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Need some advice. I replaced my head gaskets (small block 350, GM good wrench crate motor, do not know how old or how many miles) with FelPro composite gaskets (the blue ones). Reassembled motor, adjusted valves and started it up. Fired right up, adjusted timing and carb. Idled fine and sounded fine. Let run for about 5 minutes, temp was normal, checked exhaust and water was dripping out both sides ( making pretty good puddle). Did compression check All about 135-140 except #3 and #5, they had about 107 and 115. Re adjusted valves, no change. Came back a few days later. Leak down test. Would not hold any pressure. Tried compression test again, no compression. took off rockers and redid leak down test, would not hold any air. did same for other cylinders, same results. Reassembled rockers, adjusted valves again (#1 at TDC compression, IEOC, went through firing order doing the same. No compression, no air holding on leak down test. Said screw it, took off passenger side head, this is what I found. Any comments, ideas or observations would be greatly appreciated. Thank you.
Not clear on a couple things. like why did you feel the need to change head gaskets in the first place? And although I can see lots of missing gasket, I can't see how much is still stuck to the head and block. How flat is the block? How flat is the Head? New Head bolts? Torque spec and method? And maybe just a badly made gasket.
1. Are you loosing coolant?
2. Was there excessive air in the radiator?
3. Seems to be a pattern on the gasket showing blow-out. And that's the middle cylinders. Like you stated #3 & #5 + #4 & #6
Tell us about your bolt torqueing sequence:
Did you follow the std method order for GM?
Did you torque the bolts in 3 - 5 steps?
And in increments of how many lbs per step?
To me, that looks like a cheap gasket that never crushed.
I was getting white smoke and some water out exhaust. losing coolant, not a great amount but consistent. Not leaking into oil. Bought engine used about 10 years ago. Compression test before tear down was same. #3 and #5 were lower than others. Decided to change all gaskets. When removed old head gaskets, they were intact. Came off whole, not in pieces. Blue composite was still in good shape. Replaced with exact same gasket, FelPro. Placed right side up. Torqued head bolts (reused stock GM bolts, thoroughly cleaned) to 65lbs in 4 sequences. 35,50,65,65. Followed recommended sequence. These new gaskets only had 5-10 minutes of run time at idle. Just did fluid leakage test in head chambers. All held except #3 (leaked all fluid out intake valve) and #5 (about 1/5 of chamber was exposed, also out intake), which is consistent with compression test.
Gasket had 'aged' and started to decompose over that decade of non-use. Clean it all out, check out the need for valve rebuild or re-seat (likely cause of lower compression on 3 & 5), gain some amount of comfort that a simple rebuild will have reasonable success, then slap it back together with a NEW set of head gaskets. Wish you luck...
Not certain of the age of replacement Fel Pro gaskets. However I have had very good luck with them myself. make absolutely certain that surfaces are perfectly clean and flat. shouldn't have a problem.
I have been driving it for the last 10 years. Started to blow white smoke and water out exhaust recently, thus the tear down. The head gaskets that came off that were on there for the last ten years were in good shape. The ones that I replaced them with were brand new .Felpro perma torque, the exact same ones that were on there. They did not last ten minutes. I cleaned all surfaces and ran straight edge over surfaces, all good. Just do not know where I went wrong. Just hate to do it all over and get same results. Will take off valves and check them and seats. I do need to address the intake valve leaks before trying again. I am hoping that the gaskets were just bad, but will never really know.
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I agree on having the heads checked for cracks and straightness.If they are warped you may not get them to seat without being planed. Get prices before you have them do all the work, you might be 3/4 of the cost into getting aluminum heads. The aluminum would be an upgrade that you could build off of in the future if thats your plan. If you are more into the stock look you can paint the aluminum or get the new aluminum heads that look like the old camel hump heads.
And if you are replacing the gaskets without decking the block or heads then you need gaskets with a compressed thickness about .020 for the quench to be correct, a total of about .040. Any thicker and you are loosing compression and not forcing the AF mix into the center of the chamber.
Last edited by Rescue Rogers; Apr 8, 2021 at 07:21 AM.
Yes, Jebby,
New perma torque felpro gaskets from Summit. Engine ran for 7_10 minutes to adjust timing and carb. I used a bit of sealant on the end of the threads. Bolts were cleaned.
Yes, Jebby,
New perma torque felpro gaskets from Summit. Engine ran for 7_10 minutes to adjust timing and carb. I used a bit of sealant on the end of the threads. Bolts were cleaned.
One further note, upon cleaning the block, it was like scraping off heavy flaking silver paint. These were the blue perma torque gaskets.
I have never seen that before after 10 minutes.....hell, I haven’t seen that but maybe twice in my life and both cars were run to hell and back.
It would have to get really hot to do that.....no other explanation....if everything was clean, no way would it stick to anything under normal conditions.
Now you know why I posted. If it did not happen to me, I would not believe it. I monitored my temp gauge and used infra red gun. Temp never went past 185*
Now you know why I posted. If it did not happen to me, I would not believe it. I monitored my temp gauge and used infra red gun. Temp never went past 185*
Only thing I can think is that you got a bad pair of gaskets or a fake pair (yes, it exists).....
If this is a Goodwrench 350, go with a .015 steel shim gasket sprayed liberally with Copper Spray....
Also....use oil on the head bolt flange when you torque.....I like liquid PTFE on the threads myself.
Thanks for your insights. Will bring heads to machine shop for a look. If they need any serious work, I will go with aluminum heads.A weekend project turning into a month long project. That is about my luck.
I'm thinking that you got too much sealant on the ends of the bolts and it formed a hydraulic 'seal' at the bottom of the bolt hole. You applied the required torque...but you were only working to compress the sealant and their was inadequate strain in the bolts so that there was little to compress the gasket. It just blew out from the cylinder firings. I suspect that if you put another engine together without the sealant, but with very low bolt torque, you might get the same results.
P.S. The bolts only need a light wipe of sealant in the lower few threads...so any coolant seeping into the threaded holes (due to casting porosity or similar flaws) could not wick-up the threads.
Head gasket question.
