1969 4x4 crew Compression test

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Sep 9, 2005 | 01:12 PM

engineguy33

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1969 4x4 crew Compression test

Thanks for the differnt angles to think on. I would like to put 390 in it but don't have access to one I do hav ethe 360 in my other crew and it seems to run good also the trany on my 69 the sincro is out in 3rd gear were the one in my 68 is good so just swiching them would be not to bad. and a money factor is another going to have to pay for school or buy and engine well I need to finnish school ,(i could just go get the cummins I want!!!!!) any way the 360 with the 5 oil coated plugs tested for compressin all cylinder around 100-110 lbs with one at 90 lbs is this good or bad would it still be the rings??? or should I not bother with this engine? how much dose a decent 390 sell for?? againt thanks for the help everyone.

take care
Aaron

Sep 9, 2005 | 02:28 PM

qman

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I'm no engine expert but my 360 has the following compression numbers:
120,112x6, and 108. I've been told on this forum that my engine is real strong with these numbers and that it's ideal if the range is no around 10%. Yours would also seem to fall into that category I would guess.

Sep 9, 2005 | 03:09 PM

engineguy33

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1969 4x4 crew compression test

well I thought those numbers are fairly good but I have 5 of the spark plugs with oil on them I put in a hotter plug and it dose seem to help but just wondering where the oil would come from in the valves some where????

thanks
Aaron

Sep 9, 2005 | 03:55 PM

fabmandelux

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From: Paradise Found!

I use a leak down tester to tell if it is rings or valve guides, If you can't find one to borrow, you can make a cheater. Take an old spark plug, weld/braze a fitting to accept a short length of hose that will fit a airline fitting. Turn the engine over till the cyl is at top dead center,if trans is MANUAL put in low gear and block wheel's, apply air pressure SLOOOOOWLY! Listen, air leaking out of the valve cover's is leakage past rings. Air leaking from carb, is leaking past intake valves[ generally GUIDES ]. Air leaking from exaust is from exaust guides. As for compression pressures as long as all #'s are within 10% it should be ok. Good luck FABMANDELUX.

Sep 9, 2005 | 04:10 PM

1975Ford

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90 psi is low.

Sep 20, 2005 | 11:30 AM

qman

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My truck used to smoke real bad. It would fail emissions due to visible smoke eventhough the emission numbers were OK. It needed valve seals. Valve seals are little cup like rubber seals that fit over the valve guides and the valves poke through them. A whole set is about $4. They're real easy to replace but is a bit time consuming. You have to take off the valve covers and rocker arm assembly and then remove each valve spring to put on the seal. You also have to have a method to hold the valve from falling down into the cylinder. There are a couple methods. What happens is that they seals became brittle with age and fall apart. None of my seals were intact. There were many little pieces of hard brittle rubber (felt like plastic) all over the inside of the head. Even the oil drain holes were plugged with them. It took a good part of a day to replace the seals, clean everything and put it all back together. But it no longer smokes and my emissions went way down.

Sep 21, 2005 | 06:07 AM

jowilker

Fleet Owner

Joined: Jun 1999

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From: Creedmoor, North Carolina

Aaron, If the engine is running and not knocking from spun bearings, drive on. Rebuilding the engine after you graduate will cost about the same. Your education can help pay for the rebuild once you have a job.

John

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Sep 21, 2005 | 08:45 AM

1975Ford

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Quote:

Originally Posted by engineguy33

I would like to put 390 in it but don't have access to one I do hav ethe 360 in my other crew and it seems to run good also the trany on my 69 the sincro is out in 3rd gear were the one in my 68 is good so just swiching them would be not to bad. and a money factor is another going to have to pay for school or buy and engine well I need to finnish school ,(i could just go get the cummins I want!!!!!) any way the 360 with the 5 oil coated plugs tested for compressin all cylinder around 100-110 lbs with one at 90 lbs is this good or bad would it still be the rings??? or should I not bother with this engine? how much dose a decent 390 sell for?? againt thanks for the help everyone.

take care
Aaron

Aaron, Shop or look around on your spare time for a used 390 cid engine. Later when you have more time and money, you can invest on rebuilding the 390 cid. A used 390 cid engine at a wrecking yard goes anywhere from $50 to $200 dollars. Sending the engine to get rebuilt at a machine shop about $1200 to $1500 dollars. Add more money if you include upgrades.

On the 360 cid with 5 fouled spark plugs, you can purchase five (5) spark plugs non-foulers with a set of new spark plugs. This will help to keep your spark plugs from fouling up. This will buy you some time till you find your 390 cid engine you probably plan on rebuilding.

The transmission from the 68 should switch out to the 69. If a clutch assembly is required: then purchasing a clutch kit will set you back about 150 dollars, and will include the pressure plate, clutch disk, throttle bearing, a clutch alignment tool, and will need to purchase seperately the pilot bearing.

Good luck in your studies, and the non foulers for the spark plugs will buy you plenty of time in the time you need to find and fix up your truck.