4.0L TUPY head seats/inserts

[Netpackrat]

Dropped my block and head off at machine shop last week. '02 core engine w/ TUPY head (said to have about 180k miles on it) that I am going to turn into a stroker for my '01 TJ. Got a phone call from the machine shop today, said the good news is the head isn't cracked, but the bad news is the exhaust seats are recessed, and he said installing new hardened inserts is iffy on these heads, because the seats are very close to the water jacket. He also mentioned an LS-1 valve conversion, but said that is still a bit of a gamble for the same reason.

Anyway, this shop has done good work for me in the past, and it isn't that I don't trust him, but he also wants to sell me a new head. Figured I would ask here to see if what he is telling me about seat replacement on the 4.0 jibes with the experience of others.

[Russ Pottenger]

You’re machine shop shouldn’t have any concerns installing hardened exhaust seat inserts in your jeep head.
It actually would be a desirable upgrade to your cylinder head.

You could tell him to use a SB1625-9 seat.
That seat has a O.D. of 1-5/8, I.D. of 1-1/4, with a width/depth of 7/32

The majority of the cylinder heads that I port I use the Chevy LS valves. Because the LS valves have an 8 mm valve stem he’ll have to be prepared to hone the guides and machine the valve spring seats in the cylinder head for the upgraded LS spring.

I also offer a stainless steal Jeep valve that has a 1.980 intake head diameter and a 1.560 exhaust that utilizes stock valve stem diameters if that’s more desirable

You’re welcome to contact me directly if you have any further questions or would be interested in purchasing any of my Jeep or LS Valvetrain components.

Thanks,
Russ Pottenger
Bishop-Buehl Racing Engines
531 N. Lyall Avenue
West Covina, California 91790
Work (626) 967-1000
Cell (626) 673-2203
Email/PayPal: [email protected]

[Netpackrat]

Thank you for the reply, that tells me what I need to know. I already have all stock valve train parts; I am planning to keep this stock except for the stroker, overbore, and heavy duty reciprocating parts. I will suggest the inserts that you mentioned but if the guy doesn't want to do my head, I'm not going to spend a lot of energy trying to convince him otherwise or telling him he's wrong. I'll just take the head and tell him I need time to decide what to do while I concentrate on the short block. My goal is to have the Jeep running by spring anyway, so I have time to find another shop to do it. If I wasn't in Alaska I would most likely send it to you for inserts, but shipping an iron head both ways would be quite costly.

Agreed that the inserts are a desirable upgrade. I had the same shop install hardened inserts and bronze guides in my MGA head years ago, and they did a nice job.

[Netpackrat]

You could tell him to use a SB1625-9 seat.
That seat has a O.D. of 1-5/8, I.D. of 1-1/4, with a width/depth of 7/32

Russ, is that the seat you use for the LS valves, or stock valves? Because SBI's online catalog seems to be calling for an SB1562-36.

[Russ Pottenger]

It can be used for eather valve.

[Netpackrat]

Got my head back today, looks good so far and of course they didn't have any trouble with the inserts. Apparently they'd had a bad experience with an earlier 4.0 head and I doubt if they will have any reservations now about doing a TUPY head for somebody else in the future. They ended up replacing the guides as well. The bad news is it would have been slightly less expensive to have bought one of the new heads, even considering the cost of shipping to Alaska. Live and learn. The block work was relatively affordable by comparison.

My brother is planning a stroker build at some point and he may end up just ordering a head from Russ based on my experience.