5 replies to this topic

[JamesC]

Hey all. I currently have an 85 Hf running a d15a2 head. I need to replace the head gasket, and figured while I as at it, I may as well get the head rebuilt. My question is what else can I do besides a port and polish to give the head a little more? I heard someone talking once about an Si/Dx spring combo, and I know there is something you're supposed to ask the shop to do to the valves while they're working on it, some kind of cut, 3-way, 5-way, something like that. Are there any cam options? This is my daily, but if the head is going to be in the shop anyway, may as well do something with it right? When the head is done, it will go back in with a devac/weber swap. Any advice will be greatly appreciated. Thank you.

 

James

[Dirtcircle86]

A three angle valve job will flow better but on an otherwise stock build, I don't know if it's worth it (I'm a tight wad). P&P is gonna cost ya. Heavier springs would be necessary at large lift numbers (big cam) and higher rpm's. Probably not necessary on a stock daily. When I had an EW, it didn't float valves until around 8000 (stock cam). I had a shift light set but passed it so fast it just blinked.. The valve train stayed together when the bottom did not. Only made ten laps before parts separated and vented the block.

I highly recommend checking the block to make sure it isn't warped (arched). Mine was. If the block and head are flat enough, I would clean and lap the valves and carry on. But I'm different. You can put bearings in the bottom end without pulling the block.

[JamesC]

Thank you. I want my daily to at least be able to keep up with the guys in the car club, but still be effective for a daily driver. That's why I don't want to do too much. A p&P is only 200, and as far as the valve job, I haven't asked yet. But if a bigger cam isn't necessary, that's cool. I do have to run at higher rpm's a lot when on a cruise with the cub though, because I have an hf tranny, and with those tall gears, it just has no low end power. I have an si transmission sitting here, and I thought about dropping that in, but Idk yet. Thanks for the help man.

[Dirtcircle86]

I would definitely do the si tranny! $200 for a P&P is rediculously cheap.... At shop pricing, that's probably under 3 hours. Maybe closer to two. I would be suspect of how good a two or three hour P&P would be. I spent that just porting my manifold for a larger throttle body. Maybe that's just a bowl clean?

A cam upgrade would be right behind the si tranny. But would suggest wideband tuning.

There are others that will totally disagree with most of what I have typed so maybe they will sound off.

[JamesC]

I am still learning, but what is wideband tuning? Also, the shop here in town that only charges 200 has been around forever, and they only do cylinder head work. They charge by the job, not by the hour in most cases. As for the si teanny, I want to run it, but give the condition of the motor it is under, I don't know if I trust it. I will know more as I get closer to that point. First step in this whole fixer upper is carb, brakes and exhaust. All of which are bad.

[Oraclem21]

Porting all done by cnc or does anyone know off-hand if port matching is best kind of porting or if smaller/larger/rougher/key spots exist on 15/16 heads?

 

Else will feel it out.