absolutely clean an dry. Any oil on it will prevent a good seal.

3) Use composition (cork & syntetic mix) or full-synthetic gaskets. Fel-Pro is my choice. I also like the one-piece [blue] oil pan gasket as it has plastic inserts at each pan bolt hole which prevents you from over-compressing the gasket or distorting the stamped-steel pan rail.

4) If the gasket is compressible, you must 'stage' the application of bolt torque: one round at 30% of full torque, another at 60%, then a third at full torque. Reason? Full torque on the first bolts will over-squeeze the gasket and cause the pan rail to start warping.

5) NEVER use a silicone sealant on gaskets trying to seal a petroleum product. The exception to this is RTV, which is designed for such purposes and is best used to seal the junction corners of the intake manifold and the joints at the oil pan main bearings.

6) If you think the bolts you have are 'well used', buy new ones. Multiple torque applications to mild steel bolts (grade 3 or lower) will cause the threads to burnish and reduce surface friction. Eventually, those threads will wear down and the thread joint will be prone to loosening.

Good luck.
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Old Jan 21, 2011 | 06:03 PM
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Cleanliness is a must. Proper torque sequence and the judicious use of sealants where necessary.

I disassembled a CAT D336 when I was active duty and the entire engine had been assembled with permatex. This is why I say judicious use of sealants.

I am going down the same road with the one piece oil pan gasket, timing cover set and the rear main on my car, when it gets a little warmer.

Good Luck
Robie
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Old Jan 21, 2011 | 06:11 PM
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is it ok to use a sealant with the synthetic one pieces? because if thats ok, i will seal this entire damn motor with non hardening permatex.

ive had to replace the water pump more times then i care to admit, and ive never had that leak with non hardening permatex and felt gaskets.

on the head gaskets, i assume i should clean the surfaces and install those dry, right?

Last edited by another-user; Jan 21, 2011 at 06:13 PM.
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Old Jan 21, 2011 | 06:30 PM
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You can use 'good' sealants on gaskets if you want to. But the sealant and gasket material must be compatible and removal and cleaning of the components at a later disassembly will be problematic. If the surfaces are prepared properly and good quality gaskets are used, sealants (except where the gasket manufacturer recommends it) are unnecessary.
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Old Jan 22, 2011 | 09:44 AM
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The best sealant to use in place or RTV Silicone is called "The Right Stuff" by Permatex. It is far superior to RTV.
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Old Jan 22, 2011 | 09:52 AM
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Originally Posted by calif phil
The best sealant to use in place or RTV Silicone is called "The Right Stuff" by Permatex. It is far superior to RTV.
Absolutely

Here is their main page. Lots of rtv silicones that work well, but the right stuff is by far the best.

http://www.permatex.com/products/Aut..._gasketing.htm

Click on each product "tds" pdf for instructions and compatibility.
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