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Author Topic: Head rebuild was: surging.  (Read 339 times)

belleaudb

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  • Posts: 37
    • 92 XR2
Head rebuild was: surging.
« on: August 12, 2018, 06:20:05 PM »

A couple of weeks ago my XR2 started surging during light accel but would take off once boost got up over 7.

The problem progressively got worse. Everything tested fine with fuel and ignition systems. 

Decided to do a compression test. 

Cyl
1: 117 psi
2: 137 psi
3: 135 psi
4: 135 psi

Number 1 low.  Repeated the test on Cyl 1 after adding some oil to the cylinder. Same results.

Did a leakdown test. Could feel and hear air escaping from the tailpipe. Pulled valve cover. Cylinder 1 exhaust valve 2 is leaking. I can pry up under the spring retainer and the air leak sound changes. 

So today I pulled the head and will drop it off tomorrow at the machine shop for a valve job.

Cylinders look good. Still can see crosshatch pattern on the cylinder walls.

I was lucky to find a complete head set. Fel Pro HS9691pt2. Got a steal on Ama*on. I ordered the set for $32.01.  Must have been an incorrect price entry as a few hours later I found the price had gone up to $178.66.  But they fulfilled the order for the price I paid.

I will post more info as the job progresses.










« Last Edit: August 15, 2018, 09:59:43 PM by belleaudb »
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Rocketman

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  • Posts: 5080
    • 91 BPT AWD Capri & 1991 XR2
    • http://www.werbatfik.com
Re: surging!!!!
« Reply #1 on: August 12, 2018, 09:02:39 PM »

Those valves definitely need some TLC. How many miles on it? Going to get the head reworked?

Good steal on that gasket set. Showing $178 as well now.

Oooh! If you haven't done it yet, port the wastegate while you have the turbo off.
« Last Edit: August 12, 2018, 09:05:29 PM by Rocketman »
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1.8L Turbo All Wheel Drive Capri... the "GTXR2"


belleaudb

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  • Posts: 37
    • 92 XR2
Re: surging!!!!
« Reply #2 on: August 13, 2018, 11:38:36 AM »

Car has 85,000 or so miles.

Dropped the head off for a rebuild. Will install new exhaust valves instead of machining the old ones.

Estimated 3 day turnaround.

I might still make the all Ford show this weekend and Ford World HQ.

My back is killing me from bending over the car to work on it!!
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belleaudb

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  • Posts: 37
    • 92 XR2
Re: surging!!!!
« Reply #3 on: August 13, 2018, 05:47:57 PM »

More cleanup.

Intake and valve cover are cleaned. Cleanup on engine deck in progress. Will backflush oil feed to head once deck is clean. Flush oil return holes with acetone while oil drain plug is out. 

Will install new filter and oil (Delo 5w40 full synthetic) in preparation of reassembly. All coolant hoses will be replaced.

Timing belt, tensioners and water pump have less than 10,000 miles on them so they will not be changed.

Will install new Denso Iridium plugs, gapped at .028.

Back hurting more....  It sucks getting old!





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belleaudb

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  • Posts: 37
    • 92 XR2
Head rebuild
« Reply #4 on: August 14, 2018, 04:42:30 PM »

Head will be completed Wednesday.

Shop ordered SBI valves in Inconel alloy. Not sure if original valves were stainless or some other alloy but Inconel is best for turbocharged engines.

This is the tool I used to clean the deck surface, along with brake cleaner and acetone. The blades are 2 ended and a box of 150 were only $7.00. I no longer use scotchbrite pads due to concerns of damage due to residual abrasive particles. Many OEM's will void warranty if any abrasive products were used to prepare surfaces for sealing.

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belleaudb

  • Newbie
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  • Posts: 37
    • 92 XR2
Head rebuild
« Reply #5 on: August 15, 2018, 09:59:08 PM »

Work is done.

Took 4.5 hours start to finish including cleaning up the garage, detailing the car, showering and first test drive.

Will do some more fine tuning tomorrow.

Early results are smoother low rpm operation, noticable increase in torque at low rpm.












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greywolf27030

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  • Posts: 781
    • 88 Festiva, 91 Capri, 91 XR2
Re: Head rebuild was: surging.
« Reply #6 on: August 16, 2018, 09:14:59 AM »

Nice.
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Trackerrrr

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  • Posts: 79
    • 1991 BMW 525I, 1991 Capri N/A, 2011 Kia Sedona
Re: Head rebuild was: surging.
« Reply #7 on: August 20, 2018, 03:48:46 PM »

Nice.
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Chris
Retired Air Force MSgt

Rocketman

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    • 91 BPT AWD Capri & 1991 XR2
    • http://www.werbatfik.com
Re: Head rebuild was: surging.
« Reply #8 on: August 22, 2018, 03:07:59 AM »

That is gorgeous. Love the how the plated bits are still gold. How's it driving?
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1.8L Turbo All Wheel Drive Capri... the "GTXR2"


belleaudb

  • Newbie
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  • Posts: 37
    • 92 XR2
Re: Head rebuild was: surging.
« Reply #9 on: August 22, 2018, 04:57:54 PM »

Car is driving great. Had a slight bonehead moment where I forgot to tighten one of the clamps on the pipe to throttle body coupling. OOPS!!

Had the car at the All Ford car show and Ford World HQ in dearborn. Had a great time, see my post in Photos for more info.

Also found my turbo bypass valve ( cheap aftermarket Bosch style for Audi) had a leaking diaphragm. I replaced that valve yesterday with a genuine Audi valve.

Will be taking the car out tomorrow. Too much work today to be able to "play".
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