Wow, pulling the final drive with no jacks and keeping all your digits and soft parts intact is impressive. I wish I had access to a junkyard with as much Jag stuff as your apparently has. There is ONE locally and it is picked over...

 

2.88 is not a great gear for your combo. I've had 2.88, 3:31 and 3:54 behind a chevrolet and the 2.88 is not my preference. The tall gear affects driveabilty greatly. Why dont you swap your center section and keep the 3:54.

If you're going to dive in the the engine consider a roller cam. Modern oil doesnt have zinc and you need racing oil with zinc to keep your lobes in tact. Something mild with 212 degrees duration @ .050 would be perfect for a 305 with a 3.54 rear. If you going with the taller 2.88 gear you'll much less cam. Get a set of 1.5 procomp roller rockers if you're on a budget. You'll need retrofit roller lifter if you have a pre 1986 block. Find out what heads you have and make sure your cam lift is right for the heads.

 

My Jags with 700R's have either 3:31 or 4:09 gears. The 3:31's work with the SII 383 due to the higher torque. It has a very small Isky cam...it does not lug at low rpms, just shifts into third gear as it should.

The LT1 has the 4:09 gears and gets 20 mpg at 70 mph but tachs considerably higher than the other car with the 3:31 gears. It will pull well from 30 mph in OD.

I do have 2:88's with the other S1 383/200R, but it has 470# torque with over 400# around 1700 rpm. It only turns 1750 at 65 mph... It pulls those low gears really well and the change from the 3:31 was a good thing.

Be sure to get a very small cam with power starting off idle (1500-5000) to have lots of low end torque that is needed for the heavy Jag. Be sure to change the
trans gears to match the S3 rear end if you do decide to go with the 2:88's!

 

Roger: good info, but I am always confused when you discuss transmissions. You mention 700R and 200R, and by 700R I figure you must mean 700-R4, a four-speed overdrive transmission, as that's the only 700 series trans I know of.

However, there is both a THM 200 and a THM 200-4R, the first being a three speed and the second a four speed. Which do you mean?

 

Great info guys. You've convinced me to not bolt on the 2.88 rear end and probably saved me a lot of grief. The pumpkin in the S1 is really wet and will need new seals. To save some bucks, I'll probably just install the ring and pinion into the S3 rear end. Swapping a ring and pinion is easier than messing with the transmission gearing for me, especially when I have both of them out of the car. I still have paint from the last time I did it. Hopefully there was no funny changes in castings or whatnot.


I was thinking of a mild RV cam. Something for low end torque, once it gets to my Dad, he won't be revving it nearly as much as I would. I'd love to swap over to a roller cam but it would quickly out price the worth of the engine. I have a flat tappet 305 out of a Firebird which is worth about it's weight in scrap steel. If I can't get a cam, rocker, and intake for around $250, I'm better off picking up a used 350 or buying a running vehicle with transmission issues and scrapping the rest.


I'm fairly confident I brought the cam failure on myself. With fresh oil (non detergent 30w dino), the valve seals swelled and stopped the oil burning. Happy with myself and my clever oil, I drove it and then it started burning again. I had been scratching my head about why I'd be burning oil again so quickly only to find my answer in a non exhausting cylinder. I'll run a compression test in the next day or two so I can determine if the piston or valve was damaged during all this. If so, its a boat anchor and I'll start tracking down a 350.

Also Rodger, those are nice numbers on your 383, I bet that car is a hoot to drive.

 

I was spooked right before it dropped. I wedged tires and plywood trunk decks under it so it wouldn't fall too far. It wasn't fun but it was worse pulling it to the end of the row by myself so the forklift could get to it. Its still in the back of my Cherokee, I don't even want to think about moving it alone again.

 

Ya cant swap ring an pinion between 2.88 and 3.54 with out a ring gear shim which is tricky to find. The carriers have very different offsets so you'll need to swap the complete internals, ring pinion and carrier. Then you'll need new Jag side bearing which are pricey. Then seals, etc so the cost is going to grow. You're seductively being drawn in to a major project one small step at a time. I recognize the signs....I've been there. Enjoy the ride but dont become obsessed. I'd rebuild the 2:88 using a Auburn 19 spline LSD and the ring and pinion from the 3:54. I've done it and its easier and more economical then a full rebuild using all Jag bits.

 

Sorry, but those that have them always shorten the "names". 700R has
very low first gear and wide spacing between 1-2--- decent OD gearing.
Best for cars with low torque - ala Jaguar engines and small SBC engines.

200R has very good first gear and normal spacing between other gears
and .67:1 OD gearing. Best of the two and when built properly will handle
500 HP and lots of torque.

 

Thanks, Roger for the clarification. Those were my assumptions, but I have learned the hard way not to assume...

Now if someone can explain to me why one ends in "4R" and the other in "R4", I will really be impressed.

Also, it seems a shame that the 200-4R has an undeserved reputation for not being sturdy because the original 3-speed THM-200 had problems.

