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Engine Damage - Opinions are welcome


slomove

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You may have seen what happened to my engine in the "Big Sky 2015 Tour" thread. All was going well until I lost power while passing (maybe 5000-6000 rpm) and the engine (old silvertop/ZX1 Zetec) emitted some really ugly noise. I coasted to a stop, found no external problem but a valve stem was visible inside cyl #2 plug hole. So, we made the trip back to our trailer in Idaho Falls with the help of AAA and Uhaul.

 

Today I took the cylinder head off and took a few pics of the damage (see below and next post). Apparently the valve retainer disintegrated. I believe the following has happened: Last year I had new valves installed. The old valves had additional higher keeper grooves ground in to accommodate the high lift cams and avoid binding of the stronger springs. However, the engine builder who did the change swore up and down that this was not necessary according to his calculations and measurements. Being an experienced guy with all kinds of exotic and expensive engines in his shop I believed him (I guess that was a mistake). The engine did probably over 5000 miles since but I guess the aluminum retainer fatigued and fell apart. I would not think that should happen as a matter of regular use?

 

I do have a complete spare stock engine disassembled to parts. Now my options are (assuming the head is beyond salvage):

 

1. Check if the piston damage is not too bad and install my spare stock head, live with the minor power loss. I don't go the track anymore and for the road it is still ample power.

 

2. If the piston is toast, I could put the complete spare engine back together and use that as-is. Cheapest solution but then I would still have a used engine with 60k miles and hard-to-get internal spare parts.

 

3. I can get a brand new Zetec SVT engine locally and install that with some modifications. I will have a look on Saturday. It would require some changes to the alternator mount and belt configuration and I would have to use my old main bearing bolts for the crank on the SVT machine because they have stud extensions for the windage tray (not in my Raceline sump like for the ZX3 model). Otherwise I believe it should be a drop-in and I guess the ECU maps should pretty much work since the engine power is similar to my old engine.

 

4. I could buy a used Duratec. While a used engine is quite inexpensive and spares are easy to find, I would need new exhaust headers and probably a bunch of other adaptations. Cut holes in the skin and plug others. Probably cut/move a chassis tube, re-route most of the engine wiring harness and modify the exhaust can or get a new one. That sounds like a serious and more expensive project.

 

So, I will make up my mind over the next few days. Any input is welcome.

 

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Seeing that valve laying on the piston gives me the chills. That sucks. Guess it could have been worse, but must have made quite a racket. Get it fixed. If not on track, big power is a waste on the street. IMO Good luck. Tom

Edited by yellowss7
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I've never seen aluminum retainers, the broken one "looks" very thin for the load they take. Did the engine come stock with those?

 

Also, consider the loads applied to the rod and crank when that valve dropped in there at 5k rpm. Something had to give. At a minimum the rod and piston need to be removed and checked for straightness, cracks, etc. It could have even bent the crankshaft.

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I've never seen aluminum retainers, the broken one "looks" very thin for the load they take. Did the engine come stock with those?....

 

No, they are not stock. They were recommended by Burton Power in the UK who sold me the entire kit from Kent Cams, which was FZ2002 stage 2 cams, stronger springs, these retainers and the tappets.

 

Now, googling "retainer failure" I find that aluminum retainers are apparently known to have limited life and some recommend them only for racing and replacement after 7000 miles. Something like that was not mentioned in the Kent Cam information and my engine has about 50k miles on the clock. So, maybe it was not the engine builders' fault but increasing the spring pre-load surely did not help.

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FWIW. #2 sound like the shortest path to a blat. It would give you seat time sooner and time to evaluate the damaged motor and the other alternatives if you want to resume track time.

 

Your work looks 1st Class! I'm sure you will continue. :cooldude:

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Sorry to hear.

I dropped a valve in a race bike at something like 12000 rpm and the damage was way worst. The crank was OK, but the piston had a hole in the top, the rods small end was smashed, the head was a right off, and the cylinder was damaged but was salvageable with significantly oversized pistons.

You didn't state, but is the cylinder OK?

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Yikes, it looks like you were overall lucky. If there is one thing aluminum is guaranteed to do it is fatigue.

 

I vote for 2 & (3 or 4). This way you get a running car and a fun (low urgency) engine build.

 

Daniel

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Well that stinks... This Fz2002 is a sprint kit that I thought would have a much shorter service life than stock. Burton sells some cool parts for our Zetec, but it's

 

mostly geared for track duty, not long term street use. Your a sharp guy, you'll be on the road soon.... Best Wishes....

