A Twin Cam Something

This Forum is here for each member to post pics of his/her Gemini project cars. Keep it to one thread per car.. if you get more pics etc, add them to your existing thread, DO NOT start a new one
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Pistons are back from the shop with resized and with caps that actually match.


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The new G180W block is also back. Bored and honed to match the G200W pistons, decked, bead blasted and chemically cleaned. New welsh plugs.

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However there is always something it seems when you try and mix and match engine parts. In this case I have found that the water galley holes on the top a G180W block are slightly different to a G200W. Not radically different but a G200W has 4 extra small holes and the larger hole in front of No1 bore moved from the exhaust to the inlet side. Very annoying but I don’t think its a show stopper.

I should be able to drill the new holes required using the head gasket as a template.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

My photobucket account access has been out all day so not photos.

Thinking about fitting ARP studs because there are a couple of hair line cracks around the stud hole (not uncommon evidently). if I can get a stud down the full 30mm into the block it should reduce the localised stress. Does anyone have the specs for studs nuts and washers for ARP head fasteners?

Reground crank and pistons are in. Took the baffle out of the sump, bashed to straight and welded baffle back in. Looks like this motor was dropped from a great height once and landed on the sump.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Image

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[URL=http://s434.photobucket.com/user/tobytj ... b.jpg.html]Image[/URL
]

Mr Photobucket is working again.
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Jonno
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Re: A Twin Cam Something

Post by Jonno »

Yeah pics are working 100% now :)
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F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

What is it about DOHCs falling from height. I dropped mine from about 1m off the ground straight on the oil filter housing....broke the concrete! LOL. Did you ever confirm if those federal mogul "cam" bearings were the correct ones?

N-
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

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81 TE Gemini Sedan
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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A bit of glitch with the gearbox casing conversion but got there.

The welder made the mistake of leaving the adaptor plate bolted up when he welded it. Probably started at the rear instead of the sides first as well. With the plate in place the work piece was constrained expanded and pushed into the molten pool as it expanded . When it cooled it shrank.

The fix you see is an M5 screw tapped in the lip to level the adaptor plate and a layer of GB Weld to level of the gearbox casing so the started engages properly.

I since cut off the M5 screw
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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Progress on the engine has halted while I wait for new timing chains and head studs. So I will tackle the 5 speed rebuild into the modified casing while I wait. Could not get the kit i normally use but Brian from Queensland Bearings sourced the bearing and seals individually, and it was cheaper that the kit.

This is my oldest son's original box from the TX coupe and it was pretty noisy when I swapped it out. The ball bearing have lots of movement. I hope I don't find the the hard casing on the main shaft spigot too degraded once I get the input shaft disconnected - it feels awfully sloppy.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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List of bearings for a 5 speed MSG fine spline. Prices ex GST from Queensland Bearings at Zillmere. List shows input shaft bearing as a half shielded but it is actually a plain bearing remove the shield.

I have done 4 of these now and I am yet to find an layshaft bearings that show signs of wear (they are the pricey ones). Same goes for the needle rollers - except for the spigot bearings rollers at the end of the main shaft.

If you are on a budget just replace the input shaft ball bearing, the two main shaft ball bearings and rollers for the main shaft spigot
tobytj
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Re: A Twin Cam Something

Post by tobytj »

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Spigot shaft was immaculate. New bearings installed and all the bits back in the Carrier Plate. Instructions for the Gregorys are really good for gearbox rebuild but always read two ahead so you don't miss " mark the position in relation to the mainshaft" before you rip out a selector.

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All back together and looking pretty

Starting to think about carburettors but can't decide between 40 DRLA's and 40 IDF both ar a matching set and in good nic. My head says Dellorto but my heart says Weber

weber
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Dellorto
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Jonno
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Re: A Twin Cam Something

Post by Jonno »

Cool.
This is how I would have done mine.

Man so jealous.
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tobytj
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Re: A Twin Cam Something

Post by tobytj »

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ARP head studs arrived and the head is all snugged down. Tensioned down to 85 ft lbs – was not game to take it to 95 ft lbs as per the ARP instructions given that standard is about 72 ft lbs.

I am totally sold on ARP head studs and will use them on any future rebuilds or if one of the G180s or G200s does a head gasket.

Made the classic error when the head was decked of not getting the cam chain housing machined to match. As a result, the separate gasket for the cam chain was going to be too thick. Ditched it and just used form-a-gasket

Bit of cosmetic work on the valve cover and it is red again

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Have installed the cams and have made the assumption that all the dots on the three sprockets point to 12 O’Clock when No 1 is at TDC. The phasing of the cam looks to be right at this setting.

Valve clearance on intake valves is non-existent and the exhausts are about 0.13mm so I am going to have to source some new shims – any leads on a supplier would be greatly appreciated.

Small timing chain has been replaced by a new IWIS chain but I have had to use the original longer chain. Best price I could find on a new 118 link DR chain was $300! Did some research on the cheap ebay chains I bought and they are now in the rubbish bin. Discovered when reassembling that I had the foot for the tensioner upside down. Luckily the G200W is designed to allow the long chain to be removed without a lot of dismantling so I was able to get the chain out and turn the foot abound.

Next challenge I think will be sorting out the induction. Pulled down the Delloto’s, soda blasted and kitted them and they look good I am awaiting on service kits for the IDFs and will make a decision which way to go after I pull them down.
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Intake manifold building time

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Have chosen to work in steel as I do not have the experience of set up on my MIG for aluminium. Went for 10mm steel but could have probably used 8mm.

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Managed to get all but one stud hole located and tapped in the right position. The choke openings worked out well. Used a 41 mm hole saw so there awas a bit of tolerance to play with.

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The flange for the head worked out well. I will need to be careful boring the 40mm holes to match the ports as there is no margin for error if I want the match to be flush. I plan to bore the head side 40 mm for a depth of 5 mm and flip it and bore the other side 41 mm. The exhaust pipe is 41mm OD so will slot in (I hope).

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The tubes will be mandrel bent exhaust pipe. I am still tossing up how to build the jig. I am thinking two L shaped steel brackets cut from 8mm plat temporarily welded to the flanges to hold them at the correct alignment and at right angles. Really sorry I returned my oxy bottles as brazing the tubes
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Jonno
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Re: A Twin Cam Something

Post by Jonno »

SICK!!!

It's a dam shame you don't get down to the nationals. Be sweet to see one of ur cars (or this one) at one :D
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F3ARED
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Re: A Twin Cam Something

Post by F3ARED »

Whered you source the ARP studs from, and I assume they are S2000 items? What brand and what was the concern with the timing chain? Also, what did you do about the contact section on the tensioner? Mine are f*#cked. There is a mazda motor that has a lower tensioner that looks similar but for upper im scratching my head.

Thanks for the gearbox bearing link....ill be saving that one.
Previously GeminiCoupe/GeminiRollingShell/SCAR3D/Jonnoisac#nt

78 TD Gemini Sedan - R.I.P
81 TE Gemini Sedan
tobytj
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Re: A Twin Cam Something

Post by tobytj »

Got the APR studs (Kit 208-4702 Honda/Acura F20 S2000) through ebay from the states from a mob called CNC Motorsport. A lot cheaper than quoted locally even considering GST.
The faces on my tensioner are are in really good condition.
I got skittish about the chain (which I think is Indian lower grade product) after reading researching testing done on various brands where the test result was engine failure. Also the chain had more side slop in the linkages than the used chain.
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