7MGE Engine rebuild

[Bill UK]

Totally agree excellent work, thanks for sharing it with us, top marks for the write up which must have taken time to document.

[oregonjoe]

Thanks for the kind words - just trying to support the form so all can benefit.

Got all my parts finally on order. ARP Head studs from www.horsepowerfreaks.com their number part number 8021 $134.26. HG, Timing Kit and Water Pump from CarQuest.

Will be here by end of week so I can start on the top end.

In the meantime – still cleaning parts and bead blasting.

[oregonjoe]

While I was waiting for my head to come back from the shop, I worked on cleaning parts and doing some detail work. A friend let me come over and use his bead blaster to clean up the valve covers and intakes. Boy – what a fun gadget to have! Make everything look like new. Uses air pressure to shoot tiny glass beads and reach into all the places you can get sandpaper in. After about three hours, I had some nice looking parts. So nice in fact, I decided not to paint them like the original but just to clear coat them and keep the natural aluminum finish.

For the valve covers, I masked them painters tape and used several new razors and traced the relieved outlines make a cutout. Pressed the making tape hard along the edges to expose the outlines and cut away the material. Be sure to clean everything with Lacquer thinner before you mask.




Then spay with high temp paint in several very light passes. The trick is to get the paint carrier to evaporate between each pass which takes just a few minutes. It took about 10 very light passes to get it built up enough. The reason for this is that if you spray too heavy, the paint just builds up in the depressions and flows overt he top of the masking which is not what you want because when you try to remove the mask it will just tear the paint off with it. What you are trying to do is keep the paint just in the relief’s and not on the surface of the mask. Another thing I found is that the initial passes doesn’t stick to well and paint tends to run down hill. By lighter coats and waiting in between, it gets tacky and then next coats stick better.

Now here is the important part, do not let the paint dry. Wait only about 20 minutes after the last coat to peel off the masking. Again, if you wait too long, the making will be too embedded with the paint and just peel the paint off or tear the masking so you can’t get it off. Doing this while still wet (tacky) makes it real easy and gets a clean surface.

Once the mask is removed just a little cleanup is needed with some lacquer thinner and a CLEAN rag. Because the paint is just in the relief, any other paint can be removed by warping the rag around your finger and just wiping the surface – comes off real easy and leaves a nice clean edge.

When done with the clean up I sprayed several coats of clear high temp paint to give the surface a nice look and protect the aluminum from corrosion. The clear coat also helped clean up the lettering and make them stand out.



All the other aluminum parts a coat of clear coat too.

[oregonjoe]

Heare isa closeup of the cover

[oregonjoe]

Finally got the head back from the shop. Don’t want to say how much it cost!

Anyway – valve seats were done and adjusted.



I wanted to check the oil clearance on the cams so I pulled them off and used plasticgauge to find out. Put strips on the cleaned journals and torque back down. Came out to .0015 which is well within spec.



Cleaned off plasticgauge and reassembled again.



Boy – are these cams hard to turn or not? I had no idea it would be so tight but with each cam trying to open 12 valves in one revolution no wonder? Anyone know how much torque it takes to turn a normal cam? Really makes you wonder is everything is true and straight and if the bearings are binding or not? Sure hope the shop did it right!

[Bill UK]

$583 for the head refurbishment at a guess, just make sure there’s no beads left inside the cam covers. Its also very common to have radial score marks on some of the cams and journals which shouldn’t be a problem.

[oregonjoe]

Ready for the head. So I read through the directions for the STUDS and put them finger tight into the block. I had read it would be difficult to get he head on with the rear studs so I leave them out.

Now, what is wrong with this picture?



The answer is it is impossible to put the head on with the studs in the block. I don’t difficult – I mean impossible even with a single stud.

Oh – you can place the head on over the studs – you just can’t put the washers on afterwards. Once the studs stick up through the head it is impossible to place the washes on - just not enough clearance.

The trick is to not install the studs first. You should test fit them to be sure the treads are clear and they all seat at the same (correct) height but remove them.

Place the down on the block as normal. I coated both sides of the gasket with copper spray adhesive. And don’t forget to put the bead of RTV on the front of the block between the timing cover assembly and the head as documented in the manual.

Next, starting from the Middle and sequencing out as described in the manual for head boat tighten sequence, place the washer on the end of the stud and then lube the other end with the ARP assembly lube before adding the nut. I threaded the nut down all the way and back out to be sure the lube got all over the threads. And yes, there is enough lube in the packet to do all the studs so no need to skimp. Check to be sure the hex socket is on the nut end of the stud. Now with the washer on the block end of the stud, place them on the head. The washer will not go down at first but you can slide the stud left or right to clear the head bosses and get the washer to fall into place then get the stud into the hole. Now use the hex driver to secure the stud finger tight. Next you just use a deep 12 point 14 mm socket (3/8” drive and ?” is too big) to tighten down the already installed nut. I tried to place the nut on the stud after inserting the stud but its just too hard to get it in there with dropping into the head and having to fish it back out. Much easier to just put the nut on first.

I then sequence tighten the stud nuts to 90 pounds as the ARP instruction said. Took 5 passes but they all torque very smoothly.

Took me 4 hours to put the head on but that was because I had to figure this all out. Now that I know what to do – it can be done in under an hour.



Now it on to the timing stuff.

[oregonjoe]

Originally Posted by Bill UK

$583 for the head refurbishment at a guess, just make sure there’s no beads left inside the cam covers. Its also very common to have radial score marks on some of the cams and journals which shouldn’t be a problem.

Well now I don't feel as bad for the $400 it cost me. And yes there were some score marks on the CAM journals which the shop said not to worry about. But one questions is - how diffucult should the CAMs be to turn when all torqued down? I supose it would have been good to have assembled everthing with out the valves so we could feel how smooth the cams turned without resistance. Just have to trust the shop?

With the CAMs and head on the block - they can be turned by hand but sure feels strange when all th lobes engage the tappets.

Funny thing is - my very first car I every worked on was a 69 English Rover Sedan with overhead CAM and timing chain - twin carbs too!

[oregonjoe]

I am having a problem with the dipstick. Just can't get it reinstalled correctly.

When it came out was just pressed fit in but took some doing to twist it out. Even tough I did nothing to it - now when I reinstall it just slips in with out any resistance and spins around. Did not bore or scrub anything.

Checked that it bottoms out - jsut too loose in there now.

Is there some sort of adheasive to trick to reinstall?

[Bill UK]

The dipstick tube that’s protrudes into the sump was a very tight fit, the external tube that I think your referring to was very loose, I think there’s an O ring on the bottom of it, I just smeared some silicon sealant over the O ring a pushed it in, that was 2 years ago. No sign of a leak so far. If you are referring to the dipstick, then the only thing it could be is the rubber part at the top has shrunk slightly, there are products that will rejuvenate rubber seals to make them soft such as windscreen wipes etc, cant say I've ever used them though.