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How much is involved in fitting a Duratech? Obviously exhaust and motor mounts.....ECU I assume also.

 

It should would be tempting to have the simple grunt of a Duratech and have the exhaust on the other side.

 

dave

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... This Fz2002 is a sprint kit that I thought would have a much shorter service life than stock....
I don't know, they sell this kit as "Fast Road Cam" which led me to believe some regular use capability. For that matter, the engine ran very well under cruising conditions as well as track and other than that broken retainer there is nothing wrong with the parts. I will probably sell the cams separately once I get a new engine.

 

How much is involved in fitting a Duratech? Obviously exhaust and motor mounts.....ECU I assume also. It should would be tempting to have the simple grunt of a Duratech and have the exhaust on the other side. dave

 

As far as I can see (have not looked into that in detail) it would be:

- new exhaust headers, new can (or re-weld the hanger on my old can)

- New engine mounts. Since I have an older Birkin I suppose they must be fabricated.

- cut new holes for intake and exhaust and bead the edges. Cover/close the old holes on the other side.

- Re-route the cooling hose connections

- re-route the entire engine wiring harness (aargh!)

- modify the fuel supply and return

- modify or eliminate my Laminova oil cooler and remote filter system

- not sure what else, like bell housing and starter configuration

 

So, this looks like a real project to me and I am not keen on doing that. My old engine, the SVT Zetec and the stock Duratec actually have similar performance characteristics with the ITB and I guess the ECU maps will need only minor tweaks in any case.

Actually, having the exhaust on the passenger side is not that desirable for me because I drive with my wife as passenger all the time (or sometimes she is driving with me as passenger). I got used to stepping over the muffler and with good earplugs the noise does not bother me.

Edited by slomove
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In addition to Aluminum, Titanium retainers should also be considered a relatively high-frequency consumable. So, unless you're tearing down an engine each race season for an inspection/refresh, avoid both.

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You should never use Alum retainers , back in the day 50`s - 60`s it was all there was , now days you have steel and titanium on top of that the stock Retainers to Titanium is such a small difference that it isnt worth the cost

 

If you do choose to go with the duratec I would do the 2.3 vs the 2.0 , you also have the 2.5

 

Tom

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Hello Tom,

 

I wish I had known that. When I bought the Kent cams in 2004 it came with a list of required parts like upgraded springs, new tappets and these aluminum retainers. One would think Kent Cams or Burton Power know what they are recommending and actually the engine made some 50,000 miles that way. They did not warn of limited service life or fatigue.

 

In the meantime I bought the SVT engine and will leave the valve springs and retainers alone, just remove the VCT (you gave me some related advice yesterday on the FocusFanatics forum).

 

Of course nothing is easy with these cars, but at least I found that I need the 8.5" clutch from a Pinto and the release bearing from a European Escort version.

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If you go the Duratec route, I have a complete Caterham exhaust system for it (header to hangar). Not sure of your chassis but if it's a Birkin, Tom Carlin, the distributor in Vail, has specific motor mounts for it as well as the appropriate bell housing and other bits unique to the Duratec installation.. If you go this route and decide not to use the Laminova, PM me. I might be in the market for one.

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RAM has a clutch assembly for the 2.0 and 2.3 Pinto. Bought mine from Speedway.

 

Bolted right on to the Redline steel flywheel; not sure if you are using the SVT flywheel as it is setup for the larger bolts.

 

Wayne

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If you go the Duratec route, I have a complete Caterham exhaust system for it (header to hangar). Not sure of your chassis but if it's a Birkin, Tom Carlin, the distributor in Vail, has specific motor mounts for it as well as the appropriate bell housing and other bits unique to the Duratec installation.. If you go this route and decide not to use the Laminova, PM me. I might be in the market for one.

I have now the SVT engine that I will use. Just much simpler to convert (not to say really simple). I will also keep the Laminova since I have all the plumbing set up and nothing to gain from removing it.

 

...... not sure if you are using the SVT flywheel ...Wayne

No, I am using lightened steel flywheel that was provided by MSI while they were still in the Birkin import business.

I will go to Autozone today to check the stock Pinto clutch if it fits. I had a regular clutch before and it never slipped so I will probably forgo the rather expensive race clutch option. The engine is not that radical.

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SVT should be a good choice.

 

Be careful using a stock disc if the engine revs over 6k. The standard type disc will disintegrate over that RPM. I have had that happen.

 

Might suggest a RAM clutch assembly that can be purchased from Speedway. Mine revs to 8K and so far, no problems after 2 yrs of WOT shifts.

 

Wayne

 

Be interesting to hear how the intake manifold works out.

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