Latest comprssion results, major advice needed please guys.
#1
Too many posts.. I need a life!!
Thread Starter
Latest comprssion results, major advice needed please guys.
Hi,
Ive been having some compression issues of late on my 90 spec. Everything pointed to a duff head, so I purchased the NMS head in the for sale section at the weekend. Im not doing the engine work till over the winter, but curiosity got the better of me, so I put the new head on, and now Im more confuzzled than ever.
These are all the results over the last few month;
(PSI);
4/6/14 124948 miles 140 145 145 148 (original head)
12/10/14 125812 miles 123 130 87 130 (original head)
30.10/14 125812 miles 58 108 21 58 (new head)
As you can see, Ive done no miles since changing heads, and my compression has gone right down while standing still.
Im now more inclined to think Ive blown all my rings, but that would be a unfortunate coincidence.
Im now calling on my fellow ford nuts for help and advice. Is it time to pull the block and do a full rebuild?. What else could I be looking at?
Any suggestions, great, small weird and wonderful welcome.
Thank you
Wayne
Ive been having some compression issues of late on my 90 spec. Everything pointed to a duff head, so I purchased the NMS head in the for sale section at the weekend. Im not doing the engine work till over the winter, but curiosity got the better of me, so I put the new head on, and now Im more confuzzled than ever.
These are all the results over the last few month;
(PSI);
4/6/14 124948 miles 140 145 145 148 (original head)
12/10/14 125812 miles 123 130 87 130 (original head)
30.10/14 125812 miles 58 108 21 58 (new head)
As you can see, Ive done no miles since changing heads, and my compression has gone right down while standing still.
Im now more inclined to think Ive blown all my rings, but that would be a unfortunate coincidence.
Im now calling on my fellow ford nuts for help and advice. Is it time to pull the block and do a full rebuild?. What else could I be looking at?
Any suggestions, great, small weird and wonderful welcome.
Thank you
Wayne
#4
Too many posts.. I need a life!!
Thread Starter
Hi,
All results were cold.
I use Mobil 1 10-40, but there is no fluids in the car at the moment. Also no manifolds on etc. I just wanted to see if Id cured the problem, but it looks to be worse than ever.
Im stumped now, as the car was performing perfect on the drive home after the compression loss on cylinder 3.
Tomorrow, im gonna take the head off, remove the rockers and try the petrol test. not that Im doubting the head, but gonna cover all bases to be sure.
All results were cold.
I use Mobil 1 10-40, but there is no fluids in the car at the moment. Also no manifolds on etc. I just wanted to see if Id cured the problem, but it looks to be worse than ever.
Im stumped now, as the car was performing perfect on the drive home after the compression loss on cylinder 3.
Tomorrow, im gonna take the head off, remove the rockers and try the petrol test. not that Im doubting the head, but gonna cover all bases to be sure.
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#8
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Thread Starter
Front end of car wont be getting put back together till new year, so will have to wait till then to warm her up.
Is it worth popping a rod/piston out through the top of block for a look see in the meantime?
Is it worth popping a rod/piston out through the top of block for a look see in the meantime?
#9
PassionFord Regular
To be fair mate if the case is your not using it i would re-ring the pistons or look at if it needs a .5 oversize instead of chasing nightmares with good money
#10
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Thread Starter
Whats involved in doing a .5 oversize, rehoning etc?
#11
PassionFord Regular
to be honest it would be good to remove the full engine take the head off, crank out, piston/rods out and bits with them then take the block to a machine shop and ask for a re bore a .5 and get pistons and rings to suit and other parts as needed to fresh up. When you do it buy the best you can when it comes to parts as its easy to do it once right, twice is shite lol us a machine shop recommended i have used the same bloke for YEARS and always does a spot on job.
#12
Too many posts.. I need a life!!
Thread Starter
Looks like the new head is at fault.Poured petrol in, came gushing out of 7 of the ports. Ive just stripped cylinder 1 down and the valve seats are a mess. Gonna require some work. . Gonna strip it right down now, and inspect everything.
#13
PassionFord Post Troll
You also don't say what made you believe the initial comp issue was deffo head?
I take it you've done the petrol on the new head with springs etc in?
#14
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Thread Starter
Original head had a sticky lifter on No3 inlet. It was oversized on bottom edge by 2 thou. Instead of repairing and replacing on my original head, I decided to buy a already uprated one instead.
Did petrol check by just removing the rockers so valves sat tight, petrol gushed out. Ive got head stripped, and have 2 bent valves, and seats all need work.
Should just repaired mine, but you live and learn.
Did petrol check by just removing the rockers so valves sat tight, petrol gushed out. Ive got head stripped, and have 2 bent valves, and seats all need work.
Should just repaired mine, but you live and learn.
Last edited by Perfmr2; 31-10-2014 at 02:07 PM.
#16
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Thread Starter
In hindsight, maybe I should of worked mine, or bought yours.
#17
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Thread Starter
Quick update,
Ive had the head penetrant tested, and have found a multitude of cracks around the seat to spark plug area. The worst being where the 2 valves are bent.
Ive had the head penetrant tested, and have found a multitude of cracks around the seat to spark plug area. The worst being where the 2 valves are bent.
#18
Too many posts.. I need a life!!
Who did you get your "new" head from?
It sounds like it was/is a piece of poo.
Might be one of those "home built" rebuilds. Maybe even a stage 1,2, 3 or 4 or 5?
It sounds like it was/is a piece of poo.
Might be one of those "home built" rebuilds. Maybe even a stage 1,2, 3 or 4 or 5?
#19
Balls Deep!
iTrader: (4)
That's a nightmare mate, was an expensive head when I first bought it from NMS, shame to hear it's in such a state
But yeah whoever sold it to you needs a phone call/visit and to be returning your money for sure.... unless they somehow didn't know, but still.
Cracks around the plug threads is very common on CVH heads and often cause no problems (not ideal obviously but many run like this), but yeah bent valves and damaged seats are no good.
But yeah whoever sold it to you needs a phone call/visit and to be returning your money for sure.... unless they somehow didn't know, but still.
Cracks around the plug threads is very common on CVH heads and often cause no problems (not ideal obviously but many run like this), but yeah bent valves and damaged seats are no good.
#20
Too many posts.. I need a life!!
Thread Starter
It was the one for sale in the RS Turbo section. You can see its been expertly put together, and had some money spent on it, but unfortunatly it wont hold compression now
Both myself and the seller have come to a arrangement we are both happy with.
In fairness to him, you wouldnt know there was a problem without stripping and cleaning it, or putting it on the block to do a compression check.
Ill post some pictures up tomorrow of the head.
Both myself and the seller have come to a arrangement we are both happy with.
In fairness to him, you wouldnt know there was a problem without stripping and cleaning it, or putting it on the block to do a compression check.
Ill post some pictures up tomorrow of the head.
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