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oops i broke my engine.
Moorron - 17/3/08 at 01:05 PM

Hi guys.

Need some advice on a poorly engine. The story so far is I turbo charged my CBR1000F engine. It was in poor condition anyway using quite a lot of oil in NA form. But I carried on anyway knowing I will have to rebuild it soon. Turbo charging it went well, until this w/e when I blew what I thought was the head gasket. Engine was still running fine but chucking vast amounts of white smoke out the exhaust on overrun and idle.

Taking the bonnet off revealed lots of liquid which had been sprayed from the oil breather catch tank. Not sure if it was oil or water, but when I was cleaning it all up I noticed a bubbling noise coming from the rocker cover, I took the spark plugs out to see if water was boiling in the cylinders from a head gasket failure, but they were fine so I took the rocker cover off and I saw the problem right away. The bubbles were coming from one of the inlet valve springs.

After taking the head off, the gasket, pistons and surfaces look fine. Have I cracked the head? What would have caused this?

I am in 2 minds what to do now, first off do I fully rebuild the engine with new piston rings (incase this was the original oil burning problem)? Or should I just rebuild the head? If I choose to rebuild the pistons is it a necessity to hone the cylinder bores? Here is a list of things I will order anyway:

1, oil pump
2, bottom end gasket set
3, 2 head gaskets (at £10 might as well be prepared for the next one)
4, 16 valve stem seals
5, oil filter
6, 4 copper exhaust to head gaskets.
7, cam chain tensioner

I do have a spare engine but I know nothing of its condition, do I stick that head on or try the original one first?

Any help or recommendations welcome.

TimC - 17/3/08 at 01:10 PM

Murderer!

worX - 17/3/08 at 01:12 PM

I'd stick all your turbo stuff on the second engine and drop it in...

Then rebuild your engine replacing and generally making it as good an engine as you could - full strip down etc.

Then when it's complete swap em back over using all your turbo, H/G's etc knowing you have a fully sorted engine...

Steve

Mr Whippy - 17/3/08 at 01:16 PM

A crack like the titanic’s in the block from all that boost

Serves your right!

Dangle_kt - 17/3/08 at 01:26 PM

personally I'd rebuild the spare engine properly first, then fit all the good stuff to it.Whats the point in risking another engine? unless you know you can get hold of another cheaply, and even then, it will be the hassle of changing it all over again.

I'd never do any upgrades to a poorly engine, as you are just storing up trouble, but i guess you already did just that with the first engine.

Good luck sorting it!

Moorron - 17/3/08 at 01:28 PM

ive stripped the spare engine down a while ago so its no good to drop in.

Im unsure if its the block. i think its the head that is cracked as it looks clean at the bottom end. Is there anyway of testing the head before i try it again and waste a few days work?

muzchap - 17/3/08 at 01:41 PM

You need a compressor and a compression testing kit

See what efficiency your head has...

Most garages will have this stuff, or for £20 you can get one off FLEA-BAY brand new

CLICK ME

Screws into the plug hole

Very cheap and if I didnt have a mate who already had a set - I'd get one Still need the compressor tho

Cheers,

Murray

zilspeed - 17/3/08 at 05:14 PM

Why does he need a compressor as well as a compression tester ?

Is there some advanced technique involving pumping compressed air in instead of the usual technique ?

jambojeef - 17/3/08 at 05:15 PM

I always have said that if and when I do the very same to my CBR lump I'll just strip a few bits off for parts and bin the rest.

CBR engines are so cheap - just get another and drop it in.

You need to find out what caused the problem in the first place though.

Disassemble the engine before binning it and measure everything properly making notes and taking photos so you can make the necessary mods to the next engine.

Out of interest - did you run the engine without a thermostat or was teh original CBR stat in place?

Geoff

muzchap - 17/3/08 at 05:44 PM

Well - as I pointed out - I rely on my friends 'equipment' and he connects the airline to his compression gauge and it does the rest...

So fair enough - if there's another way - then do that - All I can do is recount what I've done and hope that's of some assistance...

I mean, jesus, did I ever expect anybody to agree on this forum anyway

ravingfool - 17/3/08 at 05:55 PM

I've only ever used a compression tester in the 'normal' way, but I suppose by using a compressor as well you can test whether there is leaking between specific cylinders rather than just measuring the compression attained by each cylinder on it's own.

MikeRJ - 17/3/08 at 06:29 PM

quote:
Originally posted by zilspeed
Why does he need a compressor as well as a compression tester ?

