7MGE Engine rebuild

[Bill UK]

I read your post 4.38 pm about the oil pressure, so I popped out to start the engine up, looks like you need to fire up the engine to get some revs before any sign of oil pressure as you found out. Excellent work can’t wait to see the video of the total rebuild; you did record it on video didn’t you? I recon you could sell hundreds of copies if not thousands worldwide.

[Krem]

Originally Posted by oregonjoe

Put the fuel pump fuse back in and connected the spark coil. Set the distributor to half way and shut the door.

Key in – turn, it starts.

OIL pressure gauge climbs up to normal pressure. Enough for the night.

Where might I find the fuel pump fuse on the mk3? I'd rather check for this and make sure that's not my problem before I go replacing the fuel filter and/or pump.. also, is this fuse the same thing as the fuel pump relay (which I think is located above the right front wheel well just under the hood?)

Also, what is "normal" oil pressure... this is the first car I've owned where I have a guage for oil pressure and within the two weeks of driving the car, I've noticed it'll go up around 40 psi when I start her up cold... within a few minutes, she's down to 10~12 psi and will build up to 20~25 with engine use/revs... Does this sound normal? too low? Maybe there's something I can check for or do to help keep the pressure up a bit more? Looking at the TSRM, it sounds like i'm running at the minimal threshold for oil pressure, but I also think: "It's nat. aspired... not a turbo, so the pressure shouldn't be towards the high end." but I'm no mechanic... two yrs of HS auto shop (one 9th and other in 12th grade) over a decade ago, I'm not as sharp on the subject as I'd like to be.

[oregonjoe]

Thanks Bill UK for checking that out for me.

The OIL pressure climbs to about mid scale or 40 PSI when cold which is were it has always been for this model. Rev it up and it goes to maybe 50-60, Hard to tell with these gauges. I am going to install a color after market gauge pod from CDI called the vGauge which will give me more accurate temp and pressure readings. Suction mounts to the windshield.

The fuel pump was disabled by pulling the EFI fuse in the fuse pod. Labeled EFI 15 AMP

My solution tot he dipstick problem was JB WELD. Mixed a little of that and now it don't move. Added a little RTV on top for insurance.

[oregonjoe]

Update on initial start – it was not a dream, car actually starts again!.

Ran it for about 15 minutes to get the thermostat open and get some water circulating. No bubbles in the coolant, no leaks on the asphalt.

Did two separate runs of 2 miles each with a cool down in between. Really smooth, just like it was off the show room floor. Has that nice new engine smell.

Got a few extra bolts left to locate. How many extra bolts do you need to still call it successful rebuild?

[jcastro]

dam that came out realy nice man congrats how long did it take u n i bet ur happy ass hell

[oregonjoe]

Originally Posted by jcastro

dam that came out realy nice man congrats how long did it take u n i bet ur happy ass hell

Total project was about 2 months working nights

10% Disassembly
15% Assembly
20% Figuring out what to do
55% Cleaning/painting parts

Costs about $1500
50% Machine shop work
30% Parts
10% Cleaners and rags
10% Beer

Things I should have done.

Purchased a high quality rebuild kit - most of my gaskets were cheap paper and I had to repurchase the head gasket,

Tell the shop NOT to paint the head.

Take a lot more pictures on disassembly

Use a lot more plastic bags for bolts and parts – label them with more detail.

Win the lotto so I could have bought more beer.

[Krem]

grats man I'm envious... mainly cause my ride is parked w/ a bad fuel pump and I'm not inclined enough to even replace that... let alone rebuild the engine... it came out very perty and clean... sorry to hear about the painted heads :\

[cvbikeguy]

Originally Posted by oregonjoe

I’ve taken the head and block to the shop to have them cleaned up and inspected. The head and valves looked good for 20 years of use.

The good news on the block is no cracks after the magnetic test – so its just a hone on the cylinders and good to go. The bad news is the shop wants $500 to do a valve job on the head – even without replacing any valves. Claim the 24 valves takes a lot of labor and that OHC need to be ground to adjust!

Attachment 2254

So – I took the head back to do a little porting and polish. The head had some casting marks and ridges from 20 years ago. Since I bought the car I have learned a thing or two about engines. One of which is that they are massed produced from casting molds. These molds are not all created equal and there can many flaws that are left as is in production. Some flaws include sharp ridges from casting seams and defects in the individual molds. Other are sharp angles from the machining process after the castings are poured. In production - they are all ignored.

Attachment 2255

The cylinder chambers in the head have some sharp edges that can collect heat and cause preignition so I ground them off to smooth the transitions out the valve ports. Careful to not touch the valve seats.

Attachment 2256

I focused on the exhaust ports and smoothed out the walls and take out any burrs and casting ridges. Just a little touch up on the intake side to remove any large defects as I understand its better to leave the “sandpaper” effect on the walls.

Attachment 2257

so you didnt have to take the head to the machine shop? will the replacement gasket be fine with just taking the block to the machine shop itself? sorry if im jacking your thread but this has been extremely helpful for me. thanks so much

[oregonjoe]

No - head was in shop for cleaning and resurface then I took it back once all the valves were removed to do the porting. Then - back to the shop to have the valve seats done, valves installed, and then adjusted with shims. Total machine cost for the head was $450.

You want tot do the porting before the valve seats are done so you don't mess up the seats. Critical since they determine adjustment and timing.

If you really want to do it right and can afford the time - take both head and block to machine shop so both surfaces can be done clean.

Then new head gasket will be fine - remember I used studs and tourqued down to 90 ft-lbs.

[cvbikeguy]

Originally Posted by oregonjoe

No - head was in shop for cleaning and resurface then I took it back once all the valves were removed to do the porting. Then - back to the shop to have the valve seats done, valves installed, and then adjusted with shims. Total machine cost for the head was $450.

You want tot do the porting before the valve seats are done so you don't mess up the seats. Critical since they determine adjustment and timing.

If you really want to do it right and can afford the time - take both head and block to machine shop so both surfaces can be done clean.

Then new head gasket will be fine - remember I used studs and tourqued down to 90 ft-lbs.

and you said the block was 400?

thanks so much for your help