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Discussion Starter · #1 ·
My engine blown earlier on, on the type s and sounds horrible, literally undrivable.
It has 11.5:1 +25 overbore mahle pistons. Apparently they dont last. Could this be the problem do you think.

The engine was rebuilt at 60,000miles and i bought it at 75,000 miles and the car has now done 85,000 miles.

I really hope i dont need a new engine.
 

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you need to list more info. did it have fluids? is it leaking now? is there a hole in the back of the block? any number of things could have happened
 

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Vrooom PSHHHH
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was it ever tuned?
 

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Discussion Starter · #4 ·
you need to list more info. did it have fluids? is it leaking now? is there a hole in the back of the block? any number of things could have happened
All has been topped up religiously, i have a leak in the radiator but its slow and i have kept ontop of the coolant. Only a few times has the engine temp climbed high.
Maybe the the engine has just had enough of not being cooled and has seized braking the insides.

I took it to a mechanics and he said there is no way its a blown headgasket. Its far to loud etc. Not oil is leaking, no smoke, nothing at all. Looks completely normal

But i have literally no power, it does stall when at 10mph. It did over heat when driving it home and the engine sounds like there are loads od bits moving around in the cylinder heads.

Gutted.
 

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Discussion Starter · #5 ·
All has been topped up religiously, i have a leak in the radiator but its slow and i have kept ontop of the coolant. Only a few times has the engine temp climbed high.
Maybe the the engine has just had enough of not being cooled and has seized braking the insides.

I took it to a mechanics and he said there is no way its a blown headgasket. Its far to loud etc. Not oil is leaking, no smoke, nothing at all. Looks completely normal

But i have literally no power, it does stall when at 10mph. It did over heat when driving it home and the engine sounds like there are loads od bits moving around in the cylinder heads.

Gutted.
The engine was rebuilt with a completely reground crank, the new mahle pistons and a lightweight fidanza flywheel.
 

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Vrooom PSHHHH
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so did you just not want to answer my question? lol. please tell me it was tuned, because running that high compression untuned is asking for problems...even if it was originally a type-s with 11:1
 

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People have had various problems with them (for example, valve reliefs designed wrong leading to piston/valve contact)
 

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Discussion Starter · #8 ·
so did you just not want to answer my question? lol. please tell me it was tuned, because running that high compression untuned is asking for problems...even if it was originally a type-s with 11:1
Ah sorry, im pretty sure it wasnt tuned. Literally just swapped pistons. I bought it 15000 miles after the rebuild.
 

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Vrooom PSHHHH
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Pull the plugs and shine a light down the holes to see if you can see any piston damage. Also check the plugs for metallic specs which is a sign of detonation, which it could have been doing at that high comp untuned. I'd do a compression test as well because, like blue said, there could have been piston-to-valve contact. If the results arent too bad then do a valve adjustment and see if that helps anything out. If it all checks out, GET IT TUNED! but it's not sounding very promising :/
 

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Discussion Starter · #10 ·
Pull the plugs and shine a light down the holes to see if you can see any piston damage. Also check the plugs for metallic specs which is a sign of detonation, which it could have been doing at that high comp untuned. I'd do a compression test as well because, like blue said, there could have been piston-to-valve contact. If the results arent too bad then do a valve adjustment and see if that helps anything out. If it all checks out, GET IT TUNED! but it's not sounding very promising :/
Yer also pretty sure im only running on 2 cylinders. Very slow now compaired to before. Plus the noise really vibrates the car and is so so loud. I can check inside the spark plugs.
 

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Compression test it, leak down test it, looking at the spark plugs and the inside of the engine as much as possible can't hurt either.
 

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Discussion Starter · #12 ·
Compression test it, leak down test it, looking at the spark plugs and the inside of the engine as much as possible can't hurt either.
Cant do a compression test as the car wont idle it just stalls. Unless i throttle it. Even then it sounds like im strangling the car.
 

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Compression test in this case means hooking up the gauge to the spark plug hole, and cranking the engine over but NOT starting it (remove all the plugs at once and pull your fuel pump fuse).
 

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Pull the head off and see what the damage is.

If it sounds that bad chances are whatever test you do is going to lead you to pull the head anyway.
 

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bangin' gears
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Those pistons are actually closer to 12.1 compression. Was the honing procedure done corectly? It is differnt than stock from what I have been told. A customer car curently runs them with no problems but it hasn't been running for long.
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Those pistons are actually closer to 12.1 compression. Was the honing procedure done corectly? It is differnt than stock from what I have been told. A customer car curently runs them with no problems but it hasn't been running for long.
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I was talking to the guy who will be machining my block for those pistons and he said that he has assembled many h22s with Mahle pistons. He said he actually had a local import shop sending him h22's on a regular basis for machining with those pistons. He also said that those customers have reported back to him with positive feedback about them. He said that the problem (if any problem is experienced) is with the honing and alot of people ignoring what needs to be done or how to properly do it. He also informed me that if everything is done properly there should not be a problem.

After reading multiple threads on the Mahles and several people proving their strengths with huge turbo builds they have proven, in my opinion, to have the bugs worked out of them with their lastest designs. One of the Mahle guys was stressing that they corrected the valve relief issue recently. Mahles explaination for it was they used their first design model after an after market piston thinking it was oem. Either way, it was said to have been fixed and a few people put it to test. Not only that, there does seem to be a few people on Honda-tech that say their motors are holding up fine with zero issues. At the same time their are people against them. I am going to test them out for myself. I will see if when assembled properly with a proper hone if they will actually last for a long time.
 

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Well cheers guys. Here is the thread i opened on Prelude UK.

http://preludeuk.forumup.com/viewtopic.php?t=24100&mforum=preludeuk


Some interesting view on my crank being knackered. Could be a couse as it was reground.
Any opinions?
I didn't read the UK thread, but if your car was untuned and running higher compression than stock - there is a good chance you could have had a problem with pre-detonation. This would have caused all sorts of nice issues if it had been occurring since the rebuild.

If you're mechanically inclined, pull the cylinder head and check the valves and the walls of the cylinders. You can also drop the oil pan and take a look at the crank and bearings down there.
 
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