Cosworth engine BLOWS UP after rebuild, but what happened?
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- Опубліковано 15 жов 2024
- Well after a week so far of cleaning and blasting Cosworth parts we get to strip yet another Cosworth, this time this engine has already been built, but why has it blown up? Also Isaac gets the Morris cleaned and painted and we love the colour
![Lp. Сердце Вселенной #30 ДВА В ОДНОМ [Один человек]• Майнкрафт](http://i.ytimg.com/vi/nrXy15orKhY/mqdefault.jpg)
Great video lads. I have every confidence you will get my engine singing. Barum Engine NA cossie build number 001 👍🏼
you dont even make parts... get a wife
when oit revs too hight you have to machibe the pistons
The gauze 'filters' will actually reduce power because they present a considerable restriction to flow. It is likely that the free flow area is about 50% of that of an open throttle body. The best thing to do is create an air box and feed that with preferably a K&N filter set in the cold air area.
evenflow
I remember Gold Seal engines recons.
And Silver Seal. Cannot remember if they were any good?
fitted a few of them myself in the late 70's early 80's
I fitted a Gold Seal engine into my Mini (the real one) and it was superb. Unfortunately I scrapped the car years later and took the engine out only to find that it had been stolen when I went to the, slightly remote, garage on a council estate. 😒Bob M. South Wales
Remember 'Blue Riband' engines?
Lee now Isaac is coming on so well and from what you said about the laborious time consuming cleaning surely the writing is on the wall for a new employee? John, you and Isaac would be better concentrating on the machining. John also needs to pass on his crank grinding skills and knowledge to you both.
Lee why don't you do a PSI compression test on all your engine modifications like the boy Said !! Best Regards. Bill G. Spain.
This a good observation. Is it time to hire a part timer who can clean engines, clean the machine shop and order parts. A semi retired mechanic or engineer could be perfect. You would charge their time out to each job. ie " prep and clean engine and parts", "examine components and order parts" "pack engine ready for shipping" "paint engine and parts" etc. Then, pay them for 3 or 4 hours a week for shop cleaning and for servicing and painting your equipment. Your time can them be allocated to machining, and learning about crank grinding.
@@ataxpayer723or just do their job that they should do instead of videoing all day
Looking at the piston crown of the failed one against the adjacent one it looks like it was running lot leaner which would say cause of just that one failing. May been an air leak on just that cylinder inlet or injector issue also worth getting all flow checked
Very interesting post mortem particularly the challenging geometry of big valves. I always remember the Equinox Video series when Keith Duckworth the tried to Turbocharge a Pinto block for Ford/F1. Keep up the good work gents.
Definitely an interesting failure!
Thanks Terry 👌🏼
I built a1098cc engine for a Mk1 Austin A40 back in 1968. We only built the short wheelbase A40 in Australia/
I did the suspension with an anti0roll bar at the front and converted the rear brakes to full hydraulic using Sprite/Midget reap brakes then I built the engine.
As a trainee engineer at BMC in Sydney, I had access to all the drawings and found that with an AEA731 cam and the head off the 1275cc engine that was going into the 1275cc Midget, the exhaust valves at maximum lift and the thicker 1275 head gasket the valves would have just touched the top of the block. Had any of the tolerances from the pushrods, the rockers or the valve lengths added to the nominal length of the vector path, the valves would have hit on the block.
I had a colleague in one of the tool rooms make an inlet valve into a face cutter and cut the pockets in the block with the old head and an electric drill. The 'cutter' was good for the four pockets but was knackered at the end.
I copped a roasting from one of the young engineers because another colleague - who had not done any checks - just put the head on his Morris 1100 without any problems.
One day said colleague came to me and said that the critic owed me an apology. When the head came off the 1100 there were witness marks in the carbon built up on the top of the block but no evidence of the valves touching the block..
It was that close.
I fitted the engine with a single 1 1/2" SU and it revved to 7,500 rpm before it ran out of breath. My motive was that I wanted to make the A40 a quick car but I didn't want to have to work on it every week to get the carbs in tune.
It was fun to drive and more economical than the original 946cc engine with its down draft Zenith carb, The last weekend we used the A40 we took it on a 750km round trip to the country, averaged 59mph for the trip and returned just short of 40 miles per gallon fuel economy.
Also a farting potion. Someone at work started protien shakes and keeps stinking out the shop area with vile farts due to the shakes. 🤣
Let’s hope he doesn’t add Egg Whites or you’ll have to evacuate the shop.
Re. the pocketed Moriarty head, surely using oversized valves, they will be shrouded around the pocket side, so power gain will be limited?
I'd check how the fire rings sit across the corrosion areas on the top of the 1098 block around the cooling passages especially the one at the rear of the block on the dizzy side. I had that one leak a bit due to the corrosion when I did this conversion years ago and ended up welding the problem area with nickel rod in situ and job done once dressed flat. Happy with the result it pulled well especially above about 3.5K RPM with a 276 cam. I thought I saw a duplex chain set-up on the bench for this build, I hope so as a simplex won't be durable long term with a higher lift cam.
Fasteners; When the time comes to dismantle or reassemble, the question of whether or not to reuse nuts and bolts tends to come up. It is possible to reuse fasteners in some cases. However, only fasteners that have never been torqued beyond their yield strength may be used again. If over-torquing is suspected or confirmed, these fasteners may prove unreliable to provide a durable, secure joint.
If fasteners have been exposed to extreme heat or show any signs of corrosion, they should not be reused. Previous modifications made to fasteners with paint, lubrication, or other treatments also make them unsuitable for a second application. Used bolts, nuts, washers, and other types of fasteners should not be reused on critical joints or applications, no matter their condition.
