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I am mystified by a problem we are having with my 253 V8. Over a year ago I put the engine into a reputable well known engineering shop to be totally cleaned ,bored ,tunnelhoned and whatever was required for a total rebuild . They did a great job and supplied all the parts plus new pistons and a great headjob (on the engine). A mechanic assembled the engine and let it sit for 12 months before turning it over .We got the oil up to the rockers before starting the engine but had a hard time starting it .It would fire but wouldnt run .It had fuel and spark and the timing was checked numerous times . We ended up having to put oil down the plug holes to finally get it to run . When it ran there was excessive blowby from the oil filler cap enough to set off our smoke alarm .
PLEASE DON"T SUCK THE YELLOW SNOW |
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Some of these options are obvious but I have to ask;
Was the check done one the;
1. Cam Timing?
2. Ring Gaps?
3. Bore to Piston clearance?
Not nessessarily in this order of importance.
My guess is youll have to strip it down and recheck the items 2 and 3. Might as well do item 1 also, but you probably didnt want to here this though.
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Considering that oil in the cylinder is a trick to artificially seal the rings, and that blow by is an indicator of poor ring seal, i think thats something worth looking into. Despite the effort involved its essential that you have this right! |
"Silly modern cars" |
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Obviously the pistons rings are not sealing, but how long has it been running for.
If it was rebored & had new pistons fitted, we will assume that the piston to bore clearance is OK, otherwise you might as well strip the whole thing down & check the lot.
It might just be the rings gummed up, from sitting unused for so long. The lifters may also be a little gummed up as well. Why not run it for a while (at least to full operating temperature several times) to let things bed in a bit & then do a compression test.
If there is crap in the carby from sitting, you might have issues with it idling, so hold the revs up until it warms up.
Dr Terry |
If at first you don't succeed, just call it Version 1.0 |
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If I was going to have a guess I would say someone put the rings in upside down!
"We are but a grain of sand on the beach of life" |
"We are but a grain of sand on the beach of life" |
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The fact that it was rebuilt and never run up will mean that oil was in the rings at assy has now dried or drained away. Gummed. Putting oil in the plug holes is an old trick and should work Ok to get compression up. It wil be smokey for a little while till all three sets of rings bed in. The lifters also would have dried out. I just wonder how ur cam will be in a short while as they are supposed to be run in hot and hard. In the long term it should be OK.
Cheers John
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Thanks for all your suggestions . Even though everything in the engine was brand new or bored out except the cam which was bedded into this motor just before it was stripped down for reconditioning and only travelled approx ,400 miles. We are now prepared to completely strip the engine but Ill pass your comments to my mechanic . He felt that the rings had stuck in but the 15 minutes odd that we ran the engine for made no difference in fact the blowby appeared to worsen .
PLEASE DON"T SUCK THE YELLOW SNOW |
CHANGE IS INEVITABLE , EXCEPT FROM VENDING MACHINES |
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my guess is ceased ring(condesation and non movement equals a lock up).dont feel too bad ive got 2 cars like that (non movement)and they are gonna be expensive to fire up.hope this isnt the case.
Jim in adelaide |
Jim in Adelaide.. |
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Its your ballast resistor...it has spark when its cranking...but it goes away when you release the key.
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"everything in the engine was brand new or bored out " OH, dear, maybe New standard pistons in a bored block = Max blowby. Strip down rqd fer sure.
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