Pearl_Diesel
Full Access Member
Another question, does anybody make performance pistons, rods, stroker kits, cranks, heads, intake manifolds, etc... for the IDI's? I've heard a few about head studs, rods and pistons, but not an awful lot.
It all depends on the application and the power level wanted. If it is race or pull application and there not worried about streetable then we can do some crazy stuff. The higher powers get aftermarket rods pistons and crank and compression again depends on the application. We dont sell with injectors usually unless a turnkey engine is required then we buy or have someone modify them.
Pretty soon we will offer a aftermarket block short block or long block as soon we will have a source for aftermarket blocks.
The twin turbo unit we do are custom and can be made several different ways again depends on the application.
The streetable engine we build are just that streetable and work well on the street and run very much like a stock engine does.
Thank you for this chance to serve your engine needs!
From Tim Barnett of
Barnett High Performance 517 719 5185
Russ |(typ4) already has a regrind (high torque special) that works good with a turbo. But until we understand how much piston to valve clearance we're working with, we can't get a killer grind together. Hopefully we'll have that worked out soon.
so, just for my understanding, that only is a concern if your running a stock piston, correct? ... my pistons don't protrude out of my block at all. i don't even have valve recesses in the top of the pistons any more.
Is that something you'd be willing to do with your engine, to share with the forum?
Well, that shoots a good sized hole in my engine build up plans.
All the pistons I have measured have a dome thickness of between 560 and 580 thousands. All of the pistons measured are stock 1989 Mahle oem and the new turbo pistons from Mahle. I can supply the newer piston part numbers if needed. I'm running a set of Mahle turbo low compression pistons that have been milled 12 thousands. The milng was because they stock Mahle turbo pistons were over 45 tousands above the deck... The fools at the machine shop milled the deck twice... Yeah, I know.... Why wasn't doing it once good enough.... All the pistons are where I wanted them tbe at 24 to 26 tousands above the deck... The factory setting of 31 thousands is themax setting. They can be less from the factory. I actually ran the first motor at 54 thousands above the deck. Every piston had a valve kiss in it when the motor came apart. None of them were deep enough to measure and believe me I tred. It was just something you could see but not feel. Most fingers can feel half a thousands. All my depth micscouldn't find any demension... I still have those pistons. I'll brng them to the next rally....
Cylinder Head Specifications On
Navistar International 6.9L Engines
Due to the extremely close running clearances between the pistons and valves and the pistons and cylinder head, it is extremely important to maintain the proper specifications on this engine when performing cylinder head rebuilding operations.
The cylinder head thickness should be maintained between 4.795 and 4.805. Figure 1 shows that this measurement is taken from the deck surface to the valve cover rail.
Figure 2 shows the valve angles for the Navistar 6.9L engine. Notice that the exhaust valve angle is 37 1/2° while the intake valve angle is 30°. The valve seats have the same angles as the valves.
Again, due to very close running clearances, proper valve recession must be maintained. There is only .009 running clearance between the exhaust valve and the piston when the exhaust valve is fully open. The recession specifications are as follows:
Intake: .042-.054 (1.06mm-1.37mm) A and B models
Exhaust: .043-.055 (1.09mm-1.40mm) A models *
Exhaust: .046-.058 (1.17mm-1.47mm) B models *
* All exhaust valves serviced through Navistar are the B valves only, Navistar part #1 805 917 C1. Use the B specification with all new exhaust valves and the A specification on reused valves where applicable.
When reassembling the Navistar 6.9L cylinder heads, you must snap the valve stem seal onto the bottom of the valve spring retainer. Failure to do so may create coil bind.
The AERA Technical Committee