Is there some advanced technique involving pumping compressed air in instead of the usual technique ?


A compression test uses a pressure gauage and non-return valve screwed into the spark plug hole, and you measure the peak pressure generated when the engine turns over.

A "leak down" test uses an air line plumbed into the spark plug hole, and you measure how much air leaks out of the cylinder (via rings, valves etc).

A crack in the head or block will not necessarily show for either test, combustion pressures tend to be nearly an order of magnitude higher than either test will subject the cylinder to (and a turbo charged engine gives much higher pressures again).

Chippy - 17/3/08 at 08:36 PM

You can obtain a "crack test solution" can't remember what it's called. Basicaly two solutions, you piant the item with the first one then when you put the second one on any cracks show up as a deep purple line. Not much help without the name but somebody else may have the answer. HTH Ray

Moorron - 17/3/08 at 09:12 PM

Cheers for the replies, we got the crack test stuff at work, but i cant see where it is coming from, its behind the valve guide.

Jambo, i am running the original thermostat, should i remove it?
Also where did you get you side flare fairings from? im after some and yours look just the job.

I do have a water leak under the exhaust, but i spent all last year trying to find it, seems to only leak out on the road and sprays up the block. Maybe i had run out of water (very good chance it had been stored for winter i didnt check) so maybe it had over heated and caused the problem. I think im going to order the camchain tensioner (a fault on these engines), new oil pump and a head gasket and chuck the spare engines head on this w/e. then see if it runs. If it solves it then i know its the head.

If it still burns oil i then know its the piston rings and i will do a full rebuild on it.

looking tonight at the engine the liners look fine, no scooring and in tollerance.

its all fun.

NS Dev - 17/3/08 at 10:32 PM

quote:
Originally posted by Chippy
You can obtain a "crack test solution" can't remember what it's called. Basicaly two solutions, you piant the item with the first one then when you put the second one on any cracks show up as a deep purple line. Not much help without the name but somebody else may have the answer. HTH Ray


"dye penetrant crack test" is the terms I'd use.

I have a kit in the garage for testing cranks etc before using them.

Exactly as you say, extrmely low viscosity (hence very "capilliary-y" no idea how to say that) liquid dye in an aerosol which is sprayed on the suspect area after thorough degreasing, then left for a few mins, then wiped clean with a solventy rag.

Then a second aerosol of solvent borne fine chalk powder is applied which pulls any dye out from cracks in the srface to which it was applied.

Will certainly find cracks in the cylinder head.

jambojeef - 18/3/08 at 08:36 PM

quote:
Originally posted by Moorron
Jambo, i am running the original thermostat, should i remove it?
Also where did you get you side flare fairings from? im after some and yours look just the job.


Hi, I wondered whether you were running your CBR stat since some take them out and the resulting lower pressure in the cooling system could result in hot spots around the head which in extreme cases (which you could describe turboed engines as) a softened bit or maybe even hole could result which I wondered might explain your spots of water.

I think there are a few things to eliminate before getting to that conclusion though.

As for the side panels - they are available from any metal stockist in flat pack form!

Mine were bent around some bits of 2 x 4 planed to shape - I still have them if you want to borrow them?!

Geoff

david walker - 18/3/08 at 10:25 PM

Forget the compressed air, leak down test or dye pen, only way to check it really is by taking it to an engine reconditioner and have them do a pressure test on it - on a piece of equipment designed to find cracks in cylinder heads!

Sounds to me though that it's cracked up from under a valve seat which is common or around a valve guide which would be less common.

[Edited on 18/3/08 by david walker]

Moorron - 19/3/08 at 10:10 AM

Right so taking the thermostat out is bad then. Good to hear your views on it so I don’t make the mistake of taking it out and breaking something. The more I think about it the more I convince I did have low amounts of coolant in the engine. The night before I was testing the temperature sender against the actual temp as its an aftermarket gauge running off the bikes original sender and I wanted to make sure it was reading correctly (I see 120 degrees on the gauge a lot but the fan only kicks in at 110 making me think its not actually at that temp yet). I removed the sender from the thermostat housing and water didn’t spill out.

What rad are you using?

Regarding the side fairings, I had a sample made at work on the press brake. But it looked like the sides of a 50 pence piece requiring me to sand and tap it round. I didn’t think of making one from wood and folding the sheet over it, makes sense really. What thickness of material did you use, I have 1.6 alloy.