Oh well. Perhaps one of these days I'll go for a quarterbreed kit. 'Til then, I'm pretty happy with my B-W 12

Tom

 

Well, I signed up for a project when I bought the car but yes, it is getting larger with each unexpected step. It's certainly a cause for alarm. I don't have the time (or money) to go nuts on the car and I need to get it in good running/driving order before worrying about the little things. Many of the cosmetic hopefuls have already been shelved. "Do I really need that new chrome right now? No, that can come later."

I've been thinking about combining the two rear ends and making the best out of what I have for both for the least money/time. Are the cast hubs and lower wishbone/control arms interchangeable? If so, I could swap the newer ones on the IRS that is currently in the car and be done with it for a while. I'd still have a leaky pumpkin, but that could be tended to later. I don't really have a good handle on how fast its leaking since I have no clean basepoint to work off with.

Compression test tonight if I get back before sundown, hopefully there was no valve or piston damage. Its pointless to install a cam and find out I still have a weak pot.

 

Use the newer hubs, axles, lower control arms, etc if you can. They are all dimensionally the same but the hub casting got thicker and heavier over time. The earlier ones tended to crack. I cracked an 80's era one with my stout SBC 406.
If the bearings are quiet...I'd seal up the pumpkin and swap it in. If the bearing feel gritty and sound harsh then you've got a major rebuild on ya hands.

Where is it leaking?


If it leaking out the font pinion seal then you will have to replace that seal. Somewhat difficult but inexpensive.

check this out...


If it's leaking on the stub axle's new orings are an easy fix. Also put some anerobic flange sealant on where the stub face and case meet. (Permatex Orange flange sealant, smells nasty)

If it Leaking out the rear cover a standard dana 44 diff cover will do the trick.

Chances are it's leaking from all of these places and I'd suggest you fix it in any case. A leaky diff contaminates the inboard rear brakes with oil and renders them ineffective.


Chances are it's fine.... but....How are you going to do a proper compression tested with a broken pushrod and rounded out cam lobe? You could always do a leak down test.

I recently purchased an LT1 for a conversion that is in progress and did a compression test. Half of the cyls were less then 150 and the other half were about 180psi. I was pissed because the seller said the engine was low mileage and ran perfect. It also appeared to be a newer GM replacement engine. Resigned to a rebuild I started to disassembled the engine and noticed there was no piston ridge and the bores still had cross hatch hone marks in them. I put some rubbing alcohol in the exhaust ports while the heads were on the work bench and the cylinders with low compression leaked noticeably. A professional valve grind and valve seal replacement did the trick. I put the heads back on and the compression was between 202 to 210 PSI on all cyls.

 

I have one one on my '71 car that has worked well for several years. Too
bad it cannot be seen unless jacked up!

 

My 83 is powered by a bone stock LT1 from a 94 Cadillac Fleetwood Brougham. Not so much on Hp, but good torque low down in the usual drive range. The 2.88 that it left Brownslane with is still there. No leaks and no noise!! It may not be a world beater off line, but more than enough to beat Bimmers. And, on the freeway, the long legs eat up the iles effortlessy. And a stab at the throttle enables an easy pass on most if necessary. As the Jag and The big Cad are heavy cars, the match is good. The Cas' rear ratio was 3.09 to one. Not tto far away from the 2.88 in my Jag. So, the high torque SBC, the 4l60E and the Jag 2.88 are as good as I need, by a long way.

My Jeep doesn't pull it's OD anywhere near as well as my lumped Jag does!

Czrl

 

So I did a dry compression test today and showed some interesting results. Since the broken pushrod was on the exhaust cylinder, my reasoning says a normal compression test should work. I have air going in, no air coming out. By all means, tell me if this assumption is wrong.

The unaffected cylinders all came in between 150-160 dry which sounds good for a mid-eighties 305. The bad cylinder came in at 40 both wet and dry. To me this points toward a damaged valve/valve seat. Since I'm going for light on the budget, I'm sure I can find a good 305 head in the junkyard ($30) which will be a helluva lot cheaper than getting a new valve put in the old head.

Sorry for getting sidetracked off the IRS stuff but if the car isn't moving, a clunky rear end seems like a minor issue! Also, I need to track down my neighbor who owes me a favor to get it unloaded out of the Jeep.

 

You have to have both valves operating to get a proper compresson test. I'd borrow a pushrod from another cyl to be sure. If the pressure cant exhaust out it will paritaly remain in the cyl until the the intake opens again which will limit how much air it can take in during the intake stroke giving an incorrect reading. Since you dont have an exhaust stroke your 40psi (25% of 160psi) represents the what the cylinder lost past the rings during two compression strokes. A healthy engine looses between 8% to 15% on each compression stroke. You have two compression strokes because of the inopperable exhaust valve so my calculations say the cylinder is good. Replace the pushrod and see if I'm right.

AFAIK same numbers wet and dry is usually a valve issue when both valve are working. There's only one way for find out... more work... borrow a push rod...pressurize the cyl with a leak down tool and listen for escaping air or pull the intake and head. If your crank case gets pressurized you've got a piston bore issue. If you hear air escaping from the tail pipe you've got a burnt exhaust valve. If you get air out the radiator you've got a bad head gaskit, cracked head or block. You could swap the heads from side to side and see of your compression comes back too.