It is also important to note that a used bolt should never be used in combination with a new nut. Nor should a used nut be paired with a new bolt. Tensions, heat, and age may have pushed used fasteners beyond their yield strength, which may result in deformities invisible to the naked eye. Deformed threads do not mate well with new threads and will create uneven and unstable joints.
Reusing nuts, bolts, washers, and other mechanical fasteners is generally never a good idea. If you have any doubts about a fastener’s condition, it is best to discard it in favor of new fasteners as that will always result in a stronger, more durable joint. Any money you would have saved by reusing the fasteners will be overshadowed by damage and downtime caused by fastener failure.
Source: www.marshfasteners.com/fasteners-can-nuts-and-bolts-be-safely-reused.
AND
Many of the bolts used in machine assembly, such as the automotive industry, used what are called “torque-to-yield” (TTY) bolts. These bolts feature bolt heads that are specifically designed to stretch when assembled to provide strong, reliable clamping - especially valuable in critical assemblies where bolts that loosen can cause big problems.
Because of the unique properties of TTY bolts, the TTY bolt-tightening procedure is carefully designed to provide a better, more uniform seal that will hold under all conditions. Sophisticated torqueing equipment is utilized to tighten bolts just beyond their yield point.
So what specifically is “yield”? It can be defined as the maximum tensile force that can be applied to a bolt that will produce a specified amount of permanent deformation (most commonly 0.2 percent) within a specific fastener. While deformation may not sound like a good idea, the slight stretching of the bolt evens out the loading so that each bolt in an assembly, properly installed and torqued, will provide almost exactly the same amount of clamping force for overall greater strength and uniformity.
However, because the tightening procedure does permanently stretch the bolt, there is some risk of breakage if the bolt is reused. And since there is no way to tell how many times a bolt has been reused, it doesn’t make any sense to reused TTY bolts - the risk far outweighs the replacement cost of used bolts.
Source: www.electronicfasteners.com/why-cant-you-use-a-bolt-again-after-its-been-torqued.
Do some good work but seeing more of the machining would be nice,thanks for sharing, all the best to yous and your loved ones
Lee/lsacc, to much material has been removed from those valve pockets on the pistons.
Definitely a weak mixture & overheated/melted causing piston damage. Would look at increasing bore diameter which will give a safer margin for piston life with thicker material on & around the valve cut outs...Double check that compression ratio as poor quality fuel burn will melt pistons easily with detonation...
Should be a nice strong n/a cozzy engine when sorted out.
Proper o-rings indeed!!!!
The old compression ratio worked out using a syringe job, have to wonder just how accurate the stated compression ratio of the NA cossie is/was. Are you actually using a burrette nowadays?
I presume you guys are going to check the valves / seats on the affected cylinder in case the lost material from the piston has made some impact.
Cheers Lee.
Just a comment guys BMC motors should be Larch green
The A series block is to blue on camera for British Racing Green.
Great video love all the information.
Looks like the bad piston was running lean and melted the metal where it was thinest on the valve cutouts.
a good case for an afr meter in cab - there is no evidence of pieces bouncing around inside the bore which to me suggests the edges have melted/burnt away - detonation? what was the big end like on the damaged piston?
Leaky throttle body at Wide open throttle (max power) wouldn’t affect power. would make idle and mid range poor though.
it would still be lean ...
@@colinscutt5104 not at wide open - the inlet is as atmospheric pressure therefore it’s not going to suck past a joint when it can suck through a massive open hole
@@eliotmansfield but what destroyed the valve pocket? where did the pieces go?
@@eliotmansfield oh yeah ofc there wouldn't be a pressure differential
@@Bristolcentaurusthe pistons are fine. they machined a larger pocket to accommodate the valves.
when are the decorators coming in
No mention of what octane fuel was used, 12:1 is 100 octane+ requirement.
Are the valves longer than they should be
100% ran lean from air leak , not enough meat on the piston edge to handle the extra heat
going from a faint memory, wasn't the uniroyal ford P100 race series done using NA cosworth engines ?
Enough of the cossies, what about the S50. Did you ever do a cost run down of the build, i'd be interested to know what's it's likely to cost to refurb one.
I’ll suggest this to Lee!
@@BarumBTS good lad, cheers
1.75 roller rockers
Using your misses' knickers for air filtering will not suffice. Enemy #1 for engines is silica dust in the air. You need a proper air filter for this, either a high density paper based filter or a properly oiled cotton (K&N style) jobby. The amount of power you gain from not having a proper (obviously, sized for application) filter is about 1%, which is less than what you lose in about 1 hour of runtime. You will bugger up your piston rings within a few hours of runtime, your crank and bearings in maybe double that. Ask any automotive air filtering expert about this, and make sure you do NOT warrant any engine run without proper filtering for any amount of time.
Those long throttle bodies bouncing around on rally stages will have flexed the gasket joints and weakened the seal, potentially causing leaks…..
Pockets cut far far too deep, there was no metal left.
Ground bug for protein?
Talking about cleaning and de-oiling, how's dem perkings doing???
Both stripped, just received a crank for the first one, although John reckons needs a minimal grind. Second one has wiped all 4 pistons but other than that looks perfect!
what hapenned??
What shape is the head gasket fire ring around the cylinder notch area.
Look at the previous episode. They are using the 1275 head gasket which has wider rings, nothing fouling or not getting proper sealing.
Nice diags.
Only 7 years before it goes wonky? I thought N/A Cossies lasted for ever?
Lee is the man trust him