I recently purchased a rusty 3.8 engine and transmission for parts. The engine appears to have been completely rebuilt but never started. The pistons are new but there is some rust in 3 cylinders. After adding a some oil to the cylinders the engine rotated easily.
It may be possible to clean up the cylinders, is there much of a market for a running 3.8 engine?

 

i can't imagine that there wouldn't be. it can cost upwards of $20,000 and take a year or more for a complete rebuild. would probably be worth paying for a video tape of it being dyno'd, then selling it on BAT or something similar. partial disassembly with pics would probably be necessary to make a convincing case of the rebuild and lack of use thereafter. of course, there's rust and then there's RUST!

knowing what i know now and having had no choice but to have mine rebuilt by a shop, i would have definitely preferred just buying a rebuilt one. unfortunately, i couldn't find one at the time.

 

Is it possible to use a harmonic balancer from a 4.2?

 

It should be fine. However, they still suffer from the rubber and steel unsticking from one another. On the other hand, they don't seem to explode, which is unlike some modern ones from a rival manufacturer. If you intend to spend much time above 5,000 or 5,500rev/min, it might be worth investing in a fluid damper.

Almost forgot, the 4.2 has a different pulley. But if you're also swapping to an alternator, you will probably be re-arranging pulleys anyway.

 

I've also got a 1975 4.2, that needs a starter and distributor. I assume these parts are different on the 1987 engine, correct?

 

Starter will interchange, but don't forget the spacer plate between the starter and the bellhousing. The 1987 is an electronic distributor, it will have the module ( a 4 pin GM HEI module) in a box bolted to the front of the intake manifold. The 75 might be a points distributor, not sure. You can take the coil, module and distributor +cap from the 87 and drop it into the earlier engine with no problem. For that matter, the EFI is a drop in too if you take the wiring harness back to the ECU in the trunk and the fuel pump.

All this assumes that the 87 is a Series III car, and not the later XJ40. If the 87 is a 4.2 you are ok. If it's a 3.6 nothing will interchange.

 

Here's the identification numbers on my block. It looks like C8610 FF. Any information on what it is would be appreciated.

 

That's the part number of cylinder block. Nothing special about that.

 

So do you have to measure the bore, stroke and head to find out what size liter it is?

 

It should be cast into the side of the block quite clearly, on the same side as the distributor.
You can see it in the photos here: https://parts.jaguarlandroverclassic...ine-block.html

 

The only numbers I see on the distributor side are C8610 FF and 3 1/2 Liter

 

The " 3 1/2 litre" means it is a 3.4 engine, and that corresponds to what would have come out of a Mark 1. The Mark 1 was only ever 2.4 or 3.4, never 3.8. Many regard the 3.4 as the nicer engine compared to a 3.8.

 

I appreciate the help.
What's the approximate HP and torque of 3.4?
Thanks Jay

 

Back in the day the gross numbers were 210 hp and about 220 ft lbs I think. These days a more realistic number for net power is probably about 150-160 hp. A good triple carb 4.2 with 9:1 compression is about 180-190 hp, and a 9:1 EFI 4.2 was 205 hp and 260 ft-lbs.

A low (7.5:1) compression 4.2 on dual carbs is 164hp and 236 ft lbs, while the low compression EFI 4.2 is 171hp. As a general rule of thumb, after about 1970, the US market got low compression for emissions reasons while Europe retained high compression.

With the long stroke they have lots of torque down low, so can get a car up and moving faster than the HP numbers would make you think.

 

The old SAE numbers were over stated.

 

The flywheel has some kind of material on the backside recess around outer circumference. I thought the material was dried out oil and dirt mix. The flywheel has never been used but is a little rusty, it shouldn't be oil as the engine was rebuilt and never started. It's difficult to remove. I scraped a little off and it almost looks like it was applied there. I don't have a clue what it is.

 

could be Cosmoline coated with dust. BITD many new engine parts were coated with it for rust prevention while in a warehouse or on the shelf awaiting sale. IIRC it can easily be removed with a little kerosine, mineral spirts or even gasoline, no matter how old.

from wiki; "Cosmoline is the genericized trademark for a common class of brown, wax-like petroleum-based corrosion inhibitors, typically conforming to United States Military Standard MIL-C-11796C Class 3. They are viscous when freshly applied, have a slight fluorescence, and solidify over time with exposure to air."

 

I found a small part in the distributor, it was in between the housing and the bearing plate. Is it part of the mechanical advance assembly?

The distributor is currently in a 4.2. Today, the engine had first start in years, runs great so far. It's in a test stand, nest step is an extended run at full operating temperature.

 

The 3.8 I recently purchased has all new internals. It has never been started and it's been setting for years. I'm removing the head this weekend, to check out the cylinders. There is some minor rust in a few cylinders. If the cylinders can be cleaned up, I plan on pulling the pan and doing a visual inspection of the internals. I'll also be checking bearing clearances.
Are there any issues with the oil feed line on the back of the block, like blockage? What about the pump or pickup assembly?
Any known issues with the 3.8 in general that I should check while it's open?

 

The cam oil feed line is damaged, a fitting is broken where the line attaches. It doesn't look like it can be repaired. Are there any aftermarket bajo fittings that will work with the original banjo bolt?