 

A couple of thoughts.

The pushrod was broken trying to force a valve open that was stuck closed. Or, and less likely, a rocker arm issue. And, least of all, misadjusted lash on the rocker arm.

I like the idea of a push rod swap and retest. Simple things first, lesson learned oh so long ago. Might just need a used push rod. And a lash adjustment. Messy and fun on these engines!!

Now, if that fails, the head has to come off anyway. Not that bad on the SBC. Probaly get a reconditioned valve from a local machine shop. If the seat isn't mangled, just give it an old fashioned lap along with the others.

As to a cheapo head from the junk yard. It may look right, but yet be a mismatch and have valve issues of it's own. Example, the head in the car may be virgin and hass never seen a mill. Or it may have been milled in the past. Same for the junk yard head. Virgin to virgin is a match. Milled to miled
l maybe. Milled to virgin, no match!!

Or, your local machinist may have a reconditioned 305 head gathering dust tht he would part with cheap. Might even through in the gaskets. Far from hot stock!!

Carl

 

More SBC woes!!

Pulled the cam and was in for a bit of a surprise. The cam lobes look fine, not the mushy oval I was expecting, the lifters however look atrocious. I'm wondering if dirty oil contaminated the bad lifter and caused it to fail. The particularly nasty looking lifters were working fine and not related to the broken pushrod.




As mentioned, the cam lobes look okay, used for sure but not the cause of failure. The bearing surface on the cam looks suspect though. If that is getting chewed up, it makes me wonder were else has been taking a beating. I'm a little scared to look at the main bearings. Also, I don't think I can get the oil pan off with the SBC in the car. Lumped folks, chime in if I'm wrong.





Finally (since that wasn't enough misery) the cylinders look a little shabby. I pulled the head that broke the pushrod to take a gander at the valve and piston. There are fingernail catching gouges in the non thrust side in 3 of 4 bores. Compression all looked good for these holes before tear down.




So now I'm faced with a big decision. All of this is scaring me away from keeping this engine. Am I over reacting? I'm used to motorcycles where this kind of wear is usually considered fatal. I have gotten a quote from a local (reputable) machine shop for rebuilt 350 long block at $1400 with my core. I can pick up a brand new GM Goodwrench 350 long block from JEGS 1500 w/o a core. While they're not screamers, those are the realistic options for new/rebuilt stuff. I can't dump a 5 grand beast into the car.

The other option is to buy a used engine/car. I'm looking at this mongrel tomorrow:
1986 FC RX7 - 350 V8 Chevy - T56 6 Speed
After pulling the 350, I can sell of some of the bits (T56, headers, conversion parts) and scrap the shell. I think I'd be in for less than a new engine and get more HP per dollar. If I'm really feeling spunky, that 6 speed would be lots of fun in the XJ. As a side note, this car would be devilishly fun to drive, too bad its so ugly.

 

Any reason you wouldn't just fix the immediate valve issue and bolt it back together? You can always spend the money later...

This is, of course, assuming you can fix it cheaply.

Tom

 

What usually happens is cam and lifter wear from lack of Zinc in modern oils. Then metal particles clogg the oil filter. The clogged filters causes pressure bypass to open allowing dirty un filtered oil to circulate which wipes the bores and main bearings and seals.

What was the oil pressure like hot and cold ? Finger nail grabbing gouges are not good.

Would you consider getting a LT1 caprice cop car as a doner? They're everywhere on CL and you can drive 'em and ensure the engine and trans runs right before you buy. You'll get a 4 speed auto, the performance of fuel injection and the engine / trans are run by one computer so it will be a well driving package. The Lt1 is sequential injection so it is smooth running and has a roller valve train for performance. 1500 for a jegs crate motor is a great deal but you'll need 200$ in gaskits, you'll need a cam, lifters, head rebuild, carb rebuild and after all that work you've got a grumpy carbed 350 with a lazy 3 speed trans that will wipe the cam again unless you go roller ($$$) or monitor your oil carefully. The LT1 is easy to install and get running with stand alone engine / trans wiring harness but you'll need to shorten the drive shaft a bit and install a fuel pump and return line.

 

I can shove a new cam, lifters, and timing chain in it for ~250 bucks which is the beauty of a small block chevy. That said, the first oil change I had alot of metallic bits in the oil pan, both copper and steel which makes me think the bearings are getting beaten up. The safest thing to do would be to clean the block, scrub the oil galleys, and check the bearings for wear which is an engine out job. At that point, I might as well refresh it but since it is a 305, its probably not worth the effort.

These are the kind of things that cause problems 500-2000 miles down the road. Or in other words, while I'm driving it to Chicago. I'd hate to develop a rod knock in the middle of nowhere or have the motor grenade itself after my Dad had it for a few months. If it was staying with me and I'd be able to attentively watch it, I'd just throw a cam in it and change the oil a bunch. Again, lump guys, I'd love to hear your input. Am I over reacting?

I'd never hear the end of it if I gave my dad a car that needed a